FN Thomson Reuters Web of Science™ VR 1.0 PT S AU Holmes, W Lai, A Croonquist, A McKelvey, M Chui, T Langford, D Pensinger, J Eraker, JH Abbott, R Mills, G Mohl, J Kilpatrick, M Volz, S AF Holmes, W Lai, A Croonquist, A McKelvey, M Chui, T Langford, D Pensinger, J Eraker, JH Abbott, R Mills, G Mohl, J Kilpatrick, M Volz, S BE Schurmann, B TI The development of the low temperature microgravity physics facility SO FIRST INTERNATIONAL SYMPOSIUM ON MICROGRAVITY RESEARCH & APPLICATIONS IN PHYSICAL SCIENCES AND BIOTECHNOLOGY, VOLS I AND II, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st International Symposium on Microgravity Research and Applications in Physical Sciences and Biotechnology CY SEP 10-15, 2000 CL SORRENTO, ITALY SP European Space Agcy, Seconda Univ Napoli, ASI, CNES, CSA, DLR, NASA, NASDA ID RESOLUTION AB We give an update of the development of the Low Temperature Microgravity Physics Facility (LTMPF). The Facility will provide a platform for scientific investigations requiring long duration, low temperature and microgravity conditions. It will be attached to the International Space Station and act as a host to two science instruments. Each instrument can occupying a volume of 19 cm diameter and 70 cm long, with a mass of 6 Kg. LTMPF consists of a 180-liter superfluid helium tank, a passive vibration isolation system, two electronic boxes and the radiator to dissipate the heat generated. Each science instrument is controlled using a Power PC single board computer with VME bus. Standard electronics are being developed to measure and control temperatures, including the DC SQUID magnetometers for reading magnetic salt based high-resolution thermometer. Spare VME slots are available to experimenters with custom VME boards to control sensors unique to their investigation. The facility will be launched full of cryogen, and retrieved when the cryogen is depleted. Detailed technical capabilities of the Facility will be presented. Technically challenging aspects of the Facility will also be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Holmes, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-657-0 J9 ESA SP PUBL PY 2001 VL 454 BP 971 EP 978 PG 8 WC Engineering, Aerospace; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Fluids & Plasmas SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering; Physics GA BS85H UT WOS:000171226000127 ER PT B AU Kletetschka, G AF Kletetschka, G BE ChelaFlores, J Owen, T Raulin, F TI Electric discharge in carbonaceous meteorites? SO FIRST STEPS IN THE ORIGIN OF LIFE IN THE UNIVERSE, PROCEEDINGS LA English DT Proceedings Paper CT 6th Trieste Conference on Chemical Evolution CY SEP 18-22, 2000 CL TRIESTE, ITALY SP Abdus Salam Int Ctr Theoret Phys, European Commiss, SETI Inst, CNR, Int Ctr Genet Engn & Biotechnol, European Space Agcy, NASA, Univ Paris 12, ICTP Publ Informat Off, Lab Immaginario Sci AB Discharge experiments produce amino acid distributions that are similar to distributions observed in carbonaceous meteorites (Oro, 1990). A recent work (Desch and Cuzzi, 2000) points out to the presence of lightning in the Solar Nebula. Magnetic measurements of chondrules reveal extraordinary magnetic acquisitions (Wasilewski and Dickinson, 2000) that can be explained simply by a presence of magnetic fields generated by lightning discharge (Wasilewski and Kletetschka, 1999). Thus we speculate that lightning discharge may be responsible for the origin of amino acid compounds in carbonaceous meteorites. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kletetschka, G (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI Kletetschka, Gunther/C-9996-2011 OI Kletetschka, Gunther/0000-0002-0645-9037 NR 5 TC 2 Z9 2 U1 0 U2 5 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 1-4020-0077-4 PY 2001 BP 157 EP 159 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT57Z UT WOS:000173413600029 ER PT B AU McKay, CP AF McKay, CP BE ChelaFlores, J Owen, T Raulin, F TI The search for a second genesis of life in our solar system SO FIRST STEPS IN THE ORIGIN OF LIFE IN THE UNIVERSE, PROCEEDINGS LA English DT Proceedings Paper CT 6th Trieste Conference on Chemical Evolution CY SEP 18-22, 2000 CL TRIESTE, ITALY SP Abdus Salam Int Ctr Theoret Phys, European Commiss, SETI Inst, CNR, Int Ctr Genet Engn & Biotechnol, European Space Agcy, NASA, Univ Paris 12, ICTP Publ Informat Off, Lab Immaginario Sci ID DEINOCOCCUS-RADIODURANS; MARTIAN SOIL; EARLY MARS; EARTH; REACTIVITY; BACTERIUM; ALH84001; EUROPA AB One of the key goals of Astrobiology is to search for another example of life. In the near term, Mars and Europa are the likely targets for a search for a second genesis. On Mars the search is likely to be conducted in the frozen permafrost. On Europa active life may be found in the ocean beneath the ice cover. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 24 TC 7 Z9 9 U1 2 U2 4 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 1-4020-0077-4 PY 2001 BP 269 EP 277 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT57Z UT WOS:000173413600047 ER PT J AU Gharrett, AJ Gray, AK Heifetz, J AF Gharrett, AJ Gray, AK Heifetz, J TI Identification of rockfish (Sebastes spp.) by restriction site analysis of the mitochondrial ND-3/ND-4 and 12S/16S rRNA gene regions SO FISHERY BULLETIN LA English DT Article ID COMPLETE NUCLEOTIDE-SEQUENCE; DNA; GENOME; ORGANIZATION; SCORPAENIDAE; FLOW AB Species-specific restriction site variation in the 12S/16S rRNA and ND-3/ND-4 mtDNA regions was used to distinguish among 15 rockfish species of the genus Sebastes common to the waters of Alaska. Intraspecific variation exhibited by eight of the species (based on five individuals of each species) did not obscure the interspecific variation, except possibly between S. zacentrus and S. variegatus. Intraspecific nucleotide diversity averaged 0.0024 substitutions per nucleotide, whereas interspecific nucleotide divergence averaged 0.0249. In contrast, the average nucleotide divergences between Sebastes and two other scorpaenid species, Helicolenus hilgendorfi and Sebastolobus alascanus, were 0.0805 and 0.1073, respectively. Cladistic and phenetic analyses supported some, but not all, of the subgenera assignments of Sebastes. A scheme for distinguishing among the species studied was presented. Restriction sites of 10 restriction endonucleases were mapped in the two PCR-amplified mtDNA regions by using double digests. In all, we detected 153 sites corresponding to 640 (13.5%) of the 4815 nucleotides in the two regions combined. The ND-3/ND-4 region exhibited substantially more intraspecific,interspecific,and intergeneric variation than the 12S/16S rRNA region. C1 Univ Alaska Fairbanks, Div Fisheries, Sch Fisheries & Ocean Sci, Juneau, AK 99801 USA. NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Gharrett, AJ (reprint author), Univ Alaska Fairbanks, Div Fisheries, Sch Fisheries & Ocean Sci, 11120 Glacier Highway, Juneau, AK 99801 USA. NR 46 TC 33 Z9 35 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 2001 VL 99 IS 1 BP 49 EP 62 PG 14 WC Fisheries SC Fisheries GA 403VN UT WOS:000167063300005 ER PT J AU Noll, C Varnavskaya, NV Matzak, EA Hawkins, SL Midanaya, VV Katugin, ON Russell, C Kinas, NM Guthrie, CM Mayama, H Yamazaki, F Finney, BP Gharrett, AJ AF Noll, C Varnavskaya, NV Matzak, EA Hawkins, SL Midanaya, VV Katugin, ON Russell, C Kinas, NM Guthrie, CM Mayama, H Yamazaki, F Finney, BP Gharrett, AJ TI Analysis of contemporary genetic structure of even-broodyear populations of Asian and western Alaskan pink salmon, Oncorhynchus gorbuscha SO FISHERY BULLETIN LA English DT Article ID NORTH-AMERICAN POPULATIONS; STARCH-GEL ELECTROPHORESIS; BRITISH-COLUMBIA; CHUM SALMON; STOCK IDENTIFICATION; PACIFIC COAST; BERING SEA; RECORD; OCEAN; DIFFERENTIATION AB Even-year pink salmon (Oncorhynchus gorbuscha) populations from the Russian Far East and Japan exhibit genetic structure that reflects their geographic relationships. Extension of genetic analysis to include data from Bering Sea and northern Gulf of Alaska populations shows a combined genetic structure with three prominent groupings that correspond to the three North Pacific Ocean basins-the Sea of Okhotsk, the Bering Sea, and the Gulf of Alaska-and that are consistent with geographic, geologic history, and oceanographic features. Analysis of 35 Asian collections at 39 variable allozyme loci (54 total) allowed examination of population structure of even-year pink salmon. Although most (98.5%) of the genetic variation occurred within collections (populations), the 1.5% attributable to among-collection divergence was sufficient to detect population structure and provide a basis for some stock separation. Differences between western Kamchatka populations and eastern Sakhalin Island populations indicate that little gene flow occurs between those regions and argues against an interregional fluctuating stock model. C1 Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. Inst Fisheries & Oceanog, Kamchatka Sci Res Inst, Petropavlovsk Kamchatski 683602, Kamchatka, Russia. TINRO Ctr, Vladivostok 690600, Russia. Fisheries Agcy Japan, Hokkaido Salmon Hatchery, Toyohira Ku, Sapporo, Hokkaido 062, Japan. Hokkaido Univ, Fac Fisheries, Lab Genet & Embryol, Hakodate, Hokkaido 041, Japan. Univ Alaska Fairbanks, Inst Marine Sci, Fairbanks, AK USA. Univ Alaska, Div Fisheries, Juneau, AK 99801 USA. RP Gharrett, AJ (reprint author), Natl Marine Fisheries Serv, Auke Bay Lab, 11305 Glacier Hwy, Juneau, AK 99801 USA. EM ffajg@uaf.edu NR 77 TC 8 Z9 12 U1 0 U2 2 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 EI 1937-4518 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 2001 VL 99 IS 1 BP 123 EP 138 PG 16 WC Fisheries SC Fisheries GA 403VN UT WOS:000167063300011 ER PT J AU Pella, J Masuda, M AF Pella, J Masuda, M TI Bayesian methods for analysis of stock mixtures from genetic characters SO FISHERY BULLETIN LA English DT Article ID CHAIN MONTE-CARLO; DISTRIBUTIONS; MITOCHONDRIAL; POPULATIONS; FREQUENCY; MARKERS; DNA AB An implementation of Bayesian methods to assess general stock mixtures is described. An informative prior for genetic characters of the separate stocks in a mixture is derived from baseline samples. A neutral, low-information prior is used for the stock proportions in the mixture. A Gibbs sampler-the data augmentation algorithm-is used to alternately generate samples from the posterior distribution for the genetic parameters of the separate stocks and for the stock proportions in the mixture. The posterior distribution incorporates the information about genetic characters in the baseline samples, including relatedness of stocks, with that in the stock-mixture sample to better estimate genotypic composition of the separate stocks. Advantages over usual likelihood methods include greater realism in model assumptions, better flexibility in applications, especially those with missing data, and consequent improved estimation of stock-mixture proportions from the contributing stocks. Two challenging applications illustrate the technique and its advantages. C1 NOAA, Natl Marine Fisheries Serv, Auke Bay Lab, Alaska Fisheries Sci Ctr, Juneau, AK 99801 USA. RP Pella, J (reprint author), NOAA, Natl Marine Fisheries Serv, Auke Bay Lab, Alaska Fisheries Sci Ctr, 11305 Glacier Hwy, Juneau, AK 99801 USA. NR 35 TC 185 Z9 198 U1 1 U2 13 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 2001 VL 99 IS 1 BP 151 EP 167 PG 17 WC Fisheries SC Fisheries GA 403VN UT WOS:000167063300013 ER PT S AU Egoavil, M Puster, R AF Egoavil, M Puster, R BE Chakrabarti, SK Brebbia, CA TI Unique, stabilized flame in fuel injectors created by ignitor-booster system SO FLUID STRUCTURE INTERACTION SE ADVANCES IN FLUID MECHANICS SERIES LA English DT Proceedings Paper CT 1st International Conference on Fluid Structure Interaction CY SEP 26-28, 2001 CL HALKIDIKI, GREECE SP Wessex Inst Technol AB A new airfoil-shaped fuel injector with an ignitor-booster system, was designed for the 8-Foot High-Temperature Tunnel (8-FT HTT) at NASA Langley Research Center. This fuel injector was developed so that it could be used as an uncooled injector in high-pressure, oxygen-enriched air. This effort required the development of new technology in fuel injector design. A high-velocity, vortex stabilizer injector was developed. The development and tests conducted in a simple fan-driven apparatus are explained for the injectors at atmospheric pressure. Similar tests at high pressure were carried out in the Combustor Heated Test Facility (CHTF) with air and with oxygen enriched air. The ignition of the fuel injector array is a quasi-stable ignition scheme. The stabilizing concept was obtained through tests validated with the computational fluid dynamics (CFD) code FLUENT. A large sonic jet of methane is extremely difficult to ignite. A pilot burner added to the flow at an equivalence ratio of 3 generates H-2, CO, and H2O. These products are very hot at 3000 degreesR; the reaction of the CO and H2 enables the stability of the near sonic methane air flame. The combination of pilot and near sonic jet flames yields a large, vigorous stable flame that is ideal for igniting the large fuel injector array. The results helped the design engineers of the 8-FT HTT to define the correct diameter of fuel orifices of injectors and fuel and air velocities. A final three-dimensional case using FLUENT was the simulation of the combustion processes of both the ignitor and fuel injectors to examine the size of the flame and its effect on the fuel injectors and liners of the 8-FT HTT. In conclusion, the present study helps the designers of the airfoil fuel injector and the 8-FT HTT ignitor to predict and verify the high performance and reliability of successful ignition of the tunnel. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Egoavil, M (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU WIT PRESS PI SOUTHAMPTON PA ASHURST LODGE, SOUTHAMPTON SO40 7AA, ASHURST, ENGLAND SN 1353-808X BN 1-85312-881-3 J9 ADV FLUID MECH SER PY 2001 VL 30 BP 213 EP 222 PG 10 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BT34Y UT WOS:000172715600020 ER PT S AU Guenther, EW Joergens, V Neuhauser, R Torres, G Batalha, NS Vijapurkar, J Fernandez, M Mundt, R AF Guenther, EW Joergens, V Neuhauser, R Torres, G Batalha, NS Vijapurkar, J Fernandez, M Mundt, R BE Zinnecker, H TI A spectroscopic and photometric survey for pre-main sequence binaries SO FORMATION OF BINARY STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 200th Symposium of the International-Astronomical-Union CY APR 10-15, 2000 CL ASTROPHYS INST POTSDAM, POTSDAM, GERMANY SP Int Astron Union HO ASTROPHYS INST POTSDAM AB We give here an overview of the current state of our survey for pro-main sequence spectroscopic binaries. Up to now we have taken 739 spectra of 250 pre-main sequence stars. We find that 8% of the stars show significant radial velocity variations, and are thus most likely spectroscopic binaries. In addition to the targets showing radial velocity variations, 6% of the targets are double-lined spectroscopic binaries i.e., the total fraction of spectroscopic binaries is expected to be about 14%. All short-period SB2s are monitored photometrically in order to search for eclipses. An eclipsing SB2 would allow the direct measurement of the masses of both stellar components. Measurements of the stellar masses together with determinations of the stellar radii are a crucial test of evolutionary tracks of pre-main sequence stars. C1 Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. MPI Extraterr Phys, D-85740 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Ames Res Ctr, Planetary Syst Branch, Moffett Field, CA 94035 USA. Homi Bhabha Ctr Sci Educ, Mumbai, India. Inst Astrofis Andalucia, E-18080 Granada, Spain. MPI Astron, D-69117 Heidelberg, Germany. RP Guenther, EW (reprint author), Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. NR 4 TC 0 Z9 0 U1 0 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-068-4 J9 IAU SYMP PY 2001 IS 200 BP 165 EP 168 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43W UT WOS:000175996700020 ER PT S AU Menard, F Stapelfeldt, K AF Menard, F Stapelfeldt, K BE Zinnecker, H TI Optical and near-infrared Imaging of young binary star environments SO FORMATION OF BINARY STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 200th Symposium of the International-Astronomical-Union CY APR 10-15, 2000 CL ASTROPHYS INST POTSDAM, POTSDAM, GERMANY SP Int Astron Union HO ASTROPHYS INST POTSDAM ID T-TAURI STARS; ADAPTIVE OPTICS; CIRCUMBINARY RING; UY AURIGAE; XZ TAURI; GG TAURI; DISK; CONTINUUM; DUST; IMAGES AB We review recent imaging results on the circumstellar matter of young binaries obtained using the Hubble Space Telescope (HST) and by PUEO, a ground-based adaptive optics (AO) system operating at CFHT. In the area of circumbinary disks, new results for GG Tau help form a more complete picture of this prototype system. However, HST images of the UY Aur ring indicate a more complex system than first thought. A new example of a circumstellar disk in a multiple star system has been found in HV Tau, joining HK Tau in this category. Examples of envelopes, outflow cavities, and jets are shown for several young binaries. About half of the nearby young binaries in our survey possess some kind of local nebulosity at optical or near-IR wavelengths. C1 Canada France Hawaii Telescope Corp, Kamuela, HI 96742 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Menard, F (reprint author), Canada France Hawaii Telescope Corp, POB 1597, Kamuela, HI 96742 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 24 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-068-4 J9 IAU SYMP PY 2001 IS 200 BP 234 EP 244 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43W UT WOS:000175996700028 ER PT S AU Koresko, CD Leinert, C AF Koresko, CD Leinert, C BE Zinnecker, H TI The infrared companions of T Tauri stars: Clues to the formation and early evolution of binaries SO FORMATION OF BINARY STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 200th Symposium of the International-Astronomical-Union CY APR 10-15, 2000 CL ASTROPHYS INST POTSDAM, POTSDAM, GERMANY SP Int Astron Union HO ASTROPHYS INST POTSDAM ID YOUNG STELLAR OBJECTS; MAIN-SEQUENCE STARS; SYSTEM; AURIGA; CLOUD; DISK; DUST; IMAGES; MASS AB Infrared companions are young stellar objects with unusual properties gravitationally bound to more or less typical T Tauri stars. As such they promise to be the source of information on either a particular phase in the development of young stars or on a particular mode of development. We discuss the observed properties of infrared companions as well as attempts to explain their physical status with the aim to see how much of solid conclusion has been obtained so far. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Koresko, CD (reprint author), CALTECH, Jet Prop Lab, M-S 171-113, Pasadena, CA 91109 USA. NR 40 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-068-4 J9 IAU SYMP PY 2001 IS 200 BP 265 EP 274 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43W UT WOS:000175996700032 ER PT S AU Stapelfeldt, K AF Stapelfeldt, K BE Zinnecker, H TI Future opportunities in young binary star research with space observatories SO FORMATION OF BINARY STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 200th Symposium of the International-Astronomical-Union CY APR 10-15, 2000 CL ASTROPHYS INST POTSDAM, POTSDAM, GERMANY SP Int Astron Union HO ASTROPHYS INST POTSDAM AB Ambitious infrared and astrometric space observatories are planned by both NASA and ESA for the first decade of the new millenium. I present a brief overview of their capabilities and suggest some of their likely contributions to research on young binary stars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Stapelfeldt, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-068-4 J9 IAU SYMP PY 2001 IS 200 BP 559 EP 562 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43W UT WOS:000175996700069 ER PT S AU Brown, LR AF Brown, LR GP OSA OSA TI Line intensities: the good, the bad and the ugly SO FOURIER TRANSFORM SPECTROSCOPY, TECHNICAL DIGEST SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Conference on Fourier Transform Spectroscopy CY FEB 05-08, 2001 CL COEUR DALENE, ID AB Atmospheric remote sensing requires that line intensities be measured and modeled to 5% or better in laboratory studies. Successes and failures for analyses of carbon monoxide, methane, methanol and nitric acid will be reviewed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Brown, LR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-665-6 J9 OSA TRENDS OPT PHOTO PY 2001 VL 51 BP 7 EP 8 PG 2 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BU62Z UT WOS:000176557500003 ER PT S AU Eldering, A Irion, FW Mills, FP Steele, HM Gunson, MR Kahn, BH AF Eldering, A Irion, FW Mills, FP Steele, HM Gunson, MR Kahn, BH GP OSA OSA TI Aerosol measurements in the IR: from limb to nadir? SO FOURIER TRANSFORM SPECTROSCOPY, TECHNICAL DIGEST SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Conference on Fourier Transform Spectroscopy CY FEB 05-08, 2001 CL COEUR DALENE, ID AB Vertical profiles of aerosol concentration have been derived from the ATMOS solar occultation dataset. The EOS instrument TES has motivated studies of the feasibility of quantifying aerosols in nadir and limb emission measurements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. RP Eldering, A (reprint author), CALTECH, Jet Prop Lab, MS 183-601, Pasadena, CA 91101 USA. NR 9 TC 0 Z9 0 U1 0 U2 2 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-665-6 J9 OSA TRENDS OPT PHOTO PY 2001 VL 51 BP 16 EP 18 PG 3 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BU62Z UT WOS:000176557500006 ER PT S AU Toth, RA Cohen, EA Brown, LR AF Toth, RA Cohen, EA Brown, LR GP OSA OSA TI Line positions and absolute intensities of nitric acid from 850 to 920 cm(-1) SO FOURIER TRANSFORM SPECTROSCOPY, TECHNICAL DIGEST SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Conference on Fourier Transform Spectroscopy CY FEB 05-08, 2001 CL COEUR DALENE, ID AB Line positions and strengths of HNO3 from 850 to 920 cm(-1) have been retrieved from room temperature spectra recorded at 0.00265 cm(-1) resolution using the FTS at Kitt Peak and flowing gas samples. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Toth, RA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-665-6 J9 OSA TRENDS OPT PHOTO PY 2001 VL 51 BP 62 EP 62 PG 1 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BU62Z UT WOS:000176557500022 ER PT S AU Kunde, V Brasunas, J Jennings, D AF Kunde, V Brasunas, J Jennings, D GP OSA OSA TI In-flight data obtained with the composite infrared spectrometers on the Cassini mission SO FOURIER TRANSFORM SPECTROSCOPY, TECHNICAL DIGEST SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Conference on Fourier Transform Spectroscopy CY FEB 05-08, 2001 CL COEUR DALENE, ID AB In-flight data indicates the Cassini Fourier Transform Spectrometers are performing well.. Instrument performance and calibration will be presented. Measurement of the infrared spectrum of Jupiter, obtained during the Cassini flyby of Jupiter, will be illustrated. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kunde, V (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI brasunas, john/I-2798-2013 NR 2 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-665-6 J9 OSA TRENDS OPT PHOTO PY 2001 VL 51 BP 87 EP 90 PG 4 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BU62Z UT WOS:000176557500031 ER PT S AU Crichton, D Kincaid, H Downing, GJ Srivastava, S Hughes, JS AF Crichton, D Kincaid, H Downing, GJ Srivastava, S Hughes, JS GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI An interoperable data architecture for data exchange in a biomedical research network SO FOURTEENTH IEEE SYMPOSIUM ON COMPUTER-BASED MEDICAL SYSTEMS, PROCEEDINGS SE COMPUTER-BASED MEDICAL SYSTEMS : PROCEEDINGS OF THE ANNUAL IEEE SYMPOSIUM LA English DT Proceedings Paper CT 14th IEEE Symposium on Computer-Based Medical Systems (CBMS 2001) CY JUL 26-27, 2001 CL BETHESDA, MD SP IEEE Comp Soc, Tech Comm Computat Med, NIH, Natl Lib Med, Texas Tech Univ Coll Engn AB Knowledge discovery and data correlation require a unified approach to basic data management. However, achieving such an approach is nearly impossible with hundreds of disparate data sources, legacy systems, and data formats. This problem is pervasive in the biomedical research community where data models, taxonomies, and data management systems are locally implemented. These local implementations create an environment where interoperability and collaboration between researchers and research institutions arc limited. Investigators from this paper demonstrate how technology developed by NASA's Jet Propulsion Laboratory (JPL) for space science can be used to build tin interoperable data architecture for bioinformatics. JPL has taken a novel approach towards solving this problem kv exploiting web technologies usually dedicated to e-commerce, combined with a rich, metadata-based environment. This paper discusses the approach taken to develop a Prototype data architecture for the discovery and validation of disease biomarkers within a biomedical research network. Biomarkers arc measured parameters of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. Biomarkers arc of growing importance in the biomedical research for therapeutic discovery, disease prevention, anti detection. A bioinformatics infrastructure is crucial to support the integration and analysis of large, complex biological and epidemiologic datasets. C1 CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91125 USA. RP Crichton, D (reprint author), CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91125 USA. NR 8 TC 2 Z9 2 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-7125 BN 0-7695-1004-3 J9 COMP MED SY PY 2001 BP 65 EP 72 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BS87M UT WOS:000171310500012 ER PT J AU Matta, JL Morales, M Armstrong, RA D'Antoni, H AF Matta, JL Morales, M Armstrong, RA D'Antoni, H TI Mechanisms of UV induced free radical oxidative damage in human skin fibroblasts SO FREE RADICAL BIOLOGY AND MEDICINE LA English DT Meeting Abstract C1 Univ Puerto Rico, Ponce Sch Med, Mayaguez, PR USA. NASA, Ames Res Labs, Ames, IA USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0891-5849 J9 FREE RADICAL BIO MED JI Free Radic. Biol. Med. PY 2001 VL 31 SU 1 MA 11 BP S13 EP S13 PG 1 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism SC Biochemistry & Molecular Biology; Endocrinology & Metabolism GA 491EZ UT WOS:000172096200027 ER PT S AU Biswas, A Wright, MW Sanii, B Page, NA AF Biswas, A Wright, MW Sanii, B Page, NA BE Mecherle, GS TI 45 Km horizontal path optical link demonstrations SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE atmospheric turbulence; scintillation; fade-statistics; tracking; bit error rates AB Observations made during a mountain-top-to-mountain-top horizontal optical link demonstration are described. The optical link spans a range of 46 Km at an average altitude of 2 Km above sea level. A multi-beam beacon comprised of eight laser beams emerging from four multi-mode fiber coupled lasers (780 nm) is launched through a 0.6 m diameter telescope located at the JPL Table Mountain Facility (TMF) in Wrightwood, California. The multi-beam beacon is received at Strawberry Peak located in the San Bernardino Mountains of California. The NASA, JPL developed optical communications demonstrator (OCD) receives the beacon, senses the atmospheric turbulence induced motion and using an upgraded fine steering loop actively points a communications laser beam (852 nn, 400 Mbps on-off key modulated, PN7 pseudo random bit sequence) to TMF. The eight-beam beacon allowed a four-fold reduction in normalized irradiance or scintillation index. This in turn was sufficient to eliminate beacon fades sensed by the OCD and enabled performance evaluation of the fine steering loop. The residual tracking error was determined to be +/-1.1 to +/-1.7 mu rad compared to a model prediction of +/-3.4 mu rad. The best link performance observed showed average bit error rates (BER) of 1E-5 over long durations (30 seconds), however, instantaneous BER's of at least 0.8E-6 over durations of 2 ms were observed. The paper also discusses results pertaining to atmospheric effects, link analysis, and overall performance. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91109 USA. RP Biswas, A (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 5 Z9 5 U1 1 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 60 EP 71 DI 10.1117/12.430789 PG 12 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700006 ER PT S AU Lee, SH Alexander, JW Ortiz, GG AF Lee, SH Alexander, JW Ortiz, GG BE Mecherle, GS TI Sub-microradian pointing system design for deep-space optical communications SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE optical communications; tracking; pointing AB This paper summarizes NASA/JPL progress on sub-microradian pointing system design. Sub-microradian pointing has been found to be critical for the deep space optical communications from earlier studies. The objective of current effort is to develop the needed technologies and demonstrate a sub-microradian pointing capability under simulated spacecraft vibrations. This is expected to establish the foundation for future deep space optical communication missions. The pointing system, once built, should be able to support optical communications anywhere within solar system for non-orbiting spacecraft. The proposed pointing system is based on high precision inertial sensors and large format focal plane arrays, which can operate under low intensity beacon sources such as stars. This design concept drastically deviates from the conventional design limited for short range, which assumes high signal level and quadrant detectors or small format focal plane arrays. We will present the architecture of the pointing system, pointing error analysis, and the progresses on the laboratory validations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 10 Z9 10 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 104 EP 111 DI 10.1117/12.430794 PG 8 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700010 ER PT S AU Ortiz, GG Portillo, A Lee, S Ceniceros, J AF Ortiz, GG Portillo, A Lee, S Ceniceros, J BE Mecherle, GS TI Functional demonstration of accelerometer-assisted beacon tracking SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE acquisition; tracking and pointing; inertial sensors; accelerometer; free-space optical communications; deep space communications ID OPTICAL COMMUNICATIONS DEMONSTRATOR AB NASA/JPL has been developing technologies to accurately point a laser beam from deep space with sub-micro-radian precision for data transmission systems. A novel approach to achieve this goal is based on using high bandwidth inertial sensors to compensate for jitter caused by spacecraft vibrations. The use of high bandwidth inertial sensors promises to enable the implementation of laser communication links anywhere within the solar system and beyond. A functional demonstration of closed-loop accelerometer-assisted beacon tracking under simulated spacecraft vibration was undertaken, in order to validate innovative concepts, technologies, sub-systems and algorithms that achieve the sub-micro-radian pointing accuracy necessary for optical communication systems from deep space. The laboratory demonstration included integration of the complete acquisition, tracking, and pointing system with inertial sensors (e.g. accelerometers). Double integration, bias and initial velocity estimation algorithms were developed, verified and implemented. Accelerometer performance was characterized and integrated to the system. A laser beacon was mounted on a platform that simulates spacecraft vibrations. Vibrations were introduced into the beacon and were simultaneously sampled by the accelerometer. These signals were used to close the pointing loop. Closed loop tracking of the vibrating beacon was achieved using the accelerometer information interlaced with a slow-rate reference update (laser beacon centroids). This presentation will describe the details of the functional demonstration of accelerometer-assisted beacon tracking and pointing in a laboratory environment under simulated spacecraft vibration. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ortiz, GG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 2 Z9 2 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 112 EP 117 DI 10.1117/12.430795 PG 6 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700011 ER PT S AU Srinivasan, M Madden-Woods, B Hamkins, J Biswas, A AF Srinivasan, M Madden-Woods, B Hamkins, J Biswas, A BE Mecherle, GS TI Laboratory characterization of silicon avalanche photodiodes (APD) for pulse position modulation (PPM) detection SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE avalanche photodiode; pulse position modulation AB Two commercially available large area silicon avalanche photodiodes (APD) were characterized in the laboratory. The response of the APD's to a sequence of 8-bit pulse position modulated (256-PPM) laser pulses, with and without additive background noise, was recorded and stored for post analysis. Empirical probability density functions (pdf's) were constructed from the signal and noise slot data and compared to pdf's predicted by an analytical model based on Webb+Gaussian statistics. The pulse sequence was used to generate bit-error rate (BER) versus signal photons per pulse plots, albeit with large error bars due to the limited number of signal pulses stored. These BER measurements were also compared with analytical results obtained by using the Gaussian and Webb+Gaussian models for APD channel statistics. While the measurements qualitatively reflect features predicted by theory, significant quantitative deviations were displayed between the measurements and theory. The source of these discrepancies is not currently well understood, but it is surmised that inaccurate knowledge of detector parameters such as gain and noise equivalent temperature models may explain the discrepancies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Srinivasan, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 1 Z9 1 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 133 EP 141 DI 10.1117/12.430790 PG 9 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700014 ER PT S AU Hamkins, J Dolinar, S Divsalar, D Pollara, F AF Hamkins, J Dolinar, S Divsalar, D Pollara, F BE Mecherle, GS TI Capacity and capacity sensitivity of soft output optical channels SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE capacity; pulse position modulation; avalanche photodiode detector; Webb statistics; sensitivity ID PERFORMANCE AB In this paper we derive the capacity of Pulse Position Modulation (PPM) on a general soft output, memoryless channel, and evaluate the capacity formula for a variety of optical channel models, including AWGN, Webb [1], and Webb plus Gaussian distributions. Unlike a typical RF link, the optical channel has correlated signal and noise, complicating the statistical model to the point that capacity and code performance cannot be summarized by a single SNR parameter. Nevertheless, we are able to define a small set of fundamental parameters (two for AWGN and three for Webb) which are sufficient to determine the capacity. Numerical results indicate that over a wide range of operating points, a single fundamental parameter dominates the capacity calculation. A second contribution of the paper is the description of the relationship between the fundamental parameters and a multitude of physical parameters that describe the laser, channel, and detector. Using this relationship and the gradient of capacity, the sensitivity of capacity with respect to each fundamental and physical parameter is derived. This enables engineers to focus laser and detector development efforts in areas that will result in the largest capacity increases. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hamkins, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 170 EP 180 DI 10.1117/12.430791 PG 11 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700018 ER PT S AU Ceniceros, JM Jeppesen, CD Ortiz, GG AF Ceniceros, JM Jeppesen, CD Ortiz, GG BE Mecherle, GS TI Vibration platform testbed for deep space acquisition, tracking and pointing SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE AB Precise Acquisition, Tracking and Pointing (ATP) remain a key issue in the use of free-space optical communication systems for deep space missions. The Optical Communications Group at the Jet Propulsion Laboratory is developing a vibration platform to assist with the development and characterization of an ATP system to be used for deep space optical communications. The vibration platform will provide a means for subjecting ATP systems to the vibration spectrum likely to be experienced while onboard a spacecraft. The platform consists of a 61 cm x 61 cm optical breadboard mounted on a ball bearing pivot that is driven by a single piezo-electric actuator (PZT). The PZT provides motion in a single axis, giving the platform approximately 200 mu rad of angular motion with a bandwidth in excess of 100 Hz. When placed on the platform, the performance of ATP systems can be tested under several cases of vibration. This paper will discuss the physical properties of the vibration platform. A model for the system will be discussed and experimental performance data will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ceniceros, JM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 5 Z9 5 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 209 EP 218 DI 10.1117/12.430796 PG 10 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700022 ER PT S AU Vilnrotter, V Srinivasan, M AF Vilnrotter, V Srinivasan, M BE Mecherle, GS TI Optical communications through atmospheric turbulence using photodetector arrays SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE AB Ground-based reception of optical signals from space suffers from degradation of the optical phase-front caused by atmospheric turbulence, leading to a reduction in the effective diameter of the receiving aperture and to random fluctuations of the point spread function in the focal plane. A proportional increase in the receiver's field of view, required to collect all of the signal, also causes a corresponding increase in the amount of interfering background radiation, resulting in degraded communications performance. These problems may be mitigated through the use of an optical detector array assembly in the focal plane that can adaptively select areas of higher signal density while ignoring areas predominated by background noise. This concept is investigated for both Poisson photon counting detector arrays and avalanche photodiode arrays. Kolmogorov phase screen simulations are used to model the sample functions of the focal-plane signal distribution due to turbulence and to generate realistic spatial distributions of the received optical field. The optimum photon counting array detector is derived and approximated by a simpler suboptimum structure that replaces the continuous weighting function of the optimal receiver by a hard decision on the selection of the signal detector elements. It is shown that for photon counting receivers observing Poisson distributed signals, performance improvements of up to 5 dB can be obtained over conventional single detector photon counting receivers, when observing turbulent optical fields in high background environments. For the avalanche photodiode detector case, it is shown that gains of up to 4 dB may be achieved by using the array receiver rather than a single APD, but that a photon-counting array still performs about 5.5 dB better than an APD array. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vilnrotter, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 282 EP 292 DI 10.1117/12.430793 PG 11 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700029 ER PT S AU Sanii, B AF Sanii, B BE Mecherle, GS TI Calibrating surface weather observations to atmospheric attenuation measurements SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XIII CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE atmospheric attenuation; free space optical communication; autonomous telescope; cloud cover AB A correlation between near-IR atmospheric attenuation measurements made by the Atmospheric Visibility Monitor (AVM) at the Table Mountain Facility and airport surface weather observations at Edwards Air Force Base has been performed. High correlations (over 0.93) exist between the Edwards observed sky cover and the average AVM measured attenuations over the course of the 10 months analyzed. The statistical relationship between the data-sets allows the determination of coarse attenuation statistics from the surface observations, suggesting that such statistics may be extrapolated from any surface weather observation site. Furthermore, a superior technique for converting AVM images to attenuation values by way of MODTRAN predictions has been demonstrated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sanii, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3950-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4272 BP 293 EP 301 DI 10.1117/12.430797 PG 9 WC Engineering, Aerospace; Optics; Physics, Applied; Telecommunications SC Engineering; Optics; Physics; Telecommunications GA BS74J UT WOS:000171040700030 ER PT B AU Bhat, BN Carter, RW Ding, RJ Lawless, KG Nunes, AC Russell, CK Shah, SR AF Bhat, BN Carter, RW Ding, RJ Lawless, KG Nunes, AC Russell, CK Shah, SR BE Jata, KV Mahoney, MW Mishra, RS Semiatin, SL Field, DP TI Friction stir welding development at NASA - Marshall Space Flight Center SO FRICTION STIR WELDING AND PROCESSING LA English DT Proceedings Paper CT 1st Symposium on Friction Stir Welding and Processing held in Conjunction with the Fall Meeting of the TMS CY NOV, 2001 CL INDIANAPOLIS, IN SP TMS, Mat Process & Mfg Div, Shaping & Forming Comm, Texture & Anisotropy Comm AB This paper presents an overview of friction stir welding (FSW) process development and applications at Marshall Space Flight Center (MSFC), FSW process development started as a laboratory curiosity but soon found support from many users. The FSW process advanced very quickly and has found many applications both within and outside the aerospace industry. It is currently being adapted for joining key elements of the Space Shuttle External Tank for improved producibility and reliability. FSW process modeling is done to better understand and improve the process. Special tools have been developed to weld variable thickness materials including thin and thick materials. FSW is now being applied to higher temperature materials such as copper and to advanced materials such as metal matrix composites. FSW technology is being successfully transferred from MSFC laboratory to shop floors of many commercial companies. C1 NASA, George C Marshall Space Flight Ctr, Mat Pros & Mfg Dept, Huntsville, AL 35812 USA. RP Bhat, BN (reprint author), NASA, George C Marshall Space Flight Ctr, Mat Pros & Mfg Dept, Huntsville, AL 35812 USA. NR 10 TC 1 Z9 1 U1 1 U2 4 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-502-6 PY 2001 BP 117 EP 128 PG 12 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BT49C UT WOS:000173132500011 ER PT S AU Delin, KA Jackson, SP AF Delin, KA Jackson, SP BE Descour, MR Rantala, JT TI The Sensor Web: A new instrument concept SO FUNCTIONAL INTEGRATION OF OPTO-ELECTRO-MECHANICAL DEVICES AND SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Functional Integration of Opto-Electro-Mechanical Devices and Systems CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE Sensor Web; distributed; network; smart sensors; wireless; environment monitoring; botanical ID NETWORKS AB The confluence of the rapidly expanding sensor, computation, and telecommunication industries has allowed for a new instrument concept: the Sensor Web. A Sensor Web consists of intra-communicating, spatially-distributed sensor pods that are deployed to monitor and explore environments. It is capable of automated reasoning for it can perform intelligent autonomous operations in uncertain environments, respond to changing environmental conditions, and carry out automated diagnosis and recovery. Sensor Webs could have as much an impact on the uses of sensors as the Internet did on the uses of computers. Sensor Webs are often confused with "distributed sensors" or "sensor networks". The unique feature of the Sensor Web is that information gathered by one pod is shared and used by other pods. In contrast, sensor networks merely gather data and information gathered by a particular pod on such a network does not influence the behavior of another pod. Thus, sensor networks collect data while Sensor Webs can react and modify their behavior on the basis of the collected data. This paper will outline the potential of the Sensor Web concept and describe the Jet Propulsion Laboratory Sensor Webs Project (http://sensorwebs.ipl.nasa.gov/). In particular, a prototype Sensor Web deployed at the Huntington Botanical Gardens will be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Delin, KA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 23 Z9 23 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3962-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4284 BP 1 EP 9 DI 10.1117/12.426856 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BS36R UT WOS:000169642200003 ER PT S AU Hancock, BR Stirbl, RC Cunningham, TJ Pain, B Wrigley, CJ Ringold, PG AF Hancock, BR Stirbl, RC Cunningham, TJ Pain, B Wrigley, CJ Ringold, PG BE Descour, MR Rantala, JT TI CMOS active pixel sensor specific performance effects on star tracker/imager position accuracy SO FUNCTIONAL INTEGRATION OF OPTO-ELECTRO-MECHANICAL DEVICES AND SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Functional Integration of Opto-Electro-Mechanical Devices and Systems CY JAN 24-25, 2001 CL SAN JOSE, CA SP SPIE DE star tracker; active pixel sensor; APS; radiation AB This paper gives the status of theoretical and experimental efforts at JPL in the development of environmentally robust (Radiation Hard and Radiation Tolerant), ultra-low power, high performance CMOS active pixel sensor (APS) imagers for star tracker/imager applications. The work explores the effect of imager performance on star position accuracy, specifically examining the performance of JPL designed APS imagers. Accuracy is estimated as a function of star magnitude for a nominal star tracker optical design. Using these APS sensors, which have wide dynamic range and no blooming, simultaneous imaging of widely differing star magnitudes during the same observation is possible. It is shown that prototype Rad Hard APS imagers already meet many next generation, star tracker/imager mission performance requirements when operated at reduced temperatures. These imagers also provide excellent performance at cryogenic operating temperatures appropriate to some anticipate flight missions. APS imagers with their high level of integration, on-chip timing and control, ultra-low power, and environmental robustness are excellent candidates for NASA's earth observing, interplanetary and deep space exploration missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hancock, BR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 32 Z9 35 U1 0 U2 8 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3962-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4284 BP 43 EP 53 DI 10.1117/12.426872 PG 11 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BS36R UT WOS:000169642200007 ER PT J AU Chalermwat, P El-Ghazawi, T LeMoigne, J AF Chalermwat, P El-Ghazawi, T LeMoigne, J TI 2-phase GA-based image registration on parallel clusters SO FUTURE GENERATION COMPUTER SYSTEMS LA English DT Article; Proceedings Paper CT 13th Parallel Processing Symposium / 10th Symposium on Parallel and Distributed Processing (IPPS/SPDP 1999) CY APR 12-16, 1999 CL SAN JUAN, PUERTO RICO SP IEEE Comp Soc, Tech Comm Parallel Proc, ACM SIGARCH DE genetic algorithm; image registration; parallel cluster AB Genetic algorithms (GAs) are known to be robust for search and optimization problems. Image registration can take advantage of the robustness of GAs in finding best transformation between two images, of the same location with slightly different orientation, produced by moving spaceborne remote sensing instruments. In this paper, we present 2-phase sequential and coarse-grained parallel image registration algorithms using GAs as optimization mechanism. In its first phase, the algorithm finds a small set of goad solutions using low-resolution Versions of the images. Based on these candidate low-resolution solutions, the algorithm uses the full resolution image data to refine the final registration results in the second phase. Experimental results are presented and revealed that our algorithms yield very accurate registration results for LandSat Thematic Mapper images, and the parallel algorithm scales quite well on the Beowulf parallel cluster. (C) 2001 Elsevier Science B.V. All rights reserved. C1 George Mason Univ, Inst Computat Sci & Informat, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chalermwat, P (reprint author), George Mason Univ, Inst Computat Sci & Informat, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NR 16 TC 16 Z9 19 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-739X J9 FUTURE GENER COMP SY JI Futur. Gener. Comp. Syst. PD JAN PY 2001 VL 17 IS 4 BP 467 EP 476 DI 10.1016/S0167-739X(99)00131-4 PG 10 WC Computer Science, Theory & Methods SC Computer Science GA 397FN UT WOS:000166682800013 ER PT S AU Meier, DL AF Meier, DL BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Simulations of relativistic jet formation in compact radio sources SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID BLACK-HOLES; ASTROPHYSICAL JETS; ACCRETION DISKS; MODEL AB I review recent numerical and analytic work on the magnetohydrodynamic (MHD) model of jet formation in active galactic nuclei, with an emphasis on producing the highly relativistic outflows and high radio luminosities observed in the most powerful sources. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 18 EP 19 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000003 ER PT S AU Jones, DL Wehrle, AE Piner, BG Meier, DL AF Jones, DL Wehrle, AE Piner, BG Meier, DL BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI The sub-parsec structure of accretion disks as revealed by VLBI Imaging of free-free absorption SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID NGC-4261; JETS AB The physical conditions in the inner parsec of accretion disks believed to orbit the central black holes in active galactic nuclei can be probed by imaging the absorption of background radio emission by ionized gas in the disk. High angular resolution radio observations of several nearby galaxies at multiple frequencies have revealed evidence for free-free absorption by disks or tori of ionized gas. The depth and angular width of the absorption increases with decreasing frequency. The longest possible baselines are needed to provide adequate angular resolution at low frequencies where the effects of free-free absorption are most evident. Recent results from VSOP as well as ground-based VLBI observations of the nearby galaxy NGC 4261 illustrate the critical importance of high angular resolution at frequencies below 10 GHz. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 44 EP 47 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000010 ER PT S AU Preston, RA Lister, ML Tingay, SJ Piner, BG Murphy, DW Jones, DL Meier, DL Pearson, TJ Readhead, ACS Hirabayashi, H Kobayashi, H Inoue, M AF Preston, RA Lister, ML Tingay, SJ Piner, BG Murphy, DW Jones, DL Meier, DL Pearson, TJ Readhead, ACS Hirabayashi, H Kobayashi, H Inoue, M BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Pearson-Readhead survey from space SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union AB We are using the VSOP space VLBI mission to observe a complete sample of Pearson-Readhead survey sources at 4.8 GHz to determine core brightness temperatures and pc-scale jet properties. To date we have imaged 27 of the 31 objects in our sample. Our preliminary results show that the majority of objects contain strong core components that remain unresolved on baselines of 30,000 km. The brightness temperatures of several cores significantly exceed 10(12) K, which is indicative of highly relativistically beamed emission. We also find that core brightness temperature is correlated with intraday variability in compact AGNs. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Australia Telescope Natl Facil, Narrabri, Australia. Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan. Natl Astron Observ, Mitaka, Tokyo 181, Japan. Nobeyama Radio Observ, Minamisa Ku, Nagano 38413, Japan. RP Preston, RA (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI Tingay, Steven/B-5271-2013; Pearson, Timothy/N-2376-2015 OI Pearson, Timothy/0000-0001-5213-6231 NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 124 EP 125 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000040 ER PT S AU Murphy, DW Preston, RA Piner, GB Lister, ML Marshall, HL Edwards, PG AF Murphy, DW Preston, RA Piner, GB Lister, ML Marshall, HL Edwards, PG BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Co-ordinated VSOP and Chandra observations of 0836+710 SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union AB We briefly describe the radio observations that form part of co-ordinated Chandra, HALCA+VLBA, and VLBA-only observations of the superluminal gamma-ray loud quasar 0836+710. The radio observations were at 6 frequencies (1.6, 5, 8, 15, 22, and 43 GHz) with the two lowest frequency observations being undertaken with the VLBA co-observing with the HALCA spacecraft (the space element of the Japanese VSOP mission). Combining the radio and X-ray data will allow constraints to be placed on the jet Doppler factor. C1 JPL, Pasadena, CA 91101 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. ISAS, Sagamihara, Kanagawa 2298510, Japan. RP Murphy, DW (reprint author), JPL, MS 238-332,4800 Oak Grove Dr, Pasadena, CA 91101 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 126 EP 127 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000041 ER PT S AU Chatzichristou, ET AF Chatzichristou, ET BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Mapping the dynamics of the quasar 3C 48 SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID POWERFUL RADIO GALAXIES; HOST GALAXY; JET; KINEMATICS; 3C-48; GAS AB The archetypical, nearby (z=0.37) quasar 3C 48 is an unusual CSS radio source with excess far-IR emission, whose one-sided radio jet is aligned with the extended ionized emission and a putative second nucleus. Because of its hi-h AGN luminosity and proximity, 3C 48 is a good candidate to search for kinematic signatures of the radio jet-gas coupling and/or of a recent interaction. The radio morphology and our ground-based integral field spectroscopy suggest that the jet is interacting with its immediate environment. Using STIS aboard HST in several slit positions within the central 1", we map the kinematics and physical conditions of the extended emission line gas and their relations to near-nuclear star forming regions found in existing HST images. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chatzichristou, ET (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 162 EP 165 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000055 ER PT S AU Staguhn, J Schinnerer, E Eckart, A AF Staguhn, J Schinnerer, E Eckart, A BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI BIMA sub-arcsecond carbon monoxide observations: Resolving the inner kpc region of the QSO I Zw 1 SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID STAR-FORMATION; MOLECULAR GAS; GALAXIES AB We present the first sub-kpc (similar to 0.7" P approximate to 0.8 kpc) resolution (12) CO (1-0) observations of the ISM in the host galaxy of the QSO I Zw 1 which were obtained with the BIMA mm-interferometer in its A configuration. The measurements, which are part of a multi-wavelength study of I Zw 1, will allow comparison of the ISM properties of a QSO host with those of nearby galaxies and place constraints on galaxy formation/evolution models. Our maps of the (CO)-C-12 (1-0) line emission from the host galaxy of a QSO show a ring-like structure in the circumnuclear molecular gas distribution with a radius of about 900 pc. The presence of such a molecular gas ring was already predicted from earlier lower angular resolution PdBI observations (Schinnerer, Eckart, & Tacconi 1998). A first comparison of the BIMA data with new PdBI (CO)-C-12 (2-1) observations with 0.9" angular resolution shows variations in the excitation conditions of the molecular gas in the innermost 3" comprising the nuclear region of I Zw 1. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. RP Staguhn, J (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 340 EP 343 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000112 ER PT S AU Bietenholz, MF Bartell, N Rupen, MP Beasley, AJ Graham, DA Altunin, VI Venturi, T Umana, G Cannon, WH Conway, JE AF Bietenholz, MF Bartell, N Rupen, MP Beasley, AJ Graham, DA Altunin, VI Venturi, T Umana, G Cannon, WH Conway, JE BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Supernova 1993J in M81 SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union AB Twenty-two consecutive VLBI images of supernova 1993J in the galaxy M81 taken over 7 years show, in unprecedented detail, the dynamic evolution of the expanding radio shell of an exploded star. High precision astrometry using phase-referencing shows that the supernova expands isotropically, and that its geometric center has a formal proper motion of 190 110 km s(-1) w.r.t. the core of M81. Systematic changes in the images most likely reflect a pattern of inhomogeneities in the medium left over from the progenitor star, or possibly instabilities in the expanding shell. As the shockfront sweeps up the medium, it is progressively decelerated, and after 7 years it has slowed to less than (1)/(2) its original expansion velocity. SN1993J is likely now entering the early stages of the adiabatic phase common in much older supernova remnants. C1 York Univ, Toronto, ON M3J 1P3, Canada. Natl Radio Astron Observ, Socorro, NM 87801 USA. Max Planck Inst Radioastron, D-53121 Bonn, Germany. Jet Prop Lab, Pasadena, CA 91109 USA. Inst Radioastron, CNR, Bologna, Italy. CRESTech, Toronto, ON M3J 3K1, Canada. Onsala Space Observ, S-43992 Onsala, Sweden. RP Bietenholz, MF (reprint author), York Univ, Toronto, ON M3J 1P3, Canada. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 380 EP 383 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000124 ER PT S AU Stairs, IH Thorsett, SE Taylor, JH Arzoumanian, Z AF Stairs, IH Thorsett, SE Taylor, JH Arzoumanian, Z BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Recent observations of BSR B1534+12 SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID BINARY AB We present the results of recent Arecibo observations of the relativistic double-neutron-star binary PSR B1534+12. The timing solution includes measurements of five post-Keplerian orbital parameters, whose values agree well with the predictions of general relativity. The observations show that the pulse profile is evolving secularly at both 1400 MHz and 430 MHz. This effect is similar to that seen in PSR B1913+16, and is almost certainly due to general relativistic precession of the pulsar's spin axis. We also present high-quality polarimetric profiles at both observing frequencies. C1 Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Princeton Univ, Joseph Henry Labs, Princeton, NJ 08544 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stairs, IH (reprint author), Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. NR 6 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 408 EP 409 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000134 ER PT S AU Jones, DL AF Jones, DL BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI Prospects for high angular resolution at low frequencies SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union AB High angular resolution imaging at low frequencies (below similar to 10 MHz) requires observations from above the ionosphere. A radio interferometer array in space will be able to open new vistas in solar, terrestrial, galactic, and extragalactic astrophysics. A space-based interferometer could image and track transient disturbances in the solar corona and interplanetary medium - a new capability which is crucial for understanding many aspects of solar-terrestrial interaction and space weather. It could also produce the first sensitive, high-angular-resolution radio surveys of the entire sky at low frequencies. The radio sky will look entirely different below 10-30 MHz because new emission and absorption processes become dominant at these frequencies. As a result, low frequency surveys from space will provide a fundamentally new view of the universe and an extraordinarily large and varied science return. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 418 EP 419 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000137 ER PT S AU Leisawitz, D AF Leisawitz, D CA Far-IR Interferometry Mission BE Schilizzi, RT Vogel, SN Paresce, F Elvis, MS TI The science potential of Far-IR/Sub-mm interferometry and concepts for the SPIRIT and SPECS missions SO GALAXIES AND THEIR CONSTITUENTS AT THE HIGHEST ANGULAR RESOLUTIONS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 24th General Assembly of the International-Astronomical-Union CY AUG 07-18, 2000 CL MANCHESTER, ENGLAND SP Int Astron Union ID BACKGROUND EXPERIMENT SEARCH; GALAXIES C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leisawitz, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-066-8 J9 IAU SYMP PY 2001 IS 205 BP 438 EP 439 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU43Z UT WOS:000175998000143 ER PT S AU Gehrels, N Shrader, CR AF Gehrels, N Shrader, CR BE Ritz, S Gehrels, N Shrader, CR TI The Compton Gamma Ray Observatory in review SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL AB The Compton Gamma Ray Observatory was de-orbited on 4 June 2000 after 9 highly successful years in orbit. Major discoveries were made every year with Compton. We present a retrospective overview of the mission from launch to deorbit,, highlighting some seminal scientific findings. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 3 EP 7 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400001 ER PT S AU Ling, JC AF Ling, JC BE Ritz, S Gehrels, N Shrader, CR TI A review of Cygnus X-1 soft gamma-ray observations SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID X-RAY; BLACK-HOLES; LONG-TERM; ACCRETION; TELESCOPE; SPECTRUM; VARIABILITY; EMISSION; BATSE; MODEL AB Since the first discovery of Cygnus X- I in the mid 1960's, the source has been the subject of intense soft gamma-ray (30 keV - 10 MeV) observations by many balloon and satellite experiments. A large body of spectral and temporal information about the source has been gathered to date. While these results have significantly enhanced our understanding of the Cygnus X-1 system, they have also raised new questions that need to be addressed by future missions. This paper provides a brief summary of some of the important long-term temporal and spectral results obtained over the last thirty years, and discusses the current status and issues that need to be addressed by upcoming missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Ling, JC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 35 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 135 EP 139 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400026 ER PT S AU Norris, JP Scargle, JD Bonnell, JT AF Norris, JP Scargle, JD Bonnell, JT BE Ritz, S Gehrels, N Shrader, CR TI Pulses, spectral lags, durations, and hardness ratios in long GRBs SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID GAMMA-RAY BURSTS AB We analyze BATSE 64-ms data for long gamma-ray bursts (T-90 > 2.6 s), exploring the relationships between spectral lag, duration, and the number of distinct pulses per burst, N-pulses. We measure durations using a brightness-independent technique. Within a similarly brightness- independent framework, we use a "Bayesian Block" method to find significant valleys and peaks, and thereby identify distinct pulses in bursts. Our results show that, across large dynamic ranges in peak flux and the Npulses measure, bursts have short lags and narrow pulses, while bursts with long lags tend to have just a few significant, wide pulses. There is a tendency for harder bursts to have few pulses, and these hardest bursts have short lags. Spectral lag and duration appear to be nearly independent - even for those bursts with relatively long lags: wider pulses tend to make up in duration for fewer pulses. Our brightness-independent analysis adds to the nascent picture of an intimate connection between pulse width, spectral lag, and peak luminosity for bursts with known redshifts: We infer that lower- luminosity bursts should have fewer episodes of organized emission - wider pulses with longer spectral lags. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Norris, JP (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 10 TC 9 Z9 10 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 176 EP 180 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400033 ER PT S AU Barthelmy, SD Cline, TL Butterworth, P AF Barthelmy, SD Cline, TL Butterworth, P BE Ritz, S Gehrels, N Shrader, CR TI GRB Coordinates Network (GCN): A status report SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID LOCALIZATIONS AB The GRB Coordinates Network (GCN) continues to deliver locations of GRBs to instruments and observers in real-time (a few seconds) - while the burst is still bursting - so that they can make multi-band simultaneous follow-up observations. Ibis was routine during the GRO-BATSE years and has resumed with HETE. This goal was realized with the optical detection of the burst counterpart for GRB990123 by the ROTSE instrument [1]. A brief review of the function and capabilities of the GCN system is given. Complementing the real-time location Notices, the GCN Circulars allow the follow-up observers to share the results of their observations rapidly with the community. A status report on recent improvements to the GCN system and a list of future improvements is given. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barthelmy, SD (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012 NR 8 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 213 EP 217 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400041 ER PT S AU Nandikotkur, G Jahoda, KM Swank, JH Sreekumar, P Sambruna, RM AF Nandikotkur, G Jahoda, KM Swank, JH Sreekumar, P Sambruna, RM BE Ritz, S Gehrels, N Shrader, CR TI High energy observations of Blazars - Archival analysis SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID GAMMA-RAYS; EMISSION; JET AB We are conducting a systematic study of the archival data of 14 AGNs observed simultaneously by RXTE and EGRET. The sample includes eight flat spectrum radio quasars, three high-energy-peaked BL Lacs (HBLs), and three low-energy peaked BL Lacs (LBLs). Four sources have been observed for at least two consecutive EGRET observation periods (14 days). We have extracted spectral indices using the power-law models in both XTE and EGRET energy ranges and we are studying the X-ray-to-gamma-ray spectral energy distributions and their variability as a function of classification. Preliminary results show that FSRQs and LBLs have X-ray photon indices in the energy band 3.0-20 keV in the range 1.3-2.0, while HBLs have indices in the range 1.8-2.9. Several blazars were repeatedly observed in X-rays with XTE, enabling us to study flux and spectral variation on the time scales of half a day. Correlated variations between the photon index and flux are observed in HBLs with a trend of flatter slopes for increasing fluxes. In LBLs and FSRQs, both the flux and slope vary, but with no clear trends. The results are overall consistent with the current unification schemes for blazars where HBLs are dominated in X-rays by the variable tail of synchrotron emission, while in FSRQs and LBLs the XTE spectra are dominated by the inverse Compton emission extending to higher energies. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Nandikotkur, G (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 309 EP 313 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400059 ER PT S AU Chiang, J Blaes, O AF Chiang, J Blaes, O BE Ritz, S Gehrels, N Shrader, CR TI Thermal Comptonization and disk reprocessing in type 1 Seyfert galaxies SO GAMMA 2001 SE AIP Conference Proceedings LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID ACTIVE GALACTIC NUCLEI; X-RAY; COMPACT OBJECTS; ACCRETION DISK; NGC 5548; CONTINUUM; ULTRAVIOLET; VARIABILITY; REFLECTION; EMISSION AB Using a geometry consisting of a spherical Comptonizing region surrounded and penetrated by a thin accretion disk, we model the optical through gamma-ray spectral energy distribution of the type 1 Seyfert galaxy NGC 5548. We take into account thermal reprocessing by the disk and how the resulting disk emission affects the energy balance of the Comptonizing region. These calculations allow us to infer the properties of the inner disk region including the size, temperature, and optical depth of the Comptonizing plasma. We discuss how INTEGRAL observations of AGNs such as NGC 5548 will provide stringent tests of this and other thermal Comptonization models. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chiang, J (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM jchiang@milkyway.gsfc.nasa.gov NR 23 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 390 EP 394 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400075 ER PT S AU Reimer, O Sreekumar, P AF Reimer, O Sreekumar, P BE Ritz, S Gehrels, N Shrader, CR TI Clusters of galaxies - The EGRET observations between 1991 and 2000 SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID FLUX-LIMITED SAMPLE; ALL-SKY SURVEY; MAGNETIC-FIELDS; COSMIC-RAYS; NONTHERMAL EMISSION; COMA CLUSTER; ORIGIN AB Various emission mechanism suggest clusters of galaxies to exhibit high-energy gamma-ray radiation. Galaxy clusters are predicted to be at the edge of the instrumental sensitivity currently accessible with gamma-ray telescopes. It is suggested that galaxy clusters contribute to the extragalactic diffuse background and, in few individual cases, they might be already detectable as individual sources. On the assumption that a flux limited sample of X-ray bright clusters will suit as a reasonable selection, gamma-ray fluxes (E > 100 MeV) are determined using EGRET data throughout the entire CGRO mission. In order to investigate beyond the case of the individual X-ray bright cluster, the gamma-ray data of individual clusters are cumulative stacked in a cluster-centered coordinate system and the resulting images have been analyzed. The results from EGRET are given and discussed in the light of predictions already found in the literature as well as in perspective of upcoming gamma-ray mission like INTEGRAL and, primarily, GLAST. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. RP Reimer, O (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. RI Reimer, Olaf/A-3117-2013 OI Reimer, Olaf/0000-0001-6953-1385 NR 21 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 422 EP 426 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400081 ER PT S AU Stecker, FW Salamon, MH AF Stecker, FW Salamon, MH BE Ritz, S Gehrels, N Shrader, CR TI The extragalactic gamma-ray background SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID INTERGALACTIC INFRARED RADIATION; RADIO-LOUD AGN; LUMINOSITY FUNCTION; EGRET OBSERVATIONS; BLAZARS; ORIGIN; TEV; ABSORPTION; SUPERNOVAE; EMISSION AB The COMPTEL and EGRET detectors aboard the Compton Gamma-R-ay Observatory measured an extragalactic gamma-ray background (EGRB) extending from similar to 1 MeV to similar to 100 GeV. Calculations performed making reasonable assumptions indicate that blazars can account for the background between similar to 10 MeV and similar to 10 GeV. Below 30 MeV, the background flux and spectrum are not very well determined and a dedicated satellite detector will be required to remedy this situation. Below 10 MeV, supernovae and possibly AGN may contribute to the extragalactic background flux. Above 10 GeV, the role of blazars in contributing to the background is unclear because we do not have data on their spectra at these energies and because theoretical models predict that many of them will have spectra which should cut off in this energy range. At these higher energies, a new component, perhaps from topological defects, may contribute to the background, as well as X-ray selected BL Lac objects. GLAST should provide important data on the emission of extragalactic sources above 10 GeV and help resolve this issue. GLAST may also be able to detect the signature of intergalactic absorption by pair production interactions of background gamma-rays of energy above similar to 20 GeV with starlight photons, this signature being a steepening of the background spectrum. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Stecker, FW (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. RI Stecker, Floyd/D-3169-2012 NR 31 TC 18 Z9 18 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 432 EP 441 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400083 ER PT S AU Watanabe, K Hartmann, DH AF Watanabe, K Hartmann, DH BE Ritz, S Gehrels, N Shrader, CR TI Contributions of GRBs and Cen A-like radio galaxies to the cosmic gamma-ray background SO GAMMA 2001 SE AIP Conference Proceedings LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID X-RAY; SUPERNOVAE; EMISSION; IA AB The contribution to the cosmic diffuse gamma-ray background (CGB) from Gamma Ray Bursts (GRBs) is studied in the 40 keV - 2 MeV regime. We use High Energy Resolution (HER) data from the Burst And Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) to generate a GRB template spectrum. Although the GRB contribution to the CGB is generally small, in comparison to the dominant flux from Type Ia supernovae, the integrated GRB flux is in fact comparable to that from SNIa in the narrow 10-40 keV range. GRBs contribute to the CGB at the same level as Type II supernovae do. Although BATSE data are not available below similar to40 keV, extrapolation of the template spectrum suggests that bursts can fill a significant part of the existing gap between Seyfert galaxies (dominating the CGB below similar to 100 keV) and SNIa (dominating at similar to1 MeV). We estimate contributions from Cen A-like (FRI) radio galaxies in this energy regime, where INTEGRAL data is expected to provide major advances. C1 NASA, Goddard Space Flight Ctr, EIT, LHEA, Greenbelt, MD 20771 USA. RP Watanabe, K (reprint author), NASA, Goddard Space Flight Ctr, EIT, LHEA, Code 660, Greenbelt, MD 20771 USA. EM watanabe@Iheapop.gsfc.nasa.gov; hdieter@clemson.edu NR 16 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 442 EP 445 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400084 ER PT S AU Digel, SW Hunter, SD Moskalenko, IV Ormes, JF Pohl, M AF Digel, SW Hunter, SD Moskalenko, IV Ormes, JF Pohl, M BE Ritz, S Gehrels, N Shrader, CR TI The origin of cosmic rays and the diffuse galactic gamma-ray emission SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID SNR RX J1713.7-3946; SUPERNOVA-REMNANTS; EGRET OBSERVATIONS; CASSIOPEIA-A; SHOCK ACCELERATION; MOLECULAR CLOUDS; MAGELLANIC CLOUD; ENERGY; TEV; SHELL AB Cosmic-ray interactions with interstellar gas and photons produce diffuse gamma-ray emission. In this talk we will review the current understanding of this diffuse emission and its relationship to the problem of the origin of cosmic rays. We will discuss the open issues and what progress might be possible with GLAST, which is planned for launch in 2006. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Digel, SW (reprint author), NASA, Goddard Space Flight Ctr, Code 660, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012 NR 61 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 449 EP 458 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400085 ER PT S AU Sturner, SJ Reimer, O Keohane, JW Olbert, CM Petre, R Dermer, CD AF Sturner, SJ Reimer, O Keohane, JW Olbert, CM Petre, R Dermer, CD BE Ritz, S Gehrels, N Shrader, CR TI On the nature of the nonthermal emission from the supernova remnant IC 443 SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID GAMMA-RAY PULSARS; X-RAY; SHOCK ACCELERATION; EGRET SOURCES; IC-443; IC443; RADIO; STATISTICS; ELECTRONS; DISCOVERY AB The supernova remnant (SNR) IC 443 is a nearby (similar to 1.5 kpc) remnant of intermediate age which appears to be interacting with a molecular cloud and is spatially coincident with the unidentified EGRET source 3EG J0617+2238. We present new spectra of IC 443 obtained using the PCA on RATE. The spectrum is well fit by a two-component model consisting of a non-equilibrium ionization collisional plasma model with kTsimilar to0.6 keV plus a power-law with index similar to2.2. We compare our results with the earlier results of HEAO 1 A-2, Ginga, ASCA, and BeppoSAX, and find generally good agreement. We also discuss the possible association of 3EG J0617+223 8 with IC 443 given that recent Chandra results indicate that much of its nonthermal X-ray emission originates from a pulsar wind nebula. We find that unless the calculation of the position of 3EG J0617+2238 is affected by nearby strong sources such as Geminga, the Chandra source is excluded from being associated with the EGRET source. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sturner, SJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Reimer, Olaf/A-3117-2013 OI Reimer, Olaf/0000-0001-6953-1385 NR 32 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 528 EP 532 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400097 ER PT S AU Digel, SW Grenier, IA AF Digel, SW Grenier, IA BE Ritz, S Gehrels, N Shrader, CR TI EGRET observations of diffuse gamma-ray emission in Taurus and Perseus SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL AB We present an analysis of the interstellar gamma-ray emission observed toward the extensive molecular cloud complexes in Taurus and Perseus by the Energetic Gamma-Ray Experiment Telescope (EGRET). The region's large size (more than 300 square degrees) and location below the plane in the anticenter are advantageous for straightforward interpretation of the interstellar emission. The complex of clouds in Taurus has a distance of similar to 140 pc and is near the center of the Gould Belt. The complex in Perseus, adjacent to Taurus on the sky, is near the rim of the Belt at a distance of similar to 300 pc. The findings for the cosmic-ray density and the molecular mass-calibrating ratio N(H-2)/W-CO in Taurus and Perseus are compared with results for other nearby cloud complexes resolved by EGRET. The local clouds that now have been studied in gamma rays can be used to trace the distribution of high-energy cosmic rays within I kpc of the sun. C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Digel, SW (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 661, Greenbelt, MD 20771 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 538 EP 542 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400099 ER PT S AU Harding, AK AF Harding, AK BE Ritz, S Gehrels, N Shrader, CR TI Gamma-ray pulsars: At the tip of the iceberg SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID RAPIDLY SPINNING PULSARS; POLAR-CAP CASCADES; OUTER MAGNETOSPHERE; PAIR CREATION; EMISSION; GAPS; RADIATION; GEMINGA AB Although the theory of pulsar acceleration and high energy emission has been studied for over 25 years, the origin of the pulsed gamma-rays is a question that remains unanswered. Characteristics of the seven gamma-ray pulsars detected by CGRO could not clearly distinguish between an emission site at the magnetic poles (polar cap models) and emission from the outer magnetosphere (outer gap models). The two types of models make contrasting predictions for the numbers of radio-loud and radio-quiet gamma-ray pulsars and for their spectral characteristics. GLAST will probably detect at least 50 radio-selected pulsars and possibly more radio-quiet pulsars. With this large sample, it will be possible to fully test the model predictions and finally resolve this longstanding question. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harding, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Harding, Alice/D-3160-2012 NR 42 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 545 EP 554 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400100 ER PT S AU Kazanas, D Contopoulos, J AF Kazanas, D Contopoulos, J BE Ritz, S Gehrels, N Shrader, CR TI Resolving the Crab sigma-problem SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID AXISYMMETRICAL PULSAR MAGNETOSPHERE; NEBULA; WINDS; MODEL AB Using the exact solution of the axisymmetric pulsar magnetosphere derived in a previous publication and the conservation laws of the associated MHD flow, we show that the Lorentz factor of the outflowing plasma increases linearly with distance from the light cylinder. Therefore, the ratio of the Poynting to particle energy flux, generically referred to as or, decreases inversely proportional to distance, from a large value (typically greater than or similar to10(4)) near the light cylinder to sigma similar or equal to 1 at a transistion distance R-trans. Beyond this distance the inertial effects of the outflowing plasma become important and the magnetic field geometry must deviate from the almost monopolar form it attains between R-lc, and R-trans We anticipate that this is achieved by collimation of the poloidal field lines toward the rotation axis, ensuring that the magnetic field pressure in the equatorial region will fall-off faster than 1/R-2 (R being the cylindrical radius). This leads both to a value sigma = sigma(s) much less than 1 at the nebular reverse shock at distance R-s (R-s much greater than R-trans) and to a component of the flow perpendicular to the equatorial component, as required by observation. The presence of the strong shock at R = R allows for the efficient conversion of kinetic energy into radiation. We speculate that the Crab pulsar is unique in requiring sigma(s) similar or equal to 3 x 10(-3) because of its small translational velocity, which allowed for the shock distance R-s to grow to values much greater than R-trans. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kazanas, D (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 565 EP 569 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400103 ER PT S AU Young, CA Arndt, MB Bennett, K Connors, A Debrunner, H Diehl, R McConnell, M Miller, RS Rank, G Ryan, JM Schoenfelder, V Winkler, C AF Young, CA Arndt, MB Bennett, K Connors, A Debrunner, H Diehl, R McConnell, M Miller, RS Rank, G Ryan, JM Schoenfelder, V Winkler, C BE Ritz, S Gehrels, N Shrader, CR TI COMPTEL gamma-ray observations of the C4 solar flare on 20 January 2000 SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID ABUNDANCES AB The "Pre-SMM" (Vestrand and Miller 1998) picture of gamma-ray line (GRL) flares was that they are relatively rare events. This picture was quickly put in question with the launch of the Solar Maximum Mission (SMM). Over 100 GRL flares were seen with sizes ranging from very large GOES class events (X12) down to moderately small events (M2). It was argued by some (Bai 1986) that this was still consistent with the idea that GRL events are rare. Others, however, argued the opposite (Vestrand 1988; Cliver, Crosby and Dennis 1994), stating that the lower end of this distribution was just a function of SMM's sensitivity. They stated that the launch of the Compton Gamma-ray Observatory (CGRO) would in fact continue this distribution to show-even smaller GRL flares. In response to a BACODINE cosmic gamma-ray burst alert, COMPtonTELescope on the CGRO recorded gamma rays above 1 MeV from the C4 flare at 0221 UT 20 January 2000. This event, though at the limits of COMPTEL's sensitivity, clearly shows a nuclear line excess above the continuum. Using new spectroscopy techniques we were able to resolve individual lines. This has allowed us to make a basic comparison of this event with the GRL flare distribution from SMM and also compare this flare with a well-observed large GRL flare seen by OSSE. C1 Goddard Space Flight Ctr, EmergentIT Inc, Greenbelt, MD USA. RP Young, CA (reprint author), Goddard Space Flight Ctr, EmergentIT Inc, Greenbelt, MD USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 613 EP 617 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400111 ER PT S AU Young, CA Bennett, K Connors, A Diehl, R McConnell, M Rank, G Ryan, JM Suleiman, R Schonfelder, V Winkler, C AF Young, CA Bennett, K Connors, A Diehl, R McConnell, M Rank, G Ryan, JM Suleiman, R Schonfelder, V Winkler, C BE Ritz, S Gehrels, N Shrader, CR TI Energetic proton spectra in the 11 June 1991 solar flare SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID GAMMA-RAY FLARE; COMPTON AB The June 11,1991 gamma-ray flare seen by the Compton Gamma-ray Observatory (CGRO) displays several features that make it a dynamic and rich event. It is a member of a class of long duration gamma-ray events with both 2.223 MeV and greater than 8 MeV emission for hours after the impulsive phase. It also contains an inter-phase between the impulsive and extended phases that presents a challenge to the standard gamma-ray line (GRL) flare picture. This phase has strong 2.223 MeV emission and relatively weak 4.44 MeV emission indicative of a very hard parent proton spectrum. However, this would indicate emission greater than 8 MeV, which is absent from this period. We present the application of new spectroscopy techniques to this phase of the flare in order to present a reasonable explanation for this seemly inconsistent picture. C1 Goddard Space Flight Ctr, EmergentIT Inc, Greenbelt, MD USA. RP Young, CA (reprint author), Goddard Space Flight Ctr, EmergentIT Inc, Greenbelt, MD USA. NR 21 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 623 EP 627 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400113 ER PT S AU Thompson, DJ Bertsch, DL Hartman, RC AF Thompson, DJ Bertsch, DL Hartman, RC BE Ritz, S Gehrels, N Shrader, CR TI Artifact sources near bright EGRET pulsars SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID CRAB AB As noted in the Third EGRET Catalog, six sources near the bright Vela pulsar are thought to be artifacts: 3EG J0824-4610, 3EG J0827-4247, 3EG J0828-4954, 3EG J0841-4356, 3EG J0848-4429, and 3EG J0859-4257. This conclusion is based on analysis of phase-resolved maps of the pulsar region. The artifact sources are statistically significant only in the on-pulse maps where Vela itself is bright. Details of this analysis show that there is at most one source in addition to Vela in this region. Additional analysis using the same phase-resolved-map technique suggests that one of the four sources near the Crab pulsar, 3EG J0521+2147, is also likely to be an artifact. Both of the sources closest to Geminga are detected at comparable levels in both on-pulse and off-pulse maps, supporting their validity. These results illustrate the difficulty of detecting weak sources near bright ones, even using modeling techniques such as maximum likelihood. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Thompson, DJ (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 4 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 668 EP 672 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400119 ER PT S AU Arzoumanian, Z Yusef-Zadeh, F Lazio, TJW AF Arzoumanian, Z Yusef-Zadeh, F Lazio, TJW BE Ritz, S Gehrels, N Shrader, CR TI A search for supernova-remnant masers toward unidentified EGRET sources SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID OH MASERS; EMISSION AB Supernova remnants expanding into adjacent molecular clouds are believed to be sites of cosmic ray acceleration and sources of energetic gamma-rays. Under certain environmental conditions, such interactions also give rise to unusual OH masers in which the 1720 MHz satellite line dominates over the more common 1665/7 MHz emission. Motivated by the apparent coincidence of a handful of EGRET sources with OH(1720 MHz) maser-producing supernova remnants, we have carried out a search using the Very Large Array for new OH(1720 MHz) masers within the error regions of 11 unidentified EGRET sources at low Galactic latitude. While a previously known maser associated with an HII region was serendipitously detected, initial results indicate that no new masers were found down to a limiting flux of, typically, 50 mJy. We discuss the implications of this result on the nature of the unidentified Galactic EGRET sources. C1 NASA, Goddard Space Flight Ctr, LHEA, Greenbelt, MD 20771 USA. RP Arzoumanian, Z (reprint author), NASA, Goddard Space Flight Ctr, LHEA, Code 662, Greenbelt, MD 20771 USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 678 EP 682 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400121 ER PT S AU Bridgman, WT AF Bridgman, WT BE Ritz, S Gehrels, N Shrader, CR TI Effects of background counts in RMS normalization SO GAMMA 2001 SE AIP Conference Proceedings LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID POWER SPECTRA AB Root-Mean-Square (RMS) normalization is a popular method of measuring the fast time variability in astronomical x-ray sources. The traditional definition contains the implicit assumption that the background contribution to the count rate is negligible. In this letter I illustrate that in cases where background counts are important, this can lead to erroneous results. However, I also illustrate a simple modification that can remove the effect of the background and makes RMS variability a more reliable measure of variability between observations from different instruments. C1 NASA, Goddard Space Flight Ctr, Sci Visualizat Studio, Greenbelt, MD 20771 USA. RP Bridgman, WT (reprint author), NASA, Goddard Space Flight Ctr, Sci Visualizat Studio, Code 935, Greenbelt, MD 20771 USA. EM bridgman@wyeth.gsfc.nasa.gov NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 691 EP 695 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400123 ER PT S AU Young, CA Connors, A Kolaczyk, E McConnell, M Rank, G Ryan, JM Schonfelder, V AF Young, CA Connors, A Kolaczyk, E McConnell, M Rank, G Ryan, JM Schonfelder, V BE Ritz, S Gehrels, N Shrader, CR TI Bayesian multiscale deconvolution applied to gamma-ray spectroscopy SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL AB A common task in gamma-ray astronomy is to extract spectral information, such as model constraints and incident photon spectrum estimates, given the measured energy deposited in a detector and the detector response. This is the classic problem of spectral "deconvolution" or spectral inversion. The methods of forward folding (i.e. parameter fitting) and maximum entropy "deconvolution" (i.e. estimating independent input photon rates for each individual energy bin) have been used successfully for gamma-ray solar flares (e.g. Rank, 1997; Share and Murphy, 1995). These methods have worked well under certain conditions but there are situations were they don't apply. These are: 1) when no reasonable model (e.g. fewer parameters than data bins) is yet known, for forward folding; 2) when one expects a mixture of broad and narrow features (e.g. solar flares), for the maximum entropy method; and 3) low count rates and low signal-to-noise, for both. Low count rates are a problem because these methods (as they have been implemented) assume Gaussian statistics but Poisson are applicable. Background subtraction techniques often lead to negative count rates. For Poisson data the Maximum Likelihood Estimator (MLE) with a Poisson likelihood is appropriate. Without a regularization term, trying to estimate the "true" individual input photon rates per bin can be an ill-posed problem, even without including both broad and narrow features in the spectrum (i.e. a multiscale approach). One way to implement this regularization is through the use of a suitable Bayesian prior. Nowak and Kolaczyk (1999) have developed a fast, robust, technique using a Bayesian multiscale framework that addresses these problems with added algorithmic advantages. We outline this new approach and demonstrate its use with time resolved solar flare gamma-ray spectroscopy. C1 Goddard Space Flight Ctr, EmergentIT Inc, Greenbelt, MD USA. RP Young, CA (reprint author), Goddard Space Flight Ctr, EmergentIT Inc, Greenbelt, MD USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 701 EP 705 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400125 ER PT S AU Bertsch, DL Hartman, RC Hunter, SD Thompson, DJ Sreekumar, P AF Bertsch, DL Hartman, RC Hunter, SD Thompson, DJ Sreekumar, P BE Ritz, S Gehrels, N Shrader, CR TI EGRET's detection efficiency in the later phases of the mission SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL AB The detection efficiency of EGRET varied throughout the mission due to aging of the spark gas between gas refills, and later in the mission due to partial hardware failures. After the gas refill in 1995 September until the end of the mission in 2000 May, EGRET was operated for approximately 700 days - several times as long as for earlier gas fills. The efficiency degradation was severe during this time, and it was highly energy dependent affecting the low energies the most. This paper reports on an extensive effort to determine the efficiency factors that apply to data during this period. C1 NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Greenbelt, MD 20771 USA. RP Bertsch, DL (reprint author), NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 4 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 706 EP 710 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400126 ER PT S AU Lambros, S AF Lambros, S BE Ritz, S Gehrels, N Shrader, CR TI Gamma-ray Large Area Space Telescope (GLAST) project SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL AB The Gamma-ray Large Area Space Telescope (GLAST) mission is a scientific spaceflight investigation that measures the direction, energy and arrival time of celestial gamma rays. It is planned for launch in March 2006. The scientific applications include determining the structure of high-energy astrophysical processes such as those found in active galactic nuclei, black holes, and supernovae. Several other natural phenomena in the universe will be investigated. One of the most exciting aspects of the GLAST mission is its potential for new discovery. There are two instruments on the GLAST Observatory: the Large Area Telescope (LAT), a joint development of NASA and DOE, and the GLAST Burst Monitor (GBM). Both instruments have international collaborators. The spacecraft will be a modified version of an existing design. The ground system elements and data flow are also described. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lambros, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 722 EP 728 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400128 ER PT S AU Barthelmy, S AF Barthelmy, S BE Ritz, S Gehrels, N Shrader, CR TI Swift: A gamma ray burst MIDEX SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL ID 28 FEBRUARY 1997; HIGH-REDSHIFT; AFTERGLOW; GALAXIES AB Swift is a first of its kind multiwavelength transient observatory for gamma-ray burst astronomy. It has the optimum capabilities for the next breakthroughs in determining the origin of gamma-ray bursts and their afterglows as well as using bursts to probe the early Universe. Swift will also perform the first sensitive hard X-ray survey of the sky. The mission is being developed by an international collaboration and consists of three instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT). The BAT, a wide-field gamma-ray detector, will detect similar to1 gamma-ray burst per day with a sensitivity 5 times that of BATSE. The sensitive narrow-field XRT and UVOT will be autonomously slewed to the burst location in 20 to 70 seconds to determine 0.3-5.0 arcsec positions and perform optical, UV, and X-ray spectrophotometry. On-board measurements of redshift will also be done for hundreds of bursts. Swift will incorporate superb, low-cost instruments using existing flight-spare hardware and designs. Strong education/public outreach and follow-up programs will help to engage the public and astronomical community. Swift has been selected by NASA for development and launch in late 2003. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barthelmy, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012 NR 29 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 781 EP 790 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400138 ER PT S AU Hunter, SD Bertsch, DL Deines-Jones, P AF Hunter, SD Bertsch, DL Deines-Jones, P BE Ritz, S Gehrels, N Shrader, CR TI Design of a Next Generation High-Energy Gamma-ray telescope SO GAMMA 2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Gamma-Ray Astrophysics 2001 Symposium CY APR 04-06, 2001 CL BALTIMORE, MD SP NASA, US DOE, Italian Space Agcy, TRW, Spectrum Astro, Lockheed Martin, SW Res, Orbital Sci, USRA, GLAST, Compton Gamma Ray Observ, Swift, INTEGRAL AB The Next Generation High-Energy Gamma-ray (NGHEG) mission is a recommended priority for a new mission after GLAST. One of the science goals of the NGHEG mission, mapping our Galaxy, clouds, supernova remnants, and nearby galaxies for cosmic ray sources at arcminute resolution, places stringent requirements on the design of the track imager. We examine the design requirements of a track imager for a gamma-ray telescope capable of arcminute imaging. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hunter, SD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012 NR 6 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0027-X J9 AIP CONF PROC PY 2001 VL 587 BP 848 EP 852 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT56P UT WOS:000173389400149 ER PT B AU Norris, JP Scargle, JD Bonnell, JT AF Norris, JP Scargle, JD Bonnell, JT BE Costa, E Frontera, F Hjorth, J TI Short gamma-ray bursts are different SO GAMMA-RAY BURSTS IN THE AFTERGLOW ERA SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT 2nd Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 17-20, 2000 CL CNR, ROME, ITALY SP ESO, Alenia Aerosp, Laben & Nuova Telespazio HO CNR AB We analyze BATSE time-tagged event (TTE) data for short gamma-ray bursts (T-90 duration < 2.6 s), studying spectral lag vs. peak flux and duration, as well as the number of distinct pulse structures per burst. Performing the cross-correlation between two energy bands, we measure an average lag similar to 20-40 x shorter than for long bursts, and a lag distribution close to symmetric about zero - unlike long bursts. Using a "Bayesian Block" method to identify significantly distinct pulse peaks, we find an order of magnitude fewer pulses than found in studies of long bursts. The disparity in lag magnitude is discontinuous across the similar to 2-s valley between long and short bursts. Thus, short bursts do not appear to be representable as a continuation of long bursts' temporal characteristics. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Norris, JP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 15 TC 31 Z9 31 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42771-6 J9 ESO ASTROPHY SYMP PY 2001 BP 40 EP 42 DI 10.1007/10853853_9 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT78E UT WOS:000174050300009 ER PT B AU Gehrels, N AF Gehrels, N BE Costa, E Frontera, F Hjorth, J TI The Swift panchromatic GRB mission SO GAMMA-RAY BURSTS IN THE AFTERGLOW ERA SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT 2nd Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 17-20, 2000 CL CNR, ROME, ITALY SP ESO, Alenia Aerosp, Laben & Nuova Telespazio HO CNR ID GAMMA-RAY BURST; 28 FEBRUARY 1997; AFTERGLOW C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 661, Greenbelt, MD 20771 USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42771-6 J9 ESO ASTROPHY SYMP PY 2001 BP 357 EP 359 DI 10.1007/10853853_96 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT78E UT WOS:000174050300096 ER PT B AU Cline, TL Hurley, KC Barthelmy, S Butterworth, P Feroci, M Frontera, F Golenetskii, S Mazets, E Trombka, J AF Cline, TL Hurley, KC Barthelmy, S Butterworth, P Feroci, M Frontera, F Golenetskii, S Mazets, E Trombka, J BE Costa, E Frontera, F Hjorth, J TI The IPNI: From the past to the future SO GAMMA-RAY BURSTS IN THE AFTERGLOW ERA SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT 2nd Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 17-20, 2000 CL CNR, ROME, ITALY SP ESO, Alenia Aerosp, Laben & Nuova Telespazio HO CNR AB Interplanetary spacecraft have been used with orbiting satellites for over 25 years to precisely localize gamma ray transients by the measurement of their time-delay geometry. The first interplanetary network (IPN) made both discoveries and controversies, and the latest is making possible a significant number of GRB counterpart observations. The IPN technique was pursued with dedicated payloads, with piggy-back experiments, and by the creative modifications of other experiments. The achievement of the NEAR in-flight software revision added a distant vertex to the array of Ulysses and the near-Earth group of GGS-Wind Konus, Beppo-Sax and Rossi-XTE. This 3-way long-baseline network culminated IPN history by, in the year 2000 alone, enabling over one-third of the afterglow searches and 5 redshift measurements. Future IPN possibilities are also outlined. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cline, TL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012; Golenetskii, Sergey/B-3818-2015 NR 0 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42771-6 J9 ESO ASTROPHY SYMP PY 2001 BP 375 EP 377 DI 10.1007/10853853_102 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT78E UT WOS:000174050300102 ER PT B AU Smette, A Heap, SR Williger, GM Tripp, TM Jenkins, EB Songaila, A AF Smette, A Heap, SR Williger, GM Tripp, TM Jenkins, EB Songaila, A BE Hibbard, JE Rupen, MP VanGorkom, JH TI HST/STIS observations of the HeII Gunn-Peterson effect SO GAS AND GALAXY EVOLUTION: A CONFERENCE IN HONOR OF THE 20TH ANNIVERSARY OF THE VLA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Gas and Galaxy Evolution in Honor of the 20th Anniversary of the VLA CY MAY 21-24, 2000 CL SOCORRO, NM SP Natl Radio Astron Observ, New Mexico Tech ID LY-ALPHA FOREST; HELIUM ABSORPTION AB We present HST/STIS observations of the HeII GunnPeterson effect at z similar to 3 towards Q 0302-003 and HE 2347-4342. The observed opacities axe significantly larger than the ones predicted by any existing model aimed at reproducing the characteristics of the intergalactic medium. The ratio of Hell to Hi column densities required to reproduce those opacities indicates that the UV background radiation is softer than the usually assumed Haardt & Madau spectrum, which may be explained by a significant stellar contribution at the HI Lyman limit. C1 NASA, Goddard Space Flight Ctr, LASP, Greenbelt, MD 20771 USA. RP Smette, A (reprint author), NASA, Goddard Space Flight Ctr, LASP, Code 681, Greenbelt, MD 20771 USA. RI heap, sara/E-2237-2012 NR 11 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-077-3 J9 ASTR SOC P PY 2001 VL 240 BP 17 EP 20 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU31U UT WOS:000175678800004 ER PT B AU Neff, SG Ulvestad, JS AF Neff, SG Ulvestad, JS BE Hibbard, JE Rupen, MP VanGorkom, JH TI Recent massive star formation in NGC 4038/4039, "the antennae" SO GAS AND GALAXY EVOLUTION: A CONFERENCE IN HONOR OF THE 20TH ANNIVERSARY OF THE VLA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Gas and Galaxy Evolution in Honor of the 20th Anniversary of the VLA CY MAY 21-24, 2000 CL SOCORRO, NM SP Natl Radio Astron Observ, New Mexico Tech ID NGC-4038/4039 AB High-resolution VLA observations are used to identify and to characterize regions of recent massive star formation in the nearest disk-disk merger, "the Antennae". C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Neff, SG (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-077-3 J9 ASTR SOC P PY 2001 VL 240 BP 212 EP 213 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU31U UT WOS:000175678800042 ER PT J AU Begemann, F Ludwig, KR Lugmair, GW Min, K Nyquist, LE Patchett, PJ Renne, PR Shih, CY Villa, IM Walker, RJ AF Begemann, F Ludwig, KR Lugmair, GW Min, K Nyquist, LE Patchett, PJ Renne, PR Shih, CY Villa, IM Walker, RJ TI Call for an improved set of decay constants for geochronological use SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID HALF-LIFE; IRON-METEORITES; SOLAR-SYSTEM; LU-176; AGE; PB; GEOCHEMISTRY; CHONDRITES; CHRONOLOGY; EVOLUTION AB The accuracy of radioisotopic ages is, at present, limited by the accuracy of radioactive decay constants. A literature survey reveals that decay constants used in geo- and cosmochronology usually are assigned uncertainties of ca. 1% but that then are very much larger unaccounted discrepancies between decay constants reported by different "counting groups" as well as differences between results derived from counting experiments and from the comparison of ages obtained on the same samples by utilizing different radioactive clocks. An extension and partial revision of the decay constants recommended in 1976 for adoption in geo- and cosmochronology by the International Union of Geological Sciences (IUGS) appears both desirable and feasible, given the analytical improvements of the last 20 years. We call for a concerted effort to achieve improvements in the near future. For this it will be necessary to rigorously evaluate counting biases in counting determinations, initial daughter contamination for ingrowth experiments, and the existence of truly "point-like" geological events for age comparison approaches. Copyright (C) 2001 Elsevier Science Ltd. C1 Max Planck Inst Chem, Abt Kosmochem, D-55128 Mainz, Germany. Berkeley Geochronol Ctr, Berkeley, CA 94709 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Arizona, Dept Geosci, Tucson, AZ 85721 USA. Lockheed Martin Engnn & Sci Co, Houston, TX 77258 USA. Univ Bern, CH-3012 Bern, Switzerland. Univ Maryland, Dept Geol, Isotope Geochem Lab, College Pk, MD 20742 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. RP Max Planck Inst Chem, Abt Kosmochem, Becherweg 27, D-55128 Mainz, Germany. EM Begemann@mpch-mainz.mpg.de RI Min, Kyoungwon/A-8421-2011; Walker, Richard/K-6869-2016 OI Min, Kyoungwon/0000-0001-6404-4115; Walker, Richard/0000-0003-0348-2407 NR 90 TC 227 Z9 231 U1 0 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JAN PY 2001 VL 65 IS 1 BP 111 EP 121 DI 10.1016/S0016-7037(00)00512-3 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 391NN UT WOS:000166362200009 ER PT J AU Jones, TD AF Jones, TD TI A globe that fills the sky: Geography from the space shuttle SO GEOGRAPHICAL REVIEW LA English DT Article AB Main engine cutoff! Eight and a half minutes of rocket-borne acceleration were suddenly over. The tremendous jolt of leaving the launch pad... the clang of empty booster rockers shearing away at Mach 3... the steady build of g-forces to a chest-squeezing three times the force of gravity. And now... silence. We were in orbit at Mach 25, hurtling around the platter at a speed of 8 kill every second, and the engines were, at last, quiet. I unzipped a glove and let it slowly twirl in front of my helmet faceplate. We were in free fall. Unstrapping from my downstairs seat, I grabbed a camera and floated awkwardly toward the flight deck to photograph our departing fuel tank. Oil the way, Endeavour's hatch window beckoned-the temptation to take a peek was too much for me. My reflection greeted me in the dark glass as I searched for my first glimpse of Earth from space. Peering through the looking glass, I wondered what I would see-after nearly four years of training, and a lifetime of dreams, what would geography really look like? No textbook could have prepared me for my personal discovery of the planet's face. A dark silhouette cut through the night sky, blotting out the stars. Its edge was rimmed with a delicate, robin's-egg blue, marking the literal end of the world and the beginning of my reeducation in geography. It would be a lesson I'd never forget. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77059 USA. RP Jones, TD (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77059 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOGRAPHICAL SOC PI NEW YORK PA 120 WALL ST, STE 100, NEW YORK, NY 10005 USA SN 0016-7428 J9 GEOGR REV JI Geogr. Rev. PD JAN-APR PY 2001 VL 91 IS 1-2 BP 252 EP 261 DI 10.2307/3250826 PG 10 WC Geography SC Geography GA 498UG UT WOS:000172528400030 ER PT J AU Ernstson, K Rampino, MR Hiltl, M AF Ernstson, K Rampino, MR Hiltl, M TI Cratered cobbles in Triassic Buntsandstein conglomerates in northeastern Spain: An indicator of shock deformation in the vicinity of large impacts SO GEOLOGY LA English DT Article DE impact; shock; conglomerates; spallation; Triassic; Azuara impact structure ID METAMORPHISM; QUARTZ AB Quartzite cobbles in Lower Triassic Buntsandstein conglomerates from northeastern Spain display unusual millimeter- to centimeter-sized circular craters, commonly having central mounds and surrounded by radial fractures. The conglomerates are also marked by intense fracturing down to microscopic scale. These features have traditionally been attributed to tectonic compression and pressure dissolution at cobble contacts. Sections through the cratered cobbles reveal pervasive internal fracturing, segments detached along concave spall fractures, and zones marked by quartz grains with planar deformation features. Comparison with results of impact experiments on artificial conglomerates suggests that these features were produced by internal accelerations, grain collisions, and spallation related to shock-wave propagation through inhomogeneous deposits. The proximity of the outcrops to the Azuara and proposed Rubielos de la Cerida impact structures suggests that shock deformation of conglomerates can provide an easily recognizable regional impact signature. C1 Univ Wurzburg, Fak Geowissensch, D-97070 Wurzburg, Germany. NYU, Earth & Environm Sci Program, New York, NY 10003 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Calif Lawrence Livermore Natl Lab, H Div, Phys Directorate, Livermore, CA 94551 USA. RP Ernstson, K (reprint author), Univ Wurzburg, Fak Geowissensch, D-97070 Wurzburg, Germany. NR 19 TC 11 Z9 12 U1 0 U2 0 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD JAN PY 2001 VL 29 IS 1 BP 11 EP 14 DI 10.1130/0091-7613(2001)029<0011:CCITBC>2.0.CO;2 PG 4 WC Geology SC Geology GA 392ZA UT WOS:000166441700003 ER PT J AU Ray, RD Eanes, RJ Egbert, GD Pavlis, NK AF Ray, RD Eanes, RJ Egbert, GD Pavlis, NK TI Error spectrum for the global M-2 ocean tide SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TOPEX/POSEIDON ALTIMETRY; MODELS AB The most accurate determinations of the global ocean tides are currently based on altimeter measurements made by the Topex/Poseidon satellite. The error spectrum corresponding to the Mt tidal solution is here estimated, primarily by inverse methods and secondarily by simple differencing of several of the best tidal models. The tidal error spectrum is flatter than the tidal signal spectrum, and it exceeds 10% of the signal at spherical harmonic degree 15 and above. The tide errors also exceed the anticipated sensitivity of the upcoming GRACE satellite gravity mission for all degrees below 40, and possibly below 50. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Univ Texas, CSR, Austin, TX 78759 USA. Oregon State Univ, COAS, Corvallis, OR 97331 USA. Raytheon ITSS, Greenbelt, MD 20770 USA. RP Ray, RD (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Code 926, Greenbelt, MD 20771 USA. RI Ray, Richard/D-1034-2012; OI Egbert, Gary/0000-0003-1276-8538 NR 15 TC 19 Z9 20 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2001 VL 28 IS 1 BP 21 EP 24 DI 10.1029/2000GL011674 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 390JD UT WOS:000166291200007 ER PT J AU Gao, Y Kaufman, YJ Tanre, D Kolber, D Falkowski, PG AF Gao, Y Kaufman, YJ Tanre, D Kolber, D Falkowski, PG TI Seasonal distributions of aeolian iron fluxes to the global ocean SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EQUATORIAL PACIFIC-OCEAN; ATMOSPHERIC TRANSPORT; NORTH PACIFIC; SEA-SALT; AEROSOL; DUST; DEPOSITION; CLIMATE; EVENTS; CO2 AB Among the factors affecting the photosynthetic rate of marine phytoplankton, aeolian iron (Fe) fluxes appear to be critical in several large regions of the global ocean. Here we present an analysis of in situ aerosol iron data obtained from a wide variety of marine locations to quantify the seasonal Fe inputs to the global ocean. When extrapolated to the global ocean, our results indicate strong seasonal variations in aeolian Fe fluxes in different oceanic basins. The predominant fraction of the Fe inputs enters the oceans in the Northern Hemisphere, with the summer flux rates ca. twice those of winter. The high Fe fluxes in the Northern Hemisphere are concentrated in low and mid-latitudes. With the promising new data from MODIS aboard the Terra satellite, the linkage between Fe fluxes and phytoplankton biomass and productivity may be soon further quantified. C1 Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Lille 1, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Gao, Y (reprint author), Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA. NR 25 TC 119 Z9 124 U1 1 U2 20 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2001 VL 28 IS 1 BP 29 EP 32 DI 10.1029/2000GL011926 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 390JD UT WOS:000166291200009 ER PT J AU Li, J Agee, CB AF Li, J Agee, CB TI Element partitioning constraints on the light element composition of the Earth's core SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HIGH-PRESSURE; MOLTEN IRON; SILICATE; TEMPERATURE; DIFFERENTIATION; COEFFICIENTS; SOLUBILITY; METEORITE; OXYGEN; MELTS AB Partitioning of sulfur (S), oxygen (O) and silicon (Si) between liquid Fe-Ni-alloy (LA) and liquid silicate (LS) was studied with a multi-anvil apparatus at pressures between 2 and 25 GPa and temperatures between 2073 and 2623 K. We found that S has a strong affinity for liquid Fe-Ni-alloy at all the experimental conditions investigated. Partition coefficient of S between liquid Fe-Ni-alloy and liquid silicate( D-S(LMS)) increases with pressure and decreases with temperature. At the proposed pressure and temperature of core-mantle equilibrium during early Earth differentiation [Li and Agee, 1996; Righter et al., 1997], S is highly siderophile ( D-S(LMS) similar to 1000), while Si and O are highly lithophile (D-Si(LMS), D-o(LMS) < 0.03). Our study suggests that if the core composition was largely established by equilibrium partitioning in a deep magma ocean, then S is the most plausible principle light element in the core. C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Li, J (reprint author), Carnegie Inst Washington, Geophys Lab, 5251 Broad Branch Rd NW, Washington, DC 20015 USA. NR 21 TC 32 Z9 33 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2001 VL 28 IS 1 BP 81 EP 84 DI 10.1029/2000GL012114 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 390JD UT WOS:000166291200022 ER PT J AU Buti, B Goldstein, BE Liewer, PC AF Buti, B Goldstein, BE Liewer, PC TI Ion holes in the slow solar wind: Hybrid simulations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NONLINEAR ALFVEN WAVES; INHOMOGENEOUS PLASMAS; EVOLUTION; SYSTEMS; ULYSSES AB The spatio-temporal evolution of large-amplitude Alfvenic wave packets is investigated using a one-dimensional hybrid model. For conditions prevailing in the slow solar wind plasma, namely beta similar to 1 ( beta being the ratio of kinetic pressure to magnetic pressure) and electron temperature T-e greater than proton temperature T-i, we observe two branches of ion density holes. One is propagating forward and the other backward in the inertial frame of reference. Kinetic effects as well as strong coupling between density and magnetic field fluctuations are responsible for generating these holes. For the first time, we show the possibility of an Alfvenic wave packet decay into a new and unanticipated nonlinear wave mode that does not exist in the current literature, hs T(= Ti/Te) increases, the ion holes disappear because of Landau damping. In the slaw solar wind the scale sizes of these ion density cavities are less than or equal to 2sec. We predict the occurence of such cavites in the slow solar wind; these would be observable when high time resolution plasma data become available. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Buti, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2001 VL 28 IS 1 BP 91 EP 94 DI 10.1029/2000GL000109 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 390JD UT WOS:000166291200025 ER PT J AU Haeffelin, M Wielicki, B Duvel, JP Priestley, K Viollier, M AF Haeffelin, M Wielicki, B Duvel, JP Priestley, K Viollier, M TI Inter-calibration of CERES and ScaRaB Earth radiation budget datasets using temporally and spatially collocated radiance measurements SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ENERGY SYSTEM CERES; CLOUDS AB Comparisons of radiance measurements from overlapping independent Earth and cloud radiation budget (ERB) missions are an important contribution to the validation process of these missions and are essential to the construction of a consistent long-term record of ERB observations. Measurements from two scanning radiometers of different design and calibration, the Clouds and the Earth's Radiant Energy System (CERES) and the Scanner for Radiation Budget (ScaRaB), are compared during simultaneous operation in January and March 1999. The instruments are found to be consistent to within 0.5% and 1.5% in the longwave and shortwave spectral domains, respectively. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Ecole Normale Super, Meteorol Dynam Lab, F-75231 Paris 05, France. Ecole Polytech, Meteorol Dynam Lab, F-91128 Palaiseau, France. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. RP Haeffelin, M (reprint author), NASA, Langley Res Ctr, 100 NASA Rd,MS 420, Hampton, VA 23681 USA. NR 8 TC 26 Z9 27 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2001 VL 28 IS 1 BP 167 EP 170 DI 10.1029/2000GL012233 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 390JD UT WOS:000166291200044 ER PT S AU Mukai, R Arabshahi, P Yan, TY AF Mukai, R Arabshahi, P Yan, TY GP IEEE IEEE TI An adaptive threshold detector and channel parameter estimator for deep space optical communications SO GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 01) CY NOV 25-29, 2001 CL SAN ANTONIO, TX SP IEEE, Fujitsu Network Commun, SBC Commun Inc, Siemens, CIENA Corp, Corning Cable Syst, Nortel Networks, Tellabs AB A method for optimal adaptive setting of pulse-position-modulation pulse detection thresholds, which minimizes the total probability of error for the dynamically fading optical free space channel, is presented. The threshold's adaptive setting, in response to varying channel conditions, results in orders of magnitude improvement in probability of error, as compared to use of a fixed threshold. The adaptive threshold system itself is based on a robust channel identification system that uses average signal strengths to estimate the degree of fade and total attenuation in the channel, and a radial basis function network for estimating pulse spreads, all with excellent accuracy. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mukai, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-343, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1930-529X BN 0-7803-7206-9 J9 GLOB TELECOMM CONF PY 2001 BP 50 EP 54 DI 10.1109/GLOCOM.2001.965078 PG 5 WC Optics; Telecommunications SC Optics; Telecommunications GA BV36Z UT WOS:000178714800010 ER PT S AU Gray, AA Hoy, SD Ghuman, P AF Gray, AA Hoy, SD Ghuman, P GP IEEE IEEE TI Parallel VLSI equalizer architectures for multi-Gbps satellite communications SO GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 01) CY NOV 25-29, 2001 CL SAN ANTONIO, TX SP IEEE, Fujitsu Network Commun, SBC Commun Inc, Siemens, CIENA Corp, Corning Cable Syst, Nortel Networks, Tellabs AB This paper provides an overview of a new very large scale integration (VLSI) architecture for implementing a frequency domain least-mean squares (LMS) complex equalizer [1,2]. The architecture incorporates a simple subconvolution method, digital vector processing, specialized FFT-IFFT hardware architectures, and the discrete Fourier transform-inverse discrete Fourier transform (DFT-IDFT) overlap and save filter method [3]. A key property of the new architecture is that the equalizer tap length may be chosen completely independently of the FFT-IFFT lengths and input data block lengths. Theoretically unlimited tap lengths are possible with short FFT-IFFT pairs. It will be demonstrated that the new parallel architecture is very well suited for processing multi-Gbps digital communication data rates with relatively low speed CMOS hardware. The VLSI equalizer architecture presented processes complex demodulated symbols at 1/4(th) the symbol rate. The parallel equalizer, operating on one sample per symbol, has 32 coefficients, is decision directed, and will process data modulated with quadrature phase-shift keying (QPSK) and 16 quadrature amplitude modulation (QAM). The equalizer will be integrated into the 2.4 Gbps all-digital wireless parallel demodulator application specific integrated circuit (ASIC). The receiver is currently being development by JPL/CalTech and NASA's Goddard Space Flight Center. This parallel all-digital receiver designed for satellite communications operates at 1/16(th) the analog-to-digital sample rate. Finally, a complexity comparison between this equalizer architecture and the traditional frequency domain fast LMS equalizer is given. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gray, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1930-529X BN 0-7803-7206-9 J9 GLOB TELECOMM CONF PY 2001 BP 315 EP 319 DI 10.1109/GLOCOM.2001.965130 PG 5 WC Optics; Telecommunications SC Optics; Telecommunications GA BV36Z UT WOS:000178714800062 ER PT S AU Quirk, KJ AF Quirk, KJ GP IEEE IEEE TI An energy efficient CDMA scheme for in-situ communications on Mars SO GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 01) CY NOV 25-29, 2001 CL SAN ANTONIO, TX SP IEEE, Fujitsu Network Commun, SBC Commun Inc, Siemens, CIENA Corp, Corning Cable Syst, Nortel Networks, Tellabs AB To extend the battery life of a Martian surface unit it is desired to minimize the energy consumed by the surface to orbit communications transceiver. The performance of three different transmission schemes are evaluated in terms of the energy-per-bit required by the transmit power amplifier to achieve a desired energy-per-bit at the receiver. A fixed-power variable-rate transmission scheme is shown to provide the largest savings in energy. Using this as the basis for selecting a multiple access system, a code division multiple access system is presented and its performance is analyzed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quirk, KJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1930-529X BN 0-7803-7206-9 J9 GLOB TELECOMM CONF PY 2001 BP 856 EP 860 PG 5 WC Optics; Telecommunications SC Optics; Telecommunications GA BV36Z UT WOS:000178714800169 ER PT S AU Quirk, KJ Srinivasan, M Agre, JR AF Quirk, KJ Srinivasan, M Agre, JR GP IEEE IEEE TI Cooperative modulation techniques for long haul relay in sensor networks SO GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 01) CY NOV 25-29, 2001 CL SAN ANTONIO, TX SP IEEE, Fujitsu Network Commun, SBC Commun Inc, Siemens, CIENA Corp, Corning Cable Syst, Nortel Networks, Tellabs AB Cooperative modulation techniques can reduce the energy requirements for the long haul transmission of data from localized sensor networks. This savings is vital in extending the battery life of power limited sensor nodes communicating over a time-limited channel. Several transmission methods, including a novel scheme that conveys information via node selection, are analyzed. The energy cost in local communications needed to support the cooperative long haul link is determined and used to make comparisons between the techniques. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quirk, KJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1930-529X BN 0-7803-7206-9 J9 GLOB TELECOMM CONF PY 2001 BP 1171 EP 1175 PG 5 WC Optics; Telecommunications SC Optics; Telecommunications GA BV36Z UT WOS:000178714800232 ER PT S AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS GP IEEE IEEE TI Performance analysis of generalized selection combining with threshold test per branch (T-GSC) SO GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 01) CY NOV 25-29, 2001 CL SAN ANTONIO, TX SP IEEE, Fujitsu Network Commun, SBC Commun Inc, Siemens, CIENA Corp, Corning Cable Syst, Nortel Networks, Tellabs ID DENSE MULTIPATH CHANNELS; SPREADING BANDWIDTH; RAKE RECEPTION AB We analyze the average bit error rate and outage probability performance of two types of conditional diversity combining schemes in which each branch signal-to-noise ratio is tested against a fixed predetermined threshold and applied to the combiner only if its value exceeds this threshold. The two schemes, respectively referred to as absolute threshold generalized selection combining and normalized threshold generalized selection combining differ from one another only in the manner in which the threshold is chosen. Nevertheless, when operating over a generalized fading channel, the two schemes have a markedly different behavior as reflected in the numerical results presented in the paper. The analytical method taken to obtain these results follows the moment generating function approach used previously by the authors for analyzing the performance of more conventional diversity combining schemes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM marvin.k.simon@jpl.nasa.gov; alouini@ece.umn.edu NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1930-529X BN 0-7803-7206-9 J9 GLOB TELECOMM CONF PY 2001 BP 1176 EP 1181 PG 6 WC Optics; Telecommunications SC Optics; Telecommunications GA BV36Z UT WOS:000178714800233 ER PT S AU Jennings, E Motyckova, L Carr, D AF Jennings, E Motyckova, L Carr, D GP IEEE IEEE TI Evaluating graph theoretic clustering algorithms for reliable multicasting SO GLOBECOM '01: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-6 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 01) CY NOV 25-29, 2001 CL SAN ANTONIO, TX SP IEEE, Fujitsu Network Commun, SBC Commun Inc, Siemens, CIENA Corp, Corning Cable Syst, Nortel Networks, Tellabs AB In reliable multicast protocols, each data packet being sent must be acknowledged. Collecting the acknowledgments centrally at the sources can cause ACK-implosion and can result in poor scalability. To overcome this, clustering algorithms which use virtual structures to gather acknowledgments were proposed. In this work, we analyze the complexities of three such clustering algorithms: Lorax, k-degree, and Self-adjust. We compare the quality of the virtual structures produced by these algorithms, focusing on the number of clusters, cluster size, cluster radius, and the optimal positioning of cluster leaders. Our simulation showed that the virtual structure produced by Self-adjust is better in terms of cluster radius and the location of cluster leaders. However, due to the self-adjusting nature of the algorithm, it might take longer time to compute than the other two algorithms. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1930-529X BN 0-7803-7206-9 J9 GLOB TELECOMM CONF PY 2001 BP 1688 EP 1692 PG 5 WC Optics; Telecommunications SC Optics; Telecommunications GA BV36Z UT WOS:000178714800331 ER PT B AU Jones, DL AF Jones, DL BE Brainerd, TG Kochanek, CS TI The effect of two lensing galaxies on the time delay in PKS 1830-211 SO GRAVITATIONAL LENSING: RECENT PROGRESS AND FUTURE GOALS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Gravitational Lensing - Recent Progress and Future Goals CY JUL 25-30, 1999 CL BOSTON UNIV, BOSTON, MA SP Natl Sci Fdn, NASA HO BOSTON UNIV ID GRAVITATIONAL LENS; PKS-1830-211; PKS1830-211; REDSHIFT AB The Einstein ring gravitational lens PKS 1830-211 has the potential to provide an accurate global value of Hubble's constant since the time delay and both the lens and background source redshifts are known. This paper estimates the Hubble constant based on a single-lens model and on two cosmological models. It also illustrates how the presence of the second, lower redshift intervening galaxy reduces the observed time delay and derived Hubble constant values. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, Mail Code 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-074-9 J9 ASTR SOC P PY 2001 VL 237 BP 147 EP 148 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU31R UT WOS:000175678100047 ER PT B AU Gardner, JP AF Gardner, JP BE Brainerd, TG Kochanek, CS TI Counts and sizes of galaxies in the HDF-South SO GRAVITATIONAL LENSING: RECENT PROGRESS AND FUTURE GOALS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Gravitational Lensing - Recent Progress and Future Goals CY JUL 25-30, 1999 CL BOSTON UNIV, BOSTON, MA SP Natl Sci Fdn, NASA HO BOSTON UNIV AB The Hubble Deep Field data sets include the deepest observations ever made in the ultraviolet, optical and near infrared. It was determined from the HDF-N and other deep WFPC2 imaging that fainter galaxies are smaller. This trend continues to AB=29mag in the high resolution HDF-S STIS image, where galaxies have a typical half-light radius of 0.1 arcseconds. We have run extensive Monte Carlo simulations of the detection of galaxies in the HDF-S, and show that the small measured sizes are not due to selection effects until >29mag. We compare observed sizes in the optical and near-infrared using the HDF-S NICMOS image. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gardner, JP (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-074-9 J9 ASTR SOC P PY 2001 VL 237 BP 181 EP 182 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU31R UT WOS:000175678100056 ER PT B AU Joffre, M Fischer, P Frieman, J Johnston, D McKay, T Mohr, J Nichol, B Sheldon, E Cantaloupo, C Griffin, G Peterson, J Romer, K AF Joffre, M Fischer, P Frieman, J Johnston, D McKay, T Mohr, J Nichol, B Sheldon, E Cantaloupo, C Griffin, G Peterson, J Romer, K BE Brainerd, TG Kochanek, CS TI Weak lensing mass of nearby clusters of galaxies SO GRAVITATIONAL LENSING: RECENT PROGRESS AND FUTURE GOALS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Gravitational Lensing - Recent Progress and Future Goals CY JUL 25-30, 1999 CL BOSTON UNIV, BOSTON, MA SP Natl Sci Fdn, NASA HO BOSTON UNIV AB We describe first results of a project to create weak lensing mass maps for a complete, X-ray luminosity-limited sample of 19 nearby (z < 0.1) southern galaxy clusters scheduled for Sunyaev-Zel'dovich (SZ) observations by the Viper Telescope at the South Pole. We have collected data on 1/3 of the sample and present motivation for the project as well as projected mass maps of two clusters. C1 NASA, Fermilab Astrophys Ctr, Batavia, IL USA. RP Joffre, M (reprint author), NASA, Fermilab Astrophys Ctr, Batavia, IL USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-074-9 J9 ASTR SOC P PY 2001 VL 237 BP 317 EP 318 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU31R UT WOS:000175678100095 ER PT S AU Goldberg, RA Pfaff, RF Holzworth, RH Schmidlin, FJ Voss, HD Tuzzolino, AJ Croskey, CL Mitchell, JD Friedrich, M Murtaugh, D Witt, G Gumbel, J von Zahn, U Singer, W Hoppe, UP AF Goldberg, RA Pfaff, RF Holzworth, RH Schmidlin, FJ Voss, HD Tuzzolino, AJ Croskey, CL Mitchell, JD Friedrich, M Murtaugh, D Witt, G Gumbel, J von Zahn, U Singer, W Hoppe, UP BE Chakrabarty, DK Roscoe, HK Blix, TA TI The DROPPS program to study the polar summer mesosphere SO GREENHOUSE GASES, AEROSOLS AND DUST SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C2 2/C2 5 Symposium of COSPAR Scientific Commission C held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Int Univ Geodesy & Geophys, Int Assoc Gromagnet & Aeronom, Int Assoc Meterorol & Atmospher, World Climate Res Program, Comm Space Res ID NOCTILUCENT CLOUDS; CHARGED AEROSOLS; ROCKET RADAR; ECHOES; MESOPAUSE; DUST; INSTABILITY; ATMOSPHERE; OBJECTIVES; SCATTER AB DROPPS (The Distribution and Role of Particles in the Polar Summer Mesosphere) was a highly coordinated international study conducted in July 1999. It involved two sequences of rockets launched from the Norwegian rocket range in Andoya, Norway. These studies were designed to investigate the properties of the polar summer mesosphere, particularly relating to polar mesospheric summer echoes (PMSE) and their possible relationship to particles (aerosol and dust layers) and to noctilucent clouds (NLC). Each of the two sequences included a DROPPS NASA-Black Brant payload, consisting of an array of instruments to measure the electrodynamic and optical structure of the mesosphere and lower thermosphere. The instruments were provided by participants from several US and European laboratories. The DROPPS payloads were each accompanied by a sequence of several European payloads (MIDAS, Mini-MIDAS, and Mini-DUSTY) designed to study electrodynamic and neutral atmospheric structure of the same region, and by several meteorological rockets to provide wind and temperature data in the critical region of study. ALOMAR Lidars, and MF and MST Radars (all located adjacent to the Andoya launch site) were used to continuously monitor the mesosphere for NLCs and PMSEs, respectively. EISCAT VHF radar (Tromso, Norway) provided similar information about PMSEs at 130 kin NE from Andoya. Sequence 1 was launched during the night of 5-6 July into a strong PMSE display with a weak NLC at the base of the PMSE. Sequence 2 was launched on the early morning of 14 July into a strong NLC, but surprisingly with no PMSE evident. Here we describe the details of the program along with a few preliminary results. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Washington, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, WFF, Wallops Isl, VA 23337 USA. Taylor U, Upland, IN 46989 USA. Univ Chicago, Chicago, IL 60637 USA. Penn State Univ, University Pk, PA 16802 USA. Graz Tech Univ, A-8010 Graz, Austria. Univ Stockholm, S-10691 Stockholm, Sweden. Inst Atmos Phys, D-18225 Kuhlungsborn, Germany. FFI, N-2007 Kjeller, Norway. RP Goldberg, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 690, Greenbelt, MD 20771 USA. RI Goldberg, Richard /E-1881-2012; Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 28 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 7 BP 1037 EP 1046 DI 10.1016/S0273-1177(01)80034-X PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60L UT WOS:000173494800015 ER PT S AU Croskey, CL Mitchell, JD Friedrich, M Torkar, KM Goldberg, RA AF Croskey, CL Mitchell, JD Friedrich, M Torkar, KM Goldberg, RA BE Chakrabarty, DK Roscoe, HK Blix, TA TI Charged particle measurements in the polar summer mesosphere obtained by the DROPPS sounding rockets SO GREENHOUSE GASES, AEROSOLS AND DUST SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C2 2/C2 5 Symposium of COSPAR Scientific Commission C held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Int Univ Geodesy & Geophys, Int Assoc Gromagnet & Aeronom, Int Assoc Meterorol & Atmospher, World Climate Res Program, Comm Space Res ID NOCTILUCENT CLOUDS; RADAR ECHOES; MST RADAR AB Two Black Brant V sounding rocket payloads (DROPPS) were flown as part of the DROPPS/MIDAS program from the Andoya Rocket Range, Norway, during July 1999. One of these payloads was launched during the presence of PMSE, and the other flight occurred during NLC conditions. Both payloads were equipped to measure a number of different electrodynamic parameters of the mesosphere and lower thermosphere. A fixed-bias Langmuir probe observed small-scale structure in electron concentration. Significant electron depletions (more than an order of magnitude) were measured in a narrow altitude region during both flights. Layers of a thickness between 300 and 1400 meters were observed with very sharp transitions at the edges of the layers. These electron depletions do not appear to be artifacts produced by electrode collisions with large positive particulates. Absolute electron density concentrations were determined by a multiple-frequency radio wave propagation experiment. In addition, ion conductivities, mobilities, and number densities were determined by a Gerdien condenser. In this paper, we report on the instrumentation and the preliminary observations of the charged particle environment. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Penn State Univ, Elect Engn Dept, Commun & Space Sci Lab, University Pk, PA 16802 USA. Graz Tech Univ, Dept Commun & Wave Propagat, Graz, Austria. Austrian Acad Sci, Space Res Inst, A-1010 Vienna, Austria. NASA, GSFC, Lab Extraterrestrial Phys, Greenbelt, MD USA. RP Croskey, CL (reprint author), Penn State Univ, Elect Engn Dept, Commun & Space Sci Lab, University Pk, PA 16802 USA. RI Goldberg, Richard /E-1881-2012 NR 16 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 7 BP 1047 EP 1052 DI 10.1016/S0273-1177(01)80035-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60L UT WOS:000173494800016 ER PT S AU Yarrow, M McCann, KM Biswas, R Van der Wijngaart, RF AF Yarrow, M McCann, KM Biswas, R Van der Wijngaart, RF BE Buyya, R Baker, M TI An advanced user interface approach for complex parameter study process specification on the information power grid SO GRID COMPUTING - GRID 2000, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st IEEE/ACM International Workshop on Grid Computing CY DEC 17, 2000 CL BANGALORE, INDIA SP IEEE Comp Soc, Assoc Comp Mach, European Grid Forum, EuroTools SIG Metacomp, Microsoft Res USA, Sun Mirosyst, Ctr Dev Adv Comp, Gridware Inc AB The creation of parameter study suites has recently become a more challenging problem as the parameter studies have become multi-tiered and the computational environment has become a supercomputer grid. The parameter spaces are vast, the individual problem sizes are getting larger, and researchers are seeking to combine several successive stages of parameterization and computation. Simultaneously, grid-based computing offers immense resource opportunities but at the expense of great difficulty of use. We present lLab, an advanced graphical user interface approach to this problem. Our novel strategy stresses intuitive visual design tools for parameter study creation and complex process specification, and also offers programming-free access to grid-based supercomputer resources and process automation. C1 NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. RP Yarrow, M (reprint author), NASA, Ames Res Ctr, Comp Sci Corp, Mail Stop T27A-1, Moffett Field, CA 94035 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41403-7 J9 LECT NOTES COMPUT SC PY 2001 VL 1971 BP 146 EP 157 PG 12 WC Computer Science, Theory & Methods SC Computer Science GA BS71K UT WOS:000170924000014 ER PT S AU Konefat, EH Litty, EC Voigt, SK Wright, DS AF Konefat, EH Litty, EC Voigt, SK Wright, DS BE Culp, RD Schira, CN TI Enabling technology for NASA's Europa Orbiter mission SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB NASA's Europa Orbiter mission ranks as one of the highest priority science missions for planetary exploration with its prospects for finding liquid water. Europa also represents perhaps the most daunting natural space radiation environment for spacecraft equipment encountered so far in the pursuit of planetary science due to the time that must be spent in the inner Jovian system. In order to fulfill the mission science objectives, the combined requirements of enhanced radiation tolerance, high reliability, and long life in a cost-effective, low mass and low power package were flowed down to the attitude control subsystem sensor suite. The Hemispherical Resonator Gyro (HRG) technology, as implemented in Litton's new Scalable Space Inertial Reference Unit (SIRU (TM)) product line, is the unique inertial measurement unit (IMU) available to optimally meet these requirements and has been baselined for missions requiring long life and radiation tolerance, such as Europa Orbiter. The authors will describe the drivers for the subsystem requirements in the Europa Orbiter mission, in particular the mission criticality of the IMU and the predicted natural space radiation environments that require enabling technologies to be identified. Descriptions of the Europa IMU and the HRG technology are given with emphasis on the inherent radiation hardness in the HRG principle of operation and sensor construction, as well as the steps taken to further harden the sensor electronics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Konefat, EH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 3 EP 24 PG 22 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900001 ER PT S AU Deutschmann, J Bar-Itzhack, I Harman, R AF Deutschmann, J Bar-Itzhack, I Harman, R BE Culp, RD Schira, CN TI A LEO satellite navigation algorithm based on GPS and magnetometer data SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Global Positioning System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of a GPS receiver as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system that takes advantage of the estimation qualities of both measurements. Ultimately, a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes. This work presents the development of a technique to eliminate numerical differentiation of the GPS phase measurements and also compares the use of one versus two GPS satellites. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Deutschmann, J (reprint author), NASA, Goddard Space Flight Ctr, Code 572, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 25 EP 37 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900002 ER PT S AU Lomas, J Mitchell, D Freestone, T Lee, C Lessman, C AF Lomas, J Mitchell, D Freestone, T Lee, C Lessman, C BE Culp, RD Schira, CN TI Testing the primary X-33 Navigation system SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The X-33 Reusable Launch Vehicle (R-LV) must meet the demanding requirements of landing autonomously on a narrow landing strip following a flight that reaches an attitude of up to 200,00 feet and a speed in excess of Mach 9 with significant in-flight energy bleed-off maneuvers. To execute this flight regimen a highly reliable avionics system has been designed that includes three LN-100G Inertial Navigation System / Global Positioning System (INS/GPS) units as the primary navigation system for the X-33. NASA's Marshall Space Flight Center (MSFC) tested an INS/GPS system in real-time simulations to determine the ability of this navigation suite to meet the inflight arid autonomous landing requirements of the X-33 RLV. A total of sixty-one open loop tests were performed to characterize the navigation accuracy of the LN-100G, Twenty-seven closed-loop tests were also performed to evaluate the performance of the X-33 Guidance, Navigation and Control (GN&C) algorithms with the real navigation hardware. These closed-loop tests were also designed to expose any integration or operational issues with the real-time X-33 vehicle simulation. Dynamic road tests of the INS/GPS were conducted by Litton to assess the performance of differential and nondifferential INS/GPS hybrid navigation solutions. The results of the simulations and road testing demonstrate that this novel solution is capable of meeting the demanding requirements of take-off, in-flight navigation, and autonomous landing of the X-33 RLV, This paper describes the test environment developed to stimulate the LN-100G and discusses the results of this test effort. This paper also presents recommendations for a navigation system suitable to an operational RLV system. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Lomas, J (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 135 EP 150 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900009 ER PT S AU Desai, PN Lee, WJ AF Desai, PN Lee, WJ BE Culp, RD Schira, CN TI Mars Exploration Rover entry, descent, and landing system SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Mars Exploration Rover mission will send two landers to the surface of Mars, arriving in January and February 2004. Both landers will deliver the rovers to the surface using an entry, descent, and landing (EDL) scenario based on Mars Pathfinder heritage, However, the entry conditions and environments are different from that of Mars Pathfinder. Unique challenges are present due to the entry differences of a heavier entry mass, less dense atmosphere profile, and higher surface landing site altitude. These differences result in a higher terminal velocity and less time for performing all the EDL events as compared to Mars Pathfinder. As a result of these differences, modifications are required to the EDL systems to safely deliver the rovers to the surface of Mars. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Desai, PN (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 285 EP 293 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900017 ER PT S AU Lockwood, MK Powell, RW Graves, CA Carman, GL AF Lockwood, MK Powell, RW Graves, CA Carman, GL BE Culp, RD Schira, CN TI Entry system design considerations for Mars landers SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lockwood, MK (reprint author), NASA, Langley Res Ctr, 8 Langley Blvd,MS 365, Hampton, VA 23681 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 311 EP 345 PG 35 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900019 ER PT S AU Skulsky, ED Johnson, AE Umland, J Padgett, C Martin, B Weinstein, S Wallace, M Steltzner, A Thurman, S AF Skulsky, ED Johnson, AE Umland, J Padgett, C Martin, B Weinstein, S Wallace, M Steltzner, A Thurman, S BE Culp, RD Schira, CN TI Rocket sled testing of a prototype terrain-relative navigation system SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc ID MARS AB The next generation of Martian landers (2007 and beyond) will employ a precision soft-landing capability that will make it possible to explore previously inaccessible regions on the surface of Mars. This capability will be enabled by onboard systems that automatically identify and avoid terrain containing steep slopes or rocks exceeding a particular terrain height. JPL is currently developing such a hazard detection and avoidance system; this system will map the landing zone with a scanning laser radar, identify hazards, select a safe landing zone, and then guide the vehicle to the selected landing area. This paper describes how one component of this system-hazard detection-is being tested using a rocket sled and simulated Martian terrain. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Skulsky, ED (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 198-219, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 365 EP 379 PG 15 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900021 ER PT S AU Hoge, S Vaughn, FJ AF Hoge, S Vaughn, FJ BE Culp, RD Schira, CN TI Trajectory design and control for the Compton Gamma Ray Observatory re-entry SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Compton Gamma Ray Observatory (CGRO) controlled re-entry operation was successfully conducted in June of 2000. The surviving parts of the spacecraft landed in the Pacific Ocean within the nominal impact target zone. The design of the maneuvers to control the trajectory to accomplish this re-entry presented several challenges. These challenges included the timing and duration of the maneuvers, propellant management, post-maneuver state determination, collision avoidance with other spacecraft, accounting for the break-up of the spacecraft into several pieces with a wide range of ballistic coefficients, and ensuring that the impact footprint would remain within the desired impact target zone in the event of contingencies. This paper presents the initial re-entry trajectory design and traces the evolution of that design into the maneuver sequence used for the re-entry. The paper also discusses the spacecraft systems and operational constraints imposed on the trajectory design and the required modifications to the initial design based on those constraints. Data from the re-entry operation are also presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hoge, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 657 EP 668 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900039 ER PT S AU Sabelhaus, P Bolek, J Scott, S Holmes, E O' Donnell, JR Storey, J AF Sabelhaus, P Bolek, J Scott, S Holmes, E O' Donnell, JR Storey, J BE Culp, RD Schira, CN TI On-orbit ACDS performance of the Landsat 7 spacecraft SO GUIDANCE AND CONTROL 2001 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT Annual American-Astronautical-Society Rocky-Mountain Guidance and Control Conference CY JAN 31-FEB 04, 2001 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Landsat 7 spacecraft, launched from Vandenberg AFB on April 15, 1999, has been providing the Landsat user community with highly calibrated multispectral images of the earth since it started normal operations in August 1999. Over the past year data products from the Enhanced Thematic Mapper-Plus (ETM+), Landsat Ts earth imaging instrument, have been assessed which indicate the Attitude Control and Determination System (ACDS) performance exceeds mission requirements. This paper presents an overview of the Landsat 7 mission. The ACIDS system hardware, modes, and requirements are described. Significant events of the on-orbit initialization and validation period, which included ACDS sensor activation and calibration, a cross-calibration under-fly with Landsat 5, and orbit acquisition maneuvers, are presented. The paper concludes with a brief discussion of the role that the ACDS performance has on Landsat 7 image generation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sabelhaus, P (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-479-6 J9 ADV ASTRONAUT SCI PY 2001 VL 107 BP 685 EP 695 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BS56F UT WOS:000170334900041 ER PT S AU Parker, BH Stahle, CM Roth, D Babu, S Tueller, J AF Parker, BH Stahle, CM Roth, D Babu, S Tueller, J BE James, RB TI The effect of twin boundaries on the spectroscopic performance of CdZnTe detectors SO HARD X-RAY AND GAMMA-RAY DETECTOR PHYSICS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hard X-Ray and Gamma-Ray Detector Physics III CY JUL 30-AUG 01, 2001 CL SAN DIEGO, CA SP SPIE DE CdZnTe; high pressure Bridgman; twins; detectors AB Most single grains in cadmium zinc telluride (CdZnTe) grown by the high-pressure Bridgman (HPB) technique contain multiple twin boundaries. As a consequence, twin boundaries are one of the most common macroscopic material defects found in large area (400 to 700 mm(2)) CdZnTe specimens obtained from HPB ingots. Due to the prevalence of twin boundaries, understanding their effect on detector performance is key to the material selection process. Twin boundaries in several 2 mm thick large area specimens were first documented using infrared transmission imaging. These specimens were then fabricated into either 2 mm pixel or planar detectors in order to examine the effect of the twin boundaries on detector performance. Preliminary results show that twin boundaries, which are decorated with tellurium inclusions, produce a reduction in detector efficiency and a degradation in resolution. The extent of the degradation appears to be a function of the density of tellurium inclusions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Parker, BH (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Tueller, Jack/D-5334-2012 NR 8 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4221-6 J9 P SOC PHOTO-OPT INS PY 2001 VL 4507 BP 68 EP 78 AR UNSP 4507-11 DI 10.1117/12.450743 PG 11 WC Optics; Physics, Applied; Spectroscopy SC Optics; Physics; Spectroscopy GA BU16E UT WOS:000175177900008 ER PT S AU Gehrels, N AF Gehrels, N CA GLAST Sci Team BE Aharonian, FA Volk, HJ TI GeV gamma-ray astronomy in the era of GLAST SO HIGH ENERGY GAMMA-RAY ASTRONOMY SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Symposium on High Energy Gamma-Ray Astronomy CY JUN 26-30, 2000 CL HEIDELBERG UNIV, HEIDELBERG, GERMANY SP Max Planck Inst Kernphys, DFG, Int Union Pure & Appl Phys HO HEIDELBERG UNIV ID HIGH-ENERGY; SUPERNOVA-REMNANTS; EGRET SOURCES; RADIATION; PULSARS; DISCOVERY; GEMINGA AB The Gamma Ray Large Area Space Telescope (GLAST) is a high energy astronomy mission planned for launch in 2005. GLAST features two instruments; the Large Area Telescope (LAT) operating from 20 MeV - 300 GeV and the Gamma-ray Burst Monitor (GBM) operating from 10 keV - 25 MeV. GLAST observations will contribute to our understanding of active galactic nuclei and their jets, gamma-ray bursts, extragalactic and galactic diffuse emissions, dark matter, supernova remnants, pulsars, and the unidentified high energy gamma-ray sources. The LAT sensitivity is 4 x 10(-9) photons cm(-2) s(-1) (> 100 MeV) for a one year all-sky survey, which is a factor of > 20 better than CGRO/EGRET. GLAST spectral observations of gamma-ray bursts cover over 6 orders of magnitude in energy thanks to the context observations of the GEM. The upper end of the LAT energy range merges with the low energy end of ground-based observatories to provide a remarkable new perspective on particle acceleration in the Universe. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 32 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-990-4 J9 AIP CONF PROC PY 2001 VL 558 BP 3 EP 14 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS12B UT WOS:000168728000001 ER PT S AU Thompson, DJ AF Thompson, DJ BE Aharonian, FA Volk, HJ TI Gamma ray pulsars: Observations SO HIGH ENERGY GAMMA-RAY ASTRONOMY SE AIP Conference Proceedings LA English DT Proceedings Paper CT International Symposium on High Energy Gamma-Ray Astronomy CY JUN 26-30, 2000 CL HEIDELBERG UNIV, HEIDELBERG, GERMANY SP Max Planck Inst Kernphys, DFG, Int Union Pure & Appl Phys HO HEIDELBERG UNIV ID VELA PULSAR; X-RAY; EGRET OBSERVATIONS; PSR B1509-58; CRAB PULSAR; EMISSION; RADIATION; B1951+32; COMPTEL AB High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The six or more pulsars seen by CGRO/EGRET show that: the light curves usually have double-peak structures (suggesting a broad cone of emission); gamma rays are frequently the dominant component of the radiated power; and all the spectra show evidence of a high-energy turnover. Unless a new pulsed component appears at higher energies, progress in gamma-ray pulsar studies will be greatest in the 1-20 GeV range. Ground-based telescopes whose energy ranges extend downward toward 10 GeV should make important measurements of the spectral cutoffs. The Gamma-ray Large Area Space Telescope (GLAST), now in planning for a launch in 2005, will provide a major advance in sensitivity, energy range, and sky coverage. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Thompson, DJ (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 35 TC 62 Z9 63 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-990-4 J9 AIP CONF PROC PY 2001 VL 558 BP 103 EP 114 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS12B UT WOS:000168728000009 ER PT S AU Harding, AK AF Harding, AK BE Aharonian, FA Volk, HJ TI Gamma-ray pulsars: Models and predictions SO HIGH ENERGY GAMMA-RAY ASTRONOMY SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Symposium on High Energy Gamma-Ray Astronomy CY JUN 26-30, 2000 CL HEIDELBERG UNIV, HEIDELBERG, GERMANY SP Max Planck Inst Kernphys, DFG, Int Union Pure & Appl Phys HO HEIDELBERG UNIV ID RAPIDLY SPINNING PULSARS; POLAR-CAP; OUTER MAGNETOSPHERE; PAIR CREATION; EMISSION; GAPS; RADIATION; CASCADES; GEOMETRY AB Pulsed emission from If-ray pulsars originates inside the magnetosphere, from radiation by charged particles accelerated near the magnetic poles or in the outer gaps. In polar cap models, the high energy spectrum is cut off by magnetic pair production above an energy that is dependent on the local magnetic field strength. While most young pulsars with surface fields in the range B = 10(12) - 10(13) G are expected to have high energy cutoffs around several GeV, the gamma-ray spectra of old pulsars having lower surface fields may extend to 50 GeV. Although the gamma-ray emission of older pulsars is weaker, detecting pulsed emission at high energies from nearby sources would be an important confirmation of polar cap models. Outer gap models predict more gradual high-energy turnovers at around 10 GeV, but also predict an inverse Compton component extending to TeV energies. Detection of pulsed TeV emission, which would not survive attenuation at the polar caps, is thus an important test of outer gap models. Next-generation gamma-ray telescopes sensitive to GeV-TeV emission will provide critical tests of pulsar acceleration and emission mechanisms. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harding, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Harding, Alice/D-3160-2012 NR 37 TC 26 Z9 26 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-990-4 J9 AIP CONF PROC PY 2001 VL 558 BP 115 EP 126 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS12B UT WOS:000168728000010 ER PT S AU Hunter, SD AF Hunter, SD BE Aharonian, FA Volk, HJ TI Galactic diffuse gamma ray emission > 10 GeV SO HIGH ENERGY GAMMA-RAY ASTRONOMY SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Symposium on High Energy Gamma-Ray Astronomy CY JUN 26-30, 2000 CL HEIDELBERG UNIV, HEIDELBERG, GERMANY SP Max Planck Inst Kernphys, DFG, Int Union Pure & Appl Phys HO HEIDELBERG UNIV ID COSMIC-RAY; EGRET OBSERVATIONS; GALAXY; PLANE; SPECTRUM; MODEL AB AGILE and GLAST are the next high-energy gamma-ray telescopes to be flown in space. These instruments will have angular resolution about 5 times better than EGRET above 10 GeV and much larger field of view. The on-axis effective area of AGILE will be about half that of EGRET, whereas GLAST will have about 6 times greater effective area than EGRET. The capabilities of ground based very high-energy telescopes are also improving, e.g. Whipple, and new telescopes, e.g. STACEE, CELESTE, and MAGIC are expected to have low-energy thresholds and sensitivities that will overlap the GLAST sensitivity above similar to 10GeV. In anticipation of the results from these new telescopes. our current understanding of the galactic diffuse gamma-ray emission, including the matter and cosmic ray distributions is reviewed. The outstanding questions are discussed and the potential of future observations with these new instruments to resolve these questions is examined. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hunter, SD (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012 NR 26 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-990-4 J9 AIP CONF PROC PY 2001 VL 558 BP 171 EP 182 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS12B UT WOS:000168728000014 ER PT S AU Kazanas, D AF Kazanas, D BE Aharonian, FA Volk, HJ TI Neutrinos from AGN SO HIGH ENERGY GAMMA-RAY ASTRONOMY SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Symposium on High Energy Gamma-Ray Astronomy CY JUN 26-30, 2000 CL HEIDELBERG UNIV, HEIDELBERG, GERMANY SP Max Planck Inst Kernphys, DFG, Int Union Pure & Appl Phys HO HEIDELBERG UNIV ID ACTIVE GALACTIC NUCLEI; GAMMA-RAYS; RELATIVISTIC OUTFLOWS; ORIGIN; QUASARS AB The great penetrating power of neutrinos makes them ideal probe of astrophysical sites and conditions inaccessible to other forms of radiation. These are the centers of stars (collapsing or not) and the centers of Active Galactic Nuclei (AGN). It has been suggested that AGN presented a very promising source of high energy neutrinos, possibly detectable by underwater neutrino detectors. This paper reviews the evolution of ideas concerning the emission of neutrinos from AGN in view of the more recent developments in gamma-ray astronomy and their implications for the neutrino emission from these class of objects. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Kazanas, D (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-990-4 J9 AIP CONF PROC PY 2001 VL 558 BP 370 EP 380 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS12B UT WOS:000168728000030 ER PT S AU Boldt, E Loewenstein, M AF Boldt, E Loewenstein, M BE Aharonian, FA Volk, HJ TI Cosmic ray and TeV gamma ray generation by quasar remnants SO HIGH ENERGY GAMMA-RAY ASTRONOMY SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Symposium on High Energy Gamma-Ray Astronomy CY JUN 26-30, 2000 CL HEIDELBERG UNIV, HEIDELBERG, GERMANY SP Max Planck Inst Kernphys, DFG, Int Union Pure & Appl Phys HO HEIDELBERG UNIV AB Results from new broadband (radio to X-ray) high-resolution imaging studies of the dormant quasar remnant cores of nearby giant elliptical galaxies are now shown to permit the harboring of compact dynamos capable of generating the highest energy cosmic ray particles and associated curvature radiation of TeV photons. Confirmation would imply a global inflow of interstellar gas all the way to the accretion powered supermassive black hole at the center of the host galaxy. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Boldt, E (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-990-4 J9 AIP CONF PROC PY 2001 VL 558 BP 795 EP 797 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS12B UT WOS:000168728000103 ER PT S AU Pawson, S Takacs, L Molod, A Nebuda, S Chen, M Rood, R Read, WL Fiorino, M AF Pawson, S Takacs, L Molod, A Nebuda, S Chen, M Rood, R Read, WL Fiorino, M BE VanEyken, AP Lovhaug, UP Remedios, J TI The tropical upper troposphere and lower stratosphere in the GEOS-2 GCM SO HIGH LATITUDE STUDIES AND UPPER ATMOSPHERIC PROCESSES INCLUDING CLIMATE CHANGE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C1 3/A1 3 Symposium of COSPAR Scientific Commissions C and A held at the 32nd COSPAR Scientific Assembly CY JUL, 1998 CL NAGOYA, JAPAN SP Comm Space Res, Stratospher Process & Their Role Climate, World Climate Res Programme, European Space Agcy, Natl Aeronaut & Space Adm, Natl Oceanog & Atmospher Adm ID GENERAL-CIRCULATION MODELS; CLIMATOLOGY; REANALYSES AB The structure of the tropical upper troposphere and lower stratosphere in the GEOS-2 General Circulation Model (GCM) is discussed. The emphasis of this study is on the reality of monthly-mean temperature and water vapor distributions in the model, compared to reasonable observational estimates. It is shown that although the zonal-mean temperature is in good agreement with observations, the GCM supports an excessive zonal asymmetry near the tropopause compared to the ECMWF Reanalyses. In reality there is a QBO-related variability in the zonally averaged lower stratospheric temperature which is not captured by the model. The observed upper tropospheric temperature and humidity fields show variations related to those in the sea surface temperature, which are not incorporated in the GCM; nevertheless, there is some interannual variability in the GCM, indicating a component arising from internal processes. The model is too moist in the middle troposphere (500 hPa) but too dry in the upper troposphere, suggesting that there is too little vertical transport or too much drying in the GCM. Transport into the stratosphere shows a pronounced annual cycle, with drier air entering the tropical stratosphere when the tropopause is coldest in northern winter; while the alternating dry and moist air masses can be traced ascending through the tropical lower stratosphere, the progression of the anomalies is too rapid. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Univ Space Res Assoc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Gen Sci Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. RP Pawson, S (reprint author), NASA, Univ Space Res Assoc, Goddard Space Flight Ctr, Code 910-3, Greenbelt, MD 20771 USA. RI Fiorino, Michael/N-4150-2014; Rood, Richard/C-5611-2008; Pawson, Steven/I-1865-2014 OI Fiorino, Michael/0000-0002-2819-8157; Rood, Richard/0000-0002-2310-4262; Pawson, Steven/0000-0003-0200-717X NR 23 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 27 IS 8 BP 1457 EP 1465 DI 10.1016/S0273-1177(01)00214-9 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS99Y UT WOS:000171627800017 ER PT S AU Van der Wijngaart, RF AF Van der Wijngaart, RF BE Valero, M Prasanna, VK Vajapeyam, S TI Charon message-passing toolkit for scientific computations SO HIGH PERFORMANCE COMPUTING - HIPC 2000, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on High Performance Computing (HiPC 2000) CY DEC 17-20, 2000 CL BANGALORE, INDIA SP IEEE Comp Soc, ACM ID PERFORMANCE AB Charon is a library, callable from C and Fortran, that aids the conversion of structured-grid legacy codes-such as those used in the numerical computation of fluid flows-into parallel, high-performance codes. Key are functions that define distributed arrays, that map between distributed and non-distributed arrays, and that allow easy specification of common communications on structured grids. The library is based on the widely accepted MPI message passing standard. We present an overview of the functionality of Charon, and some representative results. C1 NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. RP Van der Wijngaart, RF (reprint author), NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41429-0 J9 LECT NOTES COMPUT SC PY 2001 VL 1970 BP 3 EP 14 PG 12 WC Computer Science, Theory & Methods SC Computer Science GA BS91B UT WOS:000171367800001 ER PT S AU Djomehri, MJ Biswas, R Van der Wijngaart, RF Yarrow, M AF Djomehri, MJ Biswas, R Van der Wijngaart, RF Yarrow, M BE Valero, M Prasanna, VK Vajapeyam, S TI Parallel and distributed computational fluid dynamics: Experimental results and challenges SO HIGH PERFORMANCE COMPUTING - HIPC 2000, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on High Performance Computing (HiPC 2000) CY DEC 17-20, 2000 CL BANGALORE, INDIA SP IEEE Comp Soc, ACM AB This paper describes several results of parallel and distributed computing using a production flow solver program. A coarse grained parallelization based on clustering of discretization grids, combined with partitioning of large grids, for load balancing is presented. An assessment is given of its performance on tightly-coupled distributed and distributed-shared memory platforms using large-scale scientific problems. An experiment with this solver, adapted to a Wide Area Network environment, is also presented. C1 NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. RP Djomehri, MJ (reprint author), NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41429-0 J9 LECT NOTES COMPUT SC PY 2001 VL 1970 BP 183 EP 193 PG 11 WC Computer Science, Theory & Methods SC Computer Science GA BS91B UT WOS:000171367800017 ER PT S AU Gropp, WD Kaushik, DK Keyes, DE Smith, BF AF Gropp, WD Kaushik, DK Keyes, DE Smith, BF BE Valero, M Prasanna, VK Vajapeyam, S TI Analyzing the parallel scalability of an implicit unstructured mesh CFD code SO HIGH PERFORMANCE COMPUTING - HIPC 2000, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on High Performance Computing (HiPC 2000) CY DEC 17-20, 2000 CL BANGALORE, INDIA SP IEEE Comp Soc, ACM ID TURBULENT FLOWS; GRIDS AB In this paper, we identify the scalability bottlenecks of an unstructured grid CFD code (PETSc-FUN3D) by studying the impact of several algorithmic and architectural parameters and by examining different programming models. We discuss the basic performance characteristics of this PDE code with the help of simple performance models developed in our earlier work, presenting primarily experimental results. In addition to achieving good per-processor performance (which has been addressed in our cited work and without which scalability claims are suspect) we strive to improve the implementation and convergence scalability of PETSc-FUN3D on thousands of processors. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. Lawrence Livermore Natl Lab, ISCR, Livermore, CA 94551 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Gropp, WD (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 14 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41429-0 J9 LECT NOTES COMPUT SC PY 2001 VL 1970 BP 395 EP 404 PG 10 WC Computer Science, Theory & Methods SC Computer Science GA BS91B UT WOS:000171367800036 ER PT S AU Smialek, JL Pint, BA AF Smialek, JL Pint, BA BE Streiff, R Wright, IG Krutenat, RC Caillet, M Galerie, A TI Optimizing scale adhesion on single crystal superalloys SO HIGH TEMPERATURE CORROSION AND PROTECTION OF MATERIALS 5, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 5th International Symposium on High Temperature Corrosion and Protection of Materials CY MAY 22-26, 2000 CL LES EMBIEZ, FRANCE SP EPRI, CNRS, Oak Ridge Natl Lab, Univ Provence, CEFRACOR, SETARAM, EDF DE adhesion; Al2O3 scale; cyclic oxidation; reactive element; sulfur; superalloy ID SULFUR REMOVAL; SEGREGATION; ADHERENCE; ALUMINA; ALLOYS; BASE AB To improve scale adhesion, single crystal superalloys have been desulfurized to levels below 1 ppmw by hydrogen annealing. A transition to fully adherent behavior has been shown to occur at a sulfur level of about 0.2 ppmw, as demonstrated for PWA 1480, PWA 1484, and Rene N5 single crystal superalloys in 1100 degrees -1150 degreesC cyclic oxidation tests up to 2000 h. Small additions of yttrium (15 ppmw) also have been effective in producing adhesion for sulfur contents of about 5 ppmw. Thus the critical Y/S ratio required for adhesion was on the order of 3-to-1 by weight (1-to-1 atomic), in agreement with values estimated from solubility products for yttrium sulfides. While hydrogen annealing greatly improved an undoped alloy, yielding less than or equal to0.01 ppmw S, it also produced benefits for Y-doped alloys without measurably reducing the sulfur content. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Smialek, JL (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. RI Pint, Bruce/A-8435-2008 OI Pint, Bruce/0000-0002-9165-3335 NR 17 TC 38 Z9 38 U1 0 U2 3 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-877-X J9 MATER SCI FORUM PY 2001 VL 369-3 BP 459 EP 466 PN 1&2 PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BT27T UT WOS:000172513200051 ER PT J AU Fairbridge, RW AF Fairbridge, RW TI Six millennia in Chinese peats, relating to planetary-solar-luniterrestrial periodicities: a comment on Hong, Jiang, Liu, Zhou, Beer, Li, Leng, Hong and Qin SO HOLOCENE LA English DT Editorial Material DE solar variability; solar forcing; Holocene; climatic change; chronology; stable isotopes; peat; China AB The 6000-yr O-18 time-series obtained by Hong et al. (2000) provides a valuable new proxy base for Holocene chronology. Independent studies of astronomic evidence of solar activity may furnish a linkage between a possible exogenetic forcing potential and the terrestrial, climate-dependent record. The peat cellulose power spectrum, ranging from 86 to 1046 years, finds equivalents in planetary organization, notably the centre alignments of Jupiter-Sun-Barycenter (JSB: a 9.88553-year cycle with its seventh harmonic at 69.2 years, seen also in the 'super' El Ninos). Almost identical equivalents are seen in solar emission periodicities and their harmonics, e.g., 86.884 yr = 40 x 2.172 yr Quasi Biennial Oscillation (QBO) as well as in the lunar tidal/apsides bear frequency (17.3769 yr) which also matches closely with most of the longer spectral peaks, e.g., 140 (139) yr, 207 (208.5), 311 (312.8), 590 (590.8) and 1046 (1042.6) yr. C1 Columbia Univ, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Fairbridge, RW (reprint author), Columbia Univ, 2880 Broadway, New York, NY 10025 USA. NR 17 TC 2 Z9 3 U1 0 U2 3 PU ARNOLD, HODDER HEADLINE PLC PI LONDON PA 338 EUSTON ROAD, LONDON NW1 3BH, ENGLAND SN 0959-6836 J9 HOLOCENE JI Holocene PD JAN PY 2001 VL 11 IS 1 BP 121 EP 122 DI 10.1191/095968301671850084 PG 2 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 392FN UT WOS:000166400800012 ER PT S AU Watson, AB Kreslake, L AF Watson, AB Kreslake, L BE Rogowitz, BE Pappas, TN TI Measurement of visual impairment scales for digital video SO HUMAN VISION AND ELECTRONIC IMAGING VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging VI CY JAN 22-25, 2001 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE AB The study of subjective visual quality, and the development of computed quality metrics, require accurate and meaningful measurement of visual impairment. A natural unit for impairment is the JND (just-noticeable-difference). In many cases, what is required is a measure of an impairment scale, that is, the growth of the subjective impairment, in JNDs, as some physical parameter (such as amount of artifact) is increased. Measurement of sensory scales is a classical problem in psychophysics. In the method of pair comparison, each trial consists of a pair of samples and the observer selects the one perceived to be greater on the relevant scale. This may be regarded as an extension of the method of forced-choice: from measurement of threshold (one JND), to measurement of the larger sensory scale (multiple JNDs). While simple for the observer, pair comparison is inefficient because if all samples are compared, many comparisons will be uninformative. In general, samples separated by about 1 JND are most informative. We have developed an efficient adaptive method for selection of sample pairs. As with the QUEST adaptive threshold procedure[l], the method is based on Bayesian estimation of the sensory scale after each trial. We call the method Efficient Adaptive Scale Estimation, or EASE ("to make less painful"). We have used the EASE method to measure impairment scales for digital video. Each video was derived from an original source (SRC) by the addition of a particular artifact, produced by a particular codec at a specific bit rate, called a hypothetical reference circuit (HRC). Different amounts of artifact were produced by linear combination of the source and compressed videos. On each pair-comparison trial the observer selected which of two sequences, containing different amounts of artifact, appeared more impaired. The scale is estimated from the pair comparison data using a maximum likelihood method. At the top of the scale, when all of the artifact is present, the scale value is the total number of JNDs corresponding to that SRC/HRC condition. We have measured impairment scales for 25 video sequences, derived from five SRCs combined with each of five HRCs. We find that EASE is a reliable method for measuring impairment scales and JNDs for processed video sequences. We have compared our JND measurements with mean opinion scores for the same sequences obtained at one viewing distance using the DSCQS method by the Video Quality Experts Group (VQEG), and we find that the two measures are highly correlated. The advantages of the JND measurements are that they are in absolute and meaningful units and are unlikely to be subject to context effects. We note that JND measurements offer a means of creating calibrated artifact samples, and of testing and calibrating video quality models. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Watson, AB (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 10 TC 18 Z9 18 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3977-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4299 BP 79 EP 89 DI 10.1117/12.429526 PG 11 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Computer Science; Engineering; Optics; Imaging Science & Photographic Technology GA BT01Y UT WOS:000171643600006 ER PT S AU Ahumada, AJ Krebs, WK AF Ahumada, AJ Krebs, WK BE Rogowitz, BE Pappas, TN TI Masking in color images SO HUMAN VISION AND ELECTRONIC IMAGING VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging VI CY JAN 22-25, 2001 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE DE color vision; target detection; image discrimination; vision models; image quality metrics; visual masking; contrast energy; color channels; color representations ID CONTRAST GAIN-CONTROL; SIGNAL-DETECTION; BACKGROUNDS; MODELS; NOISE AB Masking of color targets was measured for fixed pattern noises made of all additive combinations of white/black, red/green, and blue/yellow noise. Results are compared with the predictions of a cone-contrast-based masking model with and without cross-channel masking. The model without cross-channel masking performed very well. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ahumada, AJ (reprint author), NASA, Ames Res Ctr, Mail Stop 262-2, Moffett Field, CA 94035 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3977-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4299 BP 187 EP 194 PG 8 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Computer Science; Engineering; Optics; Imaging Science & Photographic Technology GA BT01Y UT WOS:000171643600016 ER PT S AU Arend, L AF Arend, L BE Rogowitz, BE Pappas, TN TI Environmental challenges to color constancy SO HUMAN VISION AND ELECTRONIC IMAGING VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging VI CY JAN 22-25, 2001 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE DE color constancy; environmental optics; perception; surface color; illuminant color ID RETINEX THEORY; NATURAL IMAGE; ILLUMINATION; REFLECTANCE; LIGHTNESS; VISION; WORLD; REAL AB Theories of human color constancy have been based on experiments with relatively simple laboratory stimuli. Even recent "nearly natural" stimuli are optically much simpler than natural visual environments. I review here some of the complexity of natural visual environments. I argue that several kinds of optical structure exploited by theories of human color constancy may not occur in most natural scenes. Continued progress in color constancy research will require better descriptions of natural visual environments and of human color constancy performance within them. Both pose large challenges. C1 NASA, Ames Res Ctr, Moffett Fed Field, CA 94035 USA. RP Arend, L (reprint author), NASA, Ames Res Ctr, M-S 262-4, Moffett Fed Field, CA 94035 USA. NR 26 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3977-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4299 BP 392 EP 399 DI 10.1117/12.429509 PG 8 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Computer Science; Engineering; Optics; Imaging Science & Photographic Technology GA BT01Y UT WOS:000171643600035 ER PT S AU Gille, J Larimer, J AF Gille, J Larimer, J BE Rogowitz, BE Pappas, TN TI Using the human eye to characterize displays SO HUMAN VISION AND ELECTRONIC IMAGING VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging VI CY JAN 22-25, 2001 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE ID WEB AB Monitor characterization has taken on new importance for non-professional users, who are not usually equipped to make photometric measurements. Our purpose was to examine some of the visual judgments used in characterization schemes that have been proposed for web users. We studied adjusting brightness to set the black level, banding effects due to digitization, and gamma estimation in the light and in the dark, and a color-matching task in the light, on a desktop CRT and a laptop LCD. Observers demonstrated the sensitivity of the visual system for comparative judgments in black-level adjustment, banding visibility, and gamma estimation. The results of the color-matching task were ambiguous. In the brightness adjustment task, the action of the adjustment was not as presumed; however, perceptual judgments were as expected under the actual conditions. When the gamma estimates of observers were compared to photometric measurements, problems with the definition of gamma were identified. Information about absolute light levels that would be important for characterizing a display, given the shortcomings of gamma in measuring apparent contrast, are not measurable by eye alone. The LCD was not studied as extensively as the CRT because of viewing-angle problems, and its transfer function did not follow a power law, rendering gamma estimation meaningless. C1 NASA, Raytheon ITSS, Moffett Field, CA USA. RP Gille, J (reprint author), NASA, Raytheon ITSS, Moffett Field, CA USA. NR 19 TC 4 Z9 4 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3977-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4299 BP 439 EP 454 DI 10.1117/12.429514 PG 16 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Computer Science; Engineering; Optics; Imaging Science & Photographic Technology GA BT01Y UT WOS:000171643600040 ER PT J AU Peterson, WT AF Peterson, WT TI Patterns in stage duration and development among marine and freshwater calanoid and cyclopoid copepods: a review of rules, physiological constraints, and evolutionary significance SO HYDROBIOLOGIA LA English DT Review DE copepod development; isochronal development; developmental constraints ID LONG-ISLAND SOUND; PLANKTONIC COPEPODS; EGG-PRODUCTION; POPULATION-DYNAMICS; EQUIPROPORTIONAL DEVELOPMENT; PSEUDOCALANUS-ELONGATUS; CRUSTACEAN ZOOPLANKTON; TEMORA-LONGICORNIS; EUTROPHIC INLET; ACARTIA-TONSA AB Studies of development time of marine and freshwater copepods have taken separate tracks. Most studies on marine copepods report development time of each individual development stage, whereas studies on freshwater copepods report only development time, from egg to nauplius and nauplius to adult. This bias allows comparison of total development time but prevents detailed comparisons of patterns in stage-specific developmental schedules. With respect to egg to adult development time, three general relationships are known: developmental rates are dependent upon temperature and food concentration but independent of terminal body size; freshwater calanoids develop significantly slower than marine calanoids; freshwater cyclopoids develop at the same rate as marine calanoids. Two rules describe stage-specific developmental rates: the equiproportional rule and the isochronal rule. The first rule states that the duration of a given life history stage is a constant proportion of the embryonic development time; the second rule states that the time spent in each stage is the same for all stages. This review focuses on the second rule. From the 80+ published studies of copepod stage-specific developmental times, no species follows the isochronal rule strictly: Acartia spp. come closest with isochronal development from third nauplius (N3) to fourth copepodite (C4). The only pattern followed by all species is rapid development of the first and/or second naupliar stages, slow development of the second and/or third nauplius and prolonged development of the final copepodite stage. Once adulthood is reached, males are usually short-lived, but females can live for weeks to months in the laboratory. Adult longevity in the sea is, however, on the order of only a few days. The evolution of developmental patterns is discussed in the context of physiological constraints, along with consideration of possible relationships between stage-specific mortality rates and life history strategies. Physiological constraints may operate at critical bottlenecks in development (e.g. at the first feeding nauplius, N6, and the fifth copepodite stage). High mortality of eggs may explain why broadcast eggs hatch 2-3 times faster than eggs carried by females in a sac; high mortality of adults may explain why adults do not grow rather they maximize their reproductive effort by partitioning all energy for growth into egg production. C1 Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Peterson, WT (reprint author), Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM bill.peterson@noaa.gov NR 69 TC 55 Z9 60 U1 1 U2 26 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PY 2001 VL 453 IS 1-3 BP 91 EP 105 DI 10.1023/A:1013111832700 PG 15 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 499ZD UT WOS:000172600200008 ER PT J AU Dedushenko, SK Perfiliev, YD Goldfeld, MG Tsapin, AI AF Dedushenko, SK Perfiliev, YD Goldfeld, MG Tsapin, AI TI Mossbauer study of hexavalent iron compounds SO HYPERFINE INTERACTIONS LA English DT Article; Proceedings Paper CT 12th International Conference on Hyperfine Interactions CY AUG 12-17, 2001 CL PARK CITY, UTAH DE ferrate(VI); Mossbauer spectra ID FERRATE(VI) AB Six crystalline ferrates(VI): K3Na(FeO4)(2),K2FeO4,Rb2FeO4,Cs2FeO4,K2Sr(FeO4)(2) and BaFeO4, were studied by Mossbauer spectroscopy. Room-temperature spectra of potassium, rubidium and cesium ferrates are single lines, but spectra of barium, potassium-strontium and potassium-sodium ferrates show a presence of quadrupole interactions. Most of these salts display an antiferromagnetic transition with a Neel temperature within 2 to 8 K range. C1 Bauman Moscow State Tech Univ, Moscow 107005, Russia. Moscow MV Lomonosov State Univ, Dept Chem, Moscow 119899, Russia. CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dedushenko, SK (reprint author), Bauman Moscow State Tech Univ, 5,2nd Baumanskaya St, Moscow 107005, Russia. NR 19 TC 14 Z9 14 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0304-3843 J9 HYPERFINE INTERACT JI Hyperfine Interact. PY 2001 VL 136 BP 373 EP 377 DI 10.1023/A:1020541910373 PG 5 WC Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Physics, Nuclear SC Physics GA 602WU UT WOS:000178528100038 ER PT J AU Lin, JYY Kriplani, U Regehr, M Fultz, B AF Lin, JYY Kriplani, U Regehr, M Fultz, B TI Polarization factors for Fe-57 Mossbauer diffractions from polycrystals SO HYPERFINE INTERACTIONS LA English DT Article; Proceedings Paper CT 12th International Conference on Hyperfine Interactions CY AUG 12-17, 2001 CL PARK CITY, UTAH DE Mossbauer effect; diffraction; interference; polarization; angular momentum AB The intensities of Mossbauer diffractions are calculated for polycrystalline samples in the kinematical limit, including interference with X-ray electronic scattering. The orientation distribution of hyperfine magnetic fields is expanded in spherical harmonics, providing a general expression for the polarization factor for magnetic dipole radiation. A comparison is made to experimental data reported recently. C1 CALTECH, WM Keck Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Lin, JYY (reprint author), CALTECH, WM Keck Lab, Pasadena, CA 91125 USA. RI Lin, Jiao/A-2529-2016 OI Lin, Jiao/0000-0001-9233-0100 NR 12 TC 1 Z9 1 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0304-3843 J9 HYPERFINE INTERACT JI Hyperfine Interact. PY 2001 VL 136 BP 663 EP 672 DI 10.1023/A:1020547126883 PG 10 WC Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Physics, Nuclear SC Physics GA 602WU UT WOS:000178528100083 ER PT S AU McAdoo, JA AF McAdoo, JA BE Smith, WL Yasuoka, Y TI Review of concepts and applications for multispectral/hyperspectral focal plane array (FPA) technology SO HYPERSPECTRAL REMOTE SENSING OF THE LAND AND ATMOSPHERE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hyperspectral Remote Sensing of the Land and Atmosphere CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE hyperspectral; remote sensors; focal plane arrays; photodetectors; imaging; spectroscopy AB Multispectral, and ultimately hyperspectral, focal plane arrays (FPAs) represent the logical extension of two-color FPA technology, which has already shown its utility in military applications. Incorporating the spectral discrimination function directly in the FPA would offer the potential for orders-of-magnitude increase in remote sensor system performance. It would allow reduction or even elimination of optical components currently required to provide spectral discrimination in atmospheric remote sensors. The result would be smaller, simpler instruments with higher performance than exist today. Achieving these goals, however, will be difficult. There are several challenges that must be met to enable this technology. This review identifies these challenges and provides a comparison of possible technical approaches to this problem. In addition, it provides a framework for evaluation of new concepts that might be envisioned. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP McAdoo, JA (reprint author), NASA, Langley Res Ctr, Mail Stop 468, Hampton, VA 23681 USA. NR 5 TC 0 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3804-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4151 BP 60 EP 67 DI 10.1117/12.417024 PG 4 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BS25Q UT WOS:000169199200007 ER PT S AU Smith, WL Zhou, DK Harrison, FW Revercomb, HE Larar, AM Huang, HL Huang, B AF Smith, WL Zhou, DK Harrison, FW Revercomb, HE Larar, AM Huang, HL Huang, B BE Smith, WL Yasuoka, Y TI Hyperspectral remote sensing of atmospheric profiles from satellites and aircraft SO HYPERSPECTRAL REMOTE SENSING OF THE LAND AND ATMOSPHERE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hyperspectral Remote Sensing of the Land and Atmosphere CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE FTS; satellites; sensing; profiling; chemistry; radiation; infrared ID NAST-I; SOUNDER AB A future hyperspectral resolution remote imaging and sounding system, called the GIFTS, is described. An airborne system, which produces the type of hyperspectral resolution sounding data to be achieved with the GIFTS, has been flown on high altitude aircraft. Results from simulations and from the airborne measurements are presented to demonstrate the revolutionary remote sounding capabilities to be realized with future satellite hyperspectral remote imaging/sounding systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, WL (reprint author), NASA, Langley Res Ctr, 21 Langley Blvd, Hampton, VA 23681 USA. NR 8 TC 34 Z9 34 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3804-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4151 BP 94 EP 102 DI 10.1117/12.416996 PG 3 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BS25Q UT WOS:000169199200011 ER PT S AU Aumann, HH Pagano, TS Strow, L AF Aumann, HH Pagano, TS Strow, L BE Smith, WL Yasuoka, Y TI The Atmospheric Infrared Sounder (AIRS) on the Earth observing system SO HYPERSPECTRAL REMOTE SENSING OF THE LAND AND ATMOSPHERE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hyperspectral Remote Sensing of the Land and Atmosphere CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE EOS; AIRS; infrared; sounder; calibration; weather forecasting AB AIRS, the Atmospheric Infrared Sounder on the EOS-Aqua, produces global high precision spectra from 3.7 - 15.4 micron with spectral resolving power mu/Delta mu approximate to 1200 twice each day from 708 km orbital altitude. AIRS is the first hyperspectral infrared spectrometer designed to support NOAA/NCEP's the operational requirements for medium range weather forecasting during its nominal 7 year lifetime. AIRS, together with the AMSU and HSB microwave radiometers, will achieve global retrieval accuracy of better then 1K rms in the lower troposphere under clear and partly cloudy condition. Based on the excellent radiometric and spectral, performance demonstrated during the pre-launch testing, the assimilation of AIRS data into the forecast model is expected to result in a major forecast improvements. Launch of AIRS on the EOS AQUA is scheduled for May 2001. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Aumann, HH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 10 Z9 10 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3804-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4151 BP 115 EP 125 DI 10.1117/12.416998 PG 5 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BS25Q UT WOS:000169199200013 ER PT S AU Zhou, DK Smith, WL Larar, AM AF Zhou, DK Smith, WL Larar, AM BE Smith, WL Yasuoka, Y TI Tropospheric ozone near-nadir-viewing IR spectral sensitivity and ozone measurements from NAST-I SO HYPERSPECTRAL REMOTE SENSING OF THE LAND AND ATMOSPHERE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hyperspectral Remote Sensing of the Land and Atmosphere CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE remote sensing; interferometer; ozone; sensitivity; retrieval AB Infrared ozone spectra from near nadir observations have provided atmospheric ozone information from the sensor to the Earth's surface. Simulations of the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) from the NASA ER-2 aircraft (similar to 20 km altitude) with a spectral resolution of 0.25 cm(-1) were used for sensitivity analysis. The spectral sensitivity of ozone retrievals to uncertainties in atmospheric temperature and water vapor is assessed in order to understand the relationship between the IR emissions and the atmospheric state. In addition, ozone spectral radiance sensitivity to its ozone layer densities and radiance weighting functions reveals the limit of the ozone profile retrieval accuracy from NAST-I measurements. Statistical retrievals of ozone with temperature and moisture retrievals from NAST-I spectra have been investigated and the preliminary results from NAST-I field campaigns are presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Zhou, DK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 12 TC 2 Z9 2 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3804-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4151 BP 277 EP 284 DI 10.1117/12.417017 PG 4 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BS25Q UT WOS:000169199200030 ER PT B AU Hand, C AF Hand, C BE Arabnia, HR TI Deep autoassociative networks SO IC-AI'2001: PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS I-III LA English DT Proceedings Paper CT International Conference on Artificial Intelligence CY JUN 25-28, 2001 CL LAS VEGAS, NV SP Comp Sci Res, Educ & Appl Press, Int Technol Inst Korea Informat Processing Soc, World Acad Sci Informat Technol, PACT Corp DE autoassociative nets; autonomous robots; synaptic networks AB Autoassociative networks are powerful and versatile information processing systems with some inconvenient limitations. Two of these limitations are the small number of patterns that can be clearly distinguished and the impoverished ability of the net to form clearly defined neighborhoods around target patterns. This paper introduces a refinement of Autoassociative networks, called 'deep' autoassociative networks. These novel networks can distinguish between large numbers of patterns, and have clearly defined basins of attraction around target patterns. The typical performance of deep autoassociative networks is significantly superior to the typical performance of standard autoassociative networks on the same tasks. Deep autoassociative networks pay for this increased level of performance by having an increased number of weights. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hand, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU C S R E A PRESS PI ATHENS PA 115 AVALON DR, ATHENS, GA 30606 USA BN 1-892512-81-5 PY 2001 BP 1310 EP 1315 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BT75P UT WOS:000173960400202 ER PT J AU Harmon, JK Perillat, PJ Slade, MA AF Harmon, JK Perillat, PJ Slade, MA TI High-resolution radar imaging of Mercury's north pole SO ICARUS LA English DT Article DE Mercury; radar; ices ID ICE DEPOSITS; LUNAR POLES; COHERENT-BACKSCATTER; WATER ICE; STABILITY; MARS; ARECIBO; IMAGES; MOON; WAVELENGTHS AB The recently upgraded Arecibo S-band (lambda 12.6-cm) radar was used to make delay-Doppler images of Mercury's north polar region, where earlier observations had shown strong echoes from putative ice deposits in craters. The image resolution of 1.5-3 km is a substantial improvement over the 15-km resolution of the older Arecibo images (J. K, Harmon et al. 1994, Nature 369, 213-215). The new observations confirm all the original polar features and reveal many additional features, including several at latitudes as low as 72-75 degreesN and several from craters less than 10 km in diameter. All of the new features located on the Mariner-imaged side of the planet can be matched with known craters or other shaded areas. We find the north pole to be located 65 km from the original Mariner-based pole and 15 km from the new Mariner-based pole of hi. S. Robinson et al. (1999, J. Geophys. Res. 104, 30,847-30,852). The improved resolution reveals fine structure in the radar features and their respective host craters, including radar shadowing/highlighting by central peaks and rim walls, rim terracing, and preferential concentration of radar-bright deposits in shaded southern floor areas. The radar features' high brightness, circular polarization inversion (mu (c) = 1.25), and confinement to regions permanently shaded from direct sunlight are all consistent with volume scattering from a cold-trapped volatile such as clean water ice. The sizes and locations of most of the features show good agreement with the thermal model of A. R, Vasavada, D. A. Paige, and S. E. Wood (1999, Icarus 141, 179-193) for insulated (buried) water ice, although the problems of explaining radar features in small craters and the rapid burial required at lower latitudes suggest that other factors may be suppressing ice loss after emplacement. (C) 2001 Academic Press. C1 Arecibo Observ, Natl Astron & Ionosphere Ctr, Arecibo, PR 00612 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Harmon, JK (reprint author), Arecibo Observ, Natl Astron & Ionosphere Ctr, HC3 Box 53995, Arecibo, PR 00612 USA. NR 46 TC 70 Z9 71 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 1 EP 15 DI 10.1006/icar.2000.6544 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900001 ER PT J AU de Pater, I Dunn, D Romani, P Zahnle, K AF de Pater, I Dunn, D Romani, P Zahnle, K TI Reconciling Galileo probe data and ground-based radio observations of ammonia on Jupiter SO ICARUS LA English DT Article ID TROPOSPHERIC GAS-COMPOSITION; NORTH EQUATORIAL BELT; LABORATORY MEASUREMENTS; CLOUD STRUCTURE; ATMOSPHERE; NEPTUNE; PLANETS; WAVELENGTHS; SPECTRUM; ORIGIN AB Prior to the Galileo probe entry in Jupiter's atmosphere, the ammonia abundance in the planet's deep atmosphere as deduced from microwave observations was thought to be close to the solar N value at P > 3 bar and subsolar at P < 2 bar, Analysis of the attenuation of the probe radio signal during its descent in Jupiter's atmosphere suggested NH3 to be 3.6 +/- 0.5 times solar N at P > 8 bar (Folkner er al 1998). Assuming this high value is globally representative of the NH3 abundance in Jupiter's deep atmosphere, we show in this article that to match Jupiter's microwave spectrum the ammonia abundance must, globally, decrease at pressures P less than or similar to4 bar, and reach subsolar (less than or similar to0.5) values at P less than or similar to2 bar, We confirm earlier analysis of the 1.3-cm wavelength region indicating that the disk-averaged relative humidity must be of the order of 10% at P < 0.55 bar. We discuss various ways in which NH3 could decrease globally at altitudes well below the level where the NH3-ice clouds form, We also present radio images of Jupiter taken with the VLA at 2, 3.6, and 6 cm wavelength in November/December 1995 and January 1996. The Galileo probe entered Jupiter's atmosphere on 7 December 1995, at a latitude of 6.5N, i.e., at the southern edge of the north equatorial belt (NEE), Simulations of our data suggest that the longitude-averaged NH3 abundance in the NEB at the time of the Galileo probe entry is of the order of 50-70% of the value in the equatorial zone (EZ), while the NH3 abundance in the EZ is about less than or similar to0.5 x solar N, This low ammonia abundance in the NEB must exten down to the similar to4- to 6-bar level. (C) 2000 Academic Press.. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP de Pater, I (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Romani, Paul/D-2729-2012 NR 45 TC 45 Z9 45 U1 0 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 66 EP 78 DI 10.1006/icar.2000.6527 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900005 ER PT J AU Tackley, PJ Schubert, G Glatzmaier, GA Schenk, P Ratcliff, JT Matas, JP AF Tackley, PJ Schubert, G Glatzmaier, GA Schenk, P Ratcliff, JT Matas, JP TI Three-dimensional simulations of mantle convection in Io SO ICARUS LA English DT Article ID INFINITE PRANDTL NUMBER; THERMAL-CONVECTION; GALILEAN SATELLITES; GLOBAL DISTRIBUTION; SILICATE VOLCANISM; INTERNAL STRUCTURE; TIDAL DISSIPATION; ACTIVE VOLCANISM; SPHERICAL-SHELL; EARTHS MANTLE AB Io has very high surface heat flow and an abundance of volcanic activity, which are thought to be driven by nonuniform tidal heating in its interior. This nonuniform heat is transported to the base of the lithosphere by very vigorous convection in Io's silicate mantle, the form of which is presumably responsible for the distribution of surface features such as volcanoes and mountains. We here present three-dimensional spherical calculations of mantle convection in Io, in order to ascertain the likely form of this convection and the resulting distribution of heat flow at the surface and core-mantle boundary. Different models of tidal dissipation are considered: the endmember scenarios identified by M. N. Ross and G. Schubert (1985, Icarus 64, 391-400) of dissipation in the entire mantle, or dissipation in a thin (similar to 100-km-thick) asthenosphere, as well as the "preferred" distribution of M, N. Ross et al. (1990, Icarus 85, 309-325) comprising 1/3 mantle and 2/3 asthenosphere heating. The thermal structure of Io's mantle and asthenosphere is found to be strongly dependent on tidal heating mode, as well as whether the mantle-asthenosphere boundary is permeable or impermeable. Results indicate a large-scale flow pattern dominated by the distribution of tidal heating, with superimposed small-scale asthenospheric instabilities that become more pronounced with increasing Rayleigh number. These small-scale instabilities spread out the surface heat flux, resulting in smaller heat flux variations with increasing Rayleigh number. Scaled to Io's Rayleigh number of O(10(12)), variations of order a few percent are expected. This small but significant variation in surface heat flux may be compatible with the observed distributions of volcanic centers and mountains, which appear fairly uniform at first sight but display a discernible distribution when suitably processed. The observed distribution of volcanic centers is similar to the asthenosphere heating distribution, implying that most of the tidal heating in Io occurs in an asthenosphere. (C) 2000 Academic Press. C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Inst Geophys & Planetary Phys, Santa Cruz, CA 95064 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. Jet Prop Lab, Space Geodet Sci & Applicat Grp, Pasadena, CA 91109 USA. Ecole Normale Super Lyon, F-69364 Lyon, France. RP Tackley, PJ (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, 595 Charles Young Dr E, Los Angeles, CA 90095 USA. RI Tackley, Paul/D-8155-2016 OI Tackley, Paul/0000-0003-4878-621X NR 53 TC 40 Z9 40 U1 0 U2 12 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 79 EP 93 DI 10.1006/icar.2000.6536 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900006 ER PT J AU Doute, S Schmitt, B Lopes-Gautier, R Carlson, R Soderblom, L Shirley, J AF Doute, S Schmitt, B Lopes-Gautier, R Carlson, R Soderblom, L Shirley, J CA Galileo NIMS Team TI Mapping SO2 frost on Io by the modeling of NIMS hyperspectral images SO ICARUS LA English DT Article DE satellites of Jupiter; Io; infrared observations; ices; volcanism ID SUBLIMATION-DRIVEN FLOW; HUBBLE-SPACE-TELESCOPE; GLOBAL DISTRIBUTION; INFRARED WAVELENGTHS; ACTIVE VOLCANISM; SULFUR-DIOXIDE; MU-M; SURFACE; GALILEO; ATMOSPHERE AB We analyze a collection of hyperspectral images of Io acquired by the near infrared mapping spectrometer (NIMS) of Galileo during the G2 to E16 orbits of Jupiter. This analysis leads to the geographical distribution and physical characterization of SO2 frost deposits over about three-fourths of Io's surface. These deposits are excellent tracers of various phenomena, including volcanic production and emission, atmospheric transportation, condensation, metamorphism, irradiation, and sublimation, that occur throughout the SO2 cycle, We assume that the deposits of solid SO2 are optically thick and are geographically mixed with other sulfur-bearing compounds. We first assess the mean moderate backscattering behavior of the SO2 frost (Henyey Greenstein phase function parameter g = -0.27 +/- 0.05) using a sequence of spectra at two different locations over a large range of phase angles. This behavior may indicate a granular texture with many defects or a fluffy texture. Second, a more systematic inversion of the hyperspectral images is achieved based on a linear spectral model of pure SO2 with variable grain size mixed with a spectrally neutral unit. As a result, we produce two global mosaics that map SO2 frost coverage and mean grain size. SO2 deposits are omnipresent on Io's surface at the spatial scale of this study (approximate to 200 km), but the SO2 frost is concentrated within several large areas centered at medium latitudes. These SO2-rich regions (surface coverage higher than 60%) show a longitudinal correlation with plumes located lower in latitude, suggesting that these plumes are the principal sources of SO2 gas. After a possible dynamic condensation around the plumes or at the equator, the gas is remobilized by the solar or thermal fluxes and flows mostly latitudinally toward the coldest and nearest regions devoid of hot-spots. Third, the correlation of the distribution and grain size mosaics distinguishes four different SO2 physical units that indicate relative regional variations of condensation, metamorphism, and sublimation. Finally, comparisons with Voyager ultraviolet (A. S, McEwen, T. V. Johnson, D, L. Matson, and L. A. Soderblom, 1988, Icarus, Vol. 75, pp. 450-478) and Galileo visible (P. Geissler, A. S, McEwen, L. Keszthelyi, R. M. C. Lopes-Gautier, J. Granahan, and D. P. Simonelli, 1999, Icarus, Vol. 140, pp. 256-282) observations demonstrate molecular contamination of SO2 at medium and high latitudes and that these contaminated SO2 deposits may be optically thin. (C) 2000 Academic Press. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Lab Planetol Grenoble, CNRS, F-38041 Grenoble 9, France. Jet Prop Lab, Pasadena, CA 91109 USA. US Geol Survey, Branch Astrogeol, Flagstaff, AZ 86001 USA. RP Doute, S (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, 405 Hilgard,Box 951567, Los Angeles, CA 90095 USA. EM sdoute@igpp.ucla.edu RI Schmitt, Bernard/A-1064-2009; Lopes, Rosaly/D-1608-2016 OI Schmitt, Bernard/0000-0002-1230-6627; Lopes, Rosaly/0000-0002-7928-3167 NR 54 TC 74 Z9 74 U1 0 U2 4 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 107 EP 132 DI 10.1006/icar.2000.6513 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900008 ER PT J AU Cooper, JF Johnson, RE Mauk, BH Garrett, HB Gehrels, N AF Cooper, JF Johnson, RE Mauk, BH Garrett, HB Gehrels, N TI Energetic ion and electron irradiation of the icy Galilean satellites SO ICARUS LA English DT Review DE radiation chemistry; surfaces; satellite; Europa; Ganymede; Callisto ID INFRARED MAPPING SPECTROMETER; OUTER SOLAR-SYSTEM; JUPITERS INNER MAGNETOSPHERE; GANYMEDES MAGNETIC-FIELD; HUBBLE-SPACE-TELESCOPE; CONAMARA CHAOS REGION; WATER-ICE; JOVIAN MAGNETOSPHERE; OPTICAL-PROPERTIES; EUROPAS SURFACE AB Galileo Orbiter measurements of energetic ions (20 keV to 100 MeV) and electrons (20-700 keV) in Jupiter's magnetosphere are used, in conjunction with the JPL electron model (<40 MeV), to compute irradiation effects in the surface layers of Europa, Ganymede, and Callisto, Significant elemental modifications are produced on unshielded surfaces to approximately centimeter depths in times of 10(6) years, whereas micrometer depths on Europa are fully processed in similar to 10 years. Most observations of surface composition are limited to optical depths of similar to1 mm, which are in direct contact with the space environment. Incident flux modeling includes Stormer deflection by the Ganymede dipole magnetic field, likely variable over that satellite's irradiation history. Delivered energy flux of similar to8 x 10(10) keV (cm(2)-s)(-1) at Europa is comparable to total internal heat flux in the same units from tidal and radiogenic sources, while exceeding that for solar UV energies (>6 eV) relevant to ice chemistry. Particle energy fluxes to Ganymede's equator and Callisto are similar at similar to2-3 x 10(8) keV (cm(2)-s)(-1) with 5 x 10(9) at Ganymede's polar cap, the latter being comparable to radiogenic energy input. Rates of change in optical reflectance and molecular composition on Europa, and on Ganymede's polar cap, are strongly driven by energy from irradiation, even in relatively young regions. Irradiation of nonice materials can produce SO(2) and CO(2), detected on Callisto and Europa, and simple to complex hydrocarbons, Iogenic neutral atoms and meteoroids deliver negligible energy similar to 10(4-5) keV (cm(2)-s)(-1) but impacts of the latter are important for burial or removal of irradiation products, Downward transport of radiation produced oxidants and hydrocarbons could deliver significant chemical energy into the satellite interiors for astrobiological evolution in putative sub-surface oceans. (C) 2001 Academic Press. C1 NASA, Goddard Space Flight Ctr, SSDOO Project, ITSS,Raytheon Informat Techol & Sci Serv, Greenbelt, MD 20771 USA. Univ Virginia, Charlottesville, VA 22903 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Cooper, JF (reprint author), NASA, Goddard Space Flight Ctr, SSDOO Project, ITSS,Raytheon Informat Techol & Sci Serv, Code 632, Greenbelt, MD 20771 USA. EM jfcooper@pop600.gsfc.nasa.gov RI Gehrels, Neil/D-2971-2012; Cooper, John/D-4709-2012; Mauk, Barry/E-8420-2017 OI Mauk, Barry/0000-0001-9789-3797 NR 164 TC 211 Z9 212 U1 3 U2 23 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 133 EP 159 DI 10.1006/icar.2000.6498 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900009 ER PT J AU Owen, TC Cruikshank, DP Dalle Ore, CM Geballe, TR Roush, TL de Bergh, C Meier, R Pendleton, YJ Khare, BN AF Owen, TC Cruikshank, DP Dalle Ore, CM Geballe, TR Roush, TL de Bergh, C Meier, R Pendleton, YJ Khare, BN TI Decoding the domino: The dark side of Iapetus SO ICARUS LA English DT Article DE Iapetus; organic chemistry; satellites of Saturn; spectrophotometry ID NEAR-INFRARED SPECTROSCOPY; OUTER SOLAR-SYSTEM; CHARGED-PARTICLE IRRADIATION; OPTICAL-CONSTANTS; ORGANIC-MATTER; MU-M; LAPETUS; HYPERION; ICE; SPECTROPHOTOMETRY AB We present new spectra of the leading and trailing hemispheres of Iapetus from 2.4 to 3.8 mum, We have combined the leading hemisphere spectra with previous observations by others to construct a composite spectrum of the dark side (leading) hemisphere from 0.3 to 3.8 mum. We review attempts to deduce the composition of the dark material from previously available spectrophotometry, None of them (numbering more than 20 million!) leads to a synthetic spectrum that matches the new data, An intimate mixture of wafer ice, amorphous carbon, and a nitrogen-rich organic compound (modeled here as Triton tholin) can ht the entire composite dark side spect rum. Observations in this spectral region have not revealed this mix of material on any other object observed thus far, We propose that this dark material may have originated on Titan, where atmospheric photochemistry has been producing nitrogen-rich organic compounds for 4.5 GY. (C) 2001 Academic Press. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Moffett Field, CA 94035 USA. Gemini Telescope, Hilo, HI 96720 USA. Observ Paris, F-92195 Meudon, France. RP Owen, TC (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM owen@ifa.hawaii.edu NR 68 TC 64 Z9 64 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 160 EP 172 DI 10.1006/icar.2000.6521 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900010 ER PT J AU Hillier, JK Buratti, BJ AF Hillier, JK Buratti, BJ TI Monte Carlo simulations of light scattering by composite particles in a planetary surface SO ICARUS LA English DT Article DE radiative transfer; photometry; surfaces; planets; surfaces; satellites; regoliths ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; ASYMMETRY PARAMETERS; OPTICAL-PROPERTIES; PHASE FUNCTION; SATELLITES; PHOTOMETRY; TERRAINS; SPHERES; GRAINS; DUST AB Composite particles containing internal scatterers have been proposed as an explanation for the fact that most photometric studies of planetary surfaces based on Hapke's bidirectional reflectance model have found the planetary particles to exhibit moderately backscattering phase functions. However, an implicit assumption made in this explanation is that the scattering by composite particles containing multiple internal inclusions in a planetary surface can still be adequately computed using standard radiative transfer theory assuming the composite particles to be the fundamental scattering unit even though the particles are necessarily in close proximity to each other. This assumption was explored by J, K, Hillier (1997, Icarus 130, 328-335) using a Monte Carlo routine. However, in this initial study several simplifying assumptions were made. The internal scatterers were assumed to be isotropic and scattering off of the surface and absorption within the composite particle were ignored. While these assumptions are not very realistic, it was believed that the study could still provide insight into the light scattering by such surfaces, Here we relax these assumptions in order to examine the light scattering by more realistic particles. Almost all of the conclusions reached in the earlier paper remain valid, As before, we find that classical radiative transfer (assuming a random distribution of scattering particles) coupled with the assumption that the composite particle is the fundamental scatterer provides a good approximation in the high porosity limit, However, even for porosities as high as 90% the effects of close packing are clearly seen with the radiative transfer calculation underestimating the scattering by similar to 10% at high phase angles. In contrast to the earlier study we find that the radiative transfer calculation tends to overestimate, not underestimate, the scattering at high emission but moderate phase angles. As the porosity is lowered further, the discrepancy becomes more severe and can reach 100% or greater. In particular, our main conclusion remains intact: the parameters derived using the classical radiative transfer theory will yield results intermediate between those of the composite as a whole and those of the internal scatterers and thus one should exercise caution in interpreting the results of models based on classical radiative transfer theory in terms of the physical properties of the surface particles. (C) 2001 Academic Press. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Hillier, JK (reprint author), Grays Harbor Coll, 1620 Edward D Smith Dr, Aberdeen, WA 98520 USA. NR 27 TC 5 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2001 VL 149 IS 1 BP 251 EP 261 DI 10.1006/icar.2000.6500 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391EJ UT WOS:000166340900017 ER PT B AU Freed, M Matessa, M Rehling, J Remington, R Vera, A AF Freed, M Matessa, M Rehling, J Remington, R Vera, A BE Altmann, EM Cleeremans, A Schunn, CD Gray, WD TI Human-task adaptations: The next step for cognitive modeling SO ICCM - 2001: PROCEEDINGS OF THE 2001 FOURTH INTERNATIONAL CONFERENCE ON COGNITIVE MODELING LA English DT Proceedings Paper CT 4th International Conference on Cognitive Modeling CY JUL 26-28, 2001 CL GEORGE MASON UNIV, FAIRFAX, VA SP USN Off Res, Natl Sci Fdn, USAF Res Lab Human Effectiveness Directorate, CHI Syst, BBN Technologies HO GEORGE MASON UNIV C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 USA BN 0-8058-4042-7 PY 2001 BP 245 EP 246 PG 2 WC Computer Science, Artificial Intelligence; Psychology, Developmental SC Computer Science; Psychology GA BS64T UT WOS:000170688900042 ER PT B AU Rehling, J AF Rehling, J BE Altmann, EM Cleeremans, A Schunn, CD Gray, WD TI The grain size of cognitive models: How low should we go? SO ICCM - 2001: PROCEEDINGS OF THE 2001 FOURTH INTERNATIONAL CONFERENCE ON COGNITIVE MODELING LA English DT Proceedings Paper CT 4th International Conference on Cognitive Modeling CY JUL 26-28, 2001 CL GEORGE MASON UNIV, FAIRFAX, VA SP USN Off Res, Natl Sci Fdn, USAF Res Lab Human Effectiveness Directorate, CHI Syst, BBN Technologies HO GEORGE MASON UNIV AB There has been vigorous debate regarding the level at which it is appropriate and/or necessary to model human cognition (Smolensky, 1988). It is difficult to settle this issue because the many unknowns regarding human cognition confound efforts to attribute the success or failure of any particular modeling effort to one factor alone. In order to study this matter without a large number of confounds, it is useful to consider how grain size affects the predictive power of computational models in physical domains that are simpler than cognition. For this purpose, a model of a physical system that is simple to describe but nonetheless has chaotic behavior has been used to isolate grain size as a variable that affects the behavior of the model in clear ways. While this does not settle the question of how grain size affects the accuracy of cognitive models, it does offer several possibilities for how grain size may, in principle affect the accuracy of a model. This has one advantage over debate that is concerned directly with the domain of primary interest (cognition) but cannot arrange any clean tests of its hypotheses. C1 NASA, Ames Res Ctr, Cognit Res Grp, Moffett Field, CA 94035 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 USA BN 0-8058-4042-7 PY 2001 BP 261 EP 262 PG 2 WC Computer Science, Artificial Intelligence; Psychology, Developmental SC Computer Science; Psychology GA BS64T UT WOS:000170688900050 ER PT B AU Bell, JH AF Bell, JH GP IEEE IEEE TI Accuracy limitations of lifetime-based pressure-sensitive paint (PSP) measurements SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB PSP systems determine air pressure by measuring the luminescence lifetime of an oxygen-quenched luminophor in a porous matrix. While traditionally lifetime was inferred from measurements at different pressures, it is becoming increasingly common to make direct lifetime measurements by taking images at different points on the luminescence decay curve using a gated camera. Here, the accuracy of the lifetime method is evaluated through theoretical analysis, bench top studies, and small scale wind tunnel tests, with the primary aim of determining whether the lifetime method is suitable for measurements in very low speed flows (Mach similar to 0.1). It is found that the luminescence lifetime of a PSP-coated surface can vary from point to point even at constant pressure and temperature. This variation is a significant source of error in low speed measurements, and can be reduced significantly by careful paint application procedures. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bell, JH (reprint author), NASA, Ames Res Ctr, Mail Stop 260-1, Moffett Field, CA 94035 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 5 EP 16 DI 10.1109/ICIASF.2001.960231 PG 12 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700002 ER PT B AU Seasholtz, RG Buggele, AE AF Seasholtz, RG Buggele, AE GP IEEE IEEE TI Laser light scattering diagnostic for measurement of flow velocity in vicinity of propagating shock waves SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB A laser light scattering diagnostic for measurement of dynamic flow velocity at a point is described. The instrument is being developed for use in the study of propagating shock waves and detonation waves in pulse detonation engines under development at the NASA Glenn Research Center (GRC). The approach uses a Fabry-Perot interferometer to measure the Doppler shift of laser light scattered from small (submicron) particles in the flow. The high-speed detection system required to resolve the transient response as a shock wave crosses the probe volume uses fast response photodetectors and a PC based data acquisition system. Preliminary results of measurements made in the GRC Mach 4, 10x25 cm. supersonic wind tunnel are presented. Spontaneous condensation of water vapor in the flow is used as seed. The tunnel is supplied with continuous. air flow at up to 45 psia; the flow is exhausted into the GRC laboratory-wide altitude exhaust system at pressures down to 0.3 psia. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Seasholtz, RG (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 48 EP 58 DI 10.1109/ICIASF.2001.960235 PG 11 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700006 ER PT B AU Humphreys, WM Bartram, SM AF Humphreys, WM Bartram, SM GP IEEE IEEE TI Measurement of separating flow structures using a multiple-camera DPIV system SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR ID PARTICLE IMAGE VELOCIMETRY AB A novel multiple-camera system for the recording of digital particle image velocimetry (DPIV) images acquired in a two-dimensional separating/reattaching flow is described. The measurements were performed in the NASA Langley Subsonic Basic Research Tunnel as part of an overall series of experiments involving the simultaneous acquisition of dynamic surface pressures and off-body velocities. The DPIV system utilized two frequency-doubled Nd:YAG lasers to generate two coplanar, orthogonally-polarized light sheets directed upstream along the horizontal centerline of the test model. A recording system containing two pairs of matched high resolution, 8-bit cameras was used to separate and capture images of illuminated tracer particles embedded in the flow field. Background image subtraction was used to reduce undesirable flare light emanating from the surface of the model, and custom pixel alignment algorithms were employed to provide accurate registration among the various cameras. Spatial cross correlation analysis with median filter validation was used to determine the instantaneous velocity structure in the separating/reattaching flow region illuminated by the laser light sheets. In operation the DPIV system exhibited a good ability to resolve large-scale separated flow structures with acceptable accuracy over the extended field of view of the cameras. The recording system design provided enhanced performance versus traditional DPIV systems by allowing a variety of standard and non-standard cameras to be easily incorporated into the system. C1 NASA, Langley Res Ctr, Adv Measurement & Diagnost Branch, Hampton, VA 23681 USA. RP Humphreys, WM (reprint author), NASA, Langley Res Ctr, Adv Measurement & Diagnost Branch, Hampton, VA 23681 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 82 EP 93 DI 10.1109/ICIASF.2001.960238 PG 12 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700009 ER PT B AU Walker, S AF Walker, S GP IEEE IEEE TI Two-axis Scheimpflug focusing for particle image velocimetry SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB The objective of this work is to demonstrate the capabilities of a two-axis, three-dimensional Particle Image Velocimetry (PIV) system for use as a large-scale wind tunnel research tool. A two-axis Ply system provides the capability for camera placement virtually anywhere within a three-dimensional space relative to the laser sheet plane of measurement. The Scheimpflug focusing method is applied in two orthogonal axes to achieve off-axis focusing. The two-axis, three-dimensional PIV system uses off-axis stereoscopic viewing to determine two perspective measurements of a three-dimensional velocity field within the laser sheet. A unique calibration procedure is used to determine the optical parameters that describe the position of the camera systems and which are necessary to perform the three-dimensional reconstruction of the displacements. This paper presents this unique calibration for a two-axis, three-dimensional PIV system. This two-axis, three-dimensional PIV system was demonstrated first by measuring three-dimensional displacements of a target. Maximum instantaneous errors are estimated as 2% or less for all velocity components based upon the measured target displacements, and these error estimates were verified by a propagation of errors calculation. The error estimates are for instantaneous displacements and include all error sources. The two-axis, three-dimensional PIV system was also used to make measurements of the freestream velocity within a wind tunnel. The out-of-plane freestream component of velocity measured by the PIV system differed from the expected value by less than 1.1%. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Walker, S (reprint author), NASA, Ames Res Ctr, MS 260-1, Moffett Field, CA 94035 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 114 EP 124 DI 10.1109/ICIASF.2001.960241 PG 11 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700012 ER PT B AU Martin, LC Wrbanek, JD Fralick, GC AF Martin, LC Wrbanek, JD Fralick, GC GP IEEE IEEE TI Thin film sensors for surface measurements SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB Advanced thin film sensors that can provide accurate surface temperature, strain, and heat flux measurements have been developed at NASA Glenn Research Center. These sensors provide minimally intrusive characterization of advanced propulsion materials and components in hostile, high-temperature environments as well as validation of propulsion system design codes. The sensors are designed for applications on different material systems and engine components for testing in engine simulation facilities. Thin film thermocouples and strain gauges for the measurement of surface temperature and strain have been demonstrated on metals, ceramics and advanced ceramic-based composites of various component configurations. Test environments have included both air-breathing and space propulsion-based engine and burner rig environments at surface temperatures up to 1100 degreesC and under high gas flow and pressure conditions. The technologies developed for these sensors as well as for a thin film heat flux gauge have been integrated into a sin-le multifunctional gauge for the simultaneous real-time measurement of surface temperature, strain, and heat flux. This is the first step toward the development of smart sensors with integrated signal conditioning and high temperature electronics that would have the capability to provide feedback to the operating system in real-time. A description of the fabrication process for the thin film sensors and multifunctional gauge will be provided. In addition, the material systems on which the sensors have been demonstrated, the test facilities and the results of the tests to-date will be described. Finally, the results will be provided of the current effort to demonstrate the capabilities of the multifunctional gauge. C1 NASA, Glenn Res Ctr, Sensors & Elect Technol Branch, Cleveland, OH 44135 USA. RP Martin, LC (reprint author), NASA, Glenn Res Ctr, Sensors & Elect Technol Branch, Cleveland, OH 44135 USA. NR 15 TC 2 Z9 2 U1 5 U2 11 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 196 EP 203 DI 10.1109/ICIASF.2001.960251 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700022 ER PT B AU Beheim, G Ned, AA Masheeb, F Kurtz, AD Wolff, JM AF Beheim, G Ned, AA Masheeb, F Kurtz, AD Wolff, JM GP IEEE IEEE TI Dynamic pressure measurements using silicon carbide transducers SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB Pressure sensors capable of operating at higher temperatures have Iona been sought for testing of aircraft engines, since each improvement in sensor durability opens new areas of the engine to the straightforward measurement of rapidly varying pressures. A silicon carbide pressure sensor has been developed which can operate at 500 degreesC, a temperature at which the mechanical properties of silicon, the most commonly used pressure sensor material, are severely degraded. The prototype SiC pressure transducer was successfully tested on a gas turbine engine, thereby demonstrating its ability to survive the hostile engine environment. Testing in a shock tube showed the packaged sensor to have a natural frequency of 30 kHz, which is adequate for many dynamic pressure measurement applications. It is expected that the frequency response could be increased by a simple modification of the package to reduce the setback of the SiC die. C1 NASA, John H Glenn Res Ctr, Div Instrumentat & Controls, Cleveland, OH 44135 USA. RP Beheim, G (reprint author), NASA, John H Glenn Res Ctr, Div Instrumentat & Controls, Cleveland, OH 44135 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 240 EP 245 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700027 ER PT B AU Shams, QA Moniuszko, M Ingham, JC AF Shams, QA Moniuszko, M Ingham, JC GP IEEE IEEE TI Applying MEMS technology to field, flight & space deployable systems SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR ID SCALE WIND-TUNNEL; F/A-18 TAIL; BUFFET AB Over the last few years, there has been a rapid growth in Microelectro-Mechanical Systems (MEMS) technologies, on board intelligent technologies and smaller, faster, and smarter wireless telemetry systems technologies that can reduce cycle time and total measurement and test process cost. The major attraction of MEMS technology is the order of magnitude reduction of the power and thermal requirements over existing electronic components. In addition, the size and power requirements have also made them attractive for wind tunnel tests', field-deployable acoustic measurement systems, flight, and space applications. Recent advances in M-EMS technology have made it possible to produce pressure, acceleration, humidity, and temperature sensors having masses in the milligram range or even lighter. In this paper, characteristics of MEMS devices for propulsion systems, meteorological instrumentation, and space applications will be presented. C1 NASA, Langley Res Ctr, Instrument Syst Dev Branch, AAAC, Hampton, VA 23681 USA. RP Shams, QA (reprint author), NASA, Langley Res Ctr, Instrument Syst Dev Branch, AAAC, Mail Stop 236, Hampton, VA 23681 USA. NR 15 TC 1 Z9 1 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 246 EP 255 DI 10.1109/ICIASF.2001.960257 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700028 ER PT B AU Parker, PA DeLoach, R AF Parker, PA DeLoach, R GP IEEE IEEE TI Response surface methods for force balance calibration modeling SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB A "modern design of experiments" (MDOE) approach to balance calibration at NASA Langley Research Center focuses on the application of formal experimental design techniques to address weaknesses in the current calibration methodologies. The Single-Vector Balance Calibration System (SVS) has been developed as an innovative mechanical load application system specifically designed for the efficient and accurate execution of a formal experimental design. This paper emphasizes practical applications of response surface methodology with the analyses of experimental data. Calibration experimental design concepts including the estimation of the required data volume and an evaluation of the model prediction capability are presented. Randomization, replication, and blocking are proposed as means of tactical defense against systematic errors present in all calibration systems. Response surface methods are implemented in obtaining an adequate model with the minimum number of terms and partitioning of the unexplained variance. A systematic approach to augmenting a second order model with higher order terms is discussed. Applying formal experimental design techniques to force balance calibration provides a suite of sophisticated and elegant tools that advance balance calibration technology. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Parker, PA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 283 EP 294 DI 10.1109/ICIASF.2001.960262 PG 12 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700033 ER PT B AU Hart, RC Balla, RJ Herring, GC Jenkins, LN AF Hart, RC Balla, RJ Herring, GC Jenkins, LN GP IEEE IEEE TI Seedless laser velocimetry using heterodyne laser-induced thermal acoustics SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR ID THERMOMETRY; PRESSURE; GRATINGS; SOUND; SPEED; AIR AB A need exists for a seedless equivalent of laser doppler velocimetry (LDV) for use in low-turbulence or supersonic flows or elsewhere where seeding is undesirable or impractical. A compact laser velocimeter using heterodyne non-resonant laser-induced thermal acoustics (LITA) to measure a single component of velocity is described. Neither molecular (e.g. NO2) nor particulate seed is added to the flow. In non-resonant LITA two beams split from a short-pulse pump laser are crossed; interference produces two counterpropagating sound waves by electrostriction. A CW probe laser incident on the sound waves at the proper angle is diffracted towards a detector. Measurement of the beating between the Doppler-shifted light and a highly attenuated portion of the probe beam allows determination of one component of flow velocity, speed of sound, and temperature. The sound waves essentially take the place of the particulate seed used in LDV. The velocimeter was used to study the flow behind a rearward-facing step in NASA Langley Research Center's Basic Aerodynamics Research Tunnel. Comparison is made with pitot-static probe data in the freestream over the range 0 m/s - 55 m/s. Comparison with LDV is made in the recirculation region behind the step and in a well-developed boundary layer in front of the step. Good agreement is found in all cases. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Hart, RC (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 19 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 309 EP 319 DI 10.1109/ICIASF.2001.960265 PG 11 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700036 ER PT B AU Panek, JW AF Panek, JW GP IEEE IEEE TI Verifying data integrity of Electronically Scanned P Pressure Systems at the NASA Glenn Research Center SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB The proper operation of the Electronically Scanned Pressure (ESP) Systems at the NASA Glenn Research Center is critical to accomplish the following goals; acquisition of highly accurate pressure data for the development of future aerospace and commercial aviation systems and continuous confirmation of data quality to avoid costly, unplanned, repeat wind tunnel or turbine testing. Standard automated setup and checkout routines are necessary to accomplish these goals. Data verification and integrity checks occur at three distinct stages, pre-test pressure tubing and system checkouts, daily system validation and in-test confirmation of critical system parameters. This paper will give an overview of the existing hardware, software and methods used to validate data integrity. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Panek, JW (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 320 EP 326 DI 10.1109/ICIASF.2001.960266 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700037 ER PT B AU Adcock, E Bartlett, J Culliton, W Jordan, T Mau, J Bare, EA Florance, J Kahng, S AF Adcock, E Bartlett, J Culliton, W Jordan, T Mau, J Bare, EA Florance, J Kahng, S GP IEEE IEEE TI An embedded wireless data acquisition system for wind tunnel model applications SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB An in-model data acquisition system has been developed that can accept inputs from various sensors and transfer the data wirelessly to an access point outside a wind tunnel's test section. This system was developed as a potential alternative to the current state of wind tunnel data collection, which requires the use of long lengths of cable carrying low-level sensor signals that are extremely susceptible to induced noise. In addition, present methods of retrieving data require that multiple cables be routed across the balance, creating alternate load paths. With the advent of wireless data transfer, not only are these two items addressed, but also the reduction of external cables to the model will reduce wind tunnel model installation time as well as the cost of operation. This paper will describe the results of two separate wind tunnel tests, conducted at NASA Lan-ley's Transonic Dynamics Tunnel and the 16-foot Transonic Tunnel, in which this new embedded system was used to collect data from typical aerodynamic measurements. The recorded results from these wind tunnel experiments include data from pressure, model attitude, temperature, and force balance transducers. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Adcock, E (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 7 TC 3 Z9 4 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 327 EP 336 DI 10.1109/ICIASF.2001.960267 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700038 ER PT B AU Ross, RW AF Ross, RW GP IEEE IEEE TI Integrated component-based data acquisition systems for aerospace test facilities SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB The Multi-Instrument Integrated Data Acquisition System (MIIDAS), developed by the NASA Langley Research Center, uses commercial off the shelf (COTS) products, integrated with custom software, to provide a broad range of capabilities at a low cost throughout the system's entire life cycle. MIIDAS combines data acquisition capabilities with online and post-test data reduction computations. COTS products lower purchase and maintenance costs by reducing the level of effort required to meet system requirements. Object-oriented methods are used to enhance modularity, encourage reusability, and to promote adaptability, reducing software development costs. Using only COTS products and custom software supported on multiple platforms reduces the cost of porting the system to other platforms. The post-test data reduction capabilities of MIIDAS have been installed at four aerospace testing facilities at NASA Langley Research Center. The systems installed at these facilities provide a common user interface, reducing the training time required for personnel that work across multiple facilities. The techniques employed by MIIDAS enable NASA to build a system with a lower initial purchase price and reduced sustaining maintenance costs. With MIIDAS, NASA has built a highly flexible next generation data acquisition and reduction system for aerospace test facilities that meets customer expectations. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ross, RW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 344 EP 352 DI 10.1109/ICIASF.2001.960269 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700040 ER PT B AU Porro, AR AF Porro, AR GP IEEE IEEE TI Pressure probe designs for dynamic pressure measurements in a supersonic flow field SO ICIASF'01: 19TH INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES, RECORD LA English DT Proceedings Paper CT 19th International Congress on Instrumentation in Aerospace Simulation Facilities (ICIASF 01) CY AUG 27-30, 2001 CL NASA GLENN RES CTR, CLEVELAND, OH SP OAI, IEE HO NASA GLENN RES CTR AB A series of dynamic flow field pressure probes were developed for use in large-scale supersonic wind tunnels at NASA Glenn Research Center. These flow field probes include pitot, static, and five-hole conical pressure probes that are capable of capturing fast acting flow field pressure transients that occur on a millisecond time scale. The pitot and static probes can be used to determine local Mach number time histories during a transient event. The five-hole conical pressure probes are used primarily to determine local flow angularity, but can also determine local Mach number. These probes were designed, developed, and tested at the NASA Glenn Research Center. They were also used in a NASA Glenn 10- by 10-Foot Supersonic Wind Tunnel (SWT) test program where they successfully acquired flow field pressure data in the vicinity of a propulsion system during an engine compressor stall and inlet unstart transient event. Details of the design, development, and subsequent use of these probes are discussed in this report. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Porro, AR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7022-8 PY 2001 BP 417 EP 426 DI 10.1109/ICIASF.2001.960277 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BT43F UT WOS:000172972700048 ER PT J AU Kerslake, TW Gefert, LP AF Kerslake, TW Gefert, LP TI Solar power system analyses for electric propulsion missions SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB Solar electric propulsion (SEP) mission architectures are applicable to a wide range of NASA missions including human Mars exploration and robotic exploration of the outer planets. In this paper, we discuss the conceptual design and detailed performance analysis of an SEP stage electric power system (EPS). EPS performance, mass and area predictions are compared for several PV array technologies. Based on these studies, an EPS design for a 1-MW class, Human Mars Mission SEP stage was developed with a reasonable mass, 9.4 metric tons, and feasible deployed array area, 5800 m(2). An EPS was also designed for the Europa Mapper spacecraft and had a mass of 151 kg and a deployed array area of 106 m(2). C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Kerslake, TW (reprint author), NASA, Glenn Res Ctr Lewis Field, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 24 TC 0 Z9 0 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD JAN PY 2001 VL 16 IS 1 BP 3 EP 9 DI 10.1109/62.894171 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 394CN UT WOS:000166506600003 ER PT J AU Filman, RE AF Filman, RE TI Embedded Internet systems come home SO IEEE INTERNET COMPUTING LA English DT Article C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Filman, RE (reprint author), NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. NR 0 TC 9 Z9 11 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1089-7801 J9 IEEE INTERNET COMPUT JI IEEE Internet Comput. PD JAN-FEB PY 2001 VL 5 IS 1 BP 52 EP 53 DI 10.1109/MIC.2001.895142 PG 2 WC Computer Science, Software Engineering SC Computer Science GA 394XR UT WOS:000166550100015 ER PT B AU Small, C AF Small, C GP IEEE IEEE TI Multiresolution analysis of urban reflectance SO IEEE/ISPRS JOINT WORKSHOP ON REMOTE SENSING AND DATA FUSION OVER URBAN AREAS LA English DT Proceedings Paper CT IEEE/ISPRS Joint Workshop on Remote Sensing and Data Fusion over Urban Areas CY NOV 08-09, 2001 CL UNIV ROME LA SAPIENZA, ROME, ITALY SP IEEE, ISPRS, AIT, IEEE, Geosci & Remote Sensing Soc, European Space Agcy, Agenzia Spaziale Italiana, ImageSat Int, Informat Per Territorio, SchlumbergerSema, Telespazio, Amer Soc Photogrammetry & Remote Sensing, Univ Studi Pavia, European Assoc Remote Sensing Labs HO UNIV ROME LA SAPIENZA DE AVIRIS; Ikonos; scale; urban; vegetation ID VEGETATION AB Quantitative analysis of urban reflectance characteristics can provide insights into the spatial and temporal variations in urban reflectance that modulate solar energy fluxes through the urban environment. Characterization of urban reflectance may also facilitate development of algorthms for classification of urban landcover. The characteristic scale of urban reflectance variations is generally between 10 and 20 in and therefore comparable to the Ground Instantaneous Field of View of most operational sensors. This results in spectral heterogeneity that limits the accuracy of pixel-based classifications of urban imagery. Multisensor analyses of urban reflectance indicate that many urban areas can be described as mixtures of three or four spectral endmembers. Most urban building materials lie along a continuum between high and low albedo endmembers but vegetation is a persistent and distinct component of the urban mosaic. Nonlinear mixing generally diminishes with increasing vegetation cover such that linear mixing models may be generally appropriate for urban vegetation estimation. Preliminary analyses of Landsat imagery in a number of urban areas worldwide suggests that linear mixing models with three and four endmember may be generally applicable to urban areas. Spectral heterogeneity at scales of Ills of meters may be a more consistent characteristic of urban reflectance than any single reflectance spectrum. C1 Columbia Univ, Lamont Doherty Earth Observ, NASA, SEDAC Project, Palisades, NY 10964 USA. RP Small, C (reprint author), Columbia Univ, Lamont Doherty Earth Observ, NASA, SEDAC Project, Palisades, NY 10964 USA. NR 11 TC 2 Z9 2 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7059-7 PY 2001 BP 15 EP 19 DI 10.1109/DFUA.2001.985717 PG 5 WC Remote Sensing SC Remote Sensing GA BU17M UT WOS:000175227500004 ER PT B AU Houshmand, B Gamba, P AF Houshmand, B Gamba, P GP IEEE IEEE TI Interpretation of InSAR mapping for geometrical structures SO IEEE/ISPRS JOINT WORKSHOP ON REMOTE SENSING AND DATA FUSION OVER URBAN AREAS LA English DT Proceedings Paper CT IEEE/ISPRS Joint Workshop on Remote Sensing and Data Fusion over Urban Areas CY NOV 08-09, 2001 CL UNIV ROME LA SAPIENZA, ROME, ITALY SP IEEE, ISPRS, AIT, IEEE, Geosci & Remote Sensing Soc, European Space Agcy, Agenzia Spaziale Italiana, ImageSat Int, Informat Per Territorio, SchlumbergerSema, Telespazio, Amer Soc Photogrammetry & Remote Sensing, Univ Studi Pavia, European Assoc Remote Sensing Labs HO UNIV ROME LA SAPIENZA DE InSAR processing; electromagnetic scattering; radar mapping; geometrical structure ID EXTRACTION AB In this paper we present a methodology to detect large geometrical structures from Interferometric Synthetic Aperture Radar(InSAR) measurements. The ortho-rectification of Synthetic Aperture Radar imagery which is a part of Interferometric SAR processing can be a many-pixels to one-pixel mapping. This mapping is used for automatic detection of geometrical structures which are large compared to the SAR resolution. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Houshmand, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7059-7 PY 2001 BP 309 EP 311 DI 10.1109/DFUA.2001.985902 PG 3 WC Remote Sensing SC Remote Sensing GA BU17M UT WOS:000175227500065 ER PT J AU Tao, G Joshi, SM Ma, XL AF Tao, G Joshi, SM Ma, XL TI Adaptive state feedback and tracking control of systems with actuator failures SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Article DE actuator failure; adaptive control; plant-model state matching; state feedback; state tracking ID FAULT-DIAGNOSIS AB Direct adaptive-state feedback control schemes are developed for linear time-invariant plants with actuator failures with characterizations that some of the plant inputs are stuck at some fixed or varying values which cannot be influenced by control action. Conditions and controller structures for achieving plant-model state matching in the presence of actuator failures are derived. Adaptive laws are designed for updating the controller parameters when both the plant parameters and actuator-failure parameters are unknown. Closed-loop stability and asymptotic-state tracking are ensured. Simulation results show that desired system performance is achieved with the developed adaptive actuator failure compensation control designs. C1 Univ Virginia, Dept Elect Engn, Charlottesville, VA 22903 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Tao, G (reprint author), Univ Virginia, Dept Elect Engn, Charlottesville, VA 22903 USA. NR 26 TC 298 Z9 313 U1 3 U2 27 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD JAN PY 2001 VL 46 IS 1 BP 78 EP 95 DI 10.1109/9.898697 PG 18 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 398AR UT WOS:000166732000007 ER PT J AU Cabell, R Palumbo, D Vipperman, J AF Cabell, R Palumbo, D Vipperman, J TI A principal component feedforward algorithm for active noise control: Flight test results SO IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY LA English DT Article DE acoustic application; active noise control; aircraft; feedforward systems; principal component analysis ID CYLINDRICAL-SHELL; INTERIOR NOISE; VIBRATION; REDUCTION; SOUND; MINIMIZATION; SYSTEMS; CABIN AB An in-flight evaluation of a principal component algorithm for feedforward active noise control is discussed. Cabin noise at the first three harmonics of the blade passage frequency (103 Hz) of a Raytheon-Beech 1900D twin turboprop aircraft was controlled using 21 pairs of inertial force actuators bolted to the ring frames of the aircraft; 32 microphones provided error feedback inside the aircraft cabin. In a single frequency noise control test, the blade passage frequency was reduced by 15 dB averaged across the microphone array. When controlling the first three harmonics simultaneously, reductions of 11 dB at 103 Hz, 1.5 dB at 206 Hz. and 2.8 dB at 309 Hz were obtained. For single frequency feedforward control problems, the principal component algorithm is shown to be useful for reducing the computational burden and simplifying the implementation of control effort penalties in high channel count control systems. Good agreement was found between the in-flight behavior of the controller and the predicted optimal control solution. C1 NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. Univ Pittsburgh, Sound Syst & Struct Lab, Pittsburgh, PA 15261 USA. RP Cabell, R (reprint author), NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. NR 23 TC 14 Z9 16 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1063-6536 J9 IEEE T CONTR SYST T JI IEEE Trans. Control Syst. Technol. PD JAN PY 2001 VL 9 IS 1 BP 76 EP 83 DI 10.1109/87.896748 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 396GG UT WOS:000166627500010 ER PT J AU Kory, CL AF Kory, CL TI Effect of geometric azimuthal asymmetries of PPM stack on electron beam characteristics SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE beam optics; C-magnets; MAFIA; magnet misalignment; PPM focusing; shunts; 3-D PIC simulations AB A three-dimensional (3-D) beam optics model has been developed using the electromagnetic particle-in-cell (PIC) code MAFIA. The model includes an electron beam with initial transverse velocity distribution focused by a periodic permanent magnet (PPM) stack. Ail components of the model are simulated in three dimensions, allowing several azimuthally asymmetric traveling wave tube (TWT) characteristics to be investigated for the first time, These include C-magnets, shunts and magnet misalignment and their effects an electron beam behavior. The development of the model is presented and 3-D TWT electron beam characteristics are compared in the absence of and under the influence of the azimuthally asymmetric characteristics described. C1 NASA, Glenn Res Ctr, Analex Corp, Cleveland, OH 44135 USA. RP Kory, CL (reprint author), NASA, Glenn Res Ctr, Analex Corp, Cleveland, OH 44135 USA. NR 8 TC 2 Z9 6 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JAN PY 2001 VL 48 IS 1 BP 38 EP 44 DI 10.1109/16.892165 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 388KA UT WOS:000166178600006 ER PT J AU Wilson, JD AF Wilson, JD TI Design of high-efficiency wide-bandwidth coupled-cavity traveling-wave tube phase velocity tapers with simulated annealing algorithms SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE bandwidth; optimization; power efficiency; simulated annealing; space communications; traveling wave tubes ID POWER AB The output circuit section of a traveling-wave tube (TWT) routinely contains an rf phase velocity taper for the purpose of increasing rf output power and efficiency, By slowing the rf phase velocity in approximate synchronism with the decelerating electron beam bunches, the taper increases power transfer from the beam to the rf wave, Recently, the computational optimization technique of simulated annealing was shown to be very effective in the design of an rf phase velocity taper that significantly increased computed rf power and efficiency of a coupled- cavity TWT. In this paper, two new broadband simulated annealing algorithms are presented that optimize 1) minimum saturated efficiency over a frequency bandwidth and 2) simultaneous bandwidth and minimum efficiency over the frequency band with constant input power The algorithms were incorporated into the NASA 2.5-dimensional (2.5-D) coupled-cavity TWT computer model and used to design optimal phase velocity tapers using a 59-64 GHz coupled-cavity TWT as a baseline model. Compared to the baseline taper design, the computational results of the first broadband algorithm showed an improvement of 73.9% in minimum saturated efficiency, The second broadband algorithm indicates an improvement of 272.7 % in minimum rf efficiency with constant input power drive and an increase in simultaneous bandwidth of 0.5 GHz over that calculated for the baseline TWT. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Wilson, JD (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 15 Z9 19 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JAN PY 2001 VL 48 IS 1 BP 95 EP 100 DI 10.1109/16.892174 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 388KA UT WOS:000166178600015 ER PT J AU Duda, DP Spinhirne, JD Eloranta, EW AF Duda, DP Spinhirne, JD Eloranta, EW TI Atmospheric multiple scattering effects on GLAS altimetry - Part I: Calculations of single pulse bias SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID VERTICAL-DISTRIBUTION; LASER ALTIMETRY; CLOUD; ACCURACY AB Estimates of the effect of pulse stretching on satellite laser altimetry, such as planned for the Geoscience Laser Altimeter System (GLAS), by cloud multiple scattering were made from an analytical method and with Monte Carlo simulations. Altimetry is dependent an the time required for a laser pulse to complete the roundtrip to the surface and return to the transmitter. Since a transmitted Gaussian pulse will be stretched by the effects of multiple scattering, the use of the pulse centroid as the receive time will produce a biased measurement or an apparent delay in the receive time. The magnitude of this delay was found to be dependent an several factors including cloud height, cloud optical depth, cloud particle size, particle shape, and receiver held of view. The delay was found to be largest for low-level clouds with particle radii of 3-20 mum, potentially amounting to altimetry biases of tens of cm. Alternate methods for measuring the receive time, such as a simple Gaussian Bt of the return pulse peak reduce the path delay estimates for all cloud conditions. Since GLAS is a dual mode instrument that includes an atmospheric lidar channel, altimeter measurements that are likely to be significantly contaminated by multiple scattering can be identified. C1 Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. RP Duda, DP (reprint author), Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NR 17 TC 28 Z9 30 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 2001 VL 39 IS 1 BP 92 EP 101 DI 10.1109/36.898668 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 398CJ UT WOS:000166738100009 ER PT J AU Le Vine, DM Swift, CT Haken, M AF Le Vine, DM Swift, CT Haken, M TI Development of the synthetic aperture microwave radiometer, ESTAR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE microwave radiometry; remote sensing; synthetic aperture imaging ID REMOTE-SENSING APPLICATIONS; SOIL-MOISTURE; EARTH AB Ten years ago, the synthetic aperture radiometer (ESTAR) published its first image. Since then, ESTAR has successfully demonstrated the potential of aperture synthesis for microwave remote sensing. This paper summarizes the status of the instrument and presents a modern image for comparison with the "initial results" published ten years ago. C1 Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. Univ Massachusetts, Dept Elect & Comp Engn, Amherst, MA 01001 USA. Raytheon Informat Technol & Sci Serv, Greenbelt, MD 20771 USA. RP Le Vine, DM (reprint author), Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. NR 17 TC 12 Z9 13 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 2001 VL 39 IS 1 BP 199 EP 202 DI 10.1109/36.898685 PG 4 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 398CJ UT WOS:000166738100024 ER PT J AU Moision, BE Orlitsky, A Siegel, PH AF Moision, BE Orlitsky, A Siegel, PH TI On codes that avoid specified differences SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article; Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 24-30, 2000 CL SORRENTO, ITALY SP IEEE, Informat Theory Soc DE capacity; constrained coding; joint spectral radius; magnetic recording ID JOINT SPECTRAL-RADIUS; INFINITE PRODUCTS; MATRICES; CHANNELS AB Certain magnetic recording applications call for a large number of sequences whose differences do not include certain disallowed binary patterns. We show that the number of such sequences increases exponentially with their length and that the growth rate, or capacity, is the logarithm of the joint spectral radius of an appropriately defined set of matrices. We derive a new algorithm for determining the joint spectral radius of sets of nonnegative matrices and combine it with existing algorithms to determine the capacity of several sets of disallowed differences that arise in practice. C1 Lucent Technol, Math Sci Res Ctr, Murray Hill, NJ 07974 USA. Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RP CALTECH, Jet Prop Lab, Commun Syst & Res Sect, Pasadena, CA 91101 USA. EM bmoision@shannon.jpl.nasa.gov; alon@ece.ucsd.edu; psiegel@ucsd.edu NR 29 TC 37 Z9 38 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9448 EI 1557-9654 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD JAN PY 2001 VL 47 IS 1 BP 433 EP 442 DI 10.1109/18.904557 PG 10 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 404WX UT WOS:000167126100042 ER PT J AU Jacobs, WA AF Jacobs, WA TI Magnetic Launch Assist - NASA's vision for the future SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 10th Symposium on Electromagnetic Launch Technology CY APR 25-28, 2000 CL SAN FRANCISCO, CALIFORNIA SP Univ Texas Inst Adv Technol, USA DE launch systems; magnetic launch assist (maglev); National Aeronautics and Space Administration (NASA); space vehicles AB With the ever-increasing cost of getting to space and the need for safe, reliable, and inexpensive ways to access space, The National Aeronautics and Space Administration (NASA) is taking a look at technologies that will get us there, One of these technologies is Magnetic Launch Assist (MagLev), This is the concept of using both magnetic levitation and magnetic propulsion to provide an initial velocity by using electrical power from ground sources. The use of ground generated electricity can significantly reduce operational costs over the consumables necessary to attain the same velocity. The technologies to accomplish this are both old and new The concept of MagLev has been around for a longtime and several MagLev Trains have been developed. Where NASA's MagLev diverges from the traditional train is in the immense amount of power required to propel this vehicle to 183 meters per second in less than 10 seconds. New technologies or the upgrade of existing technologies will need to be investigated in the areas of energy storage and power switching. An added difficulty is the separation of a very large mass (the space vehicle) from the track and the aerodynamics of that vehicle while on the track. These are of great concern and require considerable study and testing, NASA's plan is to mature these technologies in the next 25 years to achieve our goal of launching a full sized space vehicle for under $300 a kilogram. C1 NASA, MSFC, Huntsville, AL 35812 USA. RP Jacobs, WA (reprint author), NASA, MSFC, Huntsville, AL 35812 USA. NR 7 TC 19 Z9 21 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JAN PY 2001 VL 37 IS 1 BP 55 EP 57 DI 10.1109/20.911790 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 418JC UT WOS:000167886300011 ER PT J AU Wang, H Samoska, L Gaier, T Peralta, A Liao, HH Leong, YC Weinreb, S Chen, RCC Nishimoto, M Lai, R AF Wang, H Samoska, L Gaier, T Peralta, A Liao, HH Leong, YC Weinreb, S Chen, RCC Nishimoto, M Lai, R TI Power-amplifier modules covering 70-113 GHz using MMICs SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article; Proceedings Paper CT Radio Frequency Integrated Circuits Conference/Meeting of the Automatic-Radio-Frequency-Techniques-Group CY JUN 12-16, 2000 CL BOSTON, MA SP Automat Radio Frequency Techn Grp DE GaAs; HEMT; millimeter wave; MMIC; power-amplifier module ID OUTPUT AB A set of W-band power amplifier (PA) modules using monolithic microwave integrated circuits (MMICs) have been developed for the local oscillators of the far-infrared and sub-millimeter telescope (FIRST), The MMIC PA chips include three driver and three PAs, designed using microstrip lines, and another two smaller driver amplifiers using coplanar waveguides, covering the entire W-band, The highest frequency PA, which covers 100-113 GHz, has a peak power of greater than 250 mW (25 dBm) at 105 GHz, which is the best output power performance for a monolithic amplifier above 100 GHz to date. These monolithic PA chips are fabricated using 0.1-mum AlGaAs/InGaAs/GaAs pseudomorphic T-gate power high electron-mobility transistors on a 2-mil GaAs substrate, The module assembly and testing, together with the system applications, will also be addressed in this paper. C1 Natl Taiwan Univ, Dept Elect Engn, Taipei 10617, Taiwan. Natl Taiwan Univ, Grad Inst Commun Engn, Taipei 10617, Taiwan. Jet Propuls Lab, Pasadena, CA 91149 USA. TRW Co Inc, Space & Elect Grp, Redondo Beach, CA 90278 USA. Univ Massachusetts, Dept Elect & Comp Engn, Amherst, MA 01003 USA. RP Natl Taiwan Univ, Dept Elect Engn, Taipei 10617, Taiwan. EM hueiwang@ew.ee.ntu.edu.tw RI Weinreb, Steven/K-8747-2012 NR 12 TC 41 Z9 42 U1 2 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9480 EI 1557-9670 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD JAN PY 2001 VL 49 IS 1 BP 9 EP 16 DI 10.1109/22.899956 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 398AX UT WOS:000166732500003 ER PT S AU Wright, J Hartman, F Cooper, B AF Wright, J Hartman, F Cooper, B BE Takemura, H Kiyokawa, K TI Immersive environment technologies for planetary exploration SO IEEE VIRTUAL REALITY 2001, PROCEEDINGS SE PROCEEDINGS OF THE IEEE VIRTUAL REALITY ANNUAL INTERNATIONAL SYMPOSIUM LA English DT Proceedings Paper CT IEEE Virtual Reality 2001 Conference CY MAR 13-17, 2001 CL YOKOHAMA, JAPAN SP IEEE Comp Soc Tech Comm Visualizat & Graph, Virtual Reality Soc Japan DE immersive environments; pathfinder; terrain modelling; visualization; Mars; Rover Control Workstation; JPL AB Immersive environments are successfully, being used to support mission operations at the Jet Propulsion Laboratory. This technology contributed to the Mars Pathfinder Mission in planning sor ties for the Sojourner rover. Results and operational experiences with these tools are being incorporated into the development of the second generation of mission planning tools. NASA's current plan includes two rovers being deployed to Mars in 2003 and early 2004. The next generation Rover Control Workstation utilizes existing technologies and more to provide a multimodal, collaborative, partially immersive environment. This system includes tools for planning long range sorties for highly autonomous rovers, tools for building the three-dimensional (3D) models of the terrain being explored, and advanced tools for visualizing telemetry from remote spacecraft and landers. These tools comprise a system for immersing the operator in the environment of another planet. body ol space to make the mission planning function more intuitive and effective. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP Wright, J (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr,M-S 168-514, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1087-8270 BN 0-7695-0948-7 J9 P IEEE VIRT REAL ANN PY 2001 BP 183 EP 190 DI 10.1109/VR.2001.913785 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA BR93Q UT WOS:000168102100024 ER PT S AU Frank, AO Twombly, IA Barth, TJ Smith, JD AF Frank, AO Twombly, IA Barth, TJ Smith, JD BE Takemura, H Kiyokawa, K TI Finite element methods for real-time haptic feedback of soft-tissue models in virtual reality simulators SO IEEE VIRTUAL REALITY 2001, PROCEEDINGS SE PROCEEDINGS OF THE IEEE VIRTUAL REALITY ANNUAL INTERNATIONAL SYMPOSIUM LA English DT Proceedings Paper CT IEEE Virtual Reality 2001 Conference CY MAR 13-17, 2001 CL YOKOHAMA, JAPAN SP IEEE Comp Soc Tech Comm Visualizat & Graph, Virtual Reality Soc Japan ID ITERATIVE SOLVERS; SYSTEMS AB We have applied the linear elastic finite element method to compute haptic force feedback and domain deformations of soft tissue models for use in virtual reality simulators. Our results show that, for virtual object models of high-resolution 3D data (>10,000 nodes), haptic real time computations (>500 Hz) are not currently, possible using traditional methods. Current research efforts are focused in the following areas: 1) efficient implementation of fully adaptive multi-resolution methods and 2) multi-resolution methods with specialized basis functions to capture the singularity at the haptic interface (point loading). To achieve real time computations, Ive propose parallel processing of a Jacobi preconditioned conjugate gr adient method applied to a reduced system of equations resulting from surface domain decomposition This can effectively be achieved using reconfigurable computing systems such as field programmable gate arrays (FPGA), thereby, providing a flexible solution that allows for new FPGA implementations as improved algorithms become available. The resulting soft tissue simulation system would meet NASA Virtual Glovebox requirements and, at the same time, provide a generalized simulation engine for any immersive environment application, such as biomedical/surgical procedures or interactive scientific applications. C1 NASA, Ames Res Ctr, Ctr Bioinformat, Moffett Field, CA 94035 USA. RP Frank, AO (reprint author), NASA, Ames Res Ctr, Ctr Bioinformat, Moffett Field, CA 94035 USA. NR 25 TC 13 Z9 14 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1087-8270 BN 0-7695-0948-7 J9 P IEEE VIRT REAL ANN PY 2001 BP 257 EP 263 DI 10.1109/VR.2001.913794 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA BR93Q UT WOS:000168102100033 ER PT B AU Walker, JP Houser, PR AF Walker, JP Houser, PR GP IEEE IEEE TI Temporal and spatial resolution requirements for a soil moisture mission SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The temporal and spatial resolution requirements for a soil moisture mission are addressed through a synthetic Identical twin data assimilation study. Simulations were made for observations with various temporal resolutions (1, 2, 3, 5, 10, 15, 20 and 30 days), and spatial resolutions (0.5, 6, 12 18, 30, 60 and 120 minutes of arc). It was found that daily observations of surface soil moisture achieved the best predictions of soil moisture and evapotranspiration, with the greatest impact of temporal resolution being for 1 to 5 days. It was also found that observations with a spatial resolution less than the model resolution produced the best results, with spatial resolutions greater than the model resolution yielding only a slight degradation. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Walker, JP (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 661, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 6 EP 8 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200002 ER PT B AU Owe, M de Jeu, RAM AF Owe, M de Jeu, RAM GP IEEE IEEE TI Retrieving surface soil moisture and vegetation optical depth from satellite microwave observations SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID EMISSION; SCATTERING; MODEL; GHZ AB Soil moisture is a key component of the water and energy balance of the Earth's surface, and as such, is important to many Earth science disciplines. Soil moisture has been identified as a parameter of significant potential for improving the accuracy of large-scale land surface-atmosphere interaction models. Because of high spatial variability, accurate estimates of surface soil moisture are often difficult to make by conventional ground measuring techniques, especially at large spatial scales. Since satellite remote sensing observations are already a spatially averaged value, they are ideally suited for measuring many land surface parameters such as soil moisture. Passive microwave remote sensing presents significant potential for providing regular spatially representative estimates of surface soil moisture at global scales. But, while the optimum wavelength for soil moisture sensing is in the L-band (1.4 GHz or lambda = 21 cm), such a sensor has yet to be deployed operationally. However, new and improved microwave retrieval techniques that maximize the information that can be obtained from less optimum sensors, such as C-band and even X-band, are being developed. Progress from one such study is presented, along with preliminary results from several validation studies. It is currently planned to develop a 20+ year retrospective global database of surface soil moisture, to be made available through the Goddard Space Flight Center Distributed Active Archive Center (DAAC). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Owe, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 16 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 15 EP 18 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200005 ER PT B AU Houser, PR AF Houser, PR GP IEEE IEEE TI Land data assimilation systems SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID CLIMATE; MODELS; SNOW AB Soil moisture, temperature, and snow are integrated states, so errors in land surface forcing and parameterization accumulate in these stores, which leads to incorrect surface water and energy partitioning. However, many innovative new high-resolution land surface observations are becoming available that will provide the additional information necessary to constrain land surface predictions at regional to global scales. These constraints can be imposed in two ways. Firstly, by forcing the land surface primarily by observations (such as precipitation and radiation), the often severe atmospheric numerical weather prediction land surface forcing biases can be avoided. Secondly, by employing innovative land surface data assimilation techniques, observations of land surface storages such as soil temperature and moisture can be used to constrain unrealistic simulated storages. Land Data Assimilation Systems (LDAS), are basically uncoupled land surface models that are forced primarily by observations, and are therefore not affected by NWP forcing biases. Land Data Assimilation Systems also have the ability to maximize the utility of limited land surface observations by propagating their information throughout the land system to unmeasured times and locations. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Houser, PR (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 661, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 20 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 28 EP 30 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200009 ER PT B AU O'Neill, PE Hsu, AY Kim, EJ Peters-Lidard, C England, AW AF O'Neill, PE Hsu, AY Kim, EJ Peters-Lidard, C England, AW GP IEEE IEEE TI Performance comparison of a point-scale LSP model and the NOAH distributed SVAT model for soil moisture estimation using microwave remote sensing SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch 974, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP O'Neill, PE (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch 974, Lab Hydrospher Proc, Code 661, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 34 EP 36 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200011 ER PT B AU van Zyl, JJ Kim, YJ AF van Zyl, JJ Kim, YJ GP IEEE IEEE TI A quantitative comparison of soil moisture inversion algorithms SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID SURFACE AB This paper compares the performance of four bare surface radar soil moisture inversion algorithms in the presence of measurement errors. The particular errors considered include calibration errors, system thermal noise, local topography and vegetation cover. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP van Zyl, JJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 37 EP 39 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200012 ER PT B AU Ungar, SG AF Ungar, SG GP IEEE IEEE TI Overview of EO-1, the first 120 days SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The first 120 days of the EO-1 mission, constituting the accelerated mission, far exceeded the goal of acquiring sufficient data to insure meeting minimal EO-1 validation requirements. The strategy of using Southern Hemisphere test sites during the Northern Hemisphere winter solstice has left EO-1 with a rich legacy of data for a large variety of ecosystems under varying conditions. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Ungar, SG (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 43 EP 45 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200014 ER PT B AU Reuter, DC McCabe, GH Dimitrov, R Graham, SM Jennings, DE Matsumura, MM Rapchun, DA Travis, JW AF Reuter, DC McCabe, GH Dimitrov, R Graham, SM Jennings, DE Matsumura, MM Rapchun, DA Travis, JW GP IEEE IEEE TI The LEISA/Atmospheric Corrector (LAC) on EO-1. SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The LEISA (Linear Etalon Imaging Spectral Array) Atmospheric Corrector (LAC or AC) on EO-1 is a hyperspectral imager providing 256 channel continuous spectra in the wavelength range from 0.93 to 1.58 microns. It has a single pixel spatial resolution of 250 meters, a 185 km swath-width and a spectral resolving power (lambda/Deltalambda) of 200 or greater (< 10 nm) throughout its spectral range. The imager employs a wedged filter, a sophisticated 2-dimensional filter whose transmission wavelength varies along one of the dimensions, to provide its spectral resolution. The use of the wedged filter greatly simplifies the optical/mechanical design, so that the instrument is adaptable to a wide variety of platforms (i.e. it is a "bolt on" imager). In this paper we shall present an overview of the camera highlighting its unique features from both a design and data standpoint. We shall discuss the pre-launch instrument characterization process and on-orbit performance. This shall include the use of solar and lunar calibration techniques to obtain absolute radiometric calibration. The application of the data to the problem of atmospheric correction of high-spatial resolution multi-spectral satellite images (e.g Landsat-type) shall be discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reuter, DC (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. RI Jennings, Donald/D-7978-2012 NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 46 EP 48 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200015 ER PT B AU Imhoff, ML Johnson, P Carson, S Lawrence, W Condit, R Stutzer, D Wright, J AF Imhoff, ML Johnson, P Carson, S Lawrence, W Condit, R Stutzer, D Wright, J GP IEEE IEEE TI VHF radar mapping of forest biomass in Panama SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB In 1998 a VHF (80-116 MHz) synthetic aperture radar (BioSAR) mounted on NASA's C-130 aircraft collected data over a series of Smithsonian Tropical Research Institute (STRI) test sites along the Panama Canal Zone in the Republic of Panama. A biomass surface map of the area was generated by interpolating between BioSAR measurement points for a set of parallel flight lines. Accuracy testing showed that there was good agreement (+/-10%) between the sensor-derived estimates of above ground biomass and the field data. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Imhoff, ML (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 121 EP 122 PG 2 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200038 ER PT B AU Hensley, S Chapin, E Freedman, A Le, C Madsen, S Michel, T Rodriguez, E Siqueira, P Wheeler, K AF Hensley, S Chapin, E Freedman, A Le, C Madsen, S Michel, T Rodriguez, E Siqueira, P Wheeler, K GP IEEE IEEE TI First P-band results using the GeoSAR mapping system SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hensley, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-235, Pasadena, CA 91109 USA. RI Siqueira, Paul/D-9760-2016 OI Siqueira, Paul/0000-0001-5781-8282 NR 3 TC 6 Z9 6 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 126 EP 128 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200040 ER PT B AU Einaudi, F Uccellini, L Purdom, J Rogers, D Gelaro, R Dodge, J Atlas, R Lord, S AF Einaudi, F Uccellini, L Purdom, J Rogers, D Gelaro, R Dodge, J Atlas, R Lord, S GP IEEE IEEE TI Weather prediction improvement using advanced satellite technology SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Einaudi, F (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 150 EP 153 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200048 ER PT B AU Smith, JA Wickland, DE Crawford, MK Cihlar, J Schnase, JL AF Smith, JA Wickland, DE Crawford, MK Cihlar, J Schnase, JL GP IEEE IEEE TI Advancing our biological and ecological predictive capabilities SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Policy makers, resource managers, and decision makers in the public and private sectors increasingly call for more and better predictions of future environmental conditions and of the impacts that environmental and societal change may have on ecosystems and the ecological goods and services that people depend upon. By 2025, a suite of powerful new remote sensing, analytical, and computational tools and capabilities will be in place. These tools will be used to assess the health and functioning of global ecosystems and to predict the effects of natural and anthropogenic change, such as extreme natural events, climate change, changes in land use, pollution, species invasions, and pest and disease outbreaks. The resulting ecological forecasts will incorporate the interactive effects of multiple biotic and abiotic stressors as well as socioeconomic factors. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 154 EP 156 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200049 ER PT B AU Schoeberl, MR Douglass, AR Hilsenrath, E Luce, M Barnett, J Beer, R Waters, J Gille, J Levelt, PF DeCola, P AF Schoeberl, MR Douglass, AR Hilsenrath, E Luce, M Barnett, J Beer, R Waters, J Gille, J Levelt, PF DeCola, P GP IEEE IEEE TI The EOS Aura Mission SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID TROPOSPHERIC WATER-VAPOR; MICROWAVE LIMB SOUNDER; UARS MLS; OZONE; HIRDLS; DESIGN AB The EOS Aura Mission is designed to make comprehensive chemical measurements of the troposphere and stratosphere. In addition the mission will make measurements of important climate variables such as aerosols, and upper tropospheric water vapor and ozone. Aura will launch in late 2003 and will fly 15 minutes behind EOS Aqua in a polar sun synchronous ascending node orbit with a 1:30 pm equator crossing time. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Schoeberl, MR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Douglass, Anne/D-4655-2012 NR 16 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 227 EP 232 PG 6 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200073 ER PT B AU Liu, WT Hu, H Tang, WQ Xie, XS AF Liu, WT Hu, H Tang, WQ Xie, XS GP IEEE IEEE TI Continuous strife for better coverage and more details in ocean surface winds measurements - from Midori and ADEOS-2 to GCOM SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The series of joint U.S.-Japan spaceborne scatterometers missions to provide continuous measurements of ocean wind vectors is reviewed. Examples of the scientific impact of the continuous effort in improving spatial resolution and coverage are provided,. The plan for future missions is reviewed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, WT (reprint author), CALTECH, Jet Prop Lab, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 322 EP 324 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200104 ER PT B AU Masuoka, E Teague, M AF Masuoka, E Teague, M GP IEEE IEEE TI Science investigator-iced global processing for the MODIS instrument SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Masuoka, E (reprint author), NASA, Goddard Space Flight Ctr, Code 922, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 384 EP 386 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200125 ER PT B AU Crisp, D Delin, K Chao, Y Lemmerman, L AF Crisp, D Delin, K Chao, Y Lemmerman, L GP IEEE IEEE TI Earth science system of the future: Observing, processing, and delivering data products directly to users SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Advances in our understanding and ability to predict changes in our environment will require more comprehensive and coordinated measurements, data delivery systems, and modeling tools. The advanced Earth observing system will incorporate an integrated web of sensors deployed on the surface, in the air, and in space. The space-based assets will include both active and passive sensors in low Earth orbit, large aperture sensors in geostationary orbits, and sentinel satellites at L1 and L2. Data collected by these platforms will be coordinated by an advanced, semi-autonomous, network that links these systems each other and provides a seamless interface with data processing centers. There, advanced numerical modeling tools will be used to rapidly assimilate, evaluate, and disseminate this information directly to users. To illustrate utility of this system architecture, we describe its application to studies of rapidly evolving natural hazards. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Crisp, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 429 EP 431 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200139 ER PT B AU Peri, F Hartley, JB Duda, JL AF Peri, F Hartley, JB Duda, JL GP IEEE IEEE TI The future of instrument technology for space-based remote sensing for NASA's Earth Science Enterprise SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The vision of the Earth Science Enterprise (ESE) of the National Aeronautics and Space Administration (NASA) established a variety of science challenges for the next 25 years, relating to predictions of weather, climate, and foreseeable changes in the Earth's environment. In this paper, we discuss the attendant needs for space-based remote sensing technologies. In addition, we suggest some strategies for deploying the necessary assets. C1 NASA, Goddard Space Flight Ctr, Earth Sci Technol Off, Greenbelt, MD 20771 USA. RP Peri, F (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Technol Off, Code 711, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 432 EP 435 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200140 ER PT B AU Prescott, GE Smith, SA Moe, KL AF Prescott, GE Smith, SA Moe, KL GP IEEE IEEE TI Information system technology challenges for NASA's Earth Science Enterprise SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Future NASA Earth observing satellites will carry high-precision instruments capable of producing large amounts of scientific data. The anticipated networking of these instrument-laden satellites into a web-like array of sensors creates significant challenges in the processing, transmission, storage and distribution of data and data products - the essential elements of what ire refer to as "Information Technology": Future systems will require the fastest processors, the highest communication channel transfer rates, and the largest data storage capacity to insure that data flows smoothly from the satellite-based instrument to the ground-based archive. In this paper, we discuss those critical information technologies for Earth observing satellites that mill support the next generation of space-based scientific measurements of planet Earth, and insure that data and information products provided by these systems will be accessible to scientists and the user community in general. C1 NASA HQ, Washington, DC 20546 USA. RP Prescott, GE (reprint author), NASA HQ, Code Y, Washington, DC 20546 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 436 EP 438 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200141 ER PT B AU Lemmerman, L Delin, K Hadaegh, F Lou, M Bhasin, K Bristow, J Connerton, R Pasciuto, M AF Lemmerman, L Delin, K Hadaegh, F Lou, M Bhasin, K Bristow, J Connerton, R Pasciuto, M GP IEEE IEEE TI Earth Science Vision: Platform technology challenges SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Advanced new platform technologies are critical to the realization of the Earth Science Vision in the 2020 timeframe. Examples of the platform technology challenges and current state-of-the-art capabilities are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lemmerman, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 439 EP 443 PG 5 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200142 ER PT B AU Madsen, SN Edelstein, W DiDomenico, LD LaBrecque, J AF Madsen, SN Edelstein, W DiDomenico, LD LaBrecque, J GP IEEE IEEE TI A geosynchronous synthetic aperture radar; for tectonic mapping, disaster management and measurements of vegetation and soil moisture SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB A geosynchronous synthetic aperture radar (SAR) with an orbit inclination of 50-65degrees can provide daily coverage of all of North and South America. Longitudinally, the width of the mapped area would be on the order of +/-50degrees at the Equator, somewhat more at the most northern/southern latitudes. Within the area mapped, very good temporal coverage can be obtained -up to several mappings during the 12 hours per day where the satellite is in the "right" hemisphere. This would be a key capability in relation to disaster management, tectonic mapping and modeling, vegetation and soil moisture mapping, and for operational and semi-operational requirements. A constellation of geosynchronous satellites could provide global coverage. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Madsen, SN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 35 Z9 41 U1 2 U2 8 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 447 EP 449 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200144 ER PT B AU Coughlan, JC Bjorkstead, EP AF Coughlan, JC Bjorkstead, EP GP IEEE IEEE TI Processors, pipelines, and protocols for advanced modeling networks SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB NASA's Earth Science Enterprise has established the goal of developing a predictive capability for the Earth System. NASA uses the vantage point of space to provide information about Earth's land, atmosphere, ice, oceans, and biota that is obtainable in no other way. To enhance predictive capabilities, NASA is planning a sensor web to collect data across a range of spatio-temporal scales. The end-to-end process of data collection, data assimilation, biogeophysical modeling and prediction is inseparable and predominately enabled by software. Software transforms the raw data into usable products and information and software disseminates these products to end-users. New information system technologies are needed to enable better prediction, flexible data assimilation and model coupling to build integrated Earth system models. Advancement of our modeling capabilities will require not only faster processing, but new programming methods, new algorithms, high-speed data pipelines, and interoperable architectures that allow the networking of diverse Earth System models. C1 NASA, Ames Res Ctr, Moffett Field, CA 92035 USA. RP Coughlan, JC (reprint author), NASA, Ames Res Ctr, Mail Stop 242-4, Moffett Field, CA 92035 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 450 EP 452 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200145 ER PT B AU Chapin, E Hensley, S Michel, TR AF Chapin, E Hensley, S Michel, TR GP IEEE IEEE TI Calibration of an across track interferometric P-Band SAR SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The techniques for interferometric calibration of the GeoSAR P-Band system are discussed. These techniques are demonstrated using preliminary GeoSAR data. RP Chapin, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-235, Pasadena, CA 91109 USA. NR 3 TC 6 Z9 7 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 502 EP 504 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200162 ER PT B AU Priestley, KJ Barkstrom, BR Lee, RB Green, RN AF Priestley, KJ Barkstrom, BR Lee, RB Green, RN GP IEEE IEEE TI A comprehensive radiometric validation protocol or the CERES earth radiation budget climate record sensors SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID ENERGY SYSTEM CERES; CLOUDS AB The CERES Flight Model 1 and 2 instruments were launched aboard NASA's Earth Observing System (EOS) Terra Spacecraft on December 18, 1999 into a 705 Km sunsynchronous orbit with a 10:30 a.m. equatorial crossing time. These instruments supplement measurements made by the CERES Proto Flight Model (PFM) instrument launched aboard NASA's Tropical Rainfall Measuring Mission (TRMM) spacecraft on November 27, 1997 into a 350 Kin, 38-degree mid-inclined orbit: An important aspect of the EOS program is the rapid archival and dissemination of datasets measured by EOS instruments to the scientific community. On September 22, 2000 the CERES Science Team voted to archive the Edition 1 CERES/Terra Level 1b and Level 2 and 3 ERBE-Like data products. These products consist of instantaneous filtered and unfiltered radiances through temporally and spatially averaged TOA fluxes. CERES filtered radiance measurements cover three spectral bands including shortwave (0.3 to 5 mum), total (0.3 to <100 mum) and an atmospheric window channel (8 to 12 mum). The current work summarizes both the philosophy and results of validation efforts undertaken to quantify the quality of the Terra data products as well as the level of agreement between the Terra and TRAM datasets. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Priestley, KJ (reprint author), NASA, Langley Res Ctr, 21 Langley Blvd, Hampton, VA 23681 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 511 EP 514 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200165 ER PT B AU Markham, BL Barker, JL Kaita, E Barsi, JA Helder, DL Palluconi, FD Schott, JR Thome, KJ Morfitt, R Scaramuzza, P AF Markham, BL Barker, JL Kaita, E Barsi, JA Helder, DL Palluconi, FD Schott, JR Thome, KJ Morfitt, R Scaramuzza, P GP IEEE IEEE TI Landsat-7 ETM+ radiometric calibration: Two years on-orbit SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Landsat-7 has been in orbit for 2 years as of April 15, 2001 and operationally providing calibrated data products for 2 years as of June 28, 2001. A radiometric calibration team consisting of scientists and analysts from the Landsat Project Science Office, the Landsat-7 Image Assessment System and four universities evaluates the calibration based on on-board and ground-look (vicarious) calibration methodologies. The results are assembled and compared semi-annually and the calibration parameter files are adjusted as necessary. To date the combined results for the reflective bands have not shown any change from pre-launch values. The pre-launch values continue to be used for data processing, with the uncertainty estimated at less than 5%. In the thermal band, the vicarious calibration results indicated a 0.31 W/m(2) sr mum bias in the calibration. This bias results in the ETM+ derived temperatures being about 3K high. The calibration parameter file was updated October 1, 2000 to remove this bias, however the U.S. Landsat Product Generation System (LPGS) software required modification that was not incorporated until December 20, 2000. All LPGS data products generated since this date have the correct thermal band calibration, regardless of image acquisition date, with uncertainties at approximately the 1% level. C1 NASA, Goddard Space Flight Ctr, Landsat Project Sci Off, Greenbelt, MD 20771 USA. RP Markham, BL (reprint author), NASA, Goddard Space Flight Ctr, Landsat Project Sci Off, Code 923, Greenbelt, MD 20771 USA. RI Thome, Kurtis/D-7251-2012; Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 518 EP 520 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200167 ER PT B AU Williams, DL Irons, JR Masek, JG Goward, SN AF Williams, DL Irons, JR Masek, JG Goward, SN GP IEEE IEEE TI Systematic earth observation: Significant progress as we enter the 21st century with Landsat 7 SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Landsat Earth observation approach introduced in 1972 created a new way of monitoring land cover and land use globally. The Landsat 7 mission, successfully launched on April 15, 1999, continues those observations and demonstrates significant progress in precise numerical radiometry, spectral differentiation and seasonally repetitive monitoring as we enter the 21(st) century. A long-term data acquisition plan was designed to ensure that substantially cloud-free, seasonal coverage would be recorded and archived in the U.S. for all land areas of the globe. Substantial improvements in calibration procedures have also been made to ensure long-term stability in the acquired spectral radiometry. A Landsat Science Team consisting of representatives from U.S. universities and government agencies has been addressing the technical and analytical means to process and analyze the core of this observation record. The expected outcome of these efforts is a rapid improvement in understanding the Earth system, as well as conceptual knowledge that will underpin significant advancements in the application of this technology for commercial, operational, educational and research purposes. The lessons learned from the Landsat 7 mission are expected to have a significant, positive influence on future Landsat-like missions. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Williams, DL (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. RI Masek, Jeffrey/D-7673-2012; Irons, James/D-8535-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 540 EP 542 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200174 ER PT B AU Murphy, RE Taylor, R DeVito, DS Smith, JK Henegar, J Dodge, JC Wilczynski, P Kelly, M Schneider, S Welsch, C Bloom, H Mango, SA Crison, M AF Murphy, RE Taylor, R DeVito, DS Smith, JK Henegar, J Dodge, JC Wilczynski, P Kelly, M Schneider, S Welsch, C Bloom, H Mango, SA Crison, M GP IEEE IEEE TI The NPOESS preparatory project: Mission concept and status SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB NPP is a joint NASA/IPO mission to extend selected systematic measurements initiated by the Terra and Aqua missions and to proovide risk reduction for NPOESS. The key sensor properties and mission features are summarized. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Murphy, RE (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 543 EP 545 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200175 ER PT B AU Chang, ATC Chiu, LS AF Chang, ATC Chiu, LS GP IEEE IEEE TI Non-systematic errors of monthly oceanic rain rate from microwave radiometry SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID TROPICAL RAINFALL AB Global monthly rainfall maps derived from microwave sensors are now routinely produced from data collected by the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I) and Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). Since the DMSP (F-13 and F-14) and TMI satellites have different orbits and swath structure, they have different sampling errors. In this paper the non-systematic errors, which are dominated by sampling errors, of monthly oceanic rainfall over 5degrees latitude by 5degrees longitude boxes are calculated separately for SSM/Is and TMI for three years (1998 to 2000). The non-systematic errors are 21.4%, 21.9% and 19.1% for SSM/I of F-13 and F-14, and TMI, respectively. The non-systematic error for TMI is less than 1 mm day(-1) for rain rates up to 6 mm day(-1), and is about 15-20% at higher rain rates. This is smaller than that for either F-13 or F-14 SSM/I alone at the low rain rates, but is comparable at the high rain rates (> 6 mm day(-1)). A combination of F-13 and F-14 SSM/I rain rates reduces the non-systematic error to slightly lower (15.2%) than that of the TMI alone. It is argued that a refined space-borne sampling strategy, such as that proposed by the Global Precipitation Mission (GPM), is needed to reduce the sampling errors to better than 10% at high rain rates. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Chang, ATC (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 655 EP 657 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200200 ER PT B AU Stocker, EF Kwiatkowski, J Kelley, O AF Stocker, EF Kwiatkowski, J Kelley, O GP IEEE IEEE TI Gridded hourly text products: A TRMM data reduction approach SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID MEASURING MISSION TRMM AB The quantity of satellite observations available for the study of global precipitation is both a blessing and a curse. The sheer volume and complexity of many of the data products makes it difficult for many researchers to use. This paper describes one approach that TRMM used to reduce the volume and complexity of data. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stocker, EF (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 658 EP 660 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200201 ER PT B AU Skofronick-Jackson, GM Wang, JR Weinman, JA AF Skofronick-Jackson, GM Wang, JR Weinman, JA GP IEEE IEEE TI Iterative 2D hydrometeor profile retrievals using radar and wideband radiometer observations SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID WAVE IMAGING RADIOMETER; CLOUD; PRECIPITATION C1 Univ Maryland Baltimore Cty, GEST Ctr, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Skofronick-Jackson, GM (reprint author), Univ Maryland Baltimore Cty, GEST Ctr, NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 664 EP 666 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200203 ER PT B AU Flaming, GM Adams, WJ Neeck, SP Smith, EA AF Flaming, GM Adams, WJ Neeck, SP Smith, EA GP IEEE IEEE TI Planning for global precipitation measurement SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Tropical Rainfall Measuring Mission (TRAIM) has demonstrated the importance of rain measurements for both the science and the meteorological communities. The National Aeronautics and Space Administration (NASA) has recently established a Pre-Formulation Office to initiate the planning for Global Precipitation Measurement (GPM), a follow-on to TRMM. GPM is envisioned as a multi-satellite constellation using passive and active microwave sensors to take rainfall measurements every few hours on a global basis. This paper will discuss the programmatic status of GPM, and opportunities for international partnership arrangements. In addition, the top-level science requirements as currently identified, and concepts under consideration for obtaining the desired measurements, will be briefly discussed. Finally, ground data processing and distribution, and an overview of instrument concepts will be addressed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Flaming, GM (reprint author), NASA, Goddard Space Flight Ctr, Code 700-1, Greenbelt, MD 20771 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 685 EP 687 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200210 ER PT B AU Im, E Durden, SL Li, FK Wu, C Haddad, ZS AF Im, E Durden, SL Li, FK Wu, C Haddad, ZS GP IEEE IEEE TI CloudSat radar instrument design and development status SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Cloud Profiling Radar is the key science instrument for the CloudSat Mission to acquire a global data set of vertical atmospheric cloud structure and its variability. CPR is a 94-GHz nadir-looking radar that measures the power backscattered by clouds as a function of distance from the radar. This sensor is expected to provide cloud measurements at a 500-m vertical resolution and a 1.5-km horizontal resolution. CPR will operate in a short-pulse mode and will yield measurements at a minimum detectable sensitivity of -28 dBZ. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Im, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 691 EP 693 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200212 ER PT B AU Le Moigne, J Netanyahu, NS Masek, JG Mount, DM Goward, SN AF Le Moigne, J Netanyahu, NS Masek, JG Mount, DM Goward, SN GP IEEE IEEE TI Robust matching of wavelet features for sub-pixel registration of Landsat data SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB For many Earth and Space Science applications, automatic geo-registration at sub-pixel accuracy has become a necessity. In this work, we are focusing on building an operational system, which will provide a sub-pixeI accuracy registration of Landsat-5 and Landsat-7 data. The input to our registration method consists of scenes that have been geometrically and radiometrically corrected. Such preprocessed scenes are then geo-registered relative to a database of Landsat chips. The method assumes a transformation composed of a rotation and a translation, and utilizes rotation- and translation-invariant wavelets to extract image features that are matched using statistically robust feature matching and a partial Hausdorff distance metric. The registration process is described and results on four Landsat input scenes of the Washington, D.C. area are presented. C1 NASA, Goddard Space Flight Ctr, Appl Informat & Sci Branch, Greenbelt, MD 20771 USA. RP Le Moigne, J (reprint author), NASA, Goddard Space Flight Ctr, Appl Informat & Sci Branch, Code 935, Greenbelt, MD 20771 USA. RI Masek, Jeffrey/D-7673-2012 NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 706 EP 708 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200217 ER PT B AU Rosen, PA Hensley, S Gurrola, E Rogez, F Chan, S Martin, J Rodriguez, E AF Rosen, PA Hensley, S Gurrola, E Rogez, F Chan, S Martin, J Rodriguez, E GP IEEE IEEE TI SRTM C-band topographic data: Quality assessments and calibration activities SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rosen, PA (reprint author), CALTECH, Jet Prop Lab, MS 300-235,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 14 Z9 16 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 739 EP 741 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200228 ER PT B AU Rosen, P Eineder, M Rabus, B Gurrola, E Hensley, S Knopfle, W Breit, H Roth, A Werner, M AF Rosen, P Eineder, M Rabus, B Gurrola, E Hensley, S Knopfle, W Breit, H Roth, A Werner, M GP IEEE IEEE TI SRTM-Mission - Cross comparison of X and C band data properties SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rosen, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 4 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 751 EP 753 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200232 ER PT B AU Kelly, REJ Chang, ATC Foster, JL Hall, DK AF Kelly, REJ Chang, ATC Foster, JL Hall, DK GP IEEE IEEE TI Development of a passive microwave global snow monitoring algorithm for the Advanced Microwave Scanning Radiometer-EOS SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB This paper describes research conducted to develop an integrated snow monitoring algorithm at global and regional scales for the Advanced Microwave Scanning Radiometer - EOS (AMSR-E) due for launch on Aqua in 2001. The AMSR-E will have improved spatial and spectral resolution for snow cover monitoring compared with the currently available Special Sensor Microwave Imager (SSM/I) instrument. Two algorithm calibration elements are proposed which epitomise the calibration effort. The first, which is described, is the production of a monthly geographically distributed SWE coefficient is produced that reflects long-term average monthly characteristics of SWE. The second element, which is still under development and is not described, is to encompass local variability in SWE determined by geographic variations in snowpack physical characteristics. Simulated AMSR-E PM observations (derived from SSM/I data) of land surfaces and ancillary data (forest fraction) are combined through emipirical statistical and geostatistical models to produce global monthly coefficients that are used to estimate SWE from a physically-based model. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RP Kelly, REJ (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RI Hall, Dorothy/D-5562-2012 NR 12 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 804 EP 806 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200250 ER PT B AU Foster, JL Chang, ATC Hall, DK Kelley, R AF Foster, JL Chang, ATC Hall, DK Kelley, R GP IEEE IEEE TI Passive microwave measurements of seasonal snow in South America SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Foster, JL (reprint author), NASA, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI Hall, Dorothy/D-5562-2012; Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 807 EP 809 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200251 ER PT B AU Moghaddam, M Dungan, JL AF Moghaddam, M Dungan, JL GP IEEE IEEE TI Estimating forest variables from fusion of SAR and TM data and analytical scattering and reflectance models SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB A method for simultaneous integration of synthetic aperture radar (SAR) and optical remote sensing data in an estimation algorithm is presented which results in estimates of foliage mass over a larger range of values and more accurately than would be possible with either data type alone. The improved estimates are expected to result in more accurate calculation of ecosystem exchange from biogeochemistry models. The solution uses simplified closed-form models of scattering and reflectance derived from more complicated numerical models in a nonlinear estimation algorithm. Results are compared with available field measurements for 25 reference plots. A thorough error analysis is carried out to characterize the statistical accuracy of the estimation results with respect to errors in the microwave scattering and optical reflectance models. The foliage mass data are ultimately to be used to derive leaf area index (LAI), an essential driving variable for forest process models. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Moghaddam, M (reprint author), Jet Prop Lab, MS 300-227,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Dungan, Jennifer/G-9921-2016 OI Dungan, Jennifer/0000-0002-4863-1616 NR 4 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 885 EP 887 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200277 ER PT B AU Piepmeier, J Racette, P Wang, J Crites, A Doiron, T Engler, C Lecha, J Powers, M Simon, E Triesky, M AF Piepmeier, J Racette, P Wang, J Crites, A Doiron, T Engler, C Lecha, J Powers, M Simon, E Triesky, M GP IEEE IEEE TI An airborne conical scanning millimeter-wave imaging radiometer (CoSMIR) SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB An airborne Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) for high-altitude observations from the NASA ER-2 is discussed. The primary application of the CoSMIR is water vapor profile remote sensing. Four radiometers operating at 50 (3 channels), 92, 150, and 193 (3 channels) GHz provide spectral coverage identical to nine of the SSMIS high-frequency channels. Constant polarization-basis conical and cross-track scanning capabilities are achieved using an elevation-under-azimuth two-axis gimbals. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Piepmeier, J (reprint author), NASA, Goddard Space Flight Ctr, Code 544-555-567&975, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 894 EP 896 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200280 ER PT B AU Wilson, WJ Yueh, SH Li, FK Dinardo, S Yi, C Koblinsky, C Lagerloef, G Howden, S AF Wilson, WJ Yueh, SH Li, FK Dinardo, S Yi, C Koblinsky, C Lagerloef, G Howden, S GP IEEE IEEE TI Ocean surface salinity remote sensing with the JPL Passive/Active L-/S-band (PALS) microwave instrument SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB This paper describes the measurements acquired by the aircraft Passive/Active L-/S-band (PALS) instrument from two field campaigns in 1999 and 2000. These measurements were in support of the development of ocean surface salinity remote sensing techniques for the future Aquarius space mission. The 2000 measurements demonstrated the aircraft radiometer stability of +/-0.3 K over time periods of 30 minutes with a salinity measurement accuracy of 0.2 PSS. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilson, WJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Bldg 168-327, Pasadena, CA 91109 USA. NR 3 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 937 EP 939 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200294 ER PT B AU Doiron, TA AF Doiron, TA GP IEEE IEEE TI Low power silicon germanium electronics for microwave radiometers SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Space-based radiometric observations of key hydrological parameters (e.g., soil moisture) at the spatial and temporal scales required in the post-2002 era face significant technological challenges. These measurements are based on relatively low frequency thermal microwave emission (at 1.4 GHz for soil moisture and salinity, 10 GHz and up for precipitation, and 19 and 37 GHz for snow). The long wavelengths at these frequencies coupled with the high spatial and radiometric resolutions required by the various global hydrology communities necessitate the use of very large apertures (e.g., >20 in at 1.4 GHz) and highly integrated stable RF electronics on orbit. Radio-interferometric techniques such as Synthetic Thinned Array Radiometry (STAR), using silicon germanium (SiGe) low power radio frequency integrated circuits (RFIC), is one of the most promising technologies to enable very large non-rotating apertures in space. STAR instruments are composed of arrays of small antenna/receiving elements that are arranged so that the collecting area is smaller than an equivalent real aperture system, allowing very high packing densities for launch. A 20-meter aperture at L-band, for example, will require >1000 of these receiving elements. SiGe RFIC's reduce power consumption enough to make an array like this possible in the power-limited environment of space flight. An overview of the state-of-the art will be given, and current work in the area of SiGe radiometer development for soil moisture remote sensing will be discussed. C1 NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Greenbelt, MD 20771 USA. RP Doiron, TA (reprint author), NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Code 555, Greenbelt, MD 20771 USA. NR 3 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1007 EP 1009 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200316 ER PT B AU Le Vine, D Koblinsky, C Pellerano, F Lagerloef, G Chao, Y Yueh, S Wilson, W AF Le Vine, D Koblinsky, C Pellerano, F Lagerloef, G Chao, Y Yueh, S Wilson, W GP IEEE IEEE TI The measurement of salinity from space: Sensor concept SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID MICROWAVE AB Salinity in the open ocean is important for understanding ocean dynamics and for modeling energy exchange with the atmosphere. The potential exists for obtaining global coverage of sea surface salinity using a microwave sensor in space operating at L-band (1.4 GHz). Work is currently underway at NASA's Goddard Space Flight Center and the Jet Propulsion Laboratory to define a sensor to make this measurement from space. The goal is to achieve spatial resolution on the order of 100 km with a revisit time of 14 days or less and a calibration accuracy equivalent to 0.2 psu. It is planned to combine the radiometer with a radar to help correct for surface roughness. It is believed that such a sensor system can be developed within the confines of a future Earth Sensor System Pathfinder (ESSP) mission. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Le Vine, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1010 EP 1012 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200317 ER PT B AU Thompson, AM Hudson, RD Frolov, AD Witte, JC Kucsera, TL AF Thompson, AM Hudson, RD Frolov, AD Witte, JC Kucsera, TL GP IEEE IEEE TI Tropospheric ozone from space: Tracking pollution with the TOMS (Total Ozone Mapping Spectrometer) instrument SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID MODIFIED-RESIDUAL METHOD AB Two new products [1,2] have been developed from the TOMS (Total Ozone Mapping Spectrometer) satellite instrument to resolve pollution in the tropics and mid-latitudes. The modified-residual technique [3, 4] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The second method, the TOMS-Direct method [5] is a new algorithm that uses TOMS radiances to extract tropospheric ozone in regions of constant stratospheric ozone. In these regions, tropospheric ozone displays the high mixing ratios seen in urban pollution episodes. Electronic versions of daily and 9-day averaged modified-residual tropospheric ozone ("TTO" data and images) for the Nimbus 7/TOMS observing period (1979-1992) and the Earth Probe/TOMS (8/1996-2000) are available at I-degree latitude x 1.25-degree longitude resolution at http://metosrv2.umd.edu/similar totropo. The 1998-2000 TTO (tropical tropospheric ozone) column amounts have been validated using data from a network of ozonesonde stations [6, 7];http://code916.gsfc.nasa.gov/Data-Services/shadoz. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Thompson, AM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1035 EP 1037 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200325 ER PT B AU Yueh, SH Stiles, B Tsai, WY Hu, H Liu, WT AF Yueh, SH Stiles, B Tsai, WY Hu, H Liu, WT GP IEEE IEEE TI QuikSCAT geophysical model function for hurricane wind and rain SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID OCEAN BACKSCATTER; WATER SURFACES; KU-BAND; SCATTERING AB The SeaWinds scatterometer on the QuikSCAT spacecraft has been operating since August 1999 to provide global mapping of ocean winds. The ocean surface winds from the QuikSCAT scatterometer have been shown to be accurate, except for precipitating and extreme high wind conditions. It is known that the QuikSCAT scatteroemter winds typically underestimate the strength of tropical cyclones and overestimate the wind speed for low to moderate wind speeds (3-10 m/s) under rainy conditions. We examined collocated QuikSCAT radar data and SSM/I rain rate to assess the effects of rain. It is shown that the QuikSCAT sigma0s increase with increasing rain rate for low and moderate wind speeds (<15 m/s) and has an opposite trend for hurricane force winds (>32 m/s). It is also shown that the QuikSCAT sigma0 modulation by the wind direction is reduced by the rain. The results are consistent with the existing QuikSCAT wind speed biases and characteristics of wind direction solutions at the presence of rain. Our results suggest that the rain rate can be introduced as an additional modeling parameter for the Ku-band scatterometer model function to reduce the wind retrieval bias resulting from the rain for adverse weather conditions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yueh, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-235, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1089 EP 1091 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200342 ER PT B AU Kim, Y van Zyl, J AF Kim, Y van Zyl, J GP IEEE IEEE TI Polarimetric and interferometric SAR calibration verification methods SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB It is necessary to calibrate SAR data in order to use the data for science applications. When both polarimetric-and interferometric data are collected simultaneously, these SAR data can be used for cross-calibration and verification. The frequency of polarimetric and interferometric data does not have to be the same for this purpose. For example, the NASA/JPL AIRSAR system can acquire C-band interferometric data and L-band polarimetric data simultaneously. The radiometric calibration of polarimetric data can be improved using the local slope information obtained from SAR interferometry. The accuracy of geophysical parameter estimation may be enhanced using true incidence angles derived from SAR interferometry. The calibration of interferometric SAR data can be verified by examining interferometric correlation coefficients. Both azimuth and range slopes estimated from an interferometric SAR DEM can be used to examine the polarization calibration accuracy. In this paper, we show several examples of cross-calibration verification between polarimetric and interferometric SAR data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kim, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1098 EP 1100 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200345 ER PT B AU Salomonson, VV Guenther, B Masuoka, E AF Salomonson, VV Guenther, B Masuoka, E GP IEEE IEEE TI A summary of the status of the EOS terra mission Moderate Resolution Imaging Spectroradiometer (MODIS) and attendant data product development after one year of on-orbit performance SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Moderate Resolution Imaging Spectroradiometer (MODIS) is well. The signal-to-noise (S/N) performance meets or exceeds specifications, band-to-band registration meets specifications, and geodetic registration of observations is near or at 50 meters (one sigma). Some problems with electronic noise, optical leaks, etc. have been identified and solutions to compensate or eliminate these effects have been successful. All similar to40 data products are at "Beta" status. C1 NASA, Goddard Space Flight Ctr, Space Flight Ctr, Greenbelt, MD 20771 USA. RP Salomonson, VV (reprint author), NASA, Goddard Space Flight Ctr, Space Flight Ctr, Code 900, Greenbelt, MD 20771 USA. NR 2 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1197 EP 1199 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200377 ER PT B AU Ichoku, C Chu, DA Mattoo, S Kaufman, YJ Remer, LA Tanre, D Slutsker, I Holben, BN AF Ichoku, C Chu, DA Mattoo, S Kaufman, YJ Remer, LA Tanre, D Slutsker, I Holben, BN GP IEEE IEEE TI Techniques of global validation of aerosol retrievals from MODIS SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID AERONET AB Aerosol optical thickness (AOT) and size parameters are among the main atmospheric parameters retrieved from the MODIS instrument on board the Terra satellite. We have embarked on a massive effort to validate these aerosol products globally, by cross correlating MODIS spatial statistics with ground-based AERONET temporal statistics. This has produced good validation in various parts of the earth both over land and over oceans. The validation statistical data are generated daily and are available to the science community for short and long term studies in various parts of the earth for the lifetime of MODIS. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Ichoku, C (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RI Ichoku, Charles/E-1857-2012 OI Ichoku, Charles/0000-0003-3244-4549 NR 12 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1203 EP 1205 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200379 ER PT B AU Hall, DK Salomonson, VV Riggs, GA Chien, JYL AF Hall, DK Salomonson, VV Riggs, GA Chien, JYL GP IEEE IEEE TI Snow-cover variability in North America in the 2000-2001 winter as determined from MODIS snow products SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID IMAGING SPECTRORADIOMETER MODIS; EOS-AM1 AB Moderate Resolution Imaging Spectroradiometer (MODIS) snow-cover maps have been available since September 13, 2000. These products, at 500-m spatial resolution, are available through the National Snow and Ice Data Center Distributed Active Archive Center in Boulder, Colorado. By the 2001-02 winter, 5-km climate-modeling grid (CMG) products will be available for presentation of global views of snow cover and for use in climate models. All MODIS snow-cover products are produced from automated algorithms that map snow in an objective manner. In this paper, we describe the MODIS snow products, and show snow maps from the fall of 2000 in North America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hall, DK (reprint author), NASA, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI Hall, Dorothy/D-5562-2012 NR 10 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1206 EP 1208 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200380 ER PT B AU Murphy, RE Barnes, WL Lyapustin, AI Privette, J Welsch, C DeLuccia, F Swenson, H Schueler, CF Ardanuy, PE Kealy, PSM AF Murphy, RE Barnes, WL Lyapustin, AI Privette, J Welsch, C DeLuccia, F Swenson, H Schueler, CF Ardanuy, PE Kealy, PSM GP IEEE IEEE TI Using VIIRS to provide data continuity with MODIS SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Comparisons are made between the key properties of the MODIS and VIIRS sensors. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Murphy, RE (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Lyapustin, Alexei/H-9924-2014 OI Lyapustin, Alexei/0000-0003-1105-5739 NR 0 TC 4 Z9 4 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1212 EP 1214 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200382 ER PT B AU Diner, DJ AF Diner, DJ CA MISR Sci Team GP IEEE IEEE TI MISR highlights from the first 18 months in earth orbit SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID MULTIANGLE AB The Multi-angle Imaging SpectroRadiometer (MISR) instrument was launched into polar orbit aboard the Terra spacecraft in December 1999. MISR provides a unique approach to characterizing atmospheric aerosols, the surface, and clouds. This paper provides examples of MISR products and highlights results derived from imagery acquired during the first 18 months of the Terra mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Diner, DJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 169-237, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1217 EP 1218 PG 2 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200384 ER PT B AU Wright, CW Walsh, EJ Vandemark, D Krabill, WB Garcia, AW Houston, SH Murillo, ST Powell, MD Black, PG Marks, FD AF Wright, CW Walsh, EJ Vandemark, D Krabill, WB Garcia, AW Houston, SH Murillo, ST Powell, MD Black, PG Marks, FD GP IEEE IEEE TI Bathymetric effects on a tropical cyclone wave field at landfall SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB On 26 August 1998, the NASA Scanning Radar Altimeter (SRA) flew on a NOAA hurricane research aircraft to document the directional wave spectrum as Hurricane Bonnie was making landfall near Wilmington, NC. SRA measurements In deep ocean two days earlier provided a basis of comparison for the bathymetric effects at landfall. The open ocean wave heights indicated that Hurricane Bonnie would have produced waves of I I m height on the shore had there not been wave damping by the continental shelf. The bathymetry distributed the dissipation process across the shelf so that wavelength and height were reduced gradually. The wave height 5 km from shore was about 4 m. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Wright, CW (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. NR 9 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1237 EP 1239 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200391 ER PT B AU Nghiem, SV Bertoia, C AF Nghiem, SV Bertoia, C GP IEEE IEEE TI Multi-polarization C-band SAR signatures of Arctic sea ice SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Advanced Synthetic Aperture Radar (ASAR) is scheduled to be launched on the ENVISAT satellite in summer 2001. For Arctic sea Ice mapping using future ASAR data, we carry out a study of multiple polarization C-band SAR signatures of various sea ice types. We present polarimetric SAR data acquired over sea Ice acquired by the Jet Propulsion Laboratory polarimetric AIRSAR system on the NASA DC-8 aircraft over sea ice regions in the Beaufort Sea and the Bering Sea. We use a physical sea ice model to study polarimetric scattering signatures of sea ice. The results also provides useful information to the future RADARSAT-2 multi-polarization SAR for sea ice mapping. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nghiem, SV (reprint author), CALTECH, Jet Prop Lab, MS 300-235, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1243 EP 1245 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200393 ER PT B AU Walsh, EJ Vandemark, DC Wright, CW Banner, ML Swift, RN Scott, JF Hines, DE Jensen, J Lee, S AF Walsh, EJ Vandemark, DC Wright, CW Banner, ML Swift, RN Scott, JF Hines, DE Jensen, J Lee, S GP IEEE IEEE TI Observations of sea surface mean square slope during the southern ocean waves experiment SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID RADAR AB Registered ocean wave topography and backscattered power data at 36 GHz were collected off the coast of Tasmania under a wide range of wind and sea conditions, from quiescent to gale force winds with 9 m wave height. Collection altitude varied from 35 m to 1.4 km, allowing determination of the sea surface mean squared slope (mss), the directional wave spectrum and mss variation with respect to wind and wave parameters. C1 NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. RP Walsh, EJ (reprint author), NASA, Goddard Space Flight Ctr, Code 972, Wallops Isl, VA 23337 USA. OI Banner, Michael/0000-0002-0799-5341 NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1318 EP 1320 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200417 ER PT B AU Moller, D Chu, AH Lou, YL Miller, T O'Leary, E AF Moller, D Chu, AH Lou, YL Miller, T O'Leary, E GP IEEE IEEE TI PacRIM II: A review of AirSAR operations and system performance SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID CALIBRATION AB NASA's AirSAR instrument has long been a heavily utilized resource in the international remote sensing community, including, most recently, the very successful PACRIMII mission, In this paper we briefly review the AirSAR system, its expected performance, and quality of data obtained during that mission. We discuss the system hardware calibration methodologies and present quantitative performance values of radar backscatter and interferrometric height errors (random and systematic) from PACRIMII calibration data. We also summarize the various anomalies experienced during the PACRIMII mission, their potential impacts on data quality, and possible solutions to those problems. Finally, in light of these assessments, we discuss near-term system enhancements, and expected performance improvements for future AirSAR missions. In particular we present a redesigned data acquisition system that promises to improve data reliability and system flexibility while increasing data-throughput. One distinct advantage of this system is it will allow us to collect wide-swath high-bandwidth data thereby making data collection more efficient when high bandwidth area imagery is required. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Moller, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1389 EP 1391 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200440 ER PT B AU Chu, AH O'Leary, E Tung, W Carrico, L AF Chu, AH O'Leary, E Tung, W Carrico, L GP IEEE IEEE TI The data processing and calibration of the AIRSAR PacRim II mission SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID RADAR AB In this paper, we present the results of raw echo data analysis with data error recovery, data processing, and the calibration results of the Jet Propulsion Laboratory's airborne synthetic aperture radar (AIRSAR) for the pacific Rim 11 mission. We also present the key elements of the calibration techniques for both polarimetric SAR (POLSAR) and cross-track interferometric SAR (TOPSAR) processed with the AIRSAR Integrated Processor. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chu, AH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1392 EP 1394 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200441 ER PT B AU Kim, Y van Zyl, J AF Kim, Y van Zyl, J GP IEEE IEEE TI Comparison of forest parameter estimation techniques using SAR data SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID BIOMASS; RADAR AB It is important to monitor forests in order to understand the impacts of global climate changes on terrestrial ecosystems. To characterize forest changes, it is useful to parameterize a forest using several parameters, such as biomass, basal area, tree density, tree height, and trunk diameter. These parameters are not independent and some of them are related by allometric equations. Remote sensing data can be used for estimating some forest parameters and others may be retrieved using allometric equations. Many researchers reported algorithms to estimate forest parameters using polarimetric SAR data. However, these algorithms cannot be applied to all types of forests without additional information on the forest type and environmental conditions since radar measurements depend on the tree structure, incidence angle, and environmental conditions. The backscattering cross section also saturates as forest parameters, such as biomass and the tree height, increase. Forest parameters also have been estimated using SAR interferometry. Specifically, the interferometric correlation coefficient has been used to estimate the angular range of volume scattering. In this paper, we compare and contrast polarimetric and interferometric approaches to understand their advantages and limitations using NASA/JPL AIRSAR data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kim, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 7 Z9 7 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1395 EP 1397 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200442 ER PT B AU Madsen, SN AF Madsen, SN GP IEEE IEEE TI Motion compensation for ultra wide band SAR SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The character of ultra wide band (UWB) synthetic aperture radar (SAR) data acquired from an airborne platform invalidates most conventional SAR batch processing algorithms. This paper describes an algorithm that combines wavenumber domain processing with a procedure that enables motion compensation to be applied as a function of target range and azimuth angle. First, data are processed with nominal motion compensation applied, partially focusing the image, then the motion compensation of individual subpatches is refined. The results show that the proposed algorithm is effective in compensating for deviations from a straight flight path, from both a performance and a computational efficiency point of view. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Madsen, SN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 5 Z9 9 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1436 EP 1438 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200456 ER PT B AU Pellerano, FA O'Neill, P Dod, L AF Pellerano, FA O'Neill, P Dod, L GP IEEE IEEE TI An architecture trade study for passive 10-km soil moisture measurements from low-earth orbit SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID MICROWAVE; RADIOMETER AB In 1999 NASA HQ, as a result of an internal NASA study on potential Earth Science Enterprise Post-2002 Missions, directed the hydrology community to focus on achieving a 10-km spatial resolution global soil moisture mission. This type of resolution represents a significant technological challenge for an L-band radiometer in sun-synchronous low-earth orbit. An engineering trade study has been completed to determine alternative system configurations that could achieve the science requirements and to identify the most appropriate technology investments and development path for NASA to pursue in order to bring about such a mission. The results of the study are presented here together with a short discussion of future efforts. C1 NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Greenbelt, MD 20771 USA. RP Pellerano, FA (reprint author), NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Code 555, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1445 EP 1447 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200459 ER PT B AU Bothwell, G Hansen, EG Vargo, RE AF Bothwell, G Hansen, EG Vargo, RE GP IEEE IEEE TI Science data processing for the multi-angle Imaging SpectroRadiometer SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Ground processing of data from the Multi-angle Imaging SpectroRadiometer (MISR) instrument, part of NASA's Earth Observing System (EOS), uses new and unique science algorithms because MISR's multi-camera observing method has not previously been used anywhere. Extensive prototyping was required from a relatively primitive status. The data volume is large, necessitating an innovative software design approach that maximizes throughput. While the routine processing software was developed at the Jet Propulsion Laboratory (JPL), data processing occurs at the NASA Langley Research Center using the EOS Core System (ECS), a collaborative arrangement that works well. Since the launch of MISR on the Terra Spacecraft in December 1999, with the availability of actual mission data, MISR's actual computational needs have become better known, and increased efficiencies are being implemented to make best use of available computing resources. This science software is a sound foundation for processing the data from potential future multi-angle instruments. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bothwell, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1448 EP 1450 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200460 ER PT B AU Geller, GN Pniel, M Dehghani, N AF Geller, GN Pniel, M Dehghani, N GP IEEE IEEE TI ASTER science data processing development: A look back SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is a 14 band, imaging instrument built by Japan and flying on the Terra spacecraft. The US ASTER Science Team is responsible for developing the algorithms and software for generating eight Level I standard data products. This paper discusses the approach used for that development and evaluates its effectiveness. The approach worked very well, resulting in timely software deliveries, few software problems, and products that met quality expectations. One of the key elements of this approach was to shield the algorithm developers from the complex and bureaucratic system environment that the software runs in. Another was a conservative schedule that was driven by the software rather than the algorithm developers, and vigorously enforced by management. And a third element was an independent test team that developed a variety of test tools, allowing rigorous, automated testing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Geller, GN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Geller, Gary/0000-0002-4490-6002 NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1451 EP 1453 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200461 ER PT B AU Masuoka, E Tilmes, C Devine, N Ye, G Tilmes, M AF Masuoka, E Tilmes, C Devine, N Ye, G Tilmes, M GP IEEE IEEE TI Evolution of the MODIS science data processing system SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Masuoka, E (reprint author), NASA, Goddard Space Flight Ctr, Code 922, Greenbelt, MD 20771 USA. RI Tilmes, Curt/D-5637-2012; OI Tilmes, Curt/0000-0002-6512-0287 NR 2 TC 5 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1454 EP 1457 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200462 ER PT B AU Lynnes, C Vollmer, B Berrick, S Mack, R Pham, L Zhou, B AF Lynnes, C Vollmer, B Berrick, S Mack, R Pham, L Zhou, B GP IEEE IEEE TI Simple, scalable, script-based science processor (S4P) SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The development and deployment of data processing systems to process Earth Observing System (EOS) data has proven to be costly and prone to technical and schedule risk. Integration of science algorithms into a robust operational system has been difficult. The core processing system, based on commercial tools, has demonstrated limitations at the rates needed to produce the several terabytes per day for EOS, primarily due to job management overhead. This has motivated an evolution in the EOS Data Information System toward a more distributed one incorporating Science Investigator-Led Processing Systems (SIPS). As part of this evolution, the Goddard Earth Sciences Distributed Active Archive Center (GES DAAC) has developed a simplified processing system to accommodate the increased load expected with the advent of reprocessing and launch of a second satellite. This system, the Simple, Scalable, Script-Based Science Processor (S4P) could also serve as a resource for future SIPS. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lynnes, C (reprint author), NASA, Goddard Space Flight Ctr, Code 902, Greenbelt, MD 20771 USA. RI Lynnes, Christopher/B-4506-2010 OI Lynnes, Christopher/0000-0001-6744-3349 NR 1 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1465 EP 1467 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200465 ER PT B AU Butulis, GT Tilmes, CA Hord, JK Bur, MJC Fleig, AJ AF Butulis, GT Tilmes, CA Hord, JK Bur, MJC Fleig, AJ GP IEEE IEEE TI Implementing a high-rate, low-cost data processing system SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Large-scale processing systems for producing information from high data rate instruments have traditionally been built using large, expensive multi-processor computer systems. In the last few years, improvements in commodity computing systems and storage devices have brought them to the performance territory once held exclusively by the likes of DEC, SGI, Sun, and IBM. We are now building a data processing system using PC-class machines for the Ozone Monitoring Instrument (OMI) that will be launched in 2003. OMI has a 1Mbit/second data rate and will run continuously for five years. The OMI production system, which is based on the 3(rd) generation Moderate Resolution Imaging Spectroradiometer (MODIS) data processing system, will use a heterogeneous set of low-cost processors, high-volume disks, and fast networks to provide impressive throughput for an exceptionally low cost. This approach provides an attractive alternative to the high initial outlay and continuing support costs of the traditional "heavy iron" systems. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Butulis, GT (reprint author), NASA, Goddard Space Flight Ctr, Bldg 32,Room S036B,Mailstop 922-0, Greenbelt, MD 20771 USA. OI Tilmes, Curt/0000-0002-6512-0287 NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1468 EP 1470 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200466 ER PT B AU McKay, MF AF McKay, MF GP IEEE IEEE TI See the world as the astronauts see it SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Astronauts, from John Glenn in 1962 to Bill Shepherd in 2001, have taken hundreds of thousands of photographs of the Earth from space. Twelve hundred of these photos are being chosen for a photographic atlas to enable you to see the world as the astronauts see it. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP McKay, MF (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SL, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1481 EP 1483 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200471 ER PT B AU Treuhaft, RN Chao, Y Lowe, ST Smith, MA Zuffada, C AF Treuhaft, RN Chao, Y Lowe, ST Smith, MA Zuffada, C GP IEEE IEEE TI Ground-based GPS altimetry: The crater-lake experiment and coastal monitoring SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB A GPS altimetric experiment from a cliff over Crater Lake in Oregon shows cm-level determination of the lake surface height. This experiment serves to test the limiting accuracy of air- and spaceborne GPS altimetric remote sensing. It also suggests the feasibility of accurate, ground-based GPS altimetric coastal monitoring, which is difficult for spaceborne techniques. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Treuhaft, RN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,138-212, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1521 EP 1523 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200484 ER PT B AU Yueh, SH Wilson, WJ Dinardo, S AF Yueh, SH Wilson, WJ Dinardo, S GP IEEE IEEE TI Polarimetric radar remote sensing of ocean surface wind SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Experimental data are presented to support the development of a new concept for ocean wind velocity measurement (speed and direction) with the polarimetric microwave radar technology. This new concept has strong potential for improving the wind velocity measurement accuracy and for extending the useful swath width by up to 35 percent for follow-on spaceborne scatterometers to NASA SeaWinds missions. The key issue is whether there is a relationship between the polarization state of ocean backscatter and ocean wind velocity at NASA scatterometer frequencies (13 GHz). A set of aircraft flights indicated clear and repeatable wind direction signals in polarimetric Ku-band scatteroemter observations of sea surfaces at 10 m/s wind speed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yueh, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-235, Pasadena, CA 91109 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1557 EP 1559 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200495 ER PT B AU Le Vine, DM Abraham, S AF Le Vine, DM Abraham, S GP IEEE IEEE TI Galactic noise and passive microwave remote sensing from space at L-band SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB An important consideration for remote sensing measurements at 1.4 GHz (L-band) is radiation from extraterrestrial sources such as hydrogen. Unlike the cosmic background, this radiation is spatially and temporally variable in the local sky. Recent radio astronomy surveys are employed here to produce maps of equivalent brightness temperature wit sufficient spatial and radiometric accuracy to improve approximations which have been used in the past. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Le Vine, DM (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1581 EP 1583 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200502 ER PT B AU Moghaddam, M AF Moghaddam, M GP IEEE IEEE TI Estimation of comprehensive forest variable sets from multiparameter SAR data over a large area with diverse species SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Polarimetric and multifrequency data from the NASA/JPL airborne synthetic aperture radar (AIRSAR) have been used in a multitier estimation algorithm to calculate a comprehensive set of forest canopy proper-ties including branch layer moisture and thickness, trunk density, trunk water content and diameter, trunk height, and subcanopy soil moisture. The estimation algorithm takes advantage of species-specific allometric relations, and is applied to a 100Km x 100Km area in the Canadian boreal region containing many different vegetation species types. The results show very good agreement with ground measurements taken at several focused and auxiliary study sites. This paper expands on the results reported in [1] and applies the algorithm on the regional scale. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Moghaddam, M (reprint author), Jet Prop Lab, MS 300-277,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1660 EP 1662 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200528 ER PT B AU Koziana, J Ahmad, S Leptoukh, G Sharma, AK Serafino, G AF Koziana, J Ahmad, S Leptoukh, G Sharma, AK Serafino, G GP IEEE IEEE TI MODIS atmospheric data products at the Goddard Earth Sciences DAAC SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Goddard Earth Science (GES) Distributed Active Archive Center (DAAC), an integral part of the Earth Observing System Data and Information System (EOSDIS), is the official source of Moderate Resolution Imaging Spectro radiometer (MODIS) Atmospheric data products for science community. The MODIS instrument was launched in December 1999 onboard the Terra (formally AM-1) spacecraft and the GES DAAC has been successfully ingesting, processing, archiving, and distributing MODIS data since February 24, 2000. These measurements provide unique and much needed data for the atmospheric research and applications communities. The GES DAAC archives approximately 500 Gigabytes (GB) of MODIS data per day. The full suite of Atmosphere products is archived at the NASA GES DAAC at a rate of about 40 GB/day. A significant increase in the volume of Atmospheric data being ingested, archived and distributed at the GES DAAC will occur when the MODIS instrument onboard the Aqua (formally PM-1) spacecraft begins transmission. The data is distributed to the community through a combination of EOS Data Gateways, the GES DAAC Search and Order World Wide Web (WWW) interface and an FTP site that contains samples of MODIS data. The MODIS Data Support Team (MDST) provides expert assistance to assist the users to turn data into information. Visit the MDST website at http://daac.gsfc.nasa.gov/CAMPAIGN DOCS/MODIS/index. shtml C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Koziana, J (reprint author), NASA, Goddard Space Flight Ctr, Code 902, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1708 EP 1710 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200544 ER PT B AU Habib, S Newsom, J Rawls, R AF Habib, S Newsom, J Rawls, R GP IEEE IEEE TI Experience and challenges in implementing stratospheric aerosol gas experiment on Meteor-3M platform SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Implementation of the Stratospheric Aerosol Gas Experiment (SAGE) is a joint science mission between Rosavioskosmos, also called the Russian Aviation and Space Agency (RASA) and the National Aeronautics and Space Administration (NASA). Under the global collaboration agreement established by Presidents Clinton and Yeltsin in 1995 between the United States and Russia, space was one of the major areas identified for joint scientific collaboration. There were several collaborative projects identified under space, earth, human exploration of space and aeronautics. SAGE was one of the key Earth Science instruments selected common to both countries interest in ozone research. SAGE has a long space heritage, and four earlier versions of this instrument have flown in space over the last 15-year period. It has provided vital ozone and aerosol data in the mid latitudes and has contributed in the overall ozone depletion research. SAGE 11, the fourth instrument is still flying in space on NASA's Earth Radiation Budget Satellite (ERBS) for the last 14 years. Ball Aerospace built the instrument under Langley Research Center's (LaRC) management. SAGE III for the Russian Meteor-3M mission is a third generation design with more spectral bands, elaborate data gathering and storage and intelligent-terrestrial Software. The Russian collaboration required two complete integrations of SAGE III on the Russian Meteor-3M satellite and a launch on a Zenit-2 launch vehicle manufactured in the Ukraine. The whole complex is scheduled to be launched from the Baikonur Cosmodrome around mid 2001. This cooperative mission has presented a number of management, technical and logistical challenges on both sides. This paper makes an attempt to review and document such experiences. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Habib, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1725 EP 1728 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200550 ER PT B AU Koziana, J Savtchenko, A Leptoukh, G Sharma, AK Serafino, G AF Koziana, J Savtchenko, A Leptoukh, G Sharma, AK Serafino, G GP IEEE IEEE TI Ocean data from MODIS at the NASA Goddard Earth Sciences DAAC SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Goddard Earth Science (GES) Distributed Active Archive Center (DAAC) plays a major role in enabling basic scientific research and providing access to scientific data to the general use community through the ingest, processing, archive and distribution of Moderate Resolution Imaging Spectroradiometer (MODIS) data. The full suite of ocean products is archived at the NASA GES DAAC at a rate of about 230 Gigabytes (GB)/day. A significant increase in the volume of ocean data being ingested, archived and distributed at the GES DAAC will occur when the data from the MODIS instrument onboard the Aqua (formally PM-I) spacecraft begins transmission. The challenge, to distribute such large volumes of data to the ocean community, is achieved through a combination of EOS Data Gateways, the GES DAAC Search and Order World Wide Web (WWW) interface, and an FTP site that contains samples of MODIS data. MODIS Data Support Team (MDST) provides expert assistance to users in accessing data products, information on visualization tools, documentation for data products and formats and information on the scientific content of products and metadata. Visit the MDST website at http://daac.gsfe.nasq.gov/CAMPAIGN_DOCS/MODIS/index.shtml. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Koziana, J (reprint author), NASA, Goddard Space Flight Ctr, Code 902, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1753 EP 1755 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200559 ER PT B AU Comiso, JC Stock, LV AF Comiso, JC Stock, LV GP IEEE IEEE TI Studies of Antarctic cloud cover variability from 1982 through 1999 SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID AVHRR DATA; SURFACE; RADIATION; ISCCP AB Seasonal and interannual variability of cloud cover statistics in the Antarctic region has been studied using NOAA/Advanced Very High Resolution Radiometer (AVHRR) data from 1982 through 1999. The data reveal 92% to 94% cloud cover in the open water areas from the Ice edge to 50degrees S latitude, 67% to 80% cloud cover over sea ice, and 25% to 70% cloud cover over the continental ice sheet with the least cloud cover in the Antarctic plateau. Large seasonality is also observed over ice covered areas with the most persistent clouds occuring during the summer. Year-to-year fluctuations are apparent with 1985 and 1995 having unusually cloudy summers while 1998 had the most cloudy winter. The cloud cover is also shown to be on a decline of as much as -0.50 +/- 0.06%/ year over ice sheets at elevations < 2000 m. This trend may partly explain the observed cooling in the continent during the last 2 decades. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Comiso, JC (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1782 EP 1785 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200569 ER PT B AU Teng, W Pollack, N Serafino, G Chiu, L Sweatman, P AF Teng, W Pollack, N Serafino, G Chiu, L Sweatman, P GP IEEE IEEE TI GIS and data interoperability at the NASA Goddard DAAC SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The NASA Goddard Space Flight Center (GSFC) Earth Sciences (GES) Distributed Active Archive Center (GDAAC) is developing a number of related Web capabilities that will enable it to make its vast amounts of satellite remote sensing data more easily accessible and integrated by users, regardless of differing formats (i.e., interoperable data), and thus effect a wider distribution and use of NASA remote sensing data. Two approaches were adopted, one focused on facilitating use of the data and the other on facilitating access to the data. An automated system was developed to operationally convert selected GDAAC data into GIS formats and to distribute the GIS-compatible data to a network of Remote Sensing Information Partners. The second approach provides online, interactive capabilities for GIS data searching, visualization, mapping, and analysis; access to ancillary data; and retrieval of data (in various formats) or results of analysis of the data. Specific ongoing efforts include a WebGIS, a WMT-DODS (Web Mapping Testbed-Distributed Oceanographic Data System) server, and an Open GIS Consortium (OGC)-compliant client. These related capabilities could be variously integrated into coherent, application-driven, interoperable, data access systems, which will allow a much larger and more diverse user community to make use of GDAAC data, greatly increase the information density of the data accessed by users, and enable a greater diversity of potential applications of GDAAC data. C1 NASA, Goddard Earth Sci Distributed Act Arch Ctr, Greenbelt, MD 20771 USA. RP Teng, W (reprint author), NASA, Goddard Earth Sci Distributed Act Arch Ctr, Code 902-2, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 1953 EP 1955 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200626 ER PT B AU Lou, Y Imel, DA Chu, A Miller, TW Moller, D Skotnicki, W AF Lou, Y Imel, DA Chu, A Miller, TW Moller, D Skotnicki, W GP IEEE IEEE TI Progress report on the NASA/JPL airborne synthetic aperture radar system SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB AIRSAR has served as a test-bed for both imaging radar techniques and radar technologies for over a decade. In fact, the polarimetric, cross-track interferometric, and along-track interferometric radar techniques were all developed using AIRSAR. In this paper, we present the up-to-date system configuration and expected performance in the standard radar modes. In addition, we describe the various experimental modes available to researchers. Finally, we discuss on-going improvements with AIRSAR and future direction of the program. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lou, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2046 EP 2048 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200655 ER PT B AU Cosgrove, BA Houser, PR AF Cosgrove, BA Houser, PR GP IEEE IEEE TI Remotely sensed vegetation cover in the land data assimilation systems project SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB Over the past decade, remotely sensed vegetation datasets have become increasing detailed and accurate. We examine the impact of such data sets on LDAS land surface modeling through several experiments utilizing the Mosaic LSM. Simulations were conducted using 1 degree ISLSCP data and 1 kilometer EROS data over Oklahoma, and results were compared to soil moisture and soil temperature information available from the Oklahoma Mesonet network of instruments. C1 NASA, Goddard Space Flight Ctr, SAIC Gen Sci Corp, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Cosgrove, BA (reprint author), NASA, Goddard Space Flight Ctr, SAIC Gen Sci Corp, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 5 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2079 EP 2081 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200666 ER PT B AU Vicente, GA Costa, MH AF Vicente, GA Costa, MH GP IEEE IEEE TI Real time satellite rainfall estimation over the Amazon region for hydrological applications SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB This is an overview in the recent progress in the development and implementation of an automated satellite rainfall estimation technique for the Amazonia region. The main research purpose is to provide free of cost satellite rainfall estimates to the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) researchers and other Internet users. The estimates are derived from the GOES-8 geosynchronous satellite infrared (IR) images plus model-derived precipitable water and relative humidity. The technique generates precipitation maps every half-hour over the whole South America region, acknowledges the diurnal variation of precipitation and has better temporal and spatial coverage than the TRMM and DMSP(SSM/I) satellite estimates. The real time rainfall estimates are available in GIF and GRADS format through the NOAA web site http://orbit-net.nesdis.noaa.gov/arad/ht/ff/gilberto.html. C1 NASA, Goddard Space Flight Ctr, QSS Grp Inc, DAAC, Greenbelt, MD 20771 USA. RP Vicente, GA (reprint author), NASA, Goddard Space Flight Ctr, QSS Grp Inc, DAAC, Code 902, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2121 EP 2123 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200680 ER PT B AU Kim, EJ England, AW AF Kim, EJ England, AW GP IEEE IEEE TI Diurnal and seasonal cold lands signatures in SSM/I-scale microwave radiometry of the north slope of Alaska SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Kim, EJ (reprint author), NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2127 EP 2129 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200682 ER PT B AU Leptoukh, G Ahmad, S Eaton, P Koziana, J Ouzounov, D Savtchenko, A Serafino, G Sharma, A Sikder, M Zhou, B AF Leptoukh, G Ahmad, S Eaton, P Koziana, J Ouzounov, D Savtchenko, A Serafino, G Sharma, A Sikder, M Zhou, B GP IEEE IEEE TI MODIS data ingest, processing, archiving and distribution at the Goddard Earth Sciences DAAC SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB This paper informs scientists, system developers and managers of science data about the current ingest, processing and distribution of MODIS data at the NASA GES DAAC. In addition, this paper presents the Simple, Scalable, Script-based Science Processor (S4P), a data-driven processing system. This paper also discusses data product sizes and daily volumes, different mechanisms for ordering the data, data distribution policies and data subscription services. In particular, this paper describes a Search and Order Web interface developed at the GES DAAC that provides users with an efficient gateway to MODIS and other remote sensing data. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leptoukh, G (reprint author), NASA, Goddard Space Flight Ctr, Code 902, Greenbelt, MD 20771 USA. RI Ouzounov, Dimitar/A-5929-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2286 EP 2288 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200734 ER PT B AU Qu, JH Serafino, G Kafatos, M Lathrop, R Trimble, J AF Qu, JH Serafino, G Kafatos, M Lathrop, R Trimble, J GP IEEE IEEE TI New application of Earth science remote sensing data at NASA/GES DISC: Remote Sensing Information Partner (RSIP) with Rutgers University SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The NASA Goddard Earth Science (GES) Data and Information Service Center (DISC) has been working on new applications of the Earth science remote sensing data through the Remote Sensing Information Partner (RSIP) program. The infrastructure, procedures and technical approaches are discussed for the RSIP with Rutgers University in this paper. C1 NASA, Goddard Space Flight Ctr, GES, DISC, Greenbelt, MD 20771 USA. RP Qu, JH (reprint author), NASA, Goddard Space Flight Ctr, GES, DISC, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2289 EP 2291 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200735 ER PT B AU Fleig, AJ Masuoka, EJ AF Fleig, AJ Masuoka, EJ GP IEEE IEEE TI Lessons learned from implementing science algorithms into an operational production system SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 NASA, Goddard Space Flight Ctr, PITA Analyt Sci, Greenbelt, MD 20771 USA. RP Fleig, AJ (reprint author), NASA, Goddard Space Flight Ctr, PITA Analyt Sci, Code 922, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2724 EP 2727 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200877 ER PT B AU Koblinsky, C Rienecker, M Adamec, D Abdalati, W Lindstrom, E AF Koblinsky, C Rienecker, M Adamec, D Abdalati, W Lindstrom, E GP IEEE IEEE TI Ocean, ice, and climate: The slow dance of a complex system SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES ID RADAR INTERFEROMETRY; GREENLAND; SHEET AB The time horizon of global change is on scales of years, decades, centuries, and beyond, and this variability can have tremendous regional impact. The importance of the oceans and cryosphere in climate change increases with time scale because of their large thermal inertia. Over the past few years, NASA's Earth Science Enterprise has developed a research strategy to address climate relevant questions about the ocean and cryosphere, such as: How is the global ocean circulation varying on interannual, decadal, and longer time scales?; and What changes are occurring in the mass of the Earth's ice cover? This strategy starts with basic exploration utilizing satellite measurements, leads to improved understanding by incorporating data and models, and ends with improved prediction and benefit for the future. In this paper we consider the science and technology challenges for the ocean and cyrosphere strategy over the next twenty-five years. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Koblinsky, C (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Code 971, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 1 U2 6 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 2859 EP 2862 PG 4 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200920 ER PT B AU Rall, JAR Campbell, J Abshire, JB Spinhirne, JD AF Rall, JAR Campbell, J Abshire, JB Spinhirne, JD GP IEEE IEEE TI Automatic weather station (AWS) lidar SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB A ground based, autonomous, low power atmospheric lidar instrument is being developed at NASA Goddard Space Flight Center. We report on the design and anticipated performance of the proposed instrument and show data from two prototype lidar instruments previously deployed to Antarctica. C1 NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD 20771 USA. RP Rall, JAR (reprint author), NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Mail Code 924, Greenbelt, MD 20771 USA. RI Abshire, James/I-2800-2013 NR 4 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3065 EP 3067 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297200988 ER PT B AU Schoeberl, M Paules, G Andrucyk, D Duda, JL Connerton, R AF Schoeberl, M Paules, G Andrucyk, D Duda, JL Connerton, R GP IEEE IEEE TI The earth science vision: An intelligent web of sensors SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB In this vision of the future a globally responsive web of space-based sensors, processing networks, and distribution systems will create and deliver information products to users throughout the world. Great leaps forward in the ability to predict earth systems behavior and response will be its hallmark. Revolutionary advancements are required in many scientific and technical areas. C1 NASA, GSFC, Atmospheres Lab, Greenbelt, MD USA. RP Schoeberl, M (reprint author), NASA, GSFC, Atmospheres Lab, Greenbelt, MD USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3126 EP 3128 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297201009 ER PT B AU Schwemmer, G Miller, DO Wilkerson, TD Andrus, I Guerra, DV AF Schwemmer, G Miller, DO Wilkerson, TD Andrus, I Guerra, DV GP IEEE IEEE TI Large aperture scanning lidar based on Holographic Optical Elements SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB We have developed simplified conical scanning telescopes using Holographic Optical Elements (HOEs) to reduce the size, mass, angular momentum, and cost of scanning lidar systems. This technology enables wide-angle scanning and three-dimensional measurements of atmospheric backscatter when used in airborne instruments, and high temporal resolution observations of atmospheric dynamic structure, including wind profiles from ground-based facilities. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Schwemmer, G (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3129 EP 3131 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297201010 ER PT B AU Vazquez, J AF Vazquez, J GP IEEE IEEE TI Global comparisons between the modified pathfinder derived Sea Surface Temperature and skin temperatures from the along-track scanning radiometer on-board ERS-2: How close are we getting? SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vazquez, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3233 EP 3235 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297201044 ER PT B AU Yang, K Wolfe, RE AF Yang, K Wolfe, RE GP IEEE IEEE TI MODIS Level 2 Grid with the ISIN map projection SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB The Moderate Resolution Image Spectroradiometer (MODIS) land data products are stored using Level 2 Grid (L2G) approach. We will describe some its recent improvements, which includes a scheme for more accurate observation coverage calculations, and a set of selection rules for reducing the size of L2G storage. Also, we will describe the improvement on the nesting scheme for different size grid cells of the global grid defined by the integerized sinusoidal (ISIN) map projection. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Yang, K (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 922, Greenbelt, MD 20771 USA. RI Wolfe, Robert/E-1485-2012 OI Wolfe, Robert/0000-0002-0915-1855 NR 2 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3291 EP 3293 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297201063 ER PT B AU Zuffada, C Zavorotny, V AF Zuffada, C Zavorotny, V GP IEEE IEEE TI Coherence time and statistical properties of the GPS signal scattered off the ocean surface and their impact on the accuracy of remote sensing of sea surface topography and winds SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB A GPS transmitter-receiver pair forms a bistatic radar for ocean remote sensing when the receiving platform carries a down-looking antenna capable of collecting the GPS signal scattered off the ocean surface. The average received power versus time is derived as a function of viewing geometry, system parameters and an ocean state. This waveform is crucial for the derivation of the sea surface topography (from its leading edge) or wind speed and direction (from its trailing edge). In predicting the accuracy of either measurement it is important to understand how accurately the average power can be determined in practical situations. This starts with the determination of the coherence time of the scattering, over which the received signal can be integrated for optimal signal to noise ratio. Additionally, the real signal is affected by self-noise which introduces variability from one sample to another. This work examines the coherence properties of the modeled received power as a function of sea state and scattering geometry. In particular the coherence time variability between leading and trailing edges is addressed, and its impact on the accuracy of either sea surface topography or wind speed and direction measurements is addressed. In particular, having determined the integration time necessary to produce independent samples, the incoherent summation time required for a given measurement accuracy is derived. Furthermore, the lag-to-lag correlation is addressed, leading to a covariance analysis formulation for the formal error in height retrieval. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zuffada, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-600, Pasadena, CA 91109 USA. NR 3 TC 8 Z9 8 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3332 EP 3334 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297201075 ER PT B AU Zuffada, C Fung, A Okolicanyi, M Huang, E Parker, J AF Zuffada, C Fung, A Okolicanyi, M Huang, E Parker, J GP IEEE IEEE TI The collection of GPS signal scattered off a wind-driven ocean with a down-looking GPS receiver: polarization properties versus wind speed and direction SO IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS SE IEEE International Symposium on Geoscience and Remote Sensing (IGARSS) LA English DT Proceedings Paper CT IEEE International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL UNIV NEW S WALES, SYDNEY, AUSTRALIA SP IEEE, IEEE, Geosci & Remote Sensing Soc, NASA, US Dept Commerce, Natl Ocean & Atmosphere Adm, CSA ASC, Off Naval Res, RSPAA, URSI HO UNIV NEW S WALES AB A GPS transmitter-receiver pair form a bistatic radar for ocean remote sensing when the receiving platform carries a downlooking antenna capable of collecting the GPS signal scattered off the ocean surface. The aggregate GPS signal scattered by the ocean and received in a general bistatic configuration has been calculated for representative geometries and a variety of wind speeds and directions, using the Integral Equation Method (IEM) combined with a realistic ocean correlation function (spectrum). The role of polarization of the reflected signal is investigated and its dependence on wind speed and direction is analyzed to assess its suitability as a detector of the wind vector. The complexity of the scattering calculations is handled by an efficient integration scheme based on combining Gaussian quadrature with a local interpolation of the surface correlation function. Additionally, since a large number of scattering contributions are required the code has been parallelized for efficiency. Some relevant features of the parallelization scheme are outlined. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zuffada, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-600, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7031-7 J9 INT GEOSCI REMOTE SE PY 2001 BP 3335 EP 3337 PG 3 WC Engineering, Electrical & Electronic; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA BU88J UT WOS:000177297201076 ER PT S AU Talukder, A Casasent, D AF Talukder, A Casasent, D GP IEEE IEEE IEEE IEEE TI Adaptive activation function neural net for face recognition SO IJCNN'01: INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS, VOLS 1-4, PROCEEDINGS SE IEEE International Joint Conference on Neural Networks (IJCNN) LA English DT Proceedings Paper CT International Joint Conference on Neural Networks (IJCNN 01) CY JUL 15-19, 2001 CL WASHINGTON, D.C. SP Int Neural Network Soc, IEEE, Neural Networks Council ID OBJECT CLASSES AB A new efficient two-stage algorithm to compute nonlinear features is described. Its implementation on a neural net with adaptive activation functions that raise the input data to an arbitrary power is described. Its use in face recognition with unknown input poses is presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Talukder, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1098-7576 BN 0-7803-7044-9 J9 IEEE IJCNN PY 2001 BP 549 EP 552 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Computer Science, Theory & Methods SC Computer Science GA BT36Q UT WOS:000172784800100 ER PT B AU Rosenzweig, C AF Rosenzweig, C BE Hatfield, JL Volenec, JJ Dick, WA TI Impacts of the El Nino-Southern Oscillation on agriculture: Guidelines for regional analysis SO IMPACTS OF EL NINO AND CLIMATE VARIABILITY ON AGRICULTURE, PROCEEDINGS SE ASA SPECIAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Impacts of El Nino and Climate Variability on Agriculture CY OCT 21, 1998 CL BELTSVILLE, MD SP Amer Soc Agron, Div A 3 ID SEA-SURFACE TEMPERATURE; MAIZE YIELD VARIABILITY; DAILY PRECIPITATION; CORN YIELD; ANOMALIES; PACIFIC; WEATHER; RAINFALL; PATTERNS; URUGUAY AB To discover effective modes of seasonal climate forecasts, we have undertaken a linked suite of studies that evaluates the observational and modeling tools used to predict El Nino Southern Oscillation (ENSO), its climatic manifestations around the world, and its agricultural impacts. This interdisciplinary work contributes to understanding the complex impacts of ENSO phenomena on regional agricultural production systems. Technical guidelines are developed to provide a scientific basis for regional agricultural planners to cope more effectively with climate anomalies that can otherwise disrupt food production. Methods and models include analyses of remote sensing, agronomic and climate observations; generation of climate prediction scenarios with climate models and weather generators; agricultural simulation models and decision support systems, economic analyses, and geographical information systems (GIS). C1 NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. RP Rosenzweig, C (reprint author), NASA, Goddard Space Flight Ctr, Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 23 TC 1 Z9 1 U1 1 U2 2 PU AMER SOC AGRONOMY PI MADISON PA 677 SOUTH SEGOE RD, MADISON, WI 53711 USA BN 0-89118-148-2 J9 ASA SPEC P PY 2001 IS 63 BP 21 EP 30 PG 10 WC Agronomy; Meteorology & Atmospheric Sciences SC Agriculture; Meteorology & Atmospheric Sciences GA BV02M UT WOS:000177646400002 ER PT S AU Figueroa, F Solano, W Thurman, C Schmalzel, J AF Figueroa, F Solano, W Thurman, C Schmalzel, J GP IEEE IEEE TI A future vision of data acquisition: Distributed sensing, processing, and health monitoring SO IMTC/2001: PROCEEDINGS OF THE 18TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS 1-3: REDISCOVERING MEASUREMENT IN THE AGE OF INFORMATICS SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 18th IEEE Instrumentation and Measurement Technology Conference (IMTC/2001) CY MAY 21-23, 2001 CL BUDAPEST, HUNGARY SP IEEE Instrument & Measurement Soc, Budapest Univ Technol & Econ, Int Measurement Confederat (IMEKO) DE data acquisition; intelligent sensors; propulsion testing; health monitoring; IEEE 1451 AB This paper presents a vision for a highly enhanced data acquisition and health monitoring system at NASA Stennis Space Center's (SSC) rocket engine test facility. This vision includes the use of advanced processing capabilities, in conjunction with highly autonomous distributed sensing and intelligence, to monitor and evaluate the health of data in the context of it's associated process. This method is expected to significantly reduce data acquisition costs and improve system reliability and accountability. A Universal Signal Conditioning Amplifier (USCA) based system, under development at Kennedy Space Center, is being evaluated for adaptation to the SSC testing infrastructure. Kennedy's USCA architecture offers many advantages including flexible and auto-configuring data acquisition with improved calibration and verifiability. Possible enhancements at SSC may include multiplexing the distributed USCAs to reduce per channel costs, and the use of f IEEE-485 to Allen-Bradley ControlNet gatewaysfor inter acing with the resident control system. C1 NASA, Stennis Space Ctr, MS USA. RP Figueroa, F (reprint author), NASA, Stennis Space Ctr, MS USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-6646-8 J9 IEEE IMTC P PY 2001 BP 486 EP 489 PG 2 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Computer Science; Engineering; Instruments & Instrumentation GA BT30J UT WOS:000172550900089 ER PT S AU Zrilic, D Pjevalica, N AF Zrilic, D Pjevalica, N GP IEEE IEEE TI Frequency deviation measurement based on two-arm delta-sigma modulated bridge SO IMTC/2001: PROCEEDINGS OF THE 18TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS 1-3: REDISCOVERING MEASUREMENT IN THE AGE OF INFORMATICS SE IEEE INSTRUMENTATION & MEASUREMENT TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 18th IEEE Instrumentation and Measurement Technology Conference (IMTC/2001) CY MAY 21-23, 2001 CL BUDAPEST, HUNGARY SP IEEE Instrument & Measurement Soc, Budapest Univ Technol & Econ, Int Measurement Confederat (IMEKO) DE delta-sigma modulation; arithmetic operations on delta-sigma pulse stream; two-arm bridge; frequency deviation AB A method of frequency deviation measurement is presented. this method of two-arm bridge is based on the use of the delta-sigma modulation and arithmetic operations on two synchronous delta-sigma modulated pulse streams. The simulation results showed a linear relationship between frequency deviation and a pulse count. C1 New Mexico Highlands Univ, NASA, Ctr Autonomous Control Engn, Dept Engn, Las Vegas, NM 87701 USA. RP Zrilic, D (reprint author), New Mexico Highlands Univ, NASA, Ctr Autonomous Control Engn, Dept Engn, Las Vegas, NM 87701 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 0-7803-6646-8 J9 IEEE IMTC P PY 2001 BP 756 EP 760 PG 3 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Computer Science; Engineering; Instruments & Instrumentation GA BT30J UT WOS:000172550900142 ER PT S AU Davidson, JA AF Davidson, JA BE Strojnik, M Andresen, BF TI SOFIA: Stratospheric Observatory for Infrared Astronomy - An introduction and science plans SO INFRARED SPACEBORNE REMOTE SENSING IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 9th Infrared Spaceborne Remote Sensing Conference CY AUG 01-03, 2001 CL SAN DIEGO, CA SP SPIE, NASA, Langley Res Ctr DE NASA missions; SOFIA; IR; mid-infrared; far-infrared; observatories ID MU-M; ISO AB A brief introduction to SOFIA will be given with an outline of its planned investigator program, followed with a summary of the expected performance capabilities of SOFIA at first light. The remainder of the paper will then give examples of SOFIA science to be expected from science instruments to be commissioned on the observatory within the first year of operation. C1 NASA, Ames Res Ctr, USRA SOFIA, SOFIA Project Off, Moffett Field, CA 94035 USA. RP Davidson, JA (reprint author), NASA, Ames Res Ctr, USRA SOFIA, SOFIA Project Off, MS 144-2, Moffett Field, CA 94035 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4200-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4486 BP 59 EP 70 AR UNSP 4486-11 PG 12 WC Instruments & Instrumentation; Remote Sensing; Optics SC Instruments & Instrumentation; Remote Sensing; Optics GA BU15K UT WOS:000175162700007 ER PT S AU Waddell, P Davidson, J AF Waddell, P Davidson, J BE Strojnik, M Andresen, BF TI SOFIA mission operations SO INFRARED SPACEBORNE REMOTE SENSING IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 9th Infrared Spaceborne Remote Sensing Conference CY AUG 01-03, 2001 CL SAN DIEGO, CA SP SPIE, NASA, Langley Res Ctr DE infrared; astronomy; airborne observatory; operations AB The SOFIA Airborne Observatory will operate a 2.5 m aperture telescope with the goal of obtaining over 960 successful science hours per year at a nominal altitude of 12.5 km and covering a wavelength range from 0.3 mum to 1.6 mm. The observatory platform is comprised of a Boeing 747SP with numerous significant modifications. The ground and flight mission operations architectures and plans are tailored to keep the telescope emissivity low and achieve high observing efficiency. C1 NASA, Ames Res Ctr, USRA SOFIA, Moffett Field, CA 94035 USA. RP Waddell, P (reprint author), NASA, Ames Res Ctr, USRA SOFIA, MS 144-2, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4200-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4486 BP 77 EP 82 AR UNSP 4486-14 PG 6 WC Instruments & Instrumentation; Remote Sensing; Optics SC Instruments & Instrumentation; Remote Sensing; Optics GA BU15K UT WOS:000175162700009 ER PT S AU Wolf, J AF Wolf, J BE Strojnik, M Andresen, BF TI SOFIA ground support facilities SO INFRARED SPACEBORNE REMOTE SENSING IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 9th Infrared Spaceborne Remote Sensing Conference CY AUG 01-03, 2001 CL SAN DIEGO, CA SP SPIE, NASA, Langley Res Ctr DE infrared astronomy; Stratospheric Observatory for Infrared Astronomy AB The Stratospheric Observatory for Infrared Astronomy (SOFIA) will operate from NASA's Ames Research Center in Moffett Field, CA. To insure that the observatory's objective of conducting at least 960 successful science flight hours per year will be met, a ground support facility called SOFIA Science and Missions Operation Center (SSMOC) is being developed. This new science institute will be located in an aircraft hangar housing the Boeing 747SP, laboratories supporting the aircraft and its scientific payload, and office space for 80 scientists, engineers, technical support personnel, and the flight crews. The SSMOC will include a mirror coating facility, a pre-flight integration facility for the pre-alignment of science instruments, a system integration laboratory supporting the observatory's software, communications and data acquisition systems, a science data center, and facilities for SOFIA's education and public outreach program. SOFIA and the SSMOC will be jointly operated by the U. S. and German project partners. C1 NASA, Ames Res Ctr, SOFIA USRA, Moffett Field, CA 94035 USA. RP Wolf, J (reprint author), NASA, Ames Res Ctr, SOFIA USRA, Mail Stop 144-2, Moffett Field, CA 94035 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4200-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4486 BP 83 EP 89 AR UNSP 4486-15 PG 7 WC Instruments & Instrumentation; Remote Sensing; Optics SC Instruments & Instrumentation; Remote Sensing; Optics GA BU15K UT WOS:000175162700010 ER PT S AU Dehghani, N Manning, EM Sun, QT AF Dehghani, N Manning, EM Sun, QT BE Strojnik, M Andresen, BF TI AIRS Science Processing System (ASPS): A description of architecture and capabilities SO INFRARED SPACEBORNE REMOTE SENSING IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 9th Infrared Spaceborne Remote Sensing Conference CY AUG 01-03, 2001 CL SAN DIEGO, CA SP SPIE, NASA, Langley Res Ctr AB The Atmospheric Infrared Sounder (AIRS) is a grating spectrometer designed to obtain high-resolution absorption spectra from the atmosphere. The AIRS instrument is scheduled for launch in late 2001 or early 2002 on the Earth Observing System (EOS) Aqua platform. The primary scientific objectives of AIRS are to investigate the dynamics of the atmosphere (including cloud properties), to look for climatological changes, and to improve weather prediction. These investigations will be carried out on a global scale. The instrument acquires data in the spectral range of 3.5 mum to 15.4 mum (650 - 2875 cm(-1)) using 2378 IR spectral channels. In addition four medium to broad band visible and near-IR channels are primarily used for diagnostics involving the presence and extent of clouds. This paper describes the architecture of the AIRS Science Processing System (SPS) used to process AIRS data. The AIRS SPS is a distributed parallel system designed to process AIRS data in a heterogeneous network environment. Various AIRS scientific products are generated by a set of independent Product Generation Executables (PGEs). The AIRS SPS will be operating at the Goddard Space Flight System (GSFC) Distributed Archive Center (DAAC) and also at the AIRS Team Leader Science Computing Facility (TLSCF) at the Jet Propulsion Laboratory (JPL). This paper also describes the architecture of the TLSCF Data System (TDS) which provides an environment for ingest, processing and archiving of the AIRS products at the JPL TLSCF. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dehghani, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4200-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4486 BP 104 EP 110 AR UNSP 4486-17 PG 7 WC Instruments & Instrumentation; Remote Sensing; Optics SC Instruments & Instrumentation; Remote Sensing; Optics GA BU15K UT WOS:000175162700012 ER PT S AU Foote, MC Gaalema, S AF Foote, MC Gaalema, S BE Andresen, BF Fulop, GF Strojnik, M TI Progress towards high-performance thermopile imaging arrays SO INFRARED TECHNOLOGY AND APPLICATIONS XXVII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXVII Conference CY APR 16-20, 2001 CL ORLANDO, FL SP SPIE DE detector; thermopile; infrared; uncooled; array; imaging ID LINEAR ARRAYS AB Thermopiles are uncooled, broadband detectors that require no chopper or temperature stabilizer. Their wide operating-temperature range, lack of temperature stabilization, and radiometric accuracy make thermopiles well suited for some space-based scientific imaging applications. These detectors may also offer advantages over bolometers for night vision. Previous work at JPL has produced thermopile linear arrays with D* values over 10(9) cmHz(1/2)/W by combining high-performance thermoelectric materials Bi-Te and Bi-Sb-Te with bulk micromachining processes. To date, however, 2-D thermopile arrays have demonstrated only moderate performance. The purpose of the present work is to improve thermopile 2-D arrays substantially by combining Bi-Te and Bi-Sb-Te thermoelectric materials with a unique pixel structure and low-noise readout circuitry. The initial goal is a 128x128 array with a single multiplexed analog output stream, with system D* values (including readout noise) of 10(9) cmHz(1/2)/W, and with a focal-plane power dissipation of 20 mW. 100 mum square detectors have been demonstrated with D* values of 2x10(8) cmHz(1/2)/W and response times of 4 ms. Models predict D* values well over 10(9) cmHz(1/2)/W for optimized detectors. Modeling of a preliminary readout design shows that for the expected detector resistance of 100 kOhm, the total noise will be 50% higher than the detector Johnson noise. CMOS test chips containing front-end circuits presently display a noise about 2.5 times higher than modeled and a power dissipation of 0.6 muW per pixel. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Foote, MC (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 4 Z9 6 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4064-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4369 BP 350 EP 354 DI 10.1117/12.445337 PG 5 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT65A UT WOS:000173642200037 ER PT S AU Gunapala, SD Kukkonen, CA Sirangelo, MN McQuiston, BK Chehayeb, R Kaufmann, M AF Gunapala, SD Kukkonen, CA Sirangelo, MN McQuiston, BK Chehayeb, R Kaufmann, M BE Andresen, BF Fulop, GF Strojnik, M TI QWIP technology for both military and civilian applications SO INFRARED TECHNOLOGY AND APPLICATIONS XXVII SE Proceedings of SPIE-The International Society for Optical Engineering LA English DT Proceedings Paper CT Infrared Technology and Applications XXVII Conference CY APR 16-20, 2001 CL ORLANDO, FL SP SPIE ID FOCAL-PLANE ARRAY; WELL INFRARED PHOTODETECTORS; CAMERA; FABRICATION AB Advanced thermal imaging infrared cameras have been a cost effective and reliable method to obtain the temperature of objects. Quantum Well Infrared Photodetector (QWIP) based thermal imaging systems have advanced the state-of-the-art and are the most sensitive commercially available thermal systems. QWIP Technologies LLC, under exclusive agreement with Caltech University, is currently manufacturing the QWIP-Chip(TM), a 320 x 256 element, bound-to-quasibound QWIP FPA. The camera performance falls within the long-wave IR band, spectrally peaked at 8.5 mum. The camera is equipped with a 32-bit floating-point digital signal processor combined with multi-tasking software, delivering a digital acquisition resolution of 12-bits using nominal power consumption of less than 50 Watts. With a variety of video interface options, remote control capability via an RS-232 connection, and an integrated control driver circuit to support motorized zoom and focus-compatible lenses, this camera design has excellent application in both the military and commercial sector. In the area of remote sensing, high-performance QWIP systems can be used for high-resolution, target recognition as part of a new system of airborne platforms (including UAVs). Such systems also have direct application in law enforcement, surveillance, industrial monitoring and road hazard detection systems. This presentation will cover the current performance of the commercial QWIP cameras, conceptual platform systems and advanced image processing for use in both military remote sensing and civilian applications currently being developed in road hazard monitoring. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 28 TC 3 Z9 3 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4064-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4369 BP 498 EP 505 DI 10.1117/12.445311 PG 8 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT65A UT WOS:000173642200056 ER PT S AU Gunapala, SD Bandara, SV Liu, JK Rafol, SB Mumolo, JM Reininger, FM Fastenau, JM Liu, AK AF Gunapala, SD Bandara, SV Liu, JK Rafol, SB Mumolo, JM Reininger, FM Fastenau, JM Liu, AK BE Andresen, BF Fulop, GF Strojnik, M TI 10-16 mu m broadband 640x512 GaAs/AlGaAs quantum well infrared photodetector (QWIP) focal plane array SO INFRARED TECHNOLOGY AND APPLICATIONS XXVII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXVII Conference CY APR 16-20, 2001 CL ORLANDO, FL SP SPIE DE broadband; intersubband transitions; infrared (IR); long-wavelength infrared (LWIR); very long-wavelength (VLWIR); gallium arsenide (GaAs); quantum well infrared photodetector (QWIP); focal plane arrays; noise equivalent temperature difference (NE Delta T); infrared imaging ID CAMERA AB A 10-16 mum cutoff large format broadband quantum well infrared photodetector (QWIP) focal plane array (FPA) has been demonstrated. The size of the FPA is 640x512 and its pixel pitch is 25 microns. The highest operating temperature of the FPA is 45K, and it was determined by the charge storage capacity and the other features of the particular readout multiplexer used in this demonstration. Excellent imagery, with a noise equivalent differential temperature (NEAT) of 55 mK has been achieved. In this presentation, we will discuss the development of this large format broadband infrared FPA based on a GaAs/AlGaAs materials system and its performance in quantum efficiency, NEDeltaT, uniformity, and operability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 2 Z9 2 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4064-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4369 BP 516 EP 523 DI 10.1117/12.445352 PG 8 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT65A UT WOS:000173642200058 ER PT S AU Hoover, RB Rozanov, AY AF Hoover, RB Rozanov, AY BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Chemical biomarkers and microfossils in Carbonaceous meteorites SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE Proceedings of SPIE-The International Society for Optical Engineering LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE biomarkers; microfossils; meteorites; carbonaceous chondrites; astrobiology; extremophiles; Mars ID MASSIVE SULFIDE DEPOSIT; EARLY SOLAR-SYSTEM; MURCHISON METEORITE; ORGUEIL METEORITE; AMINO-ACIDS; MAGNETOTACTIC BACTERIA; ORGANIC COMPOUNDS; ALIPHATIC-HYDROCARBONS; AROMATIC HYDROCARBONS; GREIGITE FE3S4 AB Chemical, mineral and morphological biomarkers and microfossils are present in a wide variety of ancient rocks and meteorites. We discuss previous results and present images of microfossils of cyanobacteria, magnetotactic bacteria, and acritarchs detected in the Orgueil, Mighei, Nogoya, and Murchison carbonaceous meteorites. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci SD 50, Huntsville, AL 35812 USA. RP Hoover, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci SD 50, Huntsville, AL 35812 USA. EM Richard.Hoover@msfc.nasa.gov; aroza@paleo.ru; Richard.Hoover@msfc.nasa.gov; aroza@paleo.ru NR 131 TC 0 Z9 0 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 1 EP 18 PG 18 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700001 ER PT S AU Hecht, MH AF Hecht, MH BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Aqueous environments on contemporary Mars? SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE Mars; water; astrobiology ID LIQUID WATER; GROUNDWATER AB If Mars evolved from a warm, wet, and biologically active planet to the cold desert conditions we observe today, then the last remnants of life would certainly have adapted to extreme tundra-like conditions. Such adaptation might take the form of an ability to thrive in occasional summer meltwater pools, or even the ability to subtly modify its environment to encourage the formation and persistence of such pools. Surprisingly, recent evidence of ubiquitous gullies and seeps at high latitudes suggest that such seasonal melting may have persisted even to the present day. Calculations presented here give additional credence to that suggestion by demonstrating that water is sufficiently metastable to form seasonally recurring meltwater pools under thin crusts of ice on present-day Mars. Moreover, the simplest of biological mechanisms, by affecting evaporative cooling rates and emissivity, could both encourage and prolong the lifetime of such pools. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hecht, MH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 20 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 69 EP 80 PG 12 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700006 ER PT S AU Warmflash, DM Clemett, SJ McKay, DS AF Warmflash, DM Clemett, SJ McKay, DS BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Progress in the search for organic matter on Mars: Implications for the interpretation of the Viking Labeled Release data SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE Mars; organic molecules; life; Viking; SNC meteorites; labeled release ID MARTIAN METEORITE ALH84001; ISOTOPIC EVIDENCE; AMINO-ACIDS; LIFE; SHERGOTTITE; NAKHLA; GASES AB The possibility that the positive outcome of the Viking Labeled Release Experiment (LR) had resulted from the presence of extant Martian microorganisms in samples examined on Mars was dismissed based largely on the failure of the Viking Gas Chromatograph-Mass Spectrometer (GCMS) to demonstrate the presence of organic molecules. More recent findings suggesting that the Viking GCMS would have missed such molecules if present necessitates a re-evaluation of the Viking LR data as well as a continued search for organic material and life at the Martian surface. In addition to advanced mass spectrometers to look for organic signatures of biological processes, future lander missions may use biological techniques, such as immunoassay, to directly detect bio-organic molecules. Meanwhile, several decades in advance of any planned sample return missions, the examination of Mars samples already present on Earth in the form of the SNC meteorites indicates that organic matter has existed in the Martian upper crust. It is concluded that a biological interpretation of the LR on Mars cannot be dismissed and should now be considered at least as plausible as a non-biological interpretation until more complete studies of the Martian surface are carried out. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Warmflash, DM (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 32 TC 0 Z9 0 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 89 EP 95 PG 7 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700008 ER PT S AU Zent, AP AF Zent, AP BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Strategic reevaluation of the search for martian organics SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE ID TITANIUM-DIOXIDE; MARS; SURFACE; SOIL; ADSORPTION; TIO2; OXYGEN; DEGRADATION; ATMOSPHERE; DESORPTION AB A review of the results of the Viking Biology experiments suggests that heterogeneous chemistry between the regolith and photochemically-produced oxidants best explains the data. Laboratory and numerical studies suggested that atmospherically-derived oxidants would neither survive long, nor diffuse deeply, into the martian regolith. Even including mechanical mixing, the total depth of the superoxidizing zone is Likely to be no more than a few meters. Review of additional literature suggests that some of the species responsible for the Viking experiments may also have formed in situ, directly on the regolith material. These complexes form rapidly and abundantly when stimulated with UV photons, but significantly they can apparently form in lower abundances without UV stimulation from species known to be present in the martian atmosphere. This may help explain the small amounts of oxidant seen in the subsurface sample acquired by Viking. Critical laboratory data must now be gathered on the surface diffusion of chemisorbed O-2(-) radicals in multimineralic fines, in order to assess the potential mobility of this strongly oxidizing species at depth. In addition, adsorbents above and beyond TiO2 must be examined for their interactions with a Mars-like chemical environment. If the mobility of the chemisorbed oxidants is low enough, relict organics could persist in regolith materials that would appear superoxidizing in Viking-like tests. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Zent, AP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 44 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 108 EP 119 PG 12 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700010 ER PT S AU McKay, DS Steele, A Warmflash, DM Schweitzer, M Pincus, S Mercader, JP Garcia, VP Llorente, CB AF McKay, DS Steele, A Warmflash, DM Schweitzer, M Pincus, S Mercader, JP Garcia, VP Llorente, CB BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Protein Array Sensor for Organics (PASO) SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE protein array; antibody array; immunoassay; astrobiology; Mars; organic molecules; biomarkers ID MARS; MICROARRAYS; LIFE AB Direct detection of organic biomarkers for living or fossil microbes on Mars by an in-situ instrument is a worthy goal for future lander missions. We are developing a prototype instrument based on immunological reactions to specific antibodies to cause activation of fluorescent stains. We expect to propose a fully developed version of the instrument for inclusion on the 2007 Mars landing mission. C1 NASA, Lyndon B Johnson Space Ctr, Astrobiol Inst, Houston, TX 77058 USA. RP McKay, DS (reprint author), NASA, Lyndon B Johnson Space Ctr, Astrobiol Inst, Houston, TX 77058 USA. RI schweitzer, mary/A-6756-2010 OI schweitzer, mary/0000-0002-0427-3829 NR 18 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 152 EP 157 PG 6 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700015 ER PT S AU Sandford, S Allamandola, L Bregman, J Ennico, K Greene, T Hudgins, D Strecker, D AF Sandford, S Allamandola, L Bregman, J Ennico, K Greene, T Hudgins, D Strecker, D BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Identifying organic molecules in space - The AstroBiology Explorer (ABE) MIDEX mission concept SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE Astrobiology; infrared spectroscopy; Explorers; interstellar organics; telescope; spectrometer ID POLYCYCLIC AROMATIC-HYDROCARBONS; DIFFUSE INTERSTELLAR-MEDIUM; INFRARED-EMISSION BANDS; GRAIN MANTLES; ICE ANALOGS; MICRON ABSORPTION; PRESOLAR DIAMONDS; GRAPHITE GRAINS; HIGH-RESOLUTION; CARBON-DIOXIDE AB In this paper we review our current state of knowledge regarding the identity of organic and related compounds in the interstellar medium (ISM). The remote detection and identification of organics is ideally suited to the technique of infrared spectroscopy since such data can be obtained telescopically and this spectral range encompasses the fundamental vibrational modes of common molecular bonds. Despite recent advances in our knowledge of the organic component of the ISM, we are still far from understanding the distribution, abundance, and evolutionary interrelationship of these materials within our galaxy and the universe as a whole. Many of these issues can be addressed by the acquisition of new infrared spectra. We briefly describe a potential new Explorer-class space mission capable of obtaining such data, the AstroBiology Explorer (ABE), which consists of a space observatory capable of obtaining spectra in the 2.5-16.0 mum range at a spectral resolution of Deltalambda/lambda = 2000-3000. ABE would be capable of addressing outstanding problems in Astrochemistry and Astrophysics that are particularly relevant to Astrobiology and addressable via astronomical observation. ABE would have an approximately one year lifetime during which it would obtain a coordinated set of infrared spectroscopic observations of large numbers of galaxies, stars, planetary nebulae, interstellar clouds, young star planetary systems and objects within our own Solar System. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sandford, S (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Ennico, Kimberly/L-9606-2014 NR 57 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 PROC SPIE PY 2001 VL 4495 BP 170 EP 181 PG 12 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700017 ER PT S AU Ennico, K Sandford, S Cox, S Ellis, B Gallagher, D Gautier, N Greene, T McCreight, C Mills, G Purcell, W AF Ennico, K Sandford, S Cox, S Ellis, B Gallagher, D Gautier, N Greene, T McCreight, C Mills, G Purcell, W BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI The Astrobiology Explorer (ABE) MIDEX mission concept SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE astrobiology; infrared spectroscopy; Explorers; interstellar organics; telescope; spectrometer; infrared detectors ID SI-AS; DETECTORS; SIRTF AB The Astrobiology Explorer (ABE) is a MIDEX mission concept under study at NASA's Ames Research Center in collaboration with Ball Aerospace & Technologies, Corp. ABE will conduct IR spectroscopic observations to address important problems in astrobiology, astrochemistry. and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution. identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 in aperture Cassegrain telescope and two moderate resolution (R = 2000-3000) spectrographs covering the 2.5-16 micron spectral region. Large format (1024x1024 pixel or larger) IR detector arrays and bandpass filters will allow each spectrograph to cover an entire octave of spectral range or more per exposure without any moving parts. The telescope will be cooled below 50 K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to similar to8K. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, I AU Earth driftaway orbit requiring a Delta H launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the similar to1-2 year mission lifetime. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ennico, K (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Ennico, Kimberly/L-9606-2014 NR 4 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 273 EP 282 PG 10 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700027 ER PT S AU Hoover, RB Pikuta, EV Marsic, D Ng, J AF Hoover, RB Pikuta, EV Marsic, D Ng, J BE Hoover, RB Levin, GV Paepe, RR Rozanov, AY TI Anaerobic psychrophiles from Alaska, Antarctica, and Patagonia: Implications to possible life on Mars and Europa SO INSTRUMENTS, METHODS, AND MISSIONS FOR ASTROBIOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for Astrobiology IV CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE DE astrobiology; permafrost; psychrophiles; anaerobic bacteria; deep-sea microbiota ID CRYOCONITE HOLES; ALGAL MATS; PERMAFROST; REMOVAL; EARTH; SPACE; LAKES AB Microorganisms preserved within the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered in ice or permafrost of Mars, Europa, Callisto, Ganymede, asteroids, comets or other frozen worlds in the Cosmos. The psychrophilic and psychrotolerant microbes of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to where and how we should search for evidence of fife elsewhere in the Universe. For this reason, the cold-loving microorganisms are directly relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years. Permafrost, ice wedges, pingos, glaciers, and polar ice sheets may contain intact ancient DNA, lipids, enzymes, proteins, genes, and even frozen and yet viable ancient microbiota. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperatures far below 0 degreesC. Complex microbial communities live in snow, ice-bubbles, cryoconite holes on glaciers and ancient microbial ecosystems are cryopreserved within the permafrost, glaciers, and polar caps. In the Astrobiology group of the NASA Marshall Space Flight Center and the University of Alabama at Huntsville, we have employed advanced techniques for the isolation, culture, and phylogenetic analysis of many types of microbial extremophiles. We have also used the Environmental Scanning Electron Microscope to study the morphology, ultra-microstructure and chemical composition of microorganisms in ancient permafrost and ice. We discuss several interesting and novel anaerobic microorganisms that we have isolated and cultured from the Pleistocene ice of the Fox Tunnel of Alaska, guano of the Magellanic Penguin, deep-sea sediments from the vicinity of the Rainbow Hydrothermal Vent and enrichment cultures from ice of the Patriot Hills of Antarctica. The microbial extremophiles recovered from permafrost, ice, cold pools and deep-sea sediments may provide information relevant to the question of how and where we should search for evidence of extant or extinct microbial life elsewhere in the Cosmos. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Directorate SD50, Huntsville, AL 35812 USA. RP Hoover, RB (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Directorate SD50, Huntsville, AL 35812 USA. NR 30 TC 1 Z9 1 U1 4 U2 15 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4209-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4495 BP 313 EP 324 PG 12 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BU13L UT WOS:000175125700031 ER PT J AU MacLeod, TC Ho, FD AF MacLeod, TC Ho, FD TI Electronic model of a Ferroelectric Field Effect Transistor SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 13th International Symposium on Integrated Ferroelectrics CY MAR 11-14, 2001 CL COLORADO SPRINGS, COLORADO SP aixACCT, Aixtron, Panasonic, Ramtron, Symetrix, Int Journal Integraded Ferroelect DE ferroelectric transistor; Spice model AB A pair of electronic models has been developed of a Ferroelectric Field Effect transistor. These models can be used in standard electrical circuit simulation programs to simulate the main characteristics of the FFET. The models use the Schmitt trigger circuit as a basis for their design. One model uses bipolar junction transistors and one uses MOSFET's. Each model has the main characteristics of the FFET, which are the current hysterisis with different gate voltages and decay of the drain current when the gate voltage is off. The drain current from each model has similar values to an actual FFET that was measured experimentally. The input and output resistance in the models are also similar to that of the FFET. The models are valid for all frequencies below RF levels. Each model can be used to design circuits using FFET's with standard electrical simulation packages. These circuits can be used in designing non-volatile memory circuits and logic circuits and are compatible with all SPICE based circuit analysis programs. The models consist of only standard electrical components, such as BJT's, MOSFET's, diodes, resistors, and capacitors. Each model is compared to the experimental data measured from an actual FFET. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. RP MacLeod, TC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 4 TC 0 Z9 0 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 40 IS 1-5 BP 1453 EP 1462 PG 10 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 508BH UT WOS:000173067000007 ER PT J AU Romanofsky, R Van Keuls, F Mueller, C Miranda, F Fox, G Chu, F Gladden, F Hunt, A AF Romanofsky, R Van Keuls, F Mueller, C Miranda, F Fox, G Chu, F Gladden, F Hunt, A TI Progress in economically viable phase shifters based on thin ferroelectric films SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 13th International Symposium on Integrated Ferroelectrics CY MAR 11-14, 2001 CL COLORADO SPRINGS, COLORADO SP aixACCT, Aixtron, Panasonic, Ramtron, Symetrix, Int Journal Integraded Ferroelect DE lead zirconate titanate; phase shifters; barium strontium titanate AB A considerable amount of work has been done in the area of frequency and phase agile microwave circuits employing thin ferroelectric films. The best films to date have been BaxSr1-xTiO3 (BST) grown by pulsed laser ablation. But laser ablation does not seem readily scalable for volume manufacturing, partly because the process appears limited to 5 cm diameter wafers or smaller. Another impediment to commercialization is testing. Testing is cumbersome because the devices must be inserted into a fixture to interface with coaxial launchers. And, high voltage bias tees are not commercially available to safeguard the microwave instrumentation. We have investigated alternate growth methods including MOCLD, CCVD, and sputtering and developed an on-wafer testing approach for screening phase shifters. Some of the results are reported in a companion paper. Here we report results for sputtered PLZT films on LaAlO3. Coupled microstrip phase shifters at K-band produced a figure of merit of approximate to29degrees/dB. This is within a factor of two of the best laser ablated BST films. The devices also had an uncharacteristically flat frequency response between 12 and 20 GHz. Considering the large lattice mismatch between LaAlO3 and PLZT, the film crystallinity is very good as determined by XRD. Surprisingly, the films also appeared to be cubic. We also-report results for CCVD Ba0.57Sr0.43TiO3 on sapphire. 20 GHz phase shifters yielded a figure-of-merit of 18degrees/dB. Finally we report the design and performance of a coplanar-to-microstrip transition that permits the phase shifters to be tested on wafer. Devices that pass have the virtual ground probe pads diced off so the phase shifter can be integrated into a phased array. Bias is fed directly through the coplanar probes and isolated from the network analyzer by custom high voltage bias tees. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ramtron Int Corp, Colorado Springs, CO 80921 USA. MicroCoating Technol, Chamblee, GA 30341 USA. RP Romanofsky, R (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 13 TC 1 Z9 1 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 39 IS 1-4 BP 1249 EP 1261 PG 13 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 508BF UT WOS:000173066800033 ER PT J AU Van Keuls, FW Mueller, CH Romanofsky, RR Warner, JD Miranda, FA Jiang, H AF Van Keuls, FW Mueller, CH Romanofsky, RR Warner, JD Miranda, FA Jiang, H TI A comparison of MOCLD with PLD BaxSr1-xTiO3 thin films on LaAlO3 for tunable microwave applications SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 13th International Symposium on Integrated Ferroelectrics CY MAR 11-14, 2001 CL COLORADO SPRINGS, COLORADO SP aixACCT, Aixtron, Panasonic, Ramtron, Symetrix, Int Journal Integraded Ferroelect DE ferroelectric; tunable; microwave ID PHASE AB Historically, tunable dielectric devices using thin crystalline BaxSr1-xTiO3 (BST) films deposited on lattice-matched substrates, such as LaAlO3, have generally been grown using pulsed laser deposition (PLD). Highly oriented BST films can be grown by PLD but large projects are hampered by constraints of deposition area, deposition time and expense. The Metal-Organic Chemical Liquid Deposition (MOCLD) process allows for larger areas, faster turnover and lower cost. Several BST films deposited on LaAlO3 by MOCLD have been tested in 16 GHz coupled microstrip phase shifters. They can be compared with many PLD BST films tested in the same circuit design. The MOCLD phase shifter performance of 293degrees phase shift with 53 Wpm dc bias and a figure of merit of 47degrees/dB is comparable to the most highly oriented PLD BST films. The PLD BST films used here have measured XRD full-width-at-half-maxima (FWHM) as low as 0.047degrees. The best FWHM of these MOCLD BST films has been measured to be 0.058degrees. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Corning Appl Technol Corp, Woburn, MA 01801 USA. RP Van Keuls, FW (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 1 Z9 1 U1 0 U2 5 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 39 IS 1-4 BP 1387 EP 1398 PG 12 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 508BF UT WOS:000173066800048 ER PT J AU Cabrera, CR Tremont, R Blasini, D Morales, A Mueller, CH Warner, JD Miranda, FA Guo, LJ Singh, J AF Cabrera, CR Tremont, R Blasini, D Morales, A Mueller, CH Warner, JD Miranda, FA Guo, LJ Singh, J TI Ferroelectric charge injection MOSFET devices SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 13th International Symposium on Integrated Ferroelectrics CY MAR 11-14, 2001 CL COLORADO SPRINGS, COLORADO SP aixACCT, Aixtron, Panasonic, Ramtron, Symetrix, Int Journal Integraded Ferroelect DE (Ba(0.5)Sr0.5)Ti-0.3 ferroelectric thin films; charge injection; MOSFET devices; pulse laser deposition AB As the gate dimensions of MOSFET transistors continue to shrink, the number of donors used to dope the semiconductor and achieve the requisite channel conductivity drops. The ability to reproducibly fabricate channels with a small number of dopants, using existing film growth and ion implantation techniques, is questionable. An additional problem is that as SiO2 layers become thinner, voltage breakdown becomes an issue. A possible solution to this problem is to replace the SiO2 oxide with a ferroelectric material. The higher dielectric constant (epsilon(r)) of the ferroelectric layers will enable thicker gate oxide layers for the same gate capacitance, thus minimizing the likelihood of voltage breakdown. This work summarizes our materials growth work. of (Ba0.5Sr0.5)TiO3 films deposited on Si substrates using pulsed laser deposition technique. The film microstructures were examined using atomic force microscopy and X-ray photoelectron spectroscopy. We have utilized CeO2 buffer layers to minimize interfacial degradation. The present paper discuss the material aspects of the aforementioned thin film ferroelectric-based structures. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA. Univ Puerto Rico Rio Piedras, Dept Chem, San Juan, PR 00931 USA. RP Cabrera, CR (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 38 IS 1-4 BP 913 EP 921 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 508BD UT WOS:000173066600030 ER PT J AU MacLeod, TC Ho, FD AF MacLeod, TC Ho, FD TI I-V characteristics of a ferroelectric field effect transistor SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 12th International Symposium on Integrated Ferroelectrics CY MAR 12-15, 2000 CL AACHEN, GERMANY SP German Natl Sci Fdn, Minist Educ, Sci & Res Northrhine Westphalia, Res Ctr Julich, RWTH Aachen Univ, AIXACCT Syst GmbH, Aachen, AIXTRON AG, Aachen, Infineon Technologies, Munich, Gordon & Breach DE ferroelectric transistor; I-V characteristics AB There are many possible uses for ferroelectric field effect transistors. To understand their application, a fundamental knowledge of their basic characteristics must first be found. In this research, the current and voltage characteristics of a FFET are described from empirical data. The effective gate capacitance and charge are derived from experimental data on an actual ferroelectric transistor. A general equation ([1]) for a MOSFET is used to derive the internal characteristics of the transistor. Experimental data derived from a Radiant Technologies([2]) FFET is used to calculate the internal transistor characteristics using fundamental MOSFET equations. The drain current was measured under several different gate and drain voltages and with different initial polarizations on the ferroelectric material. Two polarization conditions were used. One with the gate ferroelectric material polarized with a +9.0 volt write pulse and one with a -9.0 volt pulse. The transistor is also simulated using a mathematical model from earlier research ([3]). This model accurately predicts the I-V characteristics of the transistor. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. RP MacLeod, TC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 4 TC 2 Z9 2 U1 0 U2 3 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 34 IS 1-4 BP 1461 EP 1466 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 411XH UT WOS:000167524600004 ER PT J AU Van Keuls, FW Romanofsky, RR Mueller, CH Warner, JD Canedy, CL Ramesh, R Miranda, FA AF Van Keuls, FW Romanofsky, RR Mueller, CH Warner, JD Canedy, CL Ramesh, R Miranda, FA TI Current status of thin film (Ba,Sr)TiO3 tunable microwave components for RF communications SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 12th International Symposium on Integrated Ferroelectrics CY MAR 12-15, 2000 CL AACHEN, GERMANY SP German Natl Sci Fdn, Minist Educ, Sci & Res Northrhine Westphalia, Res Ctr Julich, RWTH Aachen Univ, AIXACCT Syst GmbH, Aachen, AIXTRON AG, Aachen, Infineon Technologies, Munich, Gordon & Breach DE BaxSr1-xTiO3 thin films; phase shifters; tunable resonators; Ku- and K-band frequencies; MgO and LaAlO3 substrates AB The performance of proof-of-concept ferroelectric microwave devices has been moving steadily closer to the level needed for satellite and other rf communications applications. This paper will review recent progress at NASA Glenn in developing thin film BaxSr1-xTiO3 tunable microwave components for these applications. Phase shifters for phased array antennas, tunable filters and tunable oscillators employing microstrip and coupled microstrip configurations will be presented. Tunabilities, maximum dielectric constants, and phase shifter parameters will be discussed (e.g., coupled microstrip phase shifters with phase shift over 200 degrees at 18 GHz and a figure of merit of 74.3 degrees /dB). Issues of post-annealing, Mn-doping and BaxSr1-xTiO3 growth on sapphire and alumina substrates will be covered. The challenges of incorporating these devices into larger systems, such as yield, variability in phase shift and insertion loss, and protective coatings will also be addressed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Maryland, College Pk, MD 20742 USA. RP Van Keuls, FW (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 1 Z9 1 U1 1 U2 6 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 34 IS 1-4 BP 1605 EP 1616 PG 12 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 411XH UT WOS:000167524600020 ER PT J AU Subramanyam, G Zaman, A Mohsina, N Van Keuls, FW Miranda, FA Romanofsky, RR Warner, JD Boolchand, P AF Subramanyam, G Zaman, A Mohsina, N Van Keuls, FW Miranda, FA Romanofsky, RR Warner, JD Boolchand, P TI Ferroelectric tunable coplanar waveguide components for Ku- and K-Band applications SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 12th International Symposium on Integrated Ferroelectrics CY MAR 12-15, 2000 CL AACHEN, GERMANY SP German Natl Sci Fdn, Minist Educ, Sci & Res Northrhine Westphalia, Res Ctr Julich, RWTH Aachen Univ, AIXACCT Syst GmbH, Aachen, AIXTRON AG, Aachen, Infineon Technologies, Munich, Gordon & Breach DE tunable coplanar waveguide transmission line; BSTO ferroelectric thin-films; Ku- and K-band frequencies ID THIN-FILM AB The main objective of this research is to study the effect of inserting a Barium Strontium Titanate (BSTO) ferroelectric tuning layer in coplanar waveguide (CPW) and conductor-backed CPW (CBCPW) components. The modeled components include CPW and CBCPW transmission lines (with and without a dielectric filling between the center conductor and the ground planes). We have modeled the characteristic impedance (Z(0)), effective dielectric constant (epsilon (eff)), attenuation and dispersion as a function of circuit geometry and the ferroelectric thin-film's dielectric properties over the 10-20 GHz frequency range. We found that the presence of a ferroelectric layer between the transmission line and the ground planes improves the percentage change in epsilon (eff) by almost two-fold with respect to a CPW deprived of this layer. This result is significant, as one could obtain larger frequency tunability with relatively lower applied fields compared to regular CPW or microstrip lines. C1 Univ Dayton, Dept ECE, Dayton, OH 45469 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Cincinnati, Dept ECECS, Cincinnati, OH 45221 USA. RP Subramanyam, G (reprint author), Univ Dayton, Dept ECE, Dayton, OH 45469 USA. RI Boolchand, Punit/A-3334-2008 NR 7 TC 0 Z9 0 U1 0 U2 2 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 34 IS 1-4 BP 1637 EP 1646 PG 10 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 411XH UT WOS:000167524600023 ER PT J AU Miranda, FA Van Keuls, FW Romanofsky, RR Mueller, CH Warner, JD AF Miranda, FA Van Keuls, FW Romanofsky, RR Mueller, CH Warner, JD TI Life cycle testing of BaxSr1-xTiO3 ferroelectric thin films in a tunable microwave device SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 12th International Symposium on Integrated Ferroelectrics CY MAR 12-15, 2000 CL AACHEN, GERMANY SP German Natl Sci Fdn, Minist Educ, Sci & Res Northrhine Westphalia, Res Ctr Julich, RWTH Aachen Univ, AIXACCT Syst GmbH, Aachen, AIXTRON AG, Aachen, Infineon Technologies, Munich, Gordon & Breach DE ferroelectric thin films; BaxSr1-xTiO3; tunable microwave components; phase shifters; reliability; operating cycles; Ku- and K-band AB Thin film ferroelectrics are being studied as candidates for novel tunable microwave components such as tunable filters, tunable oscillators, and phase shifters for applications in phased array antennas. Much work has been done optimizing the ferroelectric material and in producing proof-of-concepts of these components. However, little attention has been given to their reliability. In this study we present our results on the reliability of high quality K-band phase shifters made of BaxSr1-xTiO3 (BSTO) ferroelectric thin films (0.5-0.75 mum thick) on MgO and LAG. The phase shift and insertion loss were measured at 300 K over 10(4) operation cycles within a 0-400 V de bias range (0-40 V/mum) at 15, 18, and 22 GHz. Results for these phase shifters indicate that in general there were no appreciable changes in phase shift after 4x10(4) cycles, suggesting that these phase shifters are robust enough to sustain optimal performance under the operating mode typical of fast tracking phased arrays. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Miranda, FA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 1 Z9 1 U1 0 U2 3 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 2001 VL 34 IS 1-4 BP 1687 EP 1694 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 411XH UT WOS:000167524600028 ER PT S AU Kim, Q Lange, MJ Wrigley, CJ Cunningham, TJ Pain, B AF Kim, Q Lange, MJ Wrigley, CJ Cunningham, TJ Pain, B BE Righini, GC Honkanen, S TI Two-dimensional active pixel InGaAs focal plane arrays SO INTEGRATED OPTICS DEVICES V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Integrated Optics Devices V CY JAN 23-25, 2001 CL SAN JOSE, CA SP SPIE DE two-dimensional; low power; dual (visible/IR) responses; InGaAsPIN; InP JFETs ID FET AB Switching and amplifying characteristics of a newly developed two-dimensional InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate. It consists of an InGaAs photodiode connected to InP depletion-mode junction field effect transistors (JFETs) for low leakage, low power and fast control of circuit signal amplifying, buffering, selection and reset. This monolithically integrated active pixel sensor configuration eliminates the need for hybridization with a silicon multiplexer, and in addition, allows the sensor to be front illuminated, making it sensitive to visible as well as near infrared signal radiation. Adapting the existing 1.55 mum Fiber optical communication technology, this integration will be an ideal system of optoelectronic integration for dual band (0.5-2.5 mum Visible/IR) applications near room temperature, for use in atmospheric gas sensing in space and target identification on earth. In this paper, 4x4 test arrays will be described. The effectiveness of switching and amplifying circuits will be discussed in terms of circuit in preparation for two dimensional InGaAs active pixel sensor arrays for applications in multifunctional, transportable shipboard surveillance, night vision and emission spectroscopy. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kim, Q (reprint author), CALTECH, Jet Prop Lab, MS303-210,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3955-X J9 P SOC PHOTO-OPT INS PY 2001 VL 4277 BP 223 EP 229 DI 10.1117/12.426798 PG 7 WC Optics; Physics, Applied; Telecommunications SC Optics; Physics; Telecommunications GA BS36P UT WOS:000169641800023 ER PT B AU Some, RR Kim, WS Khanoyan, G Callum, L Agrawal, A Beahan, JJ AF Some, RR Kim, WS Khanoyan, G Callum, L Agrawal, A Beahan, JJ GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI A software-implemented fault injection methodology for design and validation of system fault tolerance SO INTERNATIONAL CONFERENCE ON DEPENDABLE SYSTEMS AND NETWORKS, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Dependable Systems and Networks (DSN 2001) CY JUL 01-04, 2001 CL GOTHENBURG, SWEDEN SP IEEE Comp Soc, TCFTC, IFIP Working Grp 10 4, Chalmers Univ Technol, LAAS CNRS, LASIGE Univ Lisboa, Carnegie Mellon Univ AB In this paper, we present our experience in developing a methodology and tool at the Jet Propulsion Laboratory (JPL) for Software-Implemented Fault Injection (SWIFI) into a parallel processing supercomputer, which is being designed for use in next generation space exploration missions. The fault injector uses software-based strategies to emulate the effects of radiation-induced transients occurring in the system hardware components. The JPL's SWIFI tool set called JIFI (JPL's Implementation of a Fault Injector) is being used, in conjunction with an appropriate system fault model, to evaluate candidate hardware and software fault tolerance architectures, determine the sensitivity of applications to faults and measure the effectiveness of fault detection, isolation, and recovery strategies. JIFI has been validated to inject faults into user-specified CPU registers and memory regions with a uniform random distribution in location and time. Together with verifiers, classifiers, and run scripts, JIFI enables massive fault injection campaigns and statistical data analysis. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Some, RR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 4 Z9 7 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1102-3 PY 2001 BP 501 EP 506 DI 10.1109/DSN.2001.941435 PG 4 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BS78F UT WOS:000171088900050 ER PT S AU Gunapala, SD Bandara, SV Liu, JK Luong, EM Rafol, SB Mumolo, JM Ting, DZ Bock, TJ Ressler, ME Werner, MW LeVan, PD Chehayeb, R Kukkonen, CA Levy, M LeVan, P Fauci, MA AF Gunapala, SD Bandara, SV Liu, JK Luong, EM Rafol, SB Mumolo, JM Ting, DZ Bock, TJ Ressler, ME Werner, MW LeVan, PD Chehayeb, R Kukkonen, CA Levy, M LeVan, P Fauci, MA BE Rutkowski, J Wenus, J Kubiak, L TI Recent developments and applications of quantum well infrared photodetector focal plane arrays SO INTERNATIONAL CONFERENCE ON SOLID STATE CRYSTALS 2000: EPILAYERS AND HETEROSTRUCTURES IN OPTOELECTRONICS AND SEMICONDUCTOR TECHNOLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd International Conference on Solid State Crystals 2000 (ICSSC 2000) CY OCT 09-13, 2000 CL ZAKOPANE, POLAND SP Military Univ Technol, Inst Appl Phys, Polish Soc Crystal Growth, SPIE, State Comm Sci Res, European Off Aerosp Res & Dev, Tech Univ Lodz, Inst Phys, Wroclaw Univ Technol, Inst Phys DE infrared detectors; long-wavelength infrared; multi quantum well; multi-color; focal plane arrays ID QWIP ARRAY; CAMERA; FABRICATION AB One of the simplest device realizations of the classic particle-in-the-hox problem of basic quantum mechanics is the Quantum Well Infrared Photodetector (QWIP). In this paper we discuss the effect of focal plane array non-uniformity an the performance, optimization of the detector design, material growth and processing that has culminated in realization of large format long-wavelength QWIP cameras, holding forth gnat promise for many applications in 6-18 micron wavelength range in science, medicine, defense and industry. In addition, we present the recent developments in long-wavelength/very long-wavelength dualband QWIP imaging camera fbr various applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4116-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4413 BP 323 EP 338 DI 10.1117/12.425451 PG 16 WC Crystallography; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Crystallography; Engineering; Optics; Physics GA BS29E UT WOS:000169369400055 ER PT B AU Sen, S Catalina, A AF Sen, S Catalina, A BE Dhindaw, BK Murty, BS Sen, S TI An analytical model for irregular eutectic growth SO INTERNATIONAL CONFERENCE ON SOLIDIFICATION SCIENCE AND PROCESSING: OUTLOOK FOR THE 21ST CENTURY LA English DT Proceedings Paper CT International Conference on Solidification Science and Processing CY FEB 18-21, 2001 CL BANGALORE, INDIA DE irregular eutectic growth; Kackson-Hunt model; lamellar spacing; undercooling; minimum spacing selection ID UNDERCOOLINGS; SPACINGS AB In this paper a modification of the present theory of irregular eutectic growth is proposed. The proposed analytical model relaxes the assumption of an isothermal interface and accounts for density differences between the liquid and solid phases. Validation of this model is presented against experimental lamellar spacing and undercooling measurements available in the literature for both regular and irregular eutectics. Based on the proposed model two separate mechanisms are identified as spacing selection criterion in the irregular Al-Si eutectic system. First, the minimum spacing selection in Al-Si is dictated by the condition of an isothermal interface, that is the spacing at which the undercoolings of the two phases alpha and beta are identical. However, the proposed theory predicts a unique value for minimum spacing, without invoking the extremum condition, as opposed to the classical Jackson and Hunt approach. Second, it will be shown that the average spacing selected by irregular eutectic systems is dictated by the minimum undercooling of the faceted phase. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Sen, S (reprint author), NASA, George C Marshall Space Flight Ctr, USRA-SD 47, Huntsville, AL 35812 USA. NR 15 TC 1 Z9 1 U1 1 U2 3 PU SCIENCE PUBLISHERS INC PI ENFIELD PA MAY ST, PO BOX 699, ENFIELD, NH 03748 USA BN 1-57808-203-X PY 2001 BP 171 EP 179 PG 9 WC Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing; Materials Science, Composites SC Metallurgy & Metallurgical Engineering; Materials Science GA BU28E UT WOS:000175560200017 ER PT B AU Duval, WMB Singh, NB Glicksman, ME Coriell, SR Zhang, H Berghmans, A AF Duval, WMB Singh, NB Glicksman, ME Coriell, SR Zhang, H Berghmans, A BE Dhindaw, BK Murty, BS Sen, S TI Convecto-diffusive solidification of electronic and optical materials SO INTERNATIONAL CONFERENCE ON SOLIDIFICATION SCIENCE AND PROCESSING: OUTLOOK FOR THE 21ST CENTURY LA English DT Proceedings Paper CT International Conference on Solidification Science and Processing CY FEB 18-21, 2001 CL BANGALORE, INDIA DE solidification; convection; diffusion; crystal; bridgman; instability; thermosolutal ID LEAD BROMIDE CRYSTALS AB Direct observations were made on the shape of solid-liquid interface of silver-doped lead bromide to study solute distribution and effect of solidification parameters on the quality of crystals. With increasing translation velocity, the interface changed from convex to depressed and then formed a cavity in the center of the growth tube. We observed a new kind of toroidal instability at the solid-liquid interface. Further increase in translation velocity caused the morphological breakdown of the interface. Theoretically predicted stability boundaries for double-diffusive convection and morphological breakdown were in good agreement with the experimentally observed growth conditions. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Duval, WMB (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU SCIENCE PUBLISHERS INC PI ENFIELD PA MAY ST, PO BOX 699, ENFIELD, NH 03748 USA BN 1-57808-203-X PY 2001 BP 195 EP 200 PG 6 WC Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing; Materials Science, Composites SC Metallurgy & Metallurgical Engineering; Materials Science GA BU28E UT WOS:000175560200019 ER PT J AU Mosier, KL Skitka, LJ Dunbar, M McDonnell, L AF Mosier, KL Skitka, LJ Dunbar, M McDonnell, L TI Aircrews and automation bias: The advantages of teamwork? SO INTERNATIONAL JOURNAL OF AVIATION PSYCHOLOGY LA English DT Article ID DECISION-MAKING; PERFORMANCE AB A series of recent studies on automation bias, the use of automation as a heuristic replacement for vigilant information seeking and processing, has investigated omission and commission errors in highly automated decision environments. Most of the research on this phenomenon has been conducted in a single-person performance configuration. This study was designed to follow up on that research to investigate whether the error rates found with single pilots and with teams of students would hold in the context of an aircraft cockpit, with a professional aircrew. In addition, this study also investigated the efficacy of possible interventions involving explicit automation bias training and display prompts to verify automated information. Results demonstrated the persistence of automation bias in crews compared with solo performers. No effects were found for either training or display prompts. Pilot performance duringthe experimental legs was most highly predicted by performance on the control leg and by event importance. The previously found phantom memory phenomenon associated with a false engine fire event persisted in crews. C1 San Francisco State Univ, Dept Psychol, San Francisco, CA 94132 USA. Univ Illinois, Dept Psychol, Chicago, IL USA. NASA, Ames Res Ctr, San Jose State Univ Fdn, Moffett Field, CA 94035 USA. RP Mosier, KL (reprint author), San Francisco State Univ, Dept Psychol, 1600 Holloway, San Francisco, CA 94132 USA. OI Skitka, Linda/0000-0002-7078-0650 NR 24 TC 16 Z9 16 U1 1 U2 1 PU LAWRENCE ERLBAUM ASSOC INC PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430-2262 USA SN 1050-8414 J9 INT J AVIAT PSYCHOL JI Int. J. Aviat. Psychol. PY 2001 VL 11 IS 1 BP 1 EP 14 DI 10.1207/S15327108IJAP1101_1 PG 14 WC Psychology, Applied SC Psychology GA 407UC UT WOS:000167288300001 ER PT J AU Flin, R Martin, L AF Flin, R Martin, L TI Behavioral markers for crew resource management: A review of current practice SO INTERNATIONAL JOURNAL OF AVIATION PSYCHOLOGY LA English DT Article ID PERFORMANCE; RATINGS; COCKPIT AB Developments in crew resource management (CRM) have progressed from the introduction of training programs to the evaluation of CRM skills, particularly for multicrew cockpits. European regulators responsible for flight operations and flight crew licensing (Joint Aviation Authorities, 1996, 1997) are introducing requirements for the training and assessment of pilots' nontechnical skills. This article reports a review of the literature and a survey of current practice in the development and use of behavioral marker systems for training and assessing nontechnical CRM skills in international and domestic (UK) airlines. In general, there appears to be a wide range of practice in the design and implementation of behavioral. markers systems within CRM programs. Emerging issues relating to content validity of marker systems and rater reliability are likely to become the focus of both researchers' and pilots' interest. C1 Univ Aberdeen, Kings Coll, Dept Psychol, Old Aberdeen AB24 2UB, Scotland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Aberdeen, Kings Coll, Dept Psychol, Old Aberdeen AB24 2UB, Scotland. EM r.flin@abdn.ac.uk RI Flin, Rhona/C-5243-2008; OI Flin, Rhona/0000-0003-4044-5699 NR 46 TC 43 Z9 44 U1 4 U2 13 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 1050-8414 EI 1532-7108 J9 INT J AVIAT PSYCHOL JI Int. J. Aviat. Psychol. PY 2001 VL 11 IS 1 BP 95 EP 118 DI 10.1207/S15327108IJAP1101_6 PG 24 WC Psychology, Applied SC Psychology GA 407UC UT WOS:000167288300006 ER PT J AU Cowings, PS Kellar, MA Folen, RA Toscano, WB Burge, JD AF Cowings, PS Kellar, MA Folen, RA Toscano, WB Burge, JD TI Autogenic feedback training exercise and pilot performance: Enhanced functioning under search-and-rescue flying conditions SO INTERNATIONAL JOURNAL OF AVIATION PSYCHOLOGY LA English DT Article ID MOTION SICKNESS; STRESS; ACCIDENTS AB Studies have shown that autonomous mode behavior is one cause of aircraft fatalities due to pilot error. In such cases, the pilot is in a high state of psychological and physiological arousal and tends to focus on one problem, while ignoring more critical information. This study examined the effect of training in physiological self-recognition and regulation, as a means of improving crew cockpit performance. Seventeen pilots were assigned to the treatment and control groups matched for accumulated flight hours. The treatment group contained 4 pilots from HC-130 Hercules aircraft and 4 HH-65 Dolphin helicopter pilots; the control group contained 3 pilots of HC-130s and 6 helicopter pilots. During an initial flight, physiological data were recorded on each crewmember and an instructor pilot rated individual crew performance. Eight crewmembers were then taught to regulate their own physiological response levels using Autogenic-Feedback Training Exercise (AFTE). The remaining participants received no training. During a second flight, treatment participants showed significant improvement in performance (rated by the same instructor pilot as in pretests) while controls did not improve. The results indicate that AFTE management of high states of physiological arousal may improve pilot performance during emergency flying conditions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Tripler Army Med Ctr, Honolulu, HI 96859 USA. Stanford Univ, Dept Psychol, Stanford, CA 94305 USA. RP Cowings, PS (reprint author), NASA, Ames Res Ctr, SLR 239-16, Moffett Field, CA 94035 USA. NR 26 TC 6 Z9 6 U1 1 U2 2 PU LAWRENCE ERLBAUM ASSOC INC PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430-2262 USA SN 1050-8414 J9 INT J AVIAT PSYCHOL JI Int. J. Aviat. Psychol. PY 2001 VL 11 IS 3 BP 303 EP 315 DI 10.1207/S15327108IJAP1103_04 PG 13 WC Psychology, Applied SC Psychology GA 469YU UT WOS:000170844300004 PM 12033232 ER PT J AU Hixon, R Shih, SH Mankbadi, RR AF Hixon, R Shih, SH Mankbadi, RR TI Numerical treatment of cylindrical coordinate centerline singularities SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE finite differences; cylindrical coordinates; centerline singularities ID COMPUTATIONAL ACOUSTICS; EQUATIONS; FLOW; SIMULATIONS; SCHEMES AB The grid singularity located at the centerline in a cylindrical coordinate system can exhibit numerical instabilities when finite differences are used to approximate the spatial derivatives contained in the equations of fluid motion. Results from previous work has indicated that the root cause of centerline instability is due to the error from the finite difference approximation of the azimuthal derivatives and not the radial derivative treatment. Using a simple test case, several formulations of the governing equations for a 2-D polar grid are investigated analytically, then tested numerically. It is demonstrated that the azimuthal derivative error can be amplified or cancelled, depending on the particular formulation of the governing equations used, and that this error is the cause of numerical instabilities at the centerline. C1 NASA, Glenn Res Ctr, ICOMP, Cleveland, OH 44135 USA. RP Hixon, R (reprint author), NASA, Glenn Res Ctr, ICOMP, Cleveland, OH 44135 USA. NR 25 TC 0 Z9 0 U1 0 U2 4 PU GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP PI PHILADELPHIA PA 325 CHESTNUT ST, 8TH FL, PHILADELPHIA, PA 19106 USA SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 2001 VL 15 IS 3 BP 251 EP 263 DI 10.1080/10618560108970032 PG 13 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 481AE UT WOS:000171495500005 ER PT J AU Jackson, KE AF Jackson, KE TI Impact testing and simulation of a crashworthy composite fuselage concept SO INTERNATIONAL JOURNAL OF CRASHWORTHINESS LA English DT Article AB A composite fuselage concept for light aircraft and rotorcraft has been developed to provide improved crash protection. The fuselage consists of a relatively rigid upper section, or passenger cabin, including a stiff structural floor and a frangible lower section which encloses the crash energy management structure. A 60-in. diameter full-scale fuselage section was manufactured using a composite sandwich construction. Vertical drop tests were conducted at both 0 degrees- and 15 degrees -roll impact attitudes to evaluate the crashworthy features of the fuselage design. The experimental data are correlated with predictions from a finite element model developed using the non-linear, explicit transient dynamic code, MSC.Dytran. C1 USA, Langley Res Ctr, Vehicle Technol Directorate, NASA,Res Lab, Hampton, VA 23681 USA. RP Jackson, KE (reprint author), USA, Langley Res Ctr, Vehicle Technol Directorate, NASA,Res Lab, Hampton, VA 23681 USA. NR 16 TC 13 Z9 15 U1 0 U2 4 PU WOODHEAD PUBL LIMITED PI LETCHWORTH PA BLACKHORSE RD, LETCHWORTH SG6 1HN, HERTS, ENGLAND SN 1358-8265 J9 INT J CRASHWORTHINES JI Int. J. Crashworthiness PY 2001 VL 6 IS 1 BP 107 EP 121 DI 10.1533/cras.2001.0166 PG 15 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA 425FL UT WOS:000168280000009 ER PT J AU Fasanella, EL Boitnott, RL Lyle, KH Jackson, KE AF Fasanella, EL Boitnott, RL Lyle, KH Jackson, KE TI Full-scale crash test and simulation of a composite helicopter SO INTERNATIONAL JOURNAL OF CRASHWORTHINESS LA English DT Article AB A finite element model of the Sikorsky Advanced Composite Airframe Program (ACAP) helicopter was developed using the non-linear, explicit transient dynamic code. MSC.Dytran. Analytical predictions were correlated with experimental data obtained from a full-scale crash test of the Sikorsky ACAP helicopter flight test article that was conducted in June 1999 at the Impact Dynamics Research Facility of NASA Langley Research Centre, Hampton, Virginia, USA. The helicopter was impacted at 11.58 m/s vertical and 9.9-m/s forward velocity with an attitude of 6.25 degrees pitch (nose up) and 3.5 degrees left roll. Due to the relatively long crash pulse duration. a rigid-body helicopter model with an energy absorbing landing gear model was executed initially. Prior to fuselage contact. a deformable structural model was executed with the rigid-body nodal displacements and velocities used as initial conditions. C1 NASA, Langley Res Ctr, Vehicle Technol Directorate, USA,Res Lab, Hampton, VA 23681 USA. RP Fasanella, EL (reprint author), NASA, Langley Res Ctr, Vehicle Technol Directorate, USA,Res Lab, Hampton, VA 23681 USA. NR 12 TC 6 Z9 6 U1 0 U2 4 PU WOODHEAD PUBL LIMITED PI LETCHWORTH PA BLACKHORSE RD, LETCHWORTH SG6 1HN, HERTS, ENGLAND SN 1358-8265 J9 INT J CRASHWORTHINES JI Int. J. Crashworthiness PY 2001 VL 6 IS 4 BP 485 EP 498 DI 10.1533/cras.2001.0192 PG 14 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA 490KN UT WOS:000172051200003 ER PT J AU Cantrell, JH Yost, WT AF Cantrell, JH Yost, WT TI Nonlinear ultrasonic characterization of fatigue microstructures SO INTERNATIONAL JOURNAL OF FATIGUE LA English DT Article; Proceedings Paper CT 3rd International Conference on Fatigue Damage of Structural Materials CY SEP 17-22, 2000 CL HYANNIS, MASSACHUSETTS DE dislocation dipoles; stress-strain nonlinearity; ultrasound; plastic strain; aluminum alloy 2024 ID COPPER; BEHAVIOR; DIPOLES AB Dislocation dipole substructures formed during metal fatigue are shown to produce a substantial distortion of ultrasonic waves propagating through the fatigued material. A model of ultrasonic wave-dislocation dipole interactions is developed that quantifies the wave distortion by means of a material nonlinearity parameter beta. Application of the model to AA2024-T4 predicts a value of beta approximately 300% larger in material cyclically loaded for 100 kcycles in stress-control at 276 MPa and R=0 than that measured for virgin material. Experimental measurements show a monotonic increase in beta as a function of the number of fatigue cycles that closely approaches the predicted increase. The experiments also suggest that the relevant dislocation substructures are localized in the material. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cantrell, JH (reprint author), NASA, Langley Res Ctr, Mail Stop 231, Hampton, VA 23681 USA. NR 18 TC 104 Z9 113 U1 3 U2 14 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-1123 J9 INT J FATIGUE JI Int. J. Fatigue PY 2001 VL 23 SU S BP S487 EP S490 PG 4 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 508DB UT WOS:000173071800057 ER PT J AU Zhuang, WZ Halford, GR AF Zhuang, WZ Halford, GR TI Investigation of residual stress relaxation under cyclic load SO INTERNATIONAL JOURNAL OF FATIGUE LA English DT Article; Proceedings Paper CT 3rd International Conference on Fatigue Damage of Structural Materials CY SEP 17-22, 2000 CL HYANNIS, MASSACHUSETTS DE residual stress; residual stress relaxation; surface treatment; cold work; fatigue of metals AB Compressive residual stresses induced by mechanical surface treatment such as shot peening, autofretage, hole expansion, laser shock peening, and low-plasticity burnishing can be highly beneficial to fatigue resistance. Cyclic relaxation of compressive residual stress, however, reduces the benefit. An analytical model is proposed for estimation of residual stress relaxation. Parameters considered by the model include the magnitude and distribution of the residual stress, the degree of cold working required, the applied alternating and mean stresses, and the number of applied loading cycles. An elasto-plastic finite element model was used to demonstrate the model. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Airframes & Engines Div, Aeronaut & Maritime Res Ctr, Melbourne, Vic 3207, Australia. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhuang, WZ (reprint author), Airframes & Engines Div, Aeronaut & Maritime Res Ctr, Melbourne, Vic 3207, Australia. NR 15 TC 83 Z9 87 U1 1 U2 14 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-1123 J9 INT J FATIGUE JI Int. J. Fatigue PY 2001 VL 23 SU S BP S31 EP S37 PG 7 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 508DB UT WOS:000173071800005 ER PT J AU Bert, CW Malik, M AF Bert, CW Malik, M TI Discussion of "Frequency characteristics of a thin rotating cylindrical shell using the generalized differential quadrature method" SO INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES LA English DT Letter C1 Univ Oklahoma, Sch Aerosp & Mech Engn, Norman, OK 73019 USA. Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. RP Bert, CW (reprint author), Univ Oklahoma, Sch Aerosp & Mech Engn, Norman, OK 73019 USA. NR 2 TC 2 Z9 2 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7403 J9 INT J MECH SCI JI Int. J. Mech. Sci. PD JAN PY 2001 VL 43 IS 1 BP 297 EP 297 DI 10.1016/S0020-7403(99)00082-X PG 1 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 361EL UT WOS:000089709900017 ER PT J AU Saleeb, AF Arnold, SM Castelli, MG Wilt, TE Graf, W AF Saleeb, AF Arnold, SM Castelli, MG Wilt, TE Graf, W TI A general hereditary multimechanism-based deformation model with application to the viscoelastoplastic response of titanium alloys SO INTERNATIONAL JOURNAL OF PLASTICITY LA English DT Article DE viscoplasticity; viscoelasticity; nonlinear hardening; isothermal; deformation; multiaxial; correlations; predictions ID CONSTITUTIVE-EQUATIONS; VISCOPLASTICITY; RECOVERY; PLASTICITY; ALGORITHMS; VARIABLES; ALUMINUM; BEHAVIOR; METALS; CREEP AB The formulation of a general model for the hereditary behavior of materials, in the viscoelastic and viscoplastic regimes, is presented. In this, we utilize the complete-potential structure as a general framework, together with the notion of strain- and stress- partitioning in terms of separate contributions of several submechanisms (viscoelastic and viscoplastic) to the thermodynamic functions (stored energy and dissipation). Detailed numerical treatments are given for both (i) the implicit integration algorithm for the governing flow and evolutionary rate equations of the model, and (ii) the automated parameter-estimation methodology (using the software code COMPARE) for characterization. For illustration, a specific form of the model presented is characterized for the TIMETAL 21S material using a very comprehensive test matrix, including creep, relaxation, constant strain-rate tension tests, etc. Discussion of these correlations tests, together with comparisons to several other experimental results, are given to assess the performance and predictive capabilities of the present model as well as the effectiveness and practical utility of the algorithms proposed. (C) 2001 Published by Elsevier Science Ltd. C1 Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. RP Saleeb, AF (reprint author), Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. NR 44 TC 30 Z9 30 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0749-6419 J9 INT J PLASTICITY JI Int. J. Plast. PY 2001 VL 17 IS 10 BP 1305 EP 1350 DI 10.1016/S0749-6419(00)00086-3 PG 46 WC Engineering, Mechanical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA 470CQ UT WOS:000170853200002 ER PT J AU Kruse, H Allman, M Griner, J Tran, D AF Kruse, H Allman, M Griner, J Tran, D TI Experimentation and modelling of HTTP over satellite channels SO INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS LA English DT Article DE TCP; HTTP; satellites; networking; ACTS AB This paper investigates the performance of various versions of the hyper text transfer protocol (HTTP) over a geosynchronous satellite link. Both HTTP/1.0, the currently popular form of the protocol, and HTTP/1.1, the recently standardized form of HTTP, are studied. Next, we quantify the impact of a moderate bit-error rate on the performance of HTTP. Finally, we expand the mathematical model of HTTP presented in Heidemann, Obraczka and Touch (IEEE/ACM Transactions on Networking 1997; 5:616-630) to encompasses a wider range of HTTP behaviour. We show this model accurately predicts HTTP throughput by comparing it with HTTP transfers made over a satellite channel. Published in 2001 by John Wiley & Sons, Ltd. C1 NASA, Glenn Res Ctr, BBN Technol, Cleveland, OH 44135 USA. Ohio Univ, J Warren McClure Sch, Athens, OH 45701 USA. RP Allman, M (reprint author), NASA, Glenn Res Ctr, BBN Technol, 21000 Brookpk Rd,MS 54-2, Cleveland, OH 44135 USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0737-2884 J9 INT J SATELL COMMUN JI Int. J. Satell. Commun. PD JAN-FEB PY 2001 VL 19 IS 1 BP 51 EP 68 DI 10.1002/sat.657 PG 18 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 406WE UT WOS:000167238500004 ER PT J AU Goyal, R Jain, R Goyal, M Fahmy, S Vandalore, B Kota, S Butts, N vonDeak, T AF Goyal, R Jain, R Goyal, M Fahmy, S Vandalore, B Kota, S Butts, N vonDeak, T TI Buffer management and rate guarantees for TCP over satellite-ATM networks SO INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS LA English DT Article DE buffer management; rate guarantees; TCP; ATM AB Future broadband satellite networks will support a variety of service types. Many such systems are being design with ATM or ATM-like technology. A majority of Internet applications use TCP for data transfer. As a result, these systems must efficiently transport TCP traffic and provide service guarantees to such traffic. Several mechanisms have been presented in recent literature to improve TCP performance. Most of these can be categorized as either TCP enhancements or network-based buffer management techniques. Providing minimum rate guarantees to TCP traffic has also been suggested as a way to improve its performance in the presence of higher priority traffic sharing the link. However, the relative performance of the TCP enhancements versus the buffer management schemes has not been analyzed for long latency networks. In this paper, we address three issues. First, we present a performance analysis of TCP over satellite-ATM links using a best effort service-the ATM unspecified bit rate (UBR) service. This analysis shows that the relative impacts of buffer management, TCP policies and rate guarantees on TCP performance, depend heavily on the latency of the network. Second, we show through simulations that the buffer size required in the network for high TCP performance is proportional to the delay-bandwidth product of the network. Third, we propose a buffer management scheme called differential fair buffer allocation (DFBA) and show how it is used to implement a service that provides minimum rate guarantees to TCP traffic. An example of such a service is the ATM guaranteed frame rate (GFR) service, which is being standardized by the ATM Forum and the ITU. Copyright (C) 2001 John Wiley & Sons, Ltd. C1 Axiowave Networks, Marlborough, MA 01752 USA. Nayna Networks Inc, Milpitas, CA 95035 USA. AT&T Labs Res, Florham Park, NJ 07932 USA. Purdue Univ, W Lafayette, IN 47907 USA. Ohio State Univ, Dept Comp & Informat Sci, Columbus, OH 43210 USA. BMS, Palo Alto, CA 94303 USA. Lockheed Martin Mission Syst, Sunnyvale, CA 94089 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Goyal, R (reprint author), Axiowave Networks, 100 Nickerson Rd, Marlborough, MA 01752 USA. NR 24 TC 8 Z9 9 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0737-2884 J9 INT J SATELL COMMUN JI Int. J. Satell. Commun. PD JAN-FEB PY 2001 VL 19 IS 1 BP 111 EP 139 DI 10.1002/sat.701 PG 29 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 406WE UT WOS:000167238500007 ER PT J AU Dorney, DJ Flitan, HC Ashpis, DE Solomon, WJ AF Dorney, DJ Flitan, HC Ashpis, DE Solomon, WJ TI The effects of blade count on boundary layer development in a low-pressure turbine SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID TRANSITION; TURBULENCE; SEPARATION AB Experimental data from jet-engine tests have indicated that turbine efficiencies at takeoff can be as much as two points higher than those at cruise conditions. Recent studies have shown that Reynolds number effects contribute to the lower efficiencies at cruise conditions. In the current study numerical simulations have been performed to study the boundary layer development in a two-stage low-pressure turbine, and to evaluate the models available for low Reynolds number flows in turbomachinery. In a previous study using the same geometry the predicted time-averaged boundary layer quantities showed excellent agreement with the experimental data, but the predicted unsteady results showed only fair agreement with the experimental data. It was surmised that the blade count approximation used in the numerical simulations generated more unsteadiness than was observed in the experiments. In this study a more accurate blade approximation has been used to model the turbine, and the method of post-processing the boundary layer information has been modified to more closely resemble the process used in the experiments. The predicted results show improved agreement with the unsteady experimental data. C1 Virginia Commonwealth Univ, Richmond, VA USA. NASA, Glenn Res Ctr, Cleveland, OH USA. Ohio Aerosp Inst, Cleveland, OH USA. RP Dorney, DJ (reprint author), Virginia Commonwealth Univ, Med Coll Virginia Campus, Richmond, VA USA. NR 30 TC 0 Z9 0 U1 0 U2 0 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 2001 VL 18 IS 1 BP 1 EP 13 PG 13 WC Engineering, Aerospace SC Engineering GA 473ZF UT WOS:000171079100001 ER PT J AU Dorney, DJ Gundy-Burlet, KL AF Dorney, DJ Gundy-Burlet, KL TI Effects of hot streak shape on rotor heating in a high-subsonic single-stage turbine SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID REDISTRIBUTION; SIMULATIONS AB Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine operating in high subsonic flow. In addition to a simulation of the baseline turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region. C1 Virginia Commonwealth Univ, Dept Mech Engn, Richmond, VA USA. NASA, Ames Res Ctr, Computat Phys & Simulat Branch, Moffett Field, CA 94035 USA. RP Dorney, DJ (reprint author), Virginia Commonwealth Univ, Dept Mech Engn, Med Coll Virginia Campus, Richmond, VA USA. NR 18 TC 1 Z9 2 U1 0 U2 0 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 2001 VL 18 IS 1 BP 15 EP 29 PG 15 WC Engineering, Aerospace SC Engineering GA 473ZF UT WOS:000171079100002 ER PT J AU Dorney, DJ Croft, RR AF Dorney, DJ Croft, RR TI Unsteady analysis of a time-dependent hot streak in a turbine stage SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article AB Experimental studies have shown that combustor temperature nonuniformities, or "hot streaks" can significantly affect the heating of first-stage rotor blading in turbines. In addition, it has been observed that these hot streaks are not constant in time, but rather fluctuate with instabilities within the combustor. The time-dependent variations in the combustor generate not only positive temperature differences from the free stream, but negative as well (i.e., "cold streaks"). The unsteady cyclic thermal loading of the blading can degrade turbine durability and efficiency. To investigate this phenomenon, two-dimensional unsteady Navier-Stokes simulations have been performed for the 1-1/2 stages of a high-pressure turbine operating in subsonic flow with unsteady hot streaks introduced at the inlet. C1 Virginia Commonwealth Univ, Dept Mech Engn, Richmond, VA 23284 USA. RP Dorney, DJ (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 2001 VL 18 IS 3 BP 145 EP 155 PG 11 WC Engineering, Aerospace SC Engineering GA 502ED UT WOS:000172730000001 ER PT S AU Huang, X Reinisch, BW Bilitza, D AF Huang, X Reinisch, BW Bilitza, D BE Rawer, K Bilitza, D Reinisch, BW TI IRI in windows environment SO INTERNATIONAL REFERENCE IONOSPHERE - WORKSHOP 1999 SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT International Reference Ionosphere Workshop (IRI) CY AUG 09-12, 1999 CL UNIV MASSACHUSETTS, CTR ATMOSPHER RES, LOWELL, MA SP Int Union Radio Sci, US Natl Sci Fdn, Spartan Electr Inc, Bruning Int Corp, Comm Space Res HO UNIV MASSACHUSETTS, CTR ATMOSPHER RES AB The International Reference Ionosphere (IRI) is a widely used model recommended for international use by URSI and COSPAR. An interface to Windows has been developed and the stand-alone IRI program is executable on PC systems using Windows 95/98 or Windows NT as the platform. This IRI-Windows version allows computation and plotting of any of the IRT, parameters as function of any one or two variables: height, latitude, longitude, UT or LT time, and solar activity. The user can conveniently specify the variables and various options of the model. This paper gives a brief description of the program features and the operating procedure. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Massachusetts Lowell, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, RITSS, Greenbelt, MD 20771 USA. RP Huang, X (reprint author), Univ Massachusetts Lowell, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 01854 USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2001 VL 27 IS 1 BP 127 EP 131 DI 10.1016/S0273-1177(00)00148-4 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43Y UT WOS:000169859500021 ER PT S AU Bilitza, D Papitashvili, N King, J AF Bilitza, D Papitashvili, N King, J BE Rawer, K Bilitza, D Reinisch, BW TI IRI related data and model services at NSSDC SO INTERNATIONAL REFERENCE IONOSPHERE - WORKSHOP 1999 SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT International Reference Ionosphere Workshop (IRI) CY AUG 09-12, 1999 CL UNIV MASSACHUSETTS, CTR ATMOSPHER RES, LOWELL, MASSACHUSETTS SP Int Union Radio Sci, US Natl Sci Fdn, Spartan Electr Inc, Bruning Int Corp, Comm Space Res HO UNIV MASSACHUSETTS, CTR ATMOSPHER RES AB NASA's National Space Science Data Center (NSSDC) provides internet access to a large number of space physics data sets and models. We will review and explain the different products and services that might be of interest to the IRI community. Data can be obtained directly through anonymous ftp or through the SPyCAT WWW interface to a large volume of space physics data on juke-box type mass storage devices. A newly developed WWW system, the ATMOWeb, provides browse and sub-setting capabilities for selected atmospheric and thermospheric data. NSSDC maintains an archive of space physics models that includes a subset of ionospheric models. The model software can be retrieved via anonymous ftp. A selection of the most frequently requested models can be fun on-line through special WWW interfaces. Currently supported models include the International Reference Ionosphere (IRI), the Mass Spectrometer and Incoherent Scatter (MSIS) atmospheric model, the International Geomagnetic Reference Field (IGRF) and the AE-8/AP-8 radiation belt models. In this article special emphasis will be given to the IRI interface and its various input/output options. Several new options and a Java-based plotting capability were recently added to the Web interface. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Raytheon STX, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Natl Space Sci Data Ctr, Greenbelt, MD 20771 USA. RP Bilitza, D (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX, Code 632, Greenbelt, MD 20771 USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 27 IS 1 BP 133 EP 141 DI 10.1016/S0273-1177(00)00149-6 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43Y UT WOS:000169859500022 ER PT S AU Abraham, S LeVine, DM AF Abraham, S LeVine, DM BE Rawer, K Bilitza, D Reinisch, BW TI Evaluation of IRI-95 to correct errors caused by Faraday rotation in passive microwave remote sensing from space SO INTERNATIONAL REFERENCE IONOSPHERE - WORKSHOP 1999 SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT International Reference Ionosphere Workshop (IRI) CY AUG 09-12, 1999 CL UNIV MASSACHUSETTS, CTR ATMOSPHER RES, LOWELL, MASSACHUSETTS SP Int Union Radio Sci, US Natl Sci Fdn, Spartan Electr Inc, Bruning Int Corp, Comm Space Res HO UNIV MASSACHUSETTS, CTR ATMOSPHER RES AB Passive remote sensing from space at the long wavelength end of the microwave spectrum has the advantages of penetrating the atmosphere and responding to parameters of the ocean and earth's surface important for understanding earth's environment. Examples are the measurements of soil moisture and sea surface salinity. These measurements can be made at L-band (1.413 GHz) and are needed to understand energy exchange with the atmosphere at the surface. Sensor systems are under serious consideration to make these measurements. However, at L-band Faraday rotation in the ionosphere can be sufficient to cause errors in the retrieval of the surface parameters. This is especially a problem for the retrieval of sea surface salinity in the open ocean because the dynamic range of the measurement is relatively small. An important question in the design of such sensor systems is whether models can be used to correct Faraday rotation. As a first step toward addressing that question, IRI-95 is used to assess the order of magnitude of the Faraday rotation and the error it causes at L-band in the observed brightness temperature. Errors on the order of several Kelvin are possible. In addition, a limited evaluation of the model is made by comparing the effects of Faraday rotation using prediction and observed vertical total electron content. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Raytheon ITSS, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Abraham, S (reprint author), Raytheon ITSS, Lanham, MD 20706 USA. NR 8 TC 6 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 27 IS 1 BP 153 EP 156 DI 10.1016/S0273-1177(00)00151-4 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43Y UT WOS:000169859500024 ER PT S AU Russell, CT Fieseler, PD Bindshadler, D Yu, ZJ Joy, SP Khurana, KK Kivelson, MG AF Russell, CT Fieseler, PD Bindshadler, D Yu, ZJ Joy, SP Khurana, KK Kivelson, MG BE Thomas, N Coustenis, A LeliwaKopysty, J Kossacki, KJ TI Large scale changes in the highly energetic charged particles in the region of the Io torus SO IO, EUROPA, TITAN AND CRATERING OF ICY SURFACES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0 5-D3 6/B0 6-C3 4-D3 7-F3 0/B0 7 Symposium of COSPAR Scientific Commission B held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Int Astronom Union, Int Union Geodesy & Geophys, IUGG, Int Assoc Geomagnet & Aeronomy, Comm Space Res, European Space Agcy, Univ Calif ID MAGNETOSPHERE AB The Galileo star sensor is heavily shielded from penetrating radiation to prevent false counts. Nevertheless in the inner jovian magnetosphere the penetrating radiation appears to be sufficiently strong that significant background counting rates are seen. The morphology and time variation of these background rates are consistent with the hypothesis that they are caused by energetic trapped particles. On the C22 pass through the torus region the count rates were unusually high as if a particularly large disturbance had occurred. We speculate that such disturbances arise at times of rare-but intense volcanic activity at Io that causes intense temporal fluctuations in the magnetic field and enhanced radial diffusion and particle energization. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Russell, CT (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RI Kivelson, Margaret/I-9019-2012 OI Kivelson, Margaret/0000-0003-3859-8581 NR 15 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 10 BP 1495 EP 1500 DI 10.1016/S0273-1177(01)00552-X PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT60N UT WOS:000173496300006 ER PT B AU Sherwood, R Mishkin, A Estlin, T Chien, S Backes, P Norris, J Cooper, B Maxwell, S Rabideau, G AF Sherwood, R Mishkin, A Estlin, T Chien, S Backes, P Norris, J Cooper, B Maxwell, S Rabideau, G GP IEEE IEEE TI Autonomously generating operations sequences for a mars rover using AI-based planning SO IROS 2001: PROCEEDINGS OF THE 2001 IEEE/RJS INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-4: EXPANDING THE SOCIETAL ROLE OF ROBOTICS IN THE NEXT MILLENNIUM LA English DT Proceedings Paper CT IEEE Conference on Intelligent Robots and Systems (IROS 2001) CY OCT 29-NOV 03, 2001 CL MAUI, HI SP IEEE Ind Electr Soc, IEEE Robot & Automat Soc, Robot Soc Japan, Soc Instrument & Control Engineers AB This paper discusses a proof-of-concept prototype for ground-based automatic generation of validated rover command sequences from high-level science and engineering activities. This prototype is based on ASPEN, the Automated Scheduling and Planning Environment This Artificial Intelligence (AI) based planning and scheduling system will automatically generate a command sequence that will execute within resource constraints and satisfy flight rules. An automated planning and scheduling system encodes rover design knowledge and uses search and reasoning techniques to automatically generate low-level command sequences while respecting rover operability constraints, science and engineering preferences, environmental predictions, and also adhering to hard temporal constraints. This prototype planning system has been field-tested using the Rocky-7 rover at JPL, and will be field-tested on more complex rovers to prove its effectiveness before transferring the technology to flight operations for an upcoming NASA mission. Enabling goal-driven commanding of planetary rovers greatly reduces the requirements for highly skilled rover engineering personnel. This in turn greatly reduces mission operations costs. In addition, goal-driven commanding permits a faster response to changes in rover state (e.g., faults) or science discoveries by removing the time consuming manual sequence validation process, allowing rapid "what-if' analyses, and thus reducing overall cycle times. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6612-3 PY 2001 BP 803 EP 808 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BU64S UT WOS:000176593900127 ER PT B AU Pirjanian, P Huntsberger, TL Barrett, A AF Pirjanian, P Huntsberger, TL Barrett, A GP IEEE IEEE TI Representation and execution of plan sequences for multi-agent systems SO IROS 2001: PROCEEDINGS OF THE 2001 IEEE/RJS INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-4: EXPANDING THE SOCIETAL ROLE OF ROBOTICS IN THE NEXT MILLENNIUM LA English DT Proceedings Paper CT IEEE Conference on Intelligent Robots and Systems (IROS 2001) CY OCT 29-NOV 03, 2001 CL MAUI, HI SP IEEE Ind Electr Soc, IEEE Robot & Automat Soc, Robot Soc Japan, Soc Instrument & Control Engineers DE team sequencing; tight coordination; distributed control architecture AB Integration of planning and execution for single-agent systems has received considerable attention and numerous interesting approaches have been proposed. This is not the case for multi-agent systems, however. In this paper, we describe one approach to representing joint team activities using a Finite State Machine augmented with synchronization primitives for orchestration of group activities. This representation encodes a sequence of activities that can be distributed across a team of robots and executed in a coordinated manner. We then show how such a representation can be mapped onto a behavior-based formalism for execution, as supported by a distributed, multi-robot control architecture, CAMPOUT We demonstrate the proposed mechanisms within the context of a challenging task, where two rovers collectively carry an extended container over rough terrain. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 82-105, Pasadena, CA 91109 USA. EM Paolo.Pirjanianj@jpl.nasa.gov NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6612-3 PY 2001 BP 2117 EP 2123 PG 7 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BU64S UT WOS:000176593900334 ER PT B AU Knight, R Fisher, F Estlin, T Engelhardt, B Chien, S AF Knight, R Fisher, F Estlin, T Engelhardt, B Chien, S GP IEEE IEEE TI Balancing deliberation and reaction, planning and execution for space robotic applications SO IROS 2001: PROCEEDINGS OF THE 2001 IEEE/RJS INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-4: EXPANDING THE SOCIETAL ROLE OF ROBOTICS IN THE NEXT MILLENNIUM LA English DT Proceedings Paper CT IEEE Conference on Intelligent Robots and Systems (IROS 2001) CY OCT 29-NOV 03, 2001 CL MAUI, HI SP IEEE Ind Electr Soc, IEEE Robot & Automat Soc, Robot Soc Japan, Soc Instrument & Control Engineers AB Intelligent behavior for robotic agents requires a careful balance of fast reactions and deliberate consideration of long-term ramifications. The need for this balance is particularly acute in space applications, where hostile environments demand fast reactions, and remote locations dictate careful management of consumables that cannot be replenished. However, fast reactions typically require procedural representations with limited scope and handling long-term considerations in a general fashion is often computationally expensive. In this paper, we describe three major areas for autonomous systems for space exploration: free-flying spacecraft, planetary rovers, and ground communications stations. In each of these broad applications areas, we identify operational considerations requiring rapid response and considerations of long-term ramifications. We describe these issues in the context of ongoing efforts to deploy autonomous systems using planning and task execution systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Knight, R (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 35 TC 2 Z9 2 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6612-3 PY 2001 BP 2131 EP 2139 PG 9 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BU64S UT WOS:000176593900336 ER PT B AU Clement, BJ Barrett, AC Rabideau, GR Durfee, EH AF Clement, BJ Barrett, AC Rabideau, GR Durfee, EH GP IEEE IEEE TI Using abstraction to coordinate multiple robotic spacecraft SO IROS 2001: PROCEEDINGS OF THE 2001 IEEE/RJS INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-4: EXPANDING THE SOCIETAL ROLE OF ROBOTICS IN THE NEXT MILLENNIUM LA English DT Proceedings Paper CT IEEE Conference on Intelligent Robots and Systems (IROS 2001) CY OCT 29-NOV 03, 2001 CL MAUI, HI SP IEEE Ind Electr Soc, IEEE Robot & Automat Soc, Robot Soc Japan, Soc Instrument & Control Engineers AB The trend toward multiple-spacecraft missions requires autonomous teams of spacecraft to coordinate their activities when sharing limited resources. This paper describes how an iterative repair planner/scheduler can reason about the activities of multiple spacecraft at abstract levels in order to greatly improve the scheduling of their use of shared resources. By finding consistent schedules at abstract levels, refinement choices can be preserved for use in robust plan execution systems. We present an algorithm for summarizing the metric resource requirements of an abstract activity based on the resource usages of its potential refinements. We find that reasoning about this summary information and that of state constraints can offer exponential improvements in the time to find consistent schedules with an iterative repair planner. We analytically describe the conditions under which these improvements are made and show that sometimes the extra overhead involved does not warrant their use. We apply these techniques within the ASPEN planner/scheduler to a domain where a team of rovers must coordinate their schedules to avoid conflicts over shared resources. Experiments using the ASPEN planner/scheduler in a Mars multi-rover domain support our analyses and compare techniques for controlling decomposition. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. EM bclement@aig.jpl.nasa.gov; barrett@aig.jpl.nasa.gov; rabideau@aig.jpl.nasa.gov; durfee@umich.edu NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6612-3 PY 2001 BP 2140 EP 2147 PG 8 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BU64S UT WOS:000176593900337 ER PT B AU Nesnas, IAD Volpe, R Estlin, T Das, H Petras, R Mutz, D AF Nesnas, IAD Volpe, R Estlin, T Das, H Petras, R Mutz, D GP IEEE IEEE TI Toward developing reusable software components for robotic applications SO IROS 2001: PROCEEDINGS OF THE 2001 IEEE/RJS INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-4: EXPANDING THE SOCIETAL ROLE OF ROBOTICS IN THE NEXT MILLENNIUM LA English DT Proceedings Paper CT IEEE Conference on Intelligent Robots and Systems (IROS 2001) CY OCT 29-NOV 03, 2001 CL MAUI, HI SP IEEE Ind Electr Soc, IEEE Robot & Automat Soc, Robot Soc Japan, Soc Instrument & Control Engineers AB We will present an overview of the CLARAty architecture which aims at developing reusable software components for robotic systems. These components are to support autonomy software which plans and schedules robot activities. The CLARAty architecture modifies the conventional three-level robotic architecture into a new two-layered design: the Functional Layer and the Decision Layer. The Functional Layer provides a I representation of the system components and an implementation of their basic functionalities. The Decision Layer is the decision making engine that drives the Functional Layer. It globally reasons about the intended goals, system resources, and state of the system and its environment. The Functional Layer is composed of a set of interrelated object-oriented hierarchies consisting of active and passive objects that represent the different levels of system abstractions. In this paper, we present an overview of the design of the Functional Layer. The Functional Layer is decomposed into a set of reusable core components and a set of extended components that adapt the reusable set to different hardware implementations. The reusable components: (a) provide interface definitions and implementations of basic functionality, (b) provide local executive capabilities, (c) manage local resources, and (d) support state and resource queries by the Decision Layer. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nesnas, IAD (reprint author), CALTECH, Jet Prop Lab, M-S 198-219, Pasadena, CA 91109 USA. NR 20 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6612-3 PY 2001 BP 2375 EP 2383 PG 9 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BU64S UT WOS:000176593900375 ER PT B AU Kawamoto, K Nakajima, T AF Kawamoto, K Nakajima, T BE Smith, WL Timofeyev, YM TI Global distribution of the water cloud microphysics derived from AVHRR remote sensing SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID NOAA AVHRR; RADIATION; ALBEDO AB An algorithm is developed for determining the cloud optical depth and effective particle radius (hereafter the cloud microphysics) simultaneously on a global scale using AVHRR (Advanced Very High Resolution Radiometer) data. This algorithm is based on Nakajima and Nakajima (1995)'s method that uses reflected solar radiation by cloud layer at visible and near-infrared. We improved the algorithm by updating the treatments of thermal emissions and water vapor absorption. The algorithm is applied to four-month GAC (Global Area Coverage) data of 1987 to generate global distributions of the cloud optical thickness and effective particle radius for every 0.5degrees x 0.5degrees box in a -60degrees to 60degrees latitudinal region, and then some geographical characteristics of the cloud microphysics are described. Finally long term analysis from 1985 to 1994 is presented as a preliminary result. C1 Virginia Polytech Inst & State Univ, NASA, Langley Res Ctr, Hampton, VA 23666 USA. RP Kawamoto, K (reprint author), Virginia Polytech Inst & State Univ, NASA, Langley Res Ctr, Hampton, VA 23666 USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 13 EP 16 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100004 ER PT B AU Smith, WL Harrison, FW Revercomb, HE Bingham, GE AF Smith, WL Harrison, FW Revercomb, HE Bingham, GE BE Smith, WL Timofeyev, YM TI Geostationary Fourier Transform Spectrometer (GIFTS) - The new millenium Earth Observing-3 mission SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID VAPOR AB The Geostationary Imaging Fourier Transform Spectrometer (GIFTS) was selected for NASA's New Millennium Program (NMP) Earth Observing-3 (EO-3) mission. GIFTS combines new and emerging sensor and data processing technologies to make geophysical measurements that will contribute to earth science, as well as lead to revolutionary improvements in meteorological observations and forecasting. This mission will conclusively prove the GIFTS breakthrough measurement concept for altitude-resolved "water vapor winds" and demonstrate revolutionary technologies for future research and operational systems. The infusion of GIFTS technologies into operational instrumentation is critical for optimizing this nation's next generation geostationary severe weather and climate observing system. The GIFTS geophysical data products are derived from measurements of atmospheric thermal emission in 2 spectral bands: 685-1130 cm(-1) and 1650-2250 cm(-1), at high spectral resolution (0.3 to 0.6 cm(-1)) on a 4-km spatial grid with an imaging Fourier Transform Spectrometer (FTS). By observing thousands of pixels simultaneously, GIFTS will provide rapid spatial coverage and detailed time sequences from geostationary orbit. Key data products are: (1) Frequent, high vertical resolution (1-2 km) temperature and water vapor sounding, allowing the vertical profile of wind velocity to be obtained by tracing the horizontal displacement of water vapor and cloud features, (2) Time-dependent ozone and carbon monoxide concentrations within several layers of the troposphere and stratosphere, (3) High-resolution time measurements of radiative properties of evolving clouds (augmented by a visible low-light-level camera to provide quasi-continuous imaging at 1-km spatial resolution). The EO-3 mission characteristics and the intended use of GIFTS data for research and for supporting the infusion of GIFTS technology into future operational geostationary satellite sensors is discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, WL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 81 EP 84 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100022 ER PT B AU Susskind, J Barnet, CD Blaisdell, JM AF Susskind, J Barnet, CD Blaisdell, JM BE Smith, WL Timofeyev, YM TI Determination of atmospheric and surface parameters from AIRS/AMSU/HSB data SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS AB New state of the art methodology is described to analyze AIRS/AMSU/HSB data in the presence of multiple cloud formations. The methodology is used in the AIRS Science Team algorithm which will be used to analyze AIRS/AMSU/HSB data on EOS Aqua. The cloud clearing methodology requires no knowledge of the spectral properties of the clouds. Results are shown for AIRS Science Team simulation studies with multiple cloud formations. These simulation studies imply that temperature soundings can be produced under partial cloud cover with RMS errors better than 1degreesK in I kin thick layers from the surface to 700 mb, 1 km layers from 700 mb to 300 mb, 3 kin layers from 300 mb to 30 mb, and 5 kin layers from 30 mb to 1 mb, and moisture profiles can be obtained with an accuracy better than 15% absolute errors in 1 km layers from the surface to 200 mb. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Susskind, J (reprint author), NASA, Goddard Space Flight Ctr, Code 910, Greenbelt, MD 20771 USA. RI Barnet, Christopher/F-5573-2010 NR 2 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 85 EP 88 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100023 ER PT B AU Lin, B Minnis, P Wielicki, B Hu, YX Ho, SP AF Lin, B Minnis, P Wielicki, B Hu, YX Ho, SP BE Smith, WL Timofeyev, YM TI Overcast clouds determined by TRMM measurements SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID VISIBLE MEASUREMENTS; SATELLITE MICROWAVE; WATER AB Using the Tropical Rainfall Measuring Mission (TRMM) Visible and Infra-Red Scanner (VIRS) and TRMM Microwave Radiometer (TMI) measurements, this study retrieves cloud optical depth (tau), liquid water path (LWP), and the frequency of co-occurrence of ice and water clouds based on radiative transfer models. Results show that LWP values for warm nonprecipitating clouds are similar to0.06mm and cold clouds have large ice water amount (similar to0.1min). The cloud systems with significant amounts of water below ice occur about 10 similar to 20% of the time. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lin, B (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. RI Hu, Yongxiang/K-4426-2012 NR 5 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 97 EP 100 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100026 ER PT B AU Yue, GK Wang, PH Weisenstein, DK Ko, MKW AF Yue, GK Wang, PH Weisenstein, DK Ko, MKW BE Smith, WL Timofeyev, YM TI Satellite observations of aerosol surface area and volume densities at upper troposphere and lower stratosphere from 1985 to 1999 SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS AB In a recent paper by Yue [1999], a new method to retrieve aerosol size distributions and integral properties from SAGE II aerosol extinction spectra was proposed. In this method, the aerosol number density, as well as the surface area and volume densities, are expressed as a linear combination of the SAGE II aerosol extinctions at four or fewer wavelengths. It was found that when all four aerosol extinctions are available for retrieval, the retrieval errors for surface area and volume densities are less than about 20 and 10%, respectively. At lower altitudes where less than four aerosol extinctions are measured, the retrieval errors are slightly higher. The proposed linear minimizing error method was applied to retrieve aerosol surface area and volume densities in the upper troposphere and lower stratosphere from 1985 to 1999. The deduced aerosol properties are presented. Preliminary analysis of the data indicates an increase of aerosol surface area and volume densities in both the upper troposphere and lower stratosphere each time after a major volcanic eruption. The decay of aerosol integral properties after volcanic eruption and the hemispheric asymmetry of aerosol properties are discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Yue, GK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI Ko, Malcolm/D-5898-2015 NR 5 TC 0 Z9 0 U1 0 U2 1 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 125 EP 128 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100033 ER PT B AU Zakharova, NT Mishchenko, MI AF Zakharova, NT Mishchenko, MI BE Smith, WL Timofeyev, YM TI Electromagnetic scattering by wavelength-sized, needle-like and plate-like ice crystals SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID LIGHT-SCATTERING; NONSPHERICAL PARTICLES; AGGREGATE PARTICLES; OPTICAL-PROPERTIES; ATMOSPHERES AB We use the advanced version of the T-matrix method to compute scattering properties of ice spheroids with aspect ratios up to 20 and surface-equivalent-sphere size parameters up to 12. We show that wavelength-sized, needle-like and plate-like ice crystals possess unique scattering properties: their asymmetry parameters and phase functions are typical of those of surface-equivalent spheres, whereas all other elements of the scattering matrix are representative of particles much smaller than the wavelength. Our results may have important implications for optical particle sizing and atmospheric remote sensing. C1 Goddard Inst Space Studies, New York, NY 10025 USA. RP Zakharova, NT (reprint author), Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Mishchenko, Michael/D-4426-2012 NR 9 TC 0 Z9 0 U1 0 U2 1 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 241 EP 244 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100063 ER PT B AU Lee, RB Priestley, KJ AF Lee, RB Priestley, KJ BE Smith, WL Timofeyev, YM TI Long-term total solar irradiance (TSI) variability based upon 1980-2000, spacecraft measurements SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID MAGNETIC ACTIVITY AB 1980-2000, long-term spacecraft total solar irradiance (TSI) data sets were compared to verify TSI variability trends and to identify radiometer response shifts or drifts which may be misinterpreted as TSI variability. In addition, an empirical TSI model fit, based upon 10.7-cm solar radio fluxes and prompt photometric sunspot indices, was used to identify possible radiometer response changes. The spacecraft data sets indicate a long-term TSI variability component of approximately 0.1% (1.4 Watts-per-squared-meter) with a 10-year period. During the 1986 and 1996 periods of minimum solar magnetic activity, the most likely TSI minimum magnitude was found to lie in the 1365-1366 Watts-per-squared-meter range. The 1999-2000, spacecraft TSI measurements and the empirical model fit suggest that the 1999-2000, TSI peak magnitudes, corresponding to maximum solar magnetic activity, may be lower than the corresponding TSI maximum magnitudes which were measured during the 1979-1981, and 1989-1991 periods of maximum solar activity. This result suggests that there may exist another long-term variability component with a period longer than 10 years. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lee, RB (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 473 EP 476 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100122 ER PT B AU Stackhouse, PW Gupta, SK Cox, SJ Chiacchio, M Mikovitz, JC AF Stackhouse, PW Gupta, SK Cox, SJ Chiacchio, M Mikovitz, JC BE Smith, WL Timofeyev, YM TI The WCRP/GEWEX Surface Radiation Budget Project release 2: An assessment of surface fluxes at 1 degree resolution SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID SATELLITE DATA; PARAMETERIZATION; CLIMATOLOGY AB The U.S. National Aeronautics and Space Administration (NASA) based Surface Radiation Budget (SRB) Project in association with the World Climate Research Programme Global Energy and Water Cycle Experiment (WCRP/GEWEX) is preparing a new 1degrees x 1degrees horizontal resolution product for distribution scheduled for release in early 2001. The new release contains several significant upgrades from the previous version. This paper summarizes the most significant upgrades and presents validation results as an assessment of the new data set. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Stackhouse, PW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 9 Z9 9 U1 0 U2 2 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 485 EP 488 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100125 ER PT B AU Haeffelin, M Wielicki, B Priestley, K Duvel, JP Viollier, M AF Haeffelin, M Wielicki, B Priestley, K Duvel, JP Viollier, M BE Smith, WL Timofeyev, YM TI Direct comparisons of radiances measured by independent contemporary ERB instruments SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID RADIATION AB Comparisons of radiance measurements from overlapping independent Earth and cloud radiation budget (ERB) missions are an important contribution to the validation process of the these missions and are essential to the construction of a consistent long-term record of ERB observations. Measurements from the CERES instrument on TRMM are compared to ScaRaB on Resurs (Jan-Mar 1999) and CERES on Terra (Mar-Apr 2000). C1 Virginia Polytech Inst & State Univ, NASA, LaRC, Hampton, VA 23681 USA. RP Haeffelin, M (reprint author), Virginia Polytech Inst & State Univ, NASA, LaRC, MS 420, Hampton, VA 23681 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 517 EP 519 PG 3 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100133 ER PT B AU Steck, T von Clarmann, T AF Steck, T von Clarmann, T BE Smith, WL Timofeyev, YM TI Regularisation in MIPAS ENVISAT off-line constituent retrieval: Strategy and diagnostics SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS AB We present an assessment how a priori knowledge can be used in inversion problems related to atmospheric limb sounding spectroscopy experiments, in particular MIPAS on ENVISAT, and how this a priori knowledge affects corresponding results. It is shown that detail modification of the optimal estimation scheme lead to different retrieval characteristics. A matrix of the structure of a covariance matrix is found which leads to a virtually bias-free Tikhonov-type smooth solution. Altitude-dependent regularization is shown to be important. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Steck, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-301, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 835 EP 838 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100214 ER PT B AU Zhou, DK Smith, WL Larar, AM AF Zhou, DK Smith, WL Larar, AM BE Smith, WL Timofeyev, YM TI Temperature and moisture retrieval algorithm development for NAST interferometer SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS AB The NPOESS Airborne Sounder Testbed Interferometer (NAST-1) provides high spatial resolution (similar to2.6 km) scanning and high spectral resolution (0.25 cm(-1)) measurements in the spectral region of 645-2700 cm(-1) from the NASA ER-2 aircraft flown It an altitude near 20 km. The technique for retrieval of temperature and moisture for NAST-1 is reported. The retrieval is performed by statistical eigenvector regression with the option to follow this by iterative physical retrieval. Detailed and accurate analyses of atmospheric temperature and moisture are achieved without resorting to "radiosonde tuning," a very important feature for a "state of the art" remote sensing system. Several field campaigns with varied meteorological conditions have provided the data needed to verify the accuracy of the spectral radiance, the retrieval algorithm, and the capabilities of this instrument. The preliminary retrievals are presented to demonstrate the ability to resolve fine-scale horizontal features with relatively high vertical resolution. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Zhou, DK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 847 EP 850 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100217 ER PT B AU Delnore, VE Cox, SK Curran, RJ AF Delnore, VE Cox, SK Curran, RJ BE Smith, WL Timofeyev, YM TI CRYSTAL - The Cirrus Regional Study of Tropical Anvils and Layers SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS AB CRYSTAL (Cirrus Regional Study of Tropical Anvils and Layers) is part of a series of field experiments to study clouds and their impact on world weather and climate, and will attempt to improve the application of cloud and radiation effects in global climate models. CRYSTAL is being planned as two parts: a limited CRYSTAL field campaign in 2002 to examine towering clouds and anvil genesis over the Everglades of Florida, and the main CRYSTAL field campaign in 2004 in the Tropical Western Pacific. The latter is timed to take advantage of several cloud measurement satellites that will be operational at that time. This paper discusses some of the issues to be addressed in CRYSTAL, gives a brief description of the research plan, and describes its relationship to other important field experiments and measurement systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Delnore, VE (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 1069 EP 1072 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100274 ER PT B AU Geogdzhayev, IV Mishchenko, M Rossow, WB AF Geogdzhayev, IV Mishchenko, M Rossow, WB BE Smith, WL Timofeyev, YM TI Satellite climatology of aerosol amount and size for use in climate research SO IRS 2000: CURRENT PROBLEMS IN ATMOSPHERIC RADIATION SE STUDIES IN GEOPHYSICAL OPTICS AND REMOTE SENSING LA English DT Proceedings Paper CT International Radiation Symposium CY JUL 24-29, 2000 CL ST PETERSBURG STATE UNIV, RES INST PHYS, ST PETERSBURG, RUSSIA SP Russian Fund Basic Res, NIERSC, NASA, EUMETSAT, NERSC HO ST PETERSBURG STATE UNIV, RES INST PHYS ID AVHRR; ATMOSPHERES; SCATTERING; RETRIEVAL; OCEAN AB The evaluation of the direct and indirect climate forcing by aerosols requires the knowledge of the global distribution of aerosol amount, size, and composition. This goal may eventually be achieved by combining satellite observations and transport models. Here we present an updated version of the algorithm for retrieving aerosol optical thickness (AOT) and Angstrom. coefficient over the ocean using channel 1 and 2 Advanced Very High Resolution Radiometer (AVHRR) radiances developed within the framework of the Global Aerosol Climatology Project (GACP). The new algorithm was applied to the ISCCP DX dataset corresponding to the period of NOAA-9 satellite observations (Feb. 1985 - Nov. 1988). C1 Columbia Univ, NASA, GISS, New York, NY 10025 USA. RP Geogdzhayev, IV (reprint author), Columbia Univ, NASA, GISS, New York, NY 10025 USA. EM igor@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 18 TC 0 Z9 0 U1 0 U2 0 PU A DEEPAK PUBLISHING PI HAMPTON PA 101 RESEARCH DRIVE, PO BOX 7390, HAMPTON, VA 23666 USA BN 0-937194-43-3 J9 STUD GEO OP PY 2001 BP 1227 EP 1230 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Spectroscopy GA BU75Q UT WOS:000176920100315 ER PT S AU Brill, RW Lutcavage, ME AF Brill, RW Lutcavage, ME BE Sedberry, GR TI Understanding environmental influences on movements and depth distributions of tunas and billfishes can significantly improve population assessments SO ISLAND IN THE STREAM: OCEANOGRAPHY AND FISHERIES OF THE CHARLESTON BUMP SE American Fisheries Society Symposium LA English DT Proceedings Paper CT Charleston Bump Colloquium CY OCT, 1999 CL CHARLESTON, SC ID ATLANTIC BLUEFIN TUNA; THUNNUS-ALBACARES; YELLOWFIN TUNA; ULTRASONIC TELEMETRY; KATSUWONUS-PELAMIS; HORIZONTAL MOVEMENTS; ACOUSTIC TELEMETRY; VERTICAL MOVEMENTS; SPORTFISHING GEAR; HAWAIIAN-ISLANDS AB The vulnerability of the highly mobile tunas (family Scombridae) and billfishes (families Istiophoridae and Xiphiidae) to various fishing gears and detection by aerial surveys is influenced by their depth distributions, travel speeds, residency times, and aggregation. As a result, understanding the effects of the physical environment on fish behavior is critical for robust population assessments. Numerous studies have attempted to understand the movements and habitat requirements of tunas and billfishes by correlating catch statistics with environmental conditions averaged over time and space. Such correlations do not necessarily elucidate the requisite relationships because the data are not gathered simultaneously, and because error terms are often too broad to demonstrate meaningful relationships. More important, using catch statistics to determine the effects of environmental conditions on catch statistics can never prove causation and result in tautology, unless independent measures of fish abundance are available. The situation is not necessarily improved when catch statistics are correlated with satellite-derived sea surface temperature data. Tunas and billfish fish do not always live at the surface and, more importantly, regularly move through vertical thermal gradients (approximate to1degreesC m(-1)) that are orders of magnitude steeper than horizontal gradients (approximate to1degreesC km(-1)). Sea surface temperature gradients per se are, therefore, unlikely to influence horizontal movements or aggregation. Direct observations of tuna and billfish behaviors (collected via acoustic telemetry or electronic data-recording tags) can, however, be readily combined with information on their physiologically-based environmental tolerances, forage abundance, and appropriate oceanographic data. The resulting models can correct both traditional catch-per-unit effort data and aerial survey data for differences in gear vulnerability, and thus significantly improve population assessments. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Brill, RW (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, 2570 Dole St, Honolulu, HI 96822 USA. NR 78 TC 103 Z9 106 U1 1 U2 13 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE, STE 110, BETHESDA, MD 20814-2199 USA SN 0892-2284 BN 1-888569-23-9 J9 AM FISH S S JI Am. Fish. Soc. Symp. PY 2001 VL 25 BP 179 EP 198 PG 20 WC Fisheries; Oceanography SC Fisheries; Oceanography GA BU51Y UT WOS:000176234800011 ER PT B AU Rubinstein, R AF Rubinstein, R BE Kambe, T Nakano, T Miyauchi, T TI Two- and three- dimensional behavior of the large scales in rotating turbulence SO IUTAM SYMPOSIUM ON GEOMETRY AND STATISTICS OF TURBULENCE SE FLUID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT IUTAM Symposium on Geometry and Statistics of Turbulence CY NOV 01-05, 1999 CL HAYAMA, JAPAN SP Int Union Theoret & Appl Mech, Sci Council Japan, Inoue Fdn Sci, Kajima Fdn, Hewlett Packard Japan Ltd, NEC Corp ID 3-DIMENSIONAL TURBULENCE AB Weak turbulence theory is treated as an approximate solution of the DIA equations for rotating turbulence. The consistency of weak turbulence theory with numerical simulations of rotating turbulence in small aspect-ratio domains is evaluated. Finally, the possibility of four-wave interactions in this problem and in the problem of compressible rotating turbulence is discussed. C1 NASA, Langley Res Ctr, Inst Comp Appl Sci & Engn, Hampton, VA 23665 USA. RP Rubinstein, R (reprint author), NASA, Langley Res Ctr, Inst Comp Appl Sci & Engn, Hampton, VA 23665 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6711-1 J9 FLUID MEC A PY 2001 VL 59 BP 261 EP 266 PG 6 WC Mechanics; Physics, Fluids & Plasmas; Physics, Mathematical SC Mechanics; Physics GA BS09M UT WOS:000168606700033 ER PT B AU Lih, SS Hickey, G Wang, DW Tzou, HS AF Lih, SS Hickey, G Wang, DW Tzou, HS BE Gabbert, U Tzou, HS TI Precision actuation of micro-space structures SO IUTAM SYMPOSIUM ON SMART STRUCTURES AND STRUCTRONIC SYSTEMS SE SOLID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT IUTAM Symposium on Smart Structures and Structronic Systems CY SEP 26-29, 2000 CL MAGDEBURG, GERMANY SP Int Union Theoret & Appl Mech, German Res Fdn, Kluwer Acad Publishers C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lih, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6968-8 J9 SOLID MECH APPL PY 2001 VL 89 BP 213 EP 222 PG 10 WC Engineering, Mechanical; Materials Science, Multidisciplinary; Mathematics, Applied; Mechanics SC Engineering; Materials Science; Mathematics; Mechanics GA BS96W UT WOS:000171526900027 ER PT B AU Adessi, C Devel, M AF Adessi, C Devel, M BE Hunt, CE Chakhovskoi, AG Chubun, NN Hajra, M TI Field enhancement properties of nanotubes in a field emission set-up SO IVMC 2000: PROCEEDINGS OF THE 14TH INTERNATIONAL VACUUM MICROELECTRONICES CONFERENCE LA English DT Proceedings Paper CT 14th International Vacuum Microelectronics Conference CY AUG 12-16, 2001 CL UNIV CALIF DAVIS, DAVIS, CA SP Univ Calif, Davis Dept Elect & Comp Engn, IEEE Electron Devices Soc HO UNIV CALIF DAVIS ID CARBON NANOTUBES AB The field enhancement properties of carbon nanotubes, involved in the emission of electrons, is investigated theoretically for various single-wall (SWNT) and multi-wall nanotubes (MWNT). We point out big differences between (n,0) and (n,n) nanotubes, and propose phenomenological laws for the variations of the enhancement factor with length and diameter. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Adessi, C (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7197-6 PY 2001 BP 27 EP 28 DI 10.1109/IVMC.2001.939636 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA BT14F UT WOS:000172068300014 ER PT B AU Marrese-Reading, CM Polk, JE AF Marrese-Reading, CM Polk, JE BE Hunt, CE Chakhovskoi, AG Chubun, NN Hajra, M TI Spacecraft propulsion applications for field emission cathodes SO IVMC 2000: PROCEEDINGS OF THE 14TH INTERNATIONAL VACUUM MICROELECTRONICES CONFERENCE LA English DT Proceedings Paper CT 14th International Vacuum Microelectronics Conference CY AUG 12-16, 2001 CL UNIV CALIF DAVIS, DAVIS, CA SP Univ Calif, Davis Dept Elect & Comp Engn, IEEE Electron Devices Soc HO UNIV CALIF DAVIS AB Many small-scale spacecraft propulsion systems under development could benefit from a compatible FE cathode. These thrusters challenge the performance of FE cathodes because of the plasma environment they create could significantly limit the cathode lifetime if it does not have the proper configuration and materials. The thruster current requirements and cathode integration challenges are discussed in this article. Cathode configurations are recommended to improve the cathode and thruster compatibility. Preliminary results are presented from the first successful test of an electric thruster with a Spindt-type FEA cathode neutralizer. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marrese-Reading, CM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 125-109, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7197-6 PY 2001 BP 123 EP 124 DI 10.1109/IVMC.2001.939684 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA BT14F UT WOS:000172068300062 ER PT S AU Pereyra, NA Kallman, TR Blondin, JM AF Pereyra, NA Kallman, TR Blondin, JM GP UNAM UNAM TI Hydrodynamic models of line-driven accretion disk winds in cataclysmic variables SO IX LATIN AMERICAN REGIONAL MEETING OF THE INTERNATIONAL-ASTRONOMICAL-UNION SE REVISTA MEXICANA DE ASTRONOMIA Y ASTROFISICA, SERIE DE CONFERENCIAS LA English DT Proceedings Paper CT 9th Latin American Regional Meeting of the International-Astronomical-Union (IAU) CY NOV 09-13, 1998 CL INST NACL ASTROFIS OPT ELECTR, TONANTZINTLA, MEXICO SP Int Astronom Union, UNESCO HO INST NACL ASTROFIS OPT ELECTR DE accretion : accretion disks; novae : cataclysmic variables; stars : mass-loss ID HIGH-VELOCITY WINDS; DWARF NOVA; OUTBURST; BINARIES; STARS AB We developed several a-disk models for line-driven winds from cataclysmic variables. Using 1-D analytic models we explore the conditions necessary for the existence of a wind, and the dependence of speed and mass-loss with radius. Using a 2-D isothermal model we explore the effects of centrifugal forces, showing that they cause stream lines to collide producing enhanced density regions in the wind. Without these effects, the mass-loss rates obtained would be too low to produce the optical depths required to explain P-Cygni profiles, showing the necessity of 2-D models. Using a 2-D adiabatic model we calculate mass-losses, terminal velocities, and C IV line profiles for various angles. For a disk with Le around a white dwarf of 0.6 M-circle dot and 0.01 R-circle dot, we obtain M-wind 8 x 10(-12) M(circle dot)yr(-1), and a terminal velocity similar to 3000 km s(-1). The profiles obtained are consistent with observations, in particular with the absorption of the blue-shifted component, the velocities implied by absorption components, the width of emission components, and the strong dependence with inclination. C1 NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Greenbelt, MD 20771 USA. RP Pereyra, NA (reprint author), NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Greenbelt, MD 20771 USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU UNIVERSIDAD NACIONAL AUTONOMA MEXICO INSTITUTO ASTRONOMIA PI MEXICO CITY PA APARTADO POSTAL 70-264, MEXICO CITY 04510, MEXICO SN 1405-2059 J9 REV MEX AST ASTR PY 2001 VL 11 BP 159 EP 164 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT78H UT WOS:000174050800050 ER PT B AU Howard, A Tunstel, E Edwards, D Carlson, A AF Howard, A Tunstel, E Edwards, D Carlson, A BE Smith, MH Gruver, WA Hall, LO TI Enhancing fuzzy robot navigation systems by mimicking human visual perception of natural terrain traversability SO JOINT 9TH IFSA WORLD CONGRESS AND 20TH NAFIPS INTERNATIONAL CONFERENCE, PROCEEDINGS, VOLS. 1-5 LA English DT Proceedings Paper CT 9th International-Fuzzy-Systems-Association World Congress/20th North-American-Fuzzy-Information-Processing-Society, International Conference CY JUL 25-28, 2001 CL VANCOUVER, CANADA SP Int Fuzzy Syst Assoc, N Amer Fuzzy Informat Proc Soc, IEEE Syst, Man & Cybernet Soc, IEEE, Neural Networks Council AB This paper presents a technique for learning to assess terrain traversability for outdoor mobile robot navigation using human-embedded logic and real-time perception of terrain features extracted from image data. The methodology utilizes a fuzzy logic framework and vision algorithms for analysis of the terrain. The terrain assessment and learning methodology is tested and validated with a set of real-world image data acquired by an onboard vision system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Howard, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 8 TC 14 Z9 14 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7078-3 PY 2001 BP 7 EP 12 PG 6 WC Computer Science, Artificial Intelligence; Mathematics, Applied SC Computer Science; Mathematics GA BT52S UT WOS:000173245100003 ER PT J AU Buchman, A Kalil, C Dodiuk-Kenig, H Rotel, M AF Buchman, A Kalil, C Dodiuk-Kenig, H Rotel, M TI Microstructure characterization of laser treated surfaces SO JOURNAL OF ADHESION LA English DT Article; Proceedings Paper CT 1st World Congress on Adhesion and Related Phenomena (WCARP-1) CY SEP 06-11, 1998 CL GARMISCH PARTENKI, GERMANY DE excimer laser; microstructure; adhesional strength; surface treatment; mechanism AB Excimer laser UV radiation presents a new technology for preadhesion surface treatment of various material adherends. The application of an ArF Excimer laser (193 nm) for surface pretreatment of polycarbonate, polyetherimide, PEEK composite, glass reinforced epoxy composite, aluminum, copper, magnesuim. PZT and fused silica was investigated. Experimental results indicated that UV laser surface treatment improved the adhesional strength significantly compared with conventionally-treated substrates for all the materials tested. The improved adhesion correlated with changes in morphology of the irradiated surface, chemical modification and removal of contaminants, which contributed to a strong and durable adhesive bond. This paper will concentrate only on the connection between the mechanical and morphological effect. The most common microstructure features on the surface after laser irradiation (examined by SEM and AFM) were small conical structures randomly distributed on the irradiated areas. Other features were periodic surface ridges or flat smoothened areas with spread arrays of microcracks. All these morphologies increase the roughness of the surface, enabling mechanical interlocking of the adhesive. It should be noted that the roughness is micronsized, and uniformly spread on the surface, which presents an advantage over abrasive treatments. The distribution of the features and their size were dependent on the laser parameters (intensity and number of pulses). Some mechanisms are presented, and these interesting phenomena are discussed. C1 RAFAEL, Dept 27, IL-31021 Haifa, Israel. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Technion Israel Inst Technol, Israel Inst Met, Haifa, Israel. RP Buchman, A (reprint author), RAFAEL, Dept 27, POB 2250, IL-31021 Haifa, Israel. NR 8 TC 5 Z9 5 U1 0 U2 5 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 0021-8464 J9 J ADHESION JI J. Adhes. PY 2001 VL 77 IS 2 BP 163 EP 181 DI 10.1080/00218460108030736 PG 19 WC Engineering, Chemical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA 522KB UT WOS:000173894200003 ER PT J AU Aglan, H Wang, QY Kehoe, M AF Aglan, H Wang, QY Kehoe, M TI Fatigue behavior of bonded composite repairs SO JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY LA English DT Article DE composite patches; bonded repair; aircraft structures; fatigue crack growth ID CRACKED PLATES; PATCH REPAIR; ALUMINUM PANELS; GROWTH; SIZE AB In this study, recent efforts into the research and development of composite repairs bonded to defective aircraft structures are discussed, The fatigue crack growth (FCG) behavior of precracked Al 7075/T6 substrates with bonded composite patches was investigated experimentally and analytically. Boron-epoxy patches with 2-, 4- and 6-plies were installed on Al substrates with single-side-crack. Tension-tension fatigue tests were also conducted on Al substrates to establish their fatigue behavior for comparing with the repaired specimens. A considerable increase in the fatigue life and a decrease in the stress intensity factor (SIF) were observed as the number of plies increased. An analytical model, based on Rose's analytical solution and Paris' power law, was developed to predict the FCG behavior of the repaired substrates. The analytical and experimental results are found to be in good agreement. C1 Tuskegee Univ, Dept Mech Engn, Tuskegee, AL 36088 USA. NASA, Dryden Flight Res Ctr, Edwards AFB, CA 93523 USA. RP Aglan, H (reprint author), Tuskegee Univ, Dept Mech Engn, Tuskegee, AL 36088 USA. RI WANG, Qing Yuan/G-5024-2010 NR 41 TC 7 Z9 7 U1 2 U2 3 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0169-4243 J9 J ADHES SCI TECHNOL JI J. Adhes. Sci. Technol. PY 2001 VL 15 IS 13 BP 1621 EP 1634 DI 10.1163/156856101753207715 PG 14 WC Engineering, Chemical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA 506TK UT WOS:000172987700005 ER PT J AU Cowan, TJ Arena, AS Gupta, KK AF Cowan, TJ Arena, AS Gupta, KK TI Accelerating computational fluid dynamics based aeroelastic predictions using system identification SO JOURNAL OF AIRCRAFT LA English DT Article AB System identification is evaluated as an efficient and accurate technique for modeling unsteady aerodynamic forces for use in time-domain aeroelastic analysis. In the system identification methodology, the constant coefficients of a linear system model are fit to the computed response time histories from a three-dimensional, unsteady computational fluid dynamics (CFD) solver. The resulting model of the unsteady CFD solution is independent of both dynamic pressure and structural parameters. Hence, this methodology has the advantage that only one CFD flowfield computation for each Mach number must be completed to determine the aeroelastic instability boundary. Results show that system identification can accurately model the unsteady aerodynamic forces for complex aerospace structures of practical interest. The methodology results in a substantial savings in computational time when predicting aeroelastic instabilities. C1 Oklahoma State Univ, Stillwater, OK 74078 USA. NASA, Dryden Flight Res Ctr, Edwards, CA 93523 USA. RP Cowan, TJ (reprint author), Oklahoma State Univ, Stillwater, OK 74078 USA. NR 10 TC 36 Z9 54 U1 0 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 2001 VL 38 IS 1 BP 81 EP 87 DI 10.2514/2.2737 PG 7 WC Engineering, Aerospace SC Engineering GA 402NG UT WOS:000166994500012 ER PT J AU Yeo, H Chopra, I AF Yeo, H Chopra, I TI Coupled rotor/fuselage vibration analysis for teetering rotor and test data comparison SO JOURNAL OF AIRCRAFT LA English DT Article AB A comprehensive vibration analysis of a coupled rotor/fuselage system for a two-bladed teetering rotor using finite element methods in space and time is developed that incorporates consistent rotor/fuselage structural, aerodynamic, and inertial couplings and a modern free-wake model. Coupled nonlinear periodic blade and fuselage equations are transformed to the modal space and solved simultaneously. The elastic line airframe model of the AH-1G helicopter is integrated into the elastic rotor finite element model. Analytical predictions of rotor control angles, blade loads, hub forces, and vibration are compared with AH-1G operation load survey test data. The blade loads predicted by the present analysis show generally fair agreement with the flight test data. Calculated 2 and 4 per revolution vertical vibration levels at the pilot seat show fair correlation with the flight test, but the predicted 2 per revolution lateral vibration level is higher than the measurement, particularly at high advance ratios. Modeling of pylon flexibility is essential in the two-bladed teetering rotor vibration analysis. Refined aerodynamics such as free wake and unsteady aerodynamics have an important role in the prediction of vibration. C1 Univ Maryland, Alfred Gessow Rotocraft Ctr, Dept Aerosp Engn, College Pk, MD 20742 USA. RP Yeo, H (reprint author), NASA, Ames Res Ctr, Raytheon Tech Serv Co, Moffett Field, CA 94035 USA. NR 23 TC 8 Z9 10 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 2001 VL 38 IS 1 BP 111 EP 121 DI 10.2514/2.2742 PG 11 WC Engineering, Aerospace SC Engineering GA 402NG UT WOS:000166994500016 ER PT J AU McGowan, DM Ambur, DR Hanna, TG McNeill, SR AF McGowan, DM Ambur, DR Hanna, TG McNeill, SR TI Evaluating the compressive response of notched composite panels using full-field displacements SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 40th Structures, Structural Dynamics, and Materials Conference CY APR 12-15, 1999 CL ST LOUIS, MO SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID IMAGE CORRELATION AB An experimental and analytical evaluation of the compressive response of two composite, notched stiffened panels representative of primary composite wing structure is presented. A three-dimensional full-held image correlation technique is used to measure all three displacement components over global and local areas of the test panels. Pointwise and full-field results obtained using the image correlation technique are presented and compared to experimental results and analytical results obtained using nonlinear finite element analysis. Both global and global-local image correlation results are presented and discussed. Results of a simple calibration test of this image correlation technique are also presented. C1 NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. Univ S Carolina, Dept Mech Engn, Columbia, SC 29208 USA. RP McGowan, DM (reprint author), NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. NR 13 TC 11 Z9 11 U1 0 U2 0 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 EI 1533-3868 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 2001 VL 38 IS 1 BP 122 EP 129 DI 10.2514/2.2743 PG 8 WC Engineering, Aerospace SC Engineering GA 402NG UT WOS:000166994500017 ER PT J AU Pritchard, J AF Pritchard, J TI Overview of landing gear dynamics SO JOURNAL OF AIRCRAFT LA English DT Article ID AIRCRAFT AB One problem facing the aircraft community is landing gear dynamics, especially shimmy and brake-induced vibration. Although neither shimmy nor brake-induced vibrations are usually catastrophic, they can lead to accidents due to excessive wear and shortened life of gear parts and contribute to pilot and passenger discomfort. Recently, NASA has initiated an effort to increase the safety of air travel by reducing the number of accidents by a factor of five in 10 years. This safety initiative has spurred an increased interest in improving landing gear design to minimize shimmy and brake-induced vibration, which are still largely misunderstood phenomena. To increase the understanding of these problems, a literature survey was performed. The major focus of this paper is to summarize work documented from the last 10 years to highlight the latest efforts in solving these vibration problems. Older publications are included to help the reader understand the longevity of the problem and the findings from earlier researchers. The Literature survey revealed a variety of analyses, testing, modeling, and simulation of aircraft landing gear. Experimental validation and characterization of shimmy and brake-induced vibration of aircraft landing gear are also reported. An overview is presented of the problem documented in the references, together with a history of landing gear dynamic problems and solutions. Based on the assessment of this survey, recommendations of the most critically needed enhancements to the state of the art are given. C1 USA, NASA, Langley Res Ctr, Res Lab,Struct Dynam Branch, Hampton, VA 23681 USA. RP Pritchard, J (reprint author), USA, NASA, Langley Res Ctr, Res Lab,Struct Dynam Branch, Hampton, VA 23681 USA. NR 64 TC 18 Z9 20 U1 3 U2 17 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN-FEB PY 2001 VL 38 IS 1 BP 130 EP 137 DI 10.2514/2.2744 PG 8 WC Engineering, Aerospace SC Engineering GA 402NG UT WOS:000166994500018 ER PT J AU Meneghini, R Jones, JA Iguchi, T Okamoto, K Kwiatkowski, J AF Meneghini, R Jones, JA Iguchi, T Okamoto, K Kwiatkowski, J TI Statistical methods of estimating average rainfall over large space-timescales using data from the TRMM precipitation radar SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PROBABILITY-DISTRIBUTION FUNCTIONS; THRESHOLD METHOD; CONVECTIVE RAINFALL; TIME INTEGRALS; AREA INTEGRALS AB Data from the Tropical Rainfall Measuring Mission (TRMM) precipitation radar represent the first global rain-rate dataset acquired by a spaceborne weather radar. Because the radar operates at an attenuating wavelength, one of the principal issues concerns the accuracy of the attenuation correction algorithms. One way to test these algorithms is by means of a statistical method in which the probability distribution of rain rates at the high end is inferred by measurements at the low to intermediate range and by the assumption that the rain rates are lognormally distributed. Investigation of this method and the area-time integral methods using a global dataset provides an indication of how well methods of this kind can be expected to perform over different space-timescales and climatological regions using the sparsely sampled TRMM radar data. Identification of statistical relationships among the rain parameters and an understanding of the rain-rate distribution as a function of time and space may help to test the validity of the high-resolution rain-rate estimates. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon STX Inc, Greenbelt, MD USA. Commun Res Lab, Tokyo, Japan. George Mason Univ, Fairfax, VA 22030 USA. RP Meneghini, R (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. RI PMM, JAXA/K-8537-2016 NR 33 TC 21 Z9 21 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 3 BP 568 EP 585 DI 10.1175/1520-0450(2001)040<0568:SMOEAR>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 417ZD UT WOS:000167864600017 ER PT J AU Joyce, R Janowiak, J Huffman, G AF Joyce, R Janowiak, J Huffman, G TI Latitudinally and seasonally dependent zenith-angle corrections for geostationary satellite IR brightness temperatures SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID CLOUD AB The equivalent brightness temperature T-b recorded by geosynchronous infrared (geo-IR) "window'' channel (10.7-11.5 mum) satellite sensors is shown to depend on the zenith angle (local angle from the zenith to the satellite for a pixel's ground location) in addition to the mix of clouds and surface that would be observed from a direct overhead viewpoint (nadir view). This zenith-angle dependence is characterized, and two corrections are developed from a collection of half-hourly geo-IR pixel data that have been parallax corrected and averaged to a 0.5 degrees X 0.5 degrees latitude/longitude grid for each geosynchronous satellite separately. First, composites of collocated T-b over tropical regions from the Geostationary Operational Environmental Satellite (GOES)-8/GOES-10 and the Meteosat-5/Meteosat-7 satellite pairs are used to produce robust estimates of isotropic zenith-angle corrections as a function of zenith angle and grid-box-averaged T-b. The corrections range from zero for a zenith angle of similar to 26.5 degrees to increases of more than 20 K at T-b 5 230 K near the limb. Near-limb corrections in clear and very cold thick overcast conditions are smaller but are still positive. This empirical result depends on the surface-tropopause temperature differences, so a second correction was developed. Using collocations from the same two satellite pairs from 60 degreesN to 60 degreesS, differences in uncorrected T-b divided by differences in the corresponding corrected values were accumulated as a function of latitude and season. The resultant ratios smoothly vary from similar to1 in the Tropics to similar to0.5 at 60 degreesN and 60 degreesS, with a quicker decrease in the winter hemisphere. In comparison with the uncorrected geo-IR data, there is a 50% reduction in the root-mean-square differences between collocated values from adjacent satellites by applying the latitude/season-adjusted zenith-angle corrections. Histograms of corrected geo-IR T-b at large zenith angles closely match histograms from collocated near-nadir-view values. Residual difference maps are smooth and indicate intersatellite differences. C1 NOAA, Climate Predict Ctr, NCEP, Washington, DC USA. Res & Data Syst Corp, Greenbelt, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Joyce, R (reprint author), NOAA, Climate Predict Ctr, NCEP, Room 605A,5200 Auth Rd, Camp Springs, MD 20746 USA. RI Huffman, George/F-4494-2014 OI Huffman, George/0000-0003-3858-8308 NR 15 TC 32 Z9 33 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 4 BP 689 EP 703 DI 10.1175/1520-0450(2001)040<0689:LASDZA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 420TV UT WOS:000168022100002 ER PT J AU Loeb, NG Priestley, KJ Kratz, DP Geier, EB Green, RN Wielicki, VA Hinton, RO Nolan, SK AF Loeb, NG Priestley, KJ Kratz, DP Geier, EB Green, RN Wielicki, VA Hinton, RO Nolan, SK TI Determination of unfiltered radiances from the clouds and the Earth's Radiant Energy System instrument SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RADIATION BUDGET EXPERIMENT; CERES; ALBEDO; MODEL; ERBE AB A new method for determining unfiltered shortwave (SW), longwave (LW), and window radiances from filtered radiances measured by the Clouds and the Earth's Radiant Energy System (CERES) satellite instrument is presented. The method uses theoretically derived regression coefficients between filtered and unfiltered radiances that are a function of viewing geometry, geotype, and whether cloud is present. Relative errors in instantaneous unfiltered radiances from this method are generally well below 1% for SW radiances (std dev approximate to0.4% or approximate to1 W m(-2) equivalent flux), less than 0.2% for LW radiances (std dev approximate to0.1% or approximate to0.3 W m(-2) equivalent flux), and less than 0.2% (std dev approximate to0.1%) for window channel radiances. When three months (June, July, and August of 1998) of CERES Earth Radiation Budget Experiment (ERBE)-like unfiltered radiances from the Tropical Rainfall Measuring Mission satellite between 20 degreesS and 20 degreesN are compared with archived Earth Radiation Budget Satellite (ERBS) scanner measurements for the same months over a 5-yr period (1985-89), significant scene-type dependent differences are observed in the SW channel. Full-resolution CERES SW unfiltered radiances are approximate to7.5% (approximate to3 W m(-2) equivalent diurnal average flux) lower than ERBS over clear ocean, as compared with approximate to1.7% (approximate to4 W m(-2) equivalent diurnal average flux) for deep convective clouds and approximate to6% (approximate to4-6 W m(-2) equivalent diurnal average flux) for clear land and desert. This dependence on scene type is shown to be partly caused by differences in spatial resolution between CERES and ERBS and by errors in the unfiltering method used in ERBS. When the CERES measurements are spatially averaged to match the ERBS spatial resolution and the unfiltering scheme proposed in this study is applied to both CERES and ERBS, the ERBS all-sky SW radiances increase by approximate to1.7%, and the CERES radiances are now consistently approximate to3.5%-5% lower than the modified ERBS values for all scene types. Further study is needed to determine the cause for this remaining difference, and even calibration errors cannot be ruled out. CERES LW radiances are closer to ERBS values for individual scene types-CERES radiances are within approximate to0.1% (approximate to0.3 W m(-2)) of ERBS over clear ocean and approximate to0.5% (approximate to1.5 W m(-2)) over clear land and desert. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 25 TC 78 Z9 78 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 4 BP 822 EP 835 DI 10.1175/1520-0450(2001)040<0822:DOURFT>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 420TV UT WOS:000168022100012 ER PT J AU Bell, TL Kundu, PK Kummerow, CD AF Bell, TL Kundu, PK Kummerow, CD TI Sampling errors of SSM/I and TRMM rainfall averages: Comparison with error estimates from surface data and a simple model SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID VERTICAL STRUCTURE INFORMATION; PASSIVE MICROWAVE TECHNIQUE; MEASURING MISSION TRMM; TROPICAL RAINFALL; STOCHASTIC-MODEL; TOGA COARE; DAY-PERIOD; SATELLITE; PRECIPITATION; SPACE AB Quantitative use of satellite-derived maps of monthly rainfall requires some measure of the accuracy of the satellite estimates. The rainfall estimate for a given map grid box is subject to both remote sensing error and, especially in the case of low-orbiting satellites, sampling error due to the limited number of observations of the grid box provided by the satellite. A simple model of rain behavior predicts that rms random error in grid-box averages should depend in a simple way on the local average rain rate, and the predicted behavior has been seen in simulations using surface rain gauge and radar data. This relationship is examined using Special Sensor Microwave Imager (SSM/I) satellite data obtained over the western equatorial Pacific during the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment. Rms error inferred directly from SSM/I rainfall estimates is found to be larger than was predicted from surface data and to depend less on local rain rate than was predicted. Preliminary examination of Tropical Rainfall Measuring Mission (TRMM) microwave estimates shows better agreement with surface data. A simple method of estimating rms error in satellite rainfall estimates is suggested, based on quantities that can be computed directly from the satellite data. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Bell, TL (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. RI Bell, Thomas/G-5425-2012; Kundu, Prasun/C-7212-2013 OI Kundu, Prasun/0000-0002-2284-9852 NR 29 TC 25 Z9 25 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 5 BP 938 EP 954 DI 10.1175/1520-0450(2001)040<0938:SEOSIA>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 422QR UT WOS:000168131200007 ER PT J AU Tao, WK Lang, S Olson, WS Meneghini, R Yang, S Simpson, J Kummerow, C Smith, E Halverson, J AF Tao, WK Lang, S Olson, WS Meneghini, R Yang, S Simpson, J Kummerow, C Smith, E Halverson, J TI Retrieved vertical profiles of latent heat release using TRMM rainfall products for February 1988 SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID MIDLATITUDE SQUALL LINE; SCALE WAVE DISTURBANCES; MEASURING MISSION TRMM; TOGA COARE; CONVECTIVE SYSTEMS; SPACEBORNE RADAR; MOISTURE BUDGETS; CLOUD CLUSTERS; STRATIFORM PRECIPITATION; HYDROMETEOR PROFILES AB This paper represents the first attempt to use Tropical Rainfall Measuring Mission (TRMM) rainfall information to estimate the four-dimensional latent heating structure over the global Tropics for one month (February 1998). The mean latent heating profiles over six oceanic regions [Tropical Ocean and Global Atmosphere (TOGA) Coupled Ocean-Atmosphere Response Experiment (COARE) Intensive Flux Array (IFA), central Pacific, South Pacific Convergence Zone (SPCZ), east Pacific, Indian Ocean, and Atlantic Ocean] and three continental regions (South America, central Africa, and Australia) are estimated and studied. The heating profiles obtained from the results of diagnostic budget studies over a broad range of geographic locations are used to provide comparisons and indirect validation for the heating algorithm-estimated heating profiles. Three different latent heating algorithms, the Goddard Space Flight Center convective-stratiform heating (CSH), the Goddard profiling (GPROF) heating, and the hydrometeor heating (HH) algorithms are used and their results are intercompared. The horizontal distribution or patterns of latent heat release from the three different heating retrieval methods are very similar. They all can identify the areas of major convective activity [i.e., a well-defined Intertropical Convergence Zone (ITCZ) in the Pacific, a distinct SPCZ] in the global Tropics. The magnitudes of their estimated latent heating release are also in good agreement with each other and with those determined from diagnostic budget studies. However, the major difference among these three heating retrieval algorithms is the altitude of the maximum heating level. The CSH algorithm-estimated heating profiles only show one maximum heating level, and the level varies among convective activity from various geographic locations. These features are in good agreement with diagnostic budget studies. A broader maximum of heating, often with two embedded peaks, is generally derived from applications of the GPROF heating and HH algorithms, and the response of the heating profiles to convective activity is less pronounced. Also, GPROF and HH generally yield heating profiles with a maximum at somewhat lower altitudes than CSH. The impact of different TRMM Microwave Imager (TMI) and precipitation radar (PR) rainfall information on latent heating structures was also examined. The rainfall estimated from the PR is smaller than that estimated from the TMI in the Pacific (TOGA COARE IFA, central Pacific, SPCZ, and east Pacific) and Indian Oceans, causing weaker latent heat release in the CSH algorithm-estimated heating. In addition, the larger stratiform amounts derived from the PR over South America and Australia consequently lead to higher maximum heating levels. Sensitivity tests addressing the appropriate selection of latent heating profiles from the CSH lookup table were performed. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Tao, WK (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. NR 57 TC 64 Z9 65 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 6 BP 957 EP 982 DI 10.1175/1520-0450(2001)040<0957:RVPOLH>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 439RZ UT WOS:000169132500001 ER PT J AU Olson, WS Bauer, P Viltard, NF Johnson, DE Tao, WK Meneghini, R Liao, L AF Olson, WS Bauer, P Viltard, NF Johnson, DE Tao, WK Meneghini, R Liao, L TI A melting-layer model for passive/active microwave remote sensing applications. Part I: Model formulation and comparison with observations SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID MICROSCALE STRUCTURE; FRONTAL RAINBANDS; CLOUD MODEL; PRECIPITATION; MESOSCALE; RAINFALL; HYDROMETEORS; ORGANIZATION; SIMULATION; PARTICLES AB In this study, a 1D steady-state microphysical model that describes the vertical distribution of melting precipitation particles is developed. The model is driven by the ice-phase precipitation distributions just above the freezing level at applicable grid points of "parent'' 3D cloud-resolving model (CRM) simulations. It extends these simulations by providing the number density and meltwater fraction of each particle in finely separated size categories through the melting layer. The depth of the modeled melting layer is primarily determined by the initial material density of the ice-phase precipitation. The radiative properties of melting precipitation at microwave frequencies are calculated based upon different methods for describing the dielectric properties of mixed-phase particles. Particle absorption and scattering efficiencies at the Tropical Rainfall Measuring Mission Microwave Imager frequencies (10.65-85.5 GHz) are enhanced greatly for relatively small (similar to0.1) meltwater fractions. The relatively large number of partially melted particles just below the freezing level in stratiform regions leads to significant microwave absorption, well exceeding the absorption by rain at the base of the melting layer. Calculated precipitation backscatter efficiencies at the precipitation radar frequency (13.8 GHz) increase with particle meltwater fraction, leading to a "bright band'' of enhanced radar reflectivities in agreement with previous studies. The radiative properties of the melting layer are determined by the choice of dielectric models and the initial water contents and material densities of the "seeding'' ice-phase precipitation particles. Simulated melting-layer profiles based upon snow described by the Fabry-Szyrmer core-shell dielectric model and graupel described by the Maxwell-Garnett water matrix dielectric model lead to reasonable agreement with radar-derived melting-layer optical depth distributions. Moreover, control profiles that do not contain mixed-phase precipitation particles yield optical depths that are systematically lower than those observed. Therefore, the use of the melting-layer model to extend 3D CRM simulations is likely justified, at least until more-realistic spectral methods for describing melting precipitation in high-resolution, 3D CRMs are implemented. C1 NASA, Joint Ctr Earth Syst Technol, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Deutsch Forsch Anstalt Luft & Raumfahrt, Cologne, Germany. Ctr Etud Environm Terr & Planetaires, Velizy, France. Sci Syst & Applicat Inc, Lanham, MD USA. Caelum Res Corp, Rockville, MD USA. RP Olson, WS (reprint author), NASA, Joint Ctr Earth Syst Technol, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 30 TC 56 Z9 60 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 7 BP 1145 EP 1163 DI 10.1175/1520-0450(2001)040<1145:AMLMFP>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 450UM UT WOS:000169762800001 ER PT J AU Olson, WS Bauer, P Kummerow, CD Hong, Y Tao, WK AF Olson, WS Bauer, P Kummerow, CD Hong, Y Tao, WK TI A melting-layer model for passive/active microwave remote sensing applications. Part II: Simulation of TRMM observations SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RADIATIVE-TRANSFER; CLOUDS; HYDROMETEORS; PRECIPITATION; RETRIEVALS; RAINFALL; PROFILES; OCEAN AB The one-dimensional, steady-state melting-layer model developed in Part I of this study is used to calculate both the microphysical and radiative properties of melting precipitation, based upon the computed concentrations of snow and graupel just above the freezing level at applicable horizontal grid points of three-dimensional cloud-resolving model simulations. The modified 3D distributions of precipitation properties serve as input to radiative transfer calculations of upwelling radiances and radar extinction/reflectivities at the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and precipitation radar (PR) frequencies, respectively. At the resolution of the cloud-resolving model grids (similar to1 km), upwelling radiances generally increase if mixed-phase precipitation is included in the model atmosphere. The magnitude of the increase depends upon the optical thickness of the cloud and precipitation, as well as the scattering characteristics of the mixed-phase particles and ice-phase precipitation aloft. Over the set of cloud-resolving model simulations utilized in this study, maximum radiance increases of 43, 28, 18, and 10 K are simulated at 10.65, 19.35, 37.0, and 85.5 GHz, respectively. The impact of melting on TMI-measured radiances is determined not only by the physics of the melting particles but also by the horizontal extent of the melting precipitation, given that the lower-frequency channels have footprints that extend over tens of kilometers. At TMI resolution, the maximum radiance increases are 16, 15, 12, and 9 K at the same frequencies. Simulated PR extinction and reflectivities in the melting layer can increase dramatically if mixed-phase precipitation is included, a result consistent with previous studies. Maximum increases of 0.46 (similar to2 dB) in extinction optical depth and 5 dB in reflectivity are simulated based upon the set of cloud-resolving model simulations. C1 NASA, Joint Ctr Earth Syst Technol, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Deutsch Forsch Anstalt Luft & Raumfahrt, Cologne, Germany. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Aerospace Corp, Los Angeles, CA 90009 USA. RP Olson, WS (reprint author), NASA, Joint Ctr Earth Syst Technol, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 22 TC 43 Z9 44 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 7 BP 1164 EP 1179 DI 10.1175/1520-0450(2001)040<1164:AMLMFP>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 450UM UT WOS:000169762800002 ER PT J AU Heymsfield, GM Halverson, JB Simpson, J Tian, L Bui, TP AF Heymsfield, GM Halverson, JB Simpson, J Tian, L Bui, TP TI ER-2 Doppler radar investigations of the eyewall of Hurricane Bonnie during the convection and moisture experiment-3 SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SATELLITE MICROWAVE DATA; TROPICAL CYCLONES; VERTICAL MOTION; INNER CORE; AIRBORNE; AIRCRAFT; SYSTEM; AIR AB A persistent, mesoscale region of intense eyewall convection contained within Hurricane Bonnie on 23 August 1998 is examined from multiple observations synthesized from the National Aeronautics and Space Administration ER-2 and DC-8 aircraft. The intense convection occurred late in the day as Bonnie was attaining its minimum central pressure and during a stage when the inner core featured a markedly asymmetric structure. The internal structure of this convective burst and its relationship to the warm core are presented using a synthesis of high-resolution satellite, aircraft radar, and in situ data. An exceptionally vigorous eyewall tower within the burst and penetrating to nearly 18 km is described. A second intense eyewall tower, adjacent to the eye, is shown to be associated with a mesoscale subsiding current of air, with vertical velocities on the order of several meters per second that descends at least 9 km and extends horizontally nearly 25 km into the eye interior. The subsidence is a much deeper and broader-scale feature than the convectively induced, symmetric overturning that commonly occurs on the upper-level flanks of convective towers in other tropical environments. The air supplying the deep current probably originates both at tropopause height and also from air detrained out of the adjacent updraft at midlevels. Strong downdrafts within the eye could not be associated with every hot tower. Whether this result was due to undersampling by aircraft or whether deep eye downdrafts are indeed sporadic, it is plausible that up to 3 degreesC of midlevel eye warming observed in Bonnie may arise from one or more of these convectively induced episodes rather than as a result of a gradual sinking motion applied uniformly throughout the eye. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Heymsfield, GM (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 41 TC 78 Z9 82 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 8 BP 1310 EP 1330 DI 10.1175/1520-0450(2001)040<1310:EDRIOT>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 461ZP UT WOS:000170394000002 ER PT J AU Olson, WS Hong, Y Kummerow, CD Turk, J AF Olson, WS Hong, Y Kummerow, CD Turk, J TI A texture-polarization method for estimating convective-stratiform precipitation area coverage from passive microwave radiometer data SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TOGA COARE; MESOSCALE; RADIATION; SYSTEMS; MODEL; WATER; RADAR AB Observational and modeling studies have revealed the relationships between convective-stratiform rain proportion and the vertical distributions of vertical motion, latent heating, and moistening in mesoscale convective systems. Therefore, remote sensing techniques that can be used to quantify the area coverage of convective or stratiform rainfall could provide useful information regarding the dynamic and thermodynamic processes in these systems. In the current study, two methods for deducing the area coverage of convective precipitation from satellite passive microwave radiometer measurements are combined to yield an improved method. If sufficient microwave scattering by ice-phase precipitation is detected, the method relies mainly on the degree of polarization in oblique-view, 85.5-GHz radiances to estimate the fraction of the radiometer footprint covered by convection. In situations where ice scattering is minimal, the method draws mostly on texture information in radiometer imagery at lower microwave frequencies to estimate the convective area fraction. Based upon observations of 10 organized convective systems over ocean and nine systems over land, instantaneous, 0.5 degrees -resolution estimates of convective area fraction from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) are compared with nearly coincident estimates from the TRMM precipitation radar (PR). TMI convective area fraction estimates are low-biased relative to PR estimates, with TMI-PR correlation coefficients of 0.78 and 0.84 over ocean and land surfaces, respectively. TMI monthly average convective area percentages in the Tropics and subtropics from February 1998 are greatest along the intertropical convergence zone and in the continental regions of the Southern (summer) Hemisphere. Although convective area percentages from the TMI are systematically lower than those derived from the PR, the monthly patterns of convective coverage are similar. Systematic differences in TMI and PR convective area percentages do not show any clear correlation or anticorrelation with differences in retrieved rain depths, and so discrepancies between TRMM version-5 TMI- and PR-retrieved rain depths are likely due to other sensor or algorithmic differences. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Aerosp Corp, Los Angeles, CA 90009 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Naval Res Lab, Monterey, CA USA. RP Olson, WS (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Code 912, Greenbelt, MD 20771 USA. OI Hong, Yang/0000-0001-8720-242X NR 26 TC 38 Z9 40 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 9 BP 1577 EP 1591 DI 10.1175/1520-0450(2001)040<1577:ATPMFE>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 464WK UT WOS:000170554600003 ER PT J AU Rodgers, EB Adler, RF Pierce, HF AF Rodgers, EB Adler, RF Pierce, HF TI Contribution of tropical cyclones to the North Atlantic climatological rainfall as observed from satellites SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SEASONAL HURRICANE FREQUENCY; EL-NINO; ASSOCIATION; OSCILLATION AB The tropical cyclone rainfall climatological study performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during an 11-yr period. These satellite-observed rainfall estimates were used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and interannual distribution of the North Atlantic total rainfall during June-November when tropical cyclones were most abundant. The main results from this study indicate 1) that tropical cyclones contribute, respectively, 4%, 3%, and 4% to the western, eastern, and entire North Atlantic; 2) similar to that observed in the North Pacific, the maximum in North Atlantic tropical cyclone rainfall is approximately 5 degrees -10 degrees poleward (depending on longitude) of the maximum nontropical cyclone rainfall; 3) tropical cyclones contribute regionally a maximum of 30% of the total rainfall northeast of Puerto Rico, within a region near 15 degreesN, 55 degreesW, and off the west coast of Africa; 4) there is no lag between the months with maximum tropical cyclone rainfall and nontropical cyclone rainfall in the western North Atlantic, whereas in the eastern North Atlantic, maximum tropical cyclone rainfall precedes maximum nontropical cyclone rainfall; 5) like the North Pacific, North Atlantic tropical cyclones of hurricane intensity generate the greatest amount of rainfall in the higher latitudes; and 6) warm El Nino-Southern Oscillation events inhibit tropical cyclone rainfall. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmosphere Proc Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Adler, RF (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmosphere Proc Branch, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. NR 24 TC 38 Z9 41 U1 1 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 11 BP 1785 EP 1800 DI 10.1175/1520-0450(2001)040<1785:COTCTT>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 486BF UT WOS:000171798000001 ER PT J AU Kummerow, C Hong, Y Olson, WS Yang, S Adler, RF McCollum, J Ferraro, R Petty, G Shin, DB Wilheit, TT AF Kummerow, C Hong, Y Olson, WS Yang, S Adler, RF McCollum, J Ferraro, R Petty, G Shin, DB Wilheit, TT TI The evolution of the Goddard profiling algorithm (GPROF) for rainfall estimation from passive microwave sensors SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PRECIPITATION RETRIEVAL; RADIATIVE-TRANSFER; CLOUD MODEL; TOGA COARE; IMAGER; APPROXIMATION; RESOLUTION; INDEXES; OCEAN; RADAR AB This paper describes the latest improvements applied to the Goddard profiling algorithm (GPROF), particularly as they apply to the Tropical Rainfall Measuring Mission (TRMM). Most of these improvements, however, are conceptual in nature and apply equally to other passive microwave sensors. The improvements were motivated by a notable overestimation of precipitation in the intertropical convergence zone. This problem was traced back to the algorithm's poor separation between convective and stratiform precipitation coupled with a poor separation between stratiform and transition regions in the a priori cloud model database. In addition to now using an improved convective-stratiform classification scheme, the new algorithm also makes use of emission and scattering indices instead of individual brightness temperatures. Brightness temperature indices have the advantage of being monotonic functions of rainfall. This, in turn, has allowed the algorithm to better define the uncertainties needed by the scheme's Bayesian inversion approach. Last, the algorithm over land has been modified primarily to better account for ambiguous classification where the scattering signature of precipitation could be confused with surface signals. All these changes have been implemented for both the TRMM Microwave Imager (TMI) and the Special Sensor Microwave Imager (SSM/I). Results from both sensors are very similar at the storm scale and for global averages. Surface rainfall products from the algorithm's operational version have been compared with conventional rainfall data over both land and oceans. Over oceans, GPROF results compare well with atoll gauge data. GPROF is biased negatively by 9% with a correlation of 0.86 for monthly 2.5 degrees averages over the atolls. If only grid boxes with two or more atolls are used, the correlation increases to 0.91 but GPROF becomes positively biased by 6%. Comparisons with TRMM ground validation products from Kwajalein reveal that GPROF is negatively biased by 32%, with a correlation of 0.95 when coincident images of the TMI and Kwajalein radar are used. The absolute magnitude of rainfall measured from the Kwajalein radar, however, remains uncertain, and GPROF overestimates the rainfall by approximately 18% when compared with estimates done by a different research group. Over land, GPROF shows a positive bias of 17% and a correlation of 0.80 over monthly 5 degrees grids when compared with the Global Precipitation Climatology Center (GPCC) gauge network. When compared with the precipitation radar (PR) over land, GPROF also retrieves higher rainfall amounts (20%). No vertical hydrometeor profile information is available over land. The correlation with the TRMM precipitation radar is 0.92 over monthly 5 degrees grids, but GPROF is positively biased by 24% relative to the radar over oceans. Differences between TMI- and PR- derived vertical hydrometeor profiles below 2 km are consistent with this bias but become more significant with altitude. Above 8 km, the sensors disagree significantly, but the information content is low from both TMI and PR. The consistent bias between these two sensors without clear guidance from the ground-based data reinforces the need for better understanding of the physical assumptions going into these retrievals. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Aerosp Corp, Los Angeles, CA 90009 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, NESDIS, Camp Springs, MD USA. Univ Wisconsin, Madison, WI USA. Texas A&M Univ, College Stn, TX USA. RP Kummerow, C (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RI Petty, Grant/E-3118-2012; Wilheit, Thomas/G-9438-2012; Ferraro, Ralph/F-5587-2010 OI Ferraro, Ralph/0000-0002-8393-7135 NR 56 TC 491 Z9 503 U1 3 U2 30 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 11 BP 1801 EP 1820 DI 10.1175/1520-0450(2001)040<1801:TEOTGP>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 486BF UT WOS:000171798000002 ER PT J AU Czekala, H Crewell, S Simmer, C Thiele, A Hornbostel, A Schroth, A AF Czekala, H Crewell, S Simmer, C Thiele, A Hornbostel, A Schroth, A TI Interpretation of polarization features in ground-based microwave observations as caused by horizontally aligned oblate raindrops SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RADIATIVE-TRANSFER; EQUILIBRIUM SHAPE; CLOUDS; MODEL; PRECIPITATION; HYDROMETEORS; PROPAGATION; RADIOMETRY; SCATTERING; DROPS AB Based on a comparison of ground-based radiometer measurements with microwave radiative transfer calculations, it is shown that raindrops with an oblate shape and a preferred horizontal orientation have a significant effect on microwave polarization signals when compared with spherical particle shape. Measurements with a dual-polarized 19-GHz radiometer reveal a polarization difference of as much as -18 K in the downwelling microwave radiation at 30 degrees elevation angle. Averaging all rain observations within 19 months leads to a signal of -6 K. Model calculations covering roughly the same range of weather conditions as that inferred from the meteorological data recorded with the radiometer measurements were carried out with spherical raindrop shape and an oblate particle shape with a fixed horizontal alignment. From the model results, positive polarization difference is expected for spherical particles. This signal was never observed in the recorded data. For oblate drops, the averaged model results lead to a polarization difference of -8 K, which is in reasonable agreement with the long-term averaged observations. Case studies that compare isolated rain events usually lead to a better match of model and observations. However, there are some major discrepancies in some cases. Possible reasons for the remaining differences are the short-term variations in the cloud microphysics for which the model does not correctly account, such as variations in the melting layer, drop oscillations, or variations in the drop size distribution or angular distribution of the drop alignment. Three-dimensional effects are also important when observing small-scale heavy precipitation. Despite remaining small uncertainties, the comparison presents strong evidence that the oblate raindrop shape, with fixed horizontal alignment, is by far the better choice for accurate radiative transfer calculations than is the spherical shape. The omission of this shape effect can cause significant errors when developing remote sensing algorithms based on model results. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. Univ Bonn, Inst Meteorol, D-5300 Bonn, Germany. Deutsch Zentrum Luft & Raumfahrt, Inst Kommunikat & Navigat, Oberpfaffenhofen, Germany. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM hczekala@giss.nasa.gov RI Simmer, Clemens/M-4949-2013; Crewell, Susanne/O-1640-2013 OI Simmer, Clemens/0000-0003-3001-8642; Crewell, Susanne/0000-0003-1251-5805 NR 30 TC 24 Z9 24 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 11 BP 1918 EP 1932 DI 10.1175/1520-0450(2001)040<1918:IOPFIG>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 486BF UT WOS:000171798000008 ER PT J AU Tokay, A Kruger, A Krajewski, WF AF Tokay, A Kruger, A Krajewski, WF TI Comparison of drop size distribution measurements by impact and optical disdrometers SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID JOSS-WALDVOGEL DISDROMETER; RAINDROP SPECTRA; CONVECTIVE CLOUDS; RADAR; UNCERTAINTIES; HYDROMETEORS; STRATIFORM AB Simultaneous observations made with optical- and impact-type disdrometers were analyzed to broaden knowledge of these instruments. These observations were designed to test how accurately they measure drop size distributions (DSDs). The instruments' use in determining radar rainfall relations such as that between reflectivity and rainfall rate also was analyzed. A unique set of instruments, including two video and one Joss-Waldvogel disdrometer along with eight tipping-bucket rain gauges, was operated within a small area of about 100 x 50 m(2) during a 2-month-long field campaign in central Florida. The disdrometers were evaluated by comparing their rain totals with the rain gauges. Both disdrometers underestimated the rain totals, but the video disdrometers had higher readings, resulting in a better agreement with the gauges. The disdrometers underreported small- to medium-size drops, which most likely caused the underestimation of rain totals. However, more medium-size drops were measured by the video disdrometer, thus producing higher rain rates for that instrument. The comparison of DSDs, averaged at different timescales, showed good agreement between the two types of disdrometers. A continuous increase in the number of drops toward smaller sizes was only evident in the video disdrometers at rain rates above 20 mm h(-1). Otherwise, the concentration of small drops remained the same or decreased to the smallest measurable size. The Joss-Waldvogel disdrometer severely underestimated only at very small drop size (diameter less than or equal to 0.5 mm). Beyond the Joss-Waldvogel disdrometer measurement limit were very large drops that fell during heavy and extreme rain intensities. The derived parameters of exponential and gamma distributions reflect the good agreement between the disdrometers' DSD measurements. The parameters of fitted distributions were close to each other, especially when all the coincident measurements were averaged. The low concentrations of very large drops observed by the video disdrometers did not have a significant impact on reflectivity measurements in terms of the relationships between reflectivity and other integral parameters (rain rate, liquid water content, and attenuation). There was almost no instrument dependency. Rather, the relations depend on the method of regression and the choice of independent variable. Also, relationships derived for S-band radars and Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) differ from each other primarily because of the higher reflectivities at the shorter PR wavelength at high rain-rate regime. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Univ Iowa, Iowa Inst Hydraul Res, Iowa City, IA 52242 USA. RP NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. EM tokay@radar.gsfc.nasa.gov NR 35 TC 109 Z9 112 U1 4 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 11 BP 2083 EP 2097 DI 10.1175/1520-0450(2001)040<2083:CODSDM>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 486BF UT WOS:000171798000018 ER PT J AU Chambers, LH Wielicki, BA Loeb, NG AF Chambers, LH Wielicki, BA Loeb, NG TI Shortwave flux from satellite-measured radiance: A theoretical study over marine boundary layer clouds SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ANGULAR-DISTRIBUTION MODELS; STRATOCUMULUS CLOUDS; RADIATIVE-TRANSFER; EARTH; IDENTIFICATION; MISSION; ALBEDO; RADIUS; ERBE AB Earth radiation budget measurements, important to climate monitoring and to validating climate models, require that radiances measured by satellite instruments be converted to hemispherical flux. This paper examines that problem theoretically, using inhomogeneous cloud models constructed from Landsat scenes of marine boundary layer clouds. The spherical harmonics discrete ordinates method (SHDOM) code is applied to the model scenes to compute full two-dimensional radiation fields, which then simulate measured radiances. Inversion to flux is performed by several different methods, including plane-parallel table lookup and empirical angular distribution models with three different ways of determining scene identification, to examine error sources and relative magnitudes. Using a simple plane-parallel table lookup results in unacceptably large flux bias errors of 11%-60%, depending on the orbital viewing geometry. This bias can be substantially reduced, to no more than 6%, by using empirical angular distribution models. Further improvement, to no more than 2% flux bias error, is obtained if known biases in optical-depth retrievals are taken into account when building the angular models. Last, the bias can be further reduced to a fraction of a percent using scene identification based on multiple views of the same area. There are limits, however, to the reduction in the instantaneous error with this approach. Trends in the flux error are also identified, in particular an equator-to-pole trend in the flux bias. Given the importance of satellite measurements for determining heat transport from equator to pole, this consistent bias should be kept in mind, and efforts should be made to reduce it in the future. C1 NASA, Radiat & Aerosols Branch, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Chambers, LH (reprint author), NASA, Radiat & Aerosols Branch, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. NR 32 TC 14 Z9 15 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PY 2001 VL 40 IS 12 BP 2144 EP 2161 DI 10.1175/1520-0450(2001)040<2144:SFFSMR>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 495WP UT WOS:000172363600004 ER PT J AU Serrador, JM Wood, SJ Picot, PA Stein, F Kassam, MS Bondar, RL Rupert, AH Schlegel, TT AF Serrador, JM Wood, SJ Picot, PA Stein, F Kassam, MS Bondar, RL Rupert, AH Schlegel, TT TI Effect of acute exposure to hypergravity (G(X) vs. G(Z)) on dynamic cerebral autoregulation SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE transcranial Doppler; middle cerebral artery; hypergravity; head-up tilt; centrifugation; orthostasis; vestibular; otolith; cerebral blood flow ID SYMPATHETIC NERVOUS-SYSTEM; BLOOD-FLOW AUTOREGULATION; STELLATE GANGLION BLOCK; TRANSCRANIAL DOPPLER; SPONTANEOUS FLUCTUATIONS; ORTHOSTATIC INTOLERANCE; FREQUENCY-DOMAIN; AUTO-REGULATION; ANGIOTENSIN; PRESSURE AB We examined the effects of 30 min of exposure to either +3G(x) (front-to-back) or +G(z) (head-to-foot) centrifugation on cerebrovascular responses to 80 degrees head-up tilt (HUT) in 14 healthy individuals. Both before and after +3 G(x) or +3 G(z) centrifugation, eye-level blood pressure (BPeye), end tidal PCO2 (PETCO2), mean cerebral flow velocity (CFV) in the middle cerebral artery (transcranial Doppler ultrasound), cerebral vascular resistance (CVR), and dynamic cerebral autoregulatory gain (GAIN) were measured with subjects in the supine position and during subsequent 80 degrees HUT for 30 min. Mean BPeye decreased with HUT in both the G(x) (n = 7) and G(z) (n = 7) groups (P< 0.001), with the decrease being greater after centrifugation only in the G(z) group (P< 0.05). PETCO2 also decreased with HUT in both groups (P< 0.01), but the absolute level of decrease was unaffected by centrifugation. CFV decreased during HUT more significantly after centrifugation than before centrifugation in both groups (P< 0.02). However, these greater decreases were not associated with greater increases in CVR. In the supine position after centrifugation compared with before centrifugation, GAIN increased in both groups (P< 0.05, suggesting an autoregulatory deficit), with the change being correlated to a measure of otolith function (the linear vestibulo-ocular reflex) in the G(x) group (r = 0.76, P< 0.05) but not in the G(z) group (r = 0.24, P = 0.60). However, GAIN was subsequently restored to precentrifugation levels during postcentrifugation HUT (i.e., as BPeye decreased), suggesting that both types of centrifugation resulted in a leftward shift of the cerebral autoregulation curve. We speculate that this leftward shift may have been due to vestibular activation (especially during +G(x)) or potentially to an adaptation to reduced cerebral perfusion pressure during +G(z). C1 Univ Western Ontario, Sch Kinesiol, Cerebral Blood Flow Res Lab, London, ON N6A 3K7, Canada. Legacy Clin Res & Technol Ctr, Dept Neurotol Res, Portland, OR 97232 USA. Ryerson Polytech Univ, Fac Engn & Appl Sci, Toronto, ON M5B 2K3, Canada. USN, Aerosp Med Res Lab, Pensacola, FL 32508 USA. NASA, Life Sci Res Labs, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Serrador, JM (reprint author), Harvard Univ, Sch Med, HRCA Res & Training Inst, Cardiovasc Res Lab, 1200 Ctr St, Boston, MA 02131 USA. RI Serrador, Jorge/A-9172-2009 NR 49 TC 11 Z9 12 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PY 2001 VL 91 IS 5 BP 1986 EP 1994 PG 9 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 486NN UT WOS:000171824000011 PM 11641334 ER PT J AU Harm, DL Jennings, RT Meck, JV Powell, MR Putcha, L Sams, CP Schneider, SM Shackelford, LC Smith, SM Whitson, PA AF Harm, DL Jennings, RT Meck, JV Powell, MR Putcha, L Sams, CP Schneider, SM Shackelford, LC Smith, SM Whitson, PA TI Genome and hormones: Gender differences in physiology - Invited review: Gender issues related to spaceflight: A NASA perspective SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE physiological responses; health issues ID SPACE MOTION SICKNESS; DURATION SPACEFLIGHT; CARDIAC-ARRHYTHMIAS; MENTAL-RETARDATION; IONIZING-RADIATION; WOMEN; PHARMACOKINETICS; PHARMACODYNAMICS; ENDOMETRIOSIS; RESPONSES AB This minireview provides an overview of known and potential gender differences in physiological responses to spaceflight. The paper covers cardiovascular and exercise physiology, barophysiology and decompression sickness, renal stone risk, immunology, neurovestibular and sensorimotor function, nutrition, pharmacotherapeutics, and reproduction. Potential health and functional impacts associated with the various physiological changes during spaceflight are discussed, and areas needing additional research are highlighted. Historically, studies of physiological responses to microgravity have not been aimed at examining gender-specific differences in the astronaut population. Insufficient data exist in most of the discipline areas at this time to draw valid conclusions about gender-specific differences in astronauts, in part due to the small ratio of women to men. The only astronaut health issue for which a large enough data set exists to allow valid conclusions to be drawn about gender differences is orthostatic intolerance following shuttle missions, in which women have a significantly higher incidence of presyncope during stand tests than do men. The most common observation across disciplines is that individual differences in physiological responses within genders are usually as large as, or larger than, differences between genders. Individual characteristics usually outweigh gender differences per se. C1 NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Houston, TX 77058 USA. Univ Texas, Med Branch, Dept Obstet & Gynecol, Galveston, TX 77555 USA. NASA, Lyndon B Johnson Space Ctr, Astronaut Off, Houston, TX 77058 USA. RP Harm, DL (reprint author), NASA, Lyndon B Johnson Space Ctr, SK3 Human Adaptat & Countermeasures Off, 2101 NASA Rd 1, Houston, TX 77508 USA. NR 65 TC 62 Z9 66 U1 2 U2 18 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PY 2001 VL 91 IS 5 BP 2374 EP 2383 PG 10 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 486NN UT WOS:000171824000060 PM 11641383 ER PT J AU Schlegel, TT Brown, TE Wood, SJ Benavides, EW Bondar, RL Stein, F Moradshahi, P Harm, DL Fritsch-Yelle, JM Low, PA AF Schlegel, TT Brown, TE Wood, SJ Benavides, EW Bondar, RL Stein, F Moradshahi, P Harm, DL Fritsch-Yelle, JM Low, PA TI Orthostatic intolerance and motion sickness after parabolic flight SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE postural tachycardia syndrome; vomiting; microgravity; hypergravity; autonomic; space flight ID POSTURAL TACHYCARDIA SYNDROME; CARDIAC REFLEX RESPONSES; HEART-RATE; VESTIBULAR SYSTEM; ARTERIAL-PRESSURE; PLASMA-VOLUME; POWER SPECTRA; SYNDROME POTS; SPACEFLIGHT; SPACE AB Because it is not clear that the induction of orthostatic intolerance in returning astronauts always requires prolonged exposure to microgravity, we investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy subjects before and after the brief micro- and hypergravity of parabolic flight. Concomitantly, we investigated the effect of parabolic flight-induced vomiting on orthostatic tolerance, R-wave-R-wave interval and arterial pressure power spectra, and carotid-cardiac baroreflex and Valsalva responses. After parabolic flight 1) 8 of 16 subjects could not tolerate 30 min of upright tilt (compared to 2 of 16 before flight); 2) 6 of 16 subjects vomited; 3) new intolerance to upright tilt was associated with exaggerated falls in total peripheral resistance, whereas vomiting was associated with increased R-wave-R-wave interval variability and carotid-cardiac baroreflex responsiveness; and 4) the proximate mode of new orthostatic failure differed in subjects who did and did not vomit, with vomiters experiencing comparatively isolated upright hypocapnia and cerebral vasoconstriction and nonvomiters experiencing signs and symptoms reminiscent of the clinical postural tachycardia syndrome. Results suggest, first, that syndromes of orthostatic intolerance resembling those developing after space flight can develop after a brief (i.e., 2-h) parabolic flight and, second, that recent vomiting can influence the results of tests of autonomic cardiovascular function commonly utilized in returning astronauts. C1 NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Wyle Labs, Houston, TX 77058 USA. Baylor Coll Med, Houston, TX 77030 USA. Ryerson Polytech Univ, Fac Engn & Appl Sci, Toronto, ON M5B 2K3, Canada. Maple Lake Noninvas Lab, Farmington, NM 87109 USA. Mayo Clin & Mayo Fdn, Auton Reflex Lab, Rochester, MN 55905 USA. RP Schlegel, TT (reprint author), NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Mail Code SD3, Houston, TX 77058 USA. EM tschlege@ems.jsc.nasa.gov NR 59 TC 23 Z9 24 U1 0 U2 2 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JAN PY 2001 VL 90 IS 1 BP 67 EP 82 PG 16 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 412GX UT WOS:000167547600011 PM 11133895 ER PT J AU Koshak, WJ Solakiewicz, RJ AF Koshak, WJ Solakiewicz, RJ TI TOA lightning location retrieval on spherical and oblate spheroidal earth geometries SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB A simple linear algebraic solution is introduced for retrieving the location and time-of-occurrence of lightning ground strikes on a spherical earth from a network of four or more time-of-arrival sensors. Since the solution accounts for earth curvature, it represents an extension to earlier planar model results. A test of the retrieval method is provided using computer-simulated datasets. The method is easy to comprehend and completely avoids reference to the mathematics of spherical hyperbolas. An extension to the spherical earth solution is provided for an oblate spheroidal earth geometry, and the importance/relevance of oblate effects are discussed. Future application of these methods in support of the North American National Lightning Detection Network is desirable, but additional theoretical investigations are required to incorporate magnetic bearing information into the present solution process. C1 NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, Huntsville, AL 35805 USA. Chicago State Univ, Dept Math & Comp Sci, Chicago, IL USA. RP Koshak, WJ (reprint author), NASA, George C Marshall Space Flight Ctr, Global Hydrol & Climate Ctr, SD60,320 Sparkman Dr, Huntsville, AL 35805 USA. NR 14 TC 6 Z9 8 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 2 BP 187 EP 199 DI 10.1175/1520-0426(2001)018<0187:TLLROS>2.0.CO;2 PG 13 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 398CB UT WOS:000166737400005 ER PT J AU Porter, JN Miller, M Pietras, C Motell, C AF Porter, JN Miller, M Pietras, C Motell, C TI Ship-based sun photometer measurements using Microtops sun photometers SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID INSTRUMENT AB The use of hand-held Microtops II sun photometers (built by Solar Light Inc.) on ship platforms is discussed. Their calibration, filter stability, and temperature effects are also described. It is found that under rough conditions, the ship motion causes the largest error, which can result in a bias toward higher optical depths. In order to minimize this bias, a large number of sun photometer measurements (similar to 25) should be taken in a short period of time, and the higher values should be discarded. Under rough ocean conditions, it is also best to shorten the Microtops sun photometer sampling period (less than 5 s) and save only a single value (no averaging) and remove the high optical depths in postprocessing. It is found that the Microtops should be turned off frequently to correct for zero drift caused by temperature effects. Calibration is maintained by routine Langley plot calibrations at the Mauna Loa Observatory for each unit or through cross calibration. C1 Univ Hawaii, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NASA, Goddard Space Flight Ctr, SAIC Gen Sci Corp, Greenbelt, MD 20771 USA. RP Porter, JN (reprint author), Univ Hawaii, Sch Ocean & Earth Sci & Technol, 2525 Correa Rd, Honolulu, HI 96822 USA. NR 16 TC 84 Z9 87 U1 1 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 5 BP 765 EP 774 DI 10.1175/1520-0426(2001)018<0765:SBSPMU>2.0.CO;2 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 424JR UT WOS:000168229600004 ER PT J AU DeLand, MT Cebula, RP Huang, LK Taylor, SL Stolarski, RS McPeters, RD AF DeLand, MT Cebula, RP Huang, LK Taylor, SL Stolarski, RS McPeters, RD TI Observations of "hysteresis'' in backscattered ultraviolet ozone data SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID INSTRUMENT; CALIBRATION; NIMBUS-4 AB Satellite measurements using the backscattered ultraviolet technique provide a powerful method for the observation of stratospheric ozone. However, rapid input signal variations over three to four orders of magnitude in several minutes can lead to problems with instrument response. Inflight data have recently been used to characterize a "hysteresis'' problem on the NOAA-9 SBUV/2 instrument, which affects measurements made shortly after emerging from darkness. Radiance values observed under these conditions can be up to 2%-3% lower than expected. A correction has been derived for NOAA-9 data that is solar zenith angle dependent and varies in amplitude and time. Typical changes to affected polar total ozone values are on the order of 1% but can reach 5% in some cases. Profile ozone changes are altitude dependent, with maximum values of 4%-5% at 1 hPa. The NOAA-11 and NOAA-14 SBUV/2 instruments have a much smaller hysteresis effect than that observed for NOAA-9 SBUV/2 due to a change in photomultiplier tubes. The Nimbus-7 SBUV instrument also shows a hysteresis effect, which has not been fully characterized at this time. C1 Raytheon ITSS Corp, Lanham, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP DeLand, MT (reprint author), Sci Syst & Applicat Inc, 10210 Greenbelt Rd,Suite 400, Lanham, MD 20706 USA. RI Stolarski, Richard/B-8499-2013; McPeters, Richard/G-4955-2013 OI Stolarski, Richard/0000-0001-8722-4012; McPeters, Richard/0000-0002-8926-8462 NR 18 TC 8 Z9 8 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 6 BP 914 EP 924 DI 10.1175/1520-0426(2001)018<0914:OOHIBU>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 439RY UT WOS:000169132400008 ER PT J AU Li, LH Sekelsky, SM Reising, SC Swift, CT Durden, SL Sadowy, GA Dinardo, SJ Li, FK Huffman, A Stephens, G Babb, DM Rosenberger, HW AF Li, LH Sekelsky, SM Reising, SC Swift, CT Durden, SL Sadowy, GA Dinardo, SJ Li, FK Huffman, A Stephens, G Babb, DM Rosenberger, HW TI Retrieval of atmospheric attenuation using combined ground-based and airborne 95-GHz cloud radar measurements SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID PRECIPITATION AB Cloud measurements at millimeter-wave frequencies are affected by attenuation due to atmospheric gases, clouds, and precipitation. Estimation of the true equivalent radar reflectivity, Z(e), is complicated because extinction mechanisms are not well characterized at these short wavelengths. This paper discusses cloud radar calibration and intercomparison of airborne and ground-based radar measurements and presents a unique algorithm for attenuation retrieval. This algorithm is based on dual 95-GHz radar measurements of the same cloud and precipitation volumes collected from opposing viewing angles. True radar reflectivity is retrieved by combining upward-looking and downward-looking radar profiles. This method reduces the uncertainty in radar reflectivity and attenuation estimates, since it does not require a priori knowledge of hydrometeors' microphysical properties. Results from this technique are compared with results retrieved from the Hitschfeld and Bordan algorithm, which uses single-radar measurements with path-integrated attenuation as a constraint. Further analysis is planned to employ this dual-radar algorithm in order to refine single-radar attenuation retrieval techniques, which will be used by operational sensors such as the CloudSat radar. C1 Univ Massachusetts, Microwave Remote Sensing Lab, Amherst, MA 01003 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. RP Li, LH (reprint author), Univ Massachusetts, Microwave Remote Sensing Lab, Knowles Bldg,Room 201, Amherst, MA 01003 USA. NR 20 TC 19 Z9 20 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 8 BP 1345 EP 1353 DI 10.1175/1520-0426(2001)018<1345:ROAAUC>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 464WJ UT WOS:000170554500004 ER PT J AU Quilfen, Y Chapron, B Vandemark, D AF Quilfen, Y Chapron, B Vandemark, D TI The ERS scatterometer wind measurement accuracy: Evidence of seasonal and regional biases SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID OCEAN CIRCULATION FEATURES; TOWER-BASED MEASUREMENTS; TOPEX/POSEIDON DATA; CROSS-SECTION; WATER-WAVES; AIR-FLOW; STRESS; MODEL; VALIDATION; SPEED AB A validation of European Space Agency (ESA) remote sensing satellite (ERS) scatterometer ocean wind measurements is performed using a formalism recently proposed for and applied to NASA scatterometer (NSCAT) and Special Sensor Microwave Imager (SSM/I) measurements. This simple analytical model relates scatterometer measurements to true winds, taking into account errors in the satellite winds as well as errors in the data used for reference. In this study, National Data Buoy Center (NDBC) buoy winds are the chosen reference. In addition, ECMWF analysis winds are used as a third data source to completely determine the errors via a triple collocation analysis. According to this development, the resulting wind speed error analysis indicates that ERS scatterometer estimates are negatively biased at light winds. This result differs from recent results determined using standard regression analysis. It is also shown that ERS and NSCAT measurement accuracies are comparable in an overall sense. This error model provides a more certain measure of both random and systematic terms and the authors use this tool to look at possible systematic scatterometer wind speed biases in two separate long-term (1992-98) ERS datasets. The chosen approach examines temporal and spatial variation between ocean buoy and ERS-derived winds to identify both seasonal and regional ERS wind error signatures. First, data indicate a time-dependent bias between NDBC and ERS winds that is strongly correlated with the seasonal cycle. Buoy-derived long-wave and atmospheric stability parameter averages exhibit similar cycles and are the likely geophysical links to this scatterometer error. An illustration of regional or spatially varying error sources is further provided using ERS data collocated with Tropical Atmosphere and Ocean (TAO) buoy array measurements. In this case the long-term average wind speed bias between TAO and ERS exhibits well-defined spatial structures within the equatorial belt (10 degreesN, 10 degreesS). Bias variations show qualitative agreement with a near-surface current climatology map for this Pacific region and also with the limited available buoy current measurements. Overall results indicate small but systematic nonwind sea surface effects on scatterometer products. It is concluded that there cannot be one set of values for ERS scatterometer wind validation parameters. Accounting for surface effects on scatterometer measurements may need consideration to ensure proper assimilation of scatterometer data into weather forecasting and climate prediction models. C1 IFREMER, Ctr Brest, Dept Oceanog Spatiale, F-29280 Plouzane, France. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. RP Quilfen, Y (reprint author), IFREMER, Ctr Brest, Dept Oceanog Spatiale, BP 70, F-29280 Plouzane, France. RI Chapron, Bertrand/O-6527-2015; Quilfen, Yves/A-1824-2016 NR 49 TC 43 Z9 43 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 10 BP 1684 EP 1697 DI 10.1175/1520-0426(2001)018<1684:TESWMA>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 483GG UT WOS:000171624800007 ER PT J AU Bauer, P Amayenc, P Kummerow, CD Smith, EA AF Bauer, P Amayenc, P Kummerow, CD Smith, EA TI Over-ocean rainfall retrieval from multisensor data of the Tropical Rainfall Measuring Mission. Part II: Algorithm implementation SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MICROWAVE; PROFILES; CLOUDS AB The objective of this paper is to establish a computationally efficient algorithm making use of the combination of Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and precipitation radar (PR) observations. To set up the TMI algorithm, the retrieval databases developed in Part I served as input for different inversion techniques: multistage regressions and neural networks as well as Bayesian estimators. It was found that both Bayesian and neural network techniques performed equally well against PR estimates if all TMI channels were used. However, not using the 85.5-GHz channels produced consistently better results. This confirms the conclusions from Part I. Generally, regressions performed worse; thus they seem less suited for general application due to the insufficient representation of the nonlinearities of the TB-rain rate relation. It is concluded that the databases represent the most sensitive part of rainfall algorithm development. Sensor combination was carried out by gridding PR estimates of rain liquid water content to 27 km x 44 km horizontal resolution at the center of gravity of the TMI 10.65-GHz channel weighting function. A liquid water dependent database collects common samples over the narrow swath covered by both TMI and PR. Average calibration functions are calculated, dynamically updated along the satellite track, and applied to the full TMI swath. The behavior of the calibration function was relatively stable. The TMI estimates showed a slight underestimation of rainfall at low rain liquid water contents (<0.1 g m(-3)) as well as at very high rainfall intensities (>0.8 g m(-3)) and excellent agreement in between. The biases were found to not depend on beam filling with a strong correlation to rain liquid water for stratiform clouds that may point to melting layer effects. The remaining standard deviations between instantaneous TMI and PR estimates after calibration may be treated as a total retrieval error, assuming the PR estimates are unbiased. The error characteristics showed a rather constant absolute error of <0.05 g m(-3) for rain liquid water contents <0.1 g m(-3). Above, the error increases to 0.6 g m(-3) for amounts up to 1 g m(-3). In terms of relative errors, this corresponds to a sharp decrease from >100% to 35% between 0.05 and 0.5 g m(-3). The database ambiguity, that is, the standard deviation of near-surface rain liquid water contents with the same radiometric signature, provides a means to estimate the contribution from the simulations to this error. In the range where brightness temperatures respond most sensitively to rainwater contents, almost the entire error originates from the ambiguity of signatures. At very low and very high rain rates (<0.05 and >0.7 g m(-3)) at least half of the total error is explained by the inversion process. C1 German Aerosp Ctr, Cologne, Germany. CETP IPSL, Velizy Villacoublay, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Bauer, P (reprint author), European Ctr Medium Range Weather Forecasts, Shinfield Pk, Reading RG2 9AX, Berks, England. NR 19 TC 43 Z9 44 U1 3 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 11 BP 1838 EP 1855 DI 10.1175/1520-0426(2001)018<1838:OORRFM>2.0.CO;2 PG 18 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 492DK UT WOS:000172153000007 ER PT J AU Liao, L Meneghini, R Iguchi, T AF Liao, L Meneghini, R Iguchi, T TI Comparisons of rain rate and reflectivity factor derived from the TRMM precipitation radar and the WSR-88D over the Melbourne, Florida, site SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MEASURING MISSION TRMM; STRATIFORM AB Validating the results from the spaceborne Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) requires comparisons with well-calibrated ground-based radar measurements. At altitudes near the storm top, where effects of PR signal attenuation are small, the data are used to check the relative calibration accuracy of the radars. Near the surface, where attenuation effects at the PR frequency of 13.8 GHz can be significant, the data provide an assessment of the performance of the PR attenuation correction algorithm. The ground-based data are taken from the Doppler Weather Surveillance (WSR-88D) radar located at Melbourne, Florida. In 1998, 24 overpasses of the TRMM satellite over the Melbourne site occurred during times when significant precipitation was present in the overlap region of the PR and WSR-88D. Resampling the ground-based and spaceborne datasets to a common grid provides a means by which the radar reflectivity factors (dBZ) can be compared at different heights and for different rain types over ocean and land. The results from 1998 show that the dBZ fields derived from the PR data after attenuation correction agree to within about 1 dB of those obtained from the WSR-88D with relatively minor variations (0.3 dB) in this difference with height. Comparisons of rain rates also yield good agreement with the conditional mean rain rate from the PR and WSR-88D of 8.5 and 7.6 mm h(-1), respectively. The agreement improves in the comparison of area-averaged rain rates where the PR and WSR-88D yield values of 1.25 and 1.21 mm h(-1), respectively, with a correlation coefficient for the 24 overpasses of 0.95. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Caelum Res Corp, Rockville, MD USA. Commun Res Labs, Appl Res & Stand Div, Tokyo, Japan. RP Meneghini, R (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. RI PMM, JAXA/K-8537-2016 NR 24 TC 51 Z9 53 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PY 2001 VL 18 IS 12 BP 1959 EP 1974 DI 10.1175/1520-0426(2001)018<1959:CORRAR>2.0.CO;2 PG 16 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 504XM UT WOS:000172881500002 ER PT J AU Reinisch, BW Haines, DM Benson, RF Green, JL Sales, GS Taylor, WWL AF Reinisch, BW Haines, DM Benson, RF Green, JL Sales, GS Taylor, WWL TI Radio sounding in space: magnetosphere and topside ionosphere SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Electromagnetic Research Symposium on Radar Applications for Atmosphere and Ionosphere Research (PIERS 1999) CY MAR 22-26, 1999 CL TAIPEI, TAIWAN SP Natl Cent Univ Taiwan, Ctr Space & Remote Sensing Res DE radio sounding; magnetosphere; topside ionosphere ID AURORAL KILOMETRIC RADIATION; NONTHERMAL CONTINUUM; POLARIZATION; PARAMETERS; CONVECTION; DIGISONDE; ARRIVAL; RADAR AB Modern sounding techniques have been developed for the space-borne exploration of Earth's magnetosphere and topside ionosphere. Two new satellite instruments will use the advanced techniques of the ground-based Digisondes. The Radio Plasma Imager (RPI), a low-frequency sounder with 500-m dipole antennas designed to sweep from 3 kHz to 3 MHz, will be part of NASA's IMAGE mission to be launched in February 2000 into an elliptical orbit with an altitude at apogee of 7R(e). While in the magnetospheric cavity, RPI will receive echoes from the magnetopause and the plasmasphere and will measure the direct response of the magnetosphere's configuration to changes in the solar wind. With three orthogonal dipole antennas (two 500-m tip-to-tip antennas in the spin plane used for transmission and reception, one 20-m antenna along the spin axis for reception only) the arrival angle of returning echoes can be determined with high accuracy. The other instrument is the TOPside Automated Sounder (TOPAS), which was originally conceived for the Ukrainian WARNING mission with a launch date in 2001, Using one antenna for transmission and three orthogonal IO-m antennas fur reception, TOPAS will be able to determine the arrival angle of ionospheric echoes and their wave polarization. It will then be possible to automatically scale the topside ionograms and calculate the electron density profiles in real time. Operating as a high-frequency radar, TOPAS will for the first time measure topside plasma velocities by tracking the motions of plasma irregularities. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Raytheon ITTS, Greenbelt, MD 20771 USA. RP Reinisch, BW (reprint author), Univ Massachusetts, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 01854 USA. EM bodo_reinisch@uml.edu NR 41 TC 17 Z9 17 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 EI 1879-1824 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD JAN-FEB PY 2001 VL 63 IS 2-3 BP 87 EP 98 DI 10.1016/S1364-6826(00)00133-4 PG 12 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 398ZU UT WOS:000166787000002 ER PT J AU Hahn, CJ Rossow, WB Warren, SG AF Hahn, CJ Rossow, WB Warren, SG TI ISCCP cloud properties associated with standard cloud types identified in individual surface observations SO JOURNAL OF CLIMATE LA English DT Article ID HIGH-LEVEL CLOUDS; CIRCULATION SYSTEMS; SATELLITE; CLIMATOLOGIES; VARIABILITY; CONVECTION; PRODUCTS; ALBEDO; COVER AB Individual surface weather observations from land stations and ships are compared with individual cloud retrievals of the International Satellite Cloud Climatology Project (ISCCP), stage C1, for an 8-yr period (1983-91) to relate cloud optical thicknesses and cloud-top pressures obtained from satellite data to the standard cloud types reported in visual observations from the surface. Each surface report is matched to the corresponding ISCCP-C1 report for the time of observation for the 280 km x 280 km grid box containing that observation. Classes of the surface reports are identified in which a particular cloud type was reported present, either alone or in combination with other clouds. For each class, cloud amounts from both surface and C1 data, base heights from surface data, and the frequency distributions of cloud-top pressure (p(c)) and optical thickness (tau) from C1 data are averaged over 15 degrees latitude zones, for land and ocean separately, for 3-month seasons. The frequency distribution of pc and t is plotted for each of the surface-defined cloud types occurring both alone and with other clouds. The average cloud-top pressures within a grid box do not always correspond well with values expected for a reported cloud type, particularly for the higher clouds Ci, Ac, and Cb. In many cases this is because the satellites also detect clouds within the grid box that are outside the field of view of the surface observer. The highest average cloud tops are found for the most extensive cloud type, Ns, averaging 7 km globally and reaching 9 km in the ITCZ. Nimbostratus also has the greatest average retrieved optical thickness, tau approximate to 20. Cumulonimbus clouds may actually attain far greater heights and depths, but they do not fill the grid box. The tau -p(c) distributions show features that distinguish the high, middle, and low clouds reported by the surface observers. However, the distribution patterns for the individual low cloud types (Cu, Sc, St) occurring alone overlap to such an extent that it is not possible to distinguish these cloud types from each other on the basis of tau -p(c) values alone. Other cloud types whose tau -p(c) distributions are indistinguishable are Cb, Ns, and thick As. However, the tau -p(c) distribution patterns for the different low cloud types are nevertheless distinguishable when all occurrences of a low cloud type are included, indicating that the different low types differ in their probabilities of co-occurrence with middle and high clouds. C1 Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Hahn, CJ (reprint author), Univ Arizona, Dept Atmospher Sci, PAS Bldg 81, Tucson, AZ 85721 USA. RI Rossow, William/F-3138-2015 NR 36 TC 82 Z9 94 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 1 BP 11 EP 28 DI 10.1175/1520-0442(2001)014<0011:ICPAWS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 393MK UT WOS:000166474100002 ER PT J AU Halpern, D Woiceshyn, PM AF Halpern, D Woiceshyn, PM TI Somali Jet in the Arabian Sea, El Nino, and India rainfall SO JOURNAL OF CLIMATE LA English DT Article ID SENSOR MICROWAVE IMAGER; ASIAN SUMMER MONSOON; SURFACE TEMPERATURE; VARIABILITY; OCEAN; OSCILLATION; ONSET; ENSO; PREDICTABILITY; MOISTURE AB Interannual variations of the Somali Jet in the Arabian Sea during 1988-99 were linked to El Nino and La Nina episodes and to India west coast rainfall. Onset dates and monthly mean strengths of the Somali Jet were described with Special Sensor Microwave Imager surface wind speeds. Each year the Somali Jet formed in a similar area in the western Arabian Sea, and always before the onset of monsoon rainfall in Goa. The average date of Somali Jet onset was two days later in El Nino events in comparison with La Nina conditions. Monthly mean strength of the Somali Jet was 0.4 m s(-1) weaker during El Nino episodes than during La Nina intervals. When the monthly mean intensity of the Somali Jet was above (below) normal, there was an excess (deficit) of rainfall along the Indian west coast. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Halpern, D (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 36 TC 20 Z9 22 U1 3 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 3 BP 434 EP 441 DI 10.1175/1520-0442(2001)014<0434:SJITAS>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 399WC UT WOS:000166836400014 ER PT J AU Lau, KM Weng, HY AF Lau, KM Weng, HY TI Coherent modes of global SST and summer rainfall over China: An assessment of the regional impacts of the 1997-98 El Nino SO JOURNAL OF CLIMATE LA English DT Article ID SINGULAR-VALUE DECOMPOSITION; SEA-SURFACE TEMPERATURE; QUASI-BIENNIAL OSCILLATION; 11-YEAR SOLAR-CYCLE; SOUTHERN OSCILLATION; NORTHERN-HEMISPHERE; INDIAN-OCEAN; CLIMATE; VARIABILITY; HEIGHT AB In this paper, the authors have identified three coherent modes of summertime rainfall variability over China and global sea surface temperature (SST) for the period of 1955-98 by Singular Value Decomposition. Based on these modes, the impacts of the 1997-98 El Nino on major drought and flood occurrences over China have been assessed. The first mode can be identified with the growing phase of El Nino superimposed on a warming trend since the mid-1950s. This mode strongly influences rainfall over northern China. The second mode comprises a quasi-biennial (QB) variability manifested in alternate wet and dry years over the Yangtze River Valley (YRV) of central China. The third mode is dominated by a quasi-decadal oscillation in eastern China between the Yangtze River and the Yellow River, with an opposite tendency in southern China. Using a mode-by-mode reconstruction, the contributions of these leading modes to the 1997 and 1998 observed rainfall anomalies are evaluated. It is found that the severe drought in northern China, and to a lesser degree the flood in southern China, in 1997 is likely a result of the influence of anomalous SST forcing during the growing phase of the 1997-98 El Nino. The severe flood over YRV in 1998 is associated with the biennial tendency of basin-scale SST anomaly during the transition from El Nino to La Nina in 1997-98. In addition, the prolonged dry tendency over northern China and wet tendency over YRV since the 1970s may be associated with a long-term warming trend in the tropical Indian Ocean and western Pacific. The long-term dry background exacerbated the drought situation over northern China in 1997, and the wet background exacerbated the flood situation over YRV in 1998, under the impacts of the 1997-98 El Nino. In contrast, the rainfall variability in southern China is most chaotic, with no clear dominance of either El Nino or QB signals. The significance, reliability, and stability of these results are also discussed. C1 NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 32 TC 100 Z9 107 U1 0 U2 15 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 6 BP 1294 EP 1308 DI 10.1175/1520-0442(2001)014<1294:CMOGSA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 414NY UT WOS:000167674000019 ER PT J AU Li, XJ Chao, Y McWilliams, JC Fu, LL AF Li, XJ Chao, Y McWilliams, JC Fu, LL TI A comparison of two vertical-mixing schemes in a Pacific Ocean general circulation model SO JOURNAL OF CLIMATE LA English DT Article ID PLANETARY BOUNDARY-LAYER; LARGE-EDDY SIMULATIONS; NORTH PACIFIC; MIXED-LAYER; EQUATORIAL PACIFIC; VARIABILITY; PARAMETERIZATION; TEMPERATURE; TURBULENCE; CLIMATOLOGY AB The upper Pacific Ocean Current and temperature have been simulated by a three-dimensional ocean general circulation model (OGCM) with two different vertical-mixing schemes. One corresponds to the modified Richardson number-dependent scheme of Pacanowski and Philander (PP); the other is adapted from the newly developed K-Profile Parameterization (KPP) scheme. The performance of both schemes in a Pacific OGCM is evaluated under the same model configuration and boundary conditions. Model and data comparisons are made for the mean state, annual cycle, and interannual-to-interdecadal variability. In the Tropics, both the PP and KPP schemes produce reasonably realistic tropical thermal and current structures; however, KPP is better than PP in several important aspects. For example, the KPP scheme simulates a more realistic thermocline and significantly reduces the cold surface temperature bias in the eastern equatorial Pacific. The depth of the maximum Equatorial Undercurrent simulated by the KPP scheme is much closer to the observation. In the extratropics the KPP scheme is significantly better than the PP scheme in simulating the thermal and current structures, including the annual mean, annual cycle, and interannual-to-interdecadal variability. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Calif Los Angeles, Los Angeles, CA USA. RP Li, XJ (reprint author), M-S 300-323,JPL,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 50 TC 38 Z9 41 U1 2 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 7 BP 1377 EP 1398 DI 10.1175/1520-0442(2001)014<1377:ACOTVM>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 418CR UT WOS:000167872600003 ER PT J AU Los, SO Collatz, GJ Bounoua, L Sellers, PJ Tucker, CJ AF Los, SO Collatz, GJ Bounoua, L Sellers, PJ Tucker, CJ TI Global interannual variations in sea surface temperature and land surface vegetation, air temperature, and precipitation SO JOURNAL OF CLIMATE LA English DT Article ID HIGH-RESOLUTION RADIOMETER; ATMOSPHERIC CO2; CLIMATE VARIABILITY; CARBON-DIOXIDE; INDEX; NDVI; AVHRR; OSCILLATION; REFLECTANCE; SENSITIVITY AB Anomalies in global vegetation greenness, SST, land surface air temperature, and precipitation exhibit linked, low-frequency interannual variations. These interannual variations were detected and analyzed for 1982-90 with a multivariate spectral method. The two most dominant signals for 1982-90 had periods of about 2.6 and 3.4 yr. Signals centered at 2.6 years per cycle corresponded to variations in the El Nino-Southern Oscillation index and explained about 28% of the variance in anomalies of SST, land surface air temperature, precipitation, and vegetation; these signals were most pronounced in 1) SST anomalies in the eastern equatorial Pacific Ocean, 2) land surface vegetation and precipitation anomalies in tropical and subtropical regions, and 3) land surface vegetation, precipitation, and temperature anomalies in North America. Signals at 3.4 years per cycle corresponded to variations in the North Atlantic oscillation index and explained 8.6% of the variance in the combined datasets; their occurrence was most pronounced in 1) Atlantic SST anomalies, 2) in land surface temperature and vegetation anomalies in Europe and eastern Asia, and 3) in precipitation and vegetation anomalies in sub-Saharan Africa, southern Africa, and eastern North America. Anomalies in vegetation were positively related to anomalies in precipitation throughout the Tropics and subtropics and in midlatitudes in the central parts of continents. Anomalies in vegetation and temperature were positively linked in coastal temperate climates such as in Europe and eastern Asia. These associations between temperature and vegetation may be explained by the sensitivity of the length of growing season to variations in temperature. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Los, SO (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 923, Greenbelt, MD 20771 USA. RI collatz, george/D-5381-2012; Los, Sietse/G-8985-2012; OI Los, Sietse/0000-0002-1325-3555 NR 51 TC 97 Z9 112 U1 3 U2 21 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 7 BP 1535 EP 1549 DI 10.1175/1520-0442(2001)014<1535:GIVISS>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 418CR UT WOS:000167872600013 ER PT J AU Ballabrera-Poy, J Busalacchi, AJ Murtugudde, R AF Ballabrera-Poy, J Busalacchi, AJ Murtugudde, R TI Application of a reduced-order Kalman filter to initialize a coupled atmosphere-ocean model: Impact on the prediction of El Nino SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; DATA ASSIMILATION; TROPICAL PACIFIC; SOUTHERN OSCILLATION; EQUATORIAL WAVES; ENSO PREDICTION; NUMERICAL-MODEL; PREDICTABILITY; VARIABILITY; DYNAMICS AB A reduced-order Kalman filter is used to assimilate observed fields of the surface wind stress, sea surface temperature, and sea level into the coupled ocean-atmosphere model of Zebiak and Cane. The method projects the Kalman filter equations onto a subspace defined by the eigenvalue decomposition of the error forecast matrix, allowing its application to high-dimensional systems. The Zebiak and Cane model couples a linear, reduced-gravity ocean model with a single, vertical-mode atmospheric model. The compatibility between the simplified physics of the model and each observed variable is studied separately and together. The results show the ability of the empirical orthogonal functions (EOFs) of the model to represent the simultaneous value of the wind stress, SST, and sea level, when the fields are limited to the latitude band 10 degreesS-10 degreesN, and when the number of EOFs is greater than the number of statistically significant modes. In this first application of the Kalman filter to a coupled ocean-atmosphere prediction model, the sea level fields are assimilated in terms of the Kelvin and Rossby modes of the thermocline depth anomaly. An estimation of the error of these modes is derived from the projection of an estimation of the sea level error over such modes. The ability of the method to reconstruct the state of the equatorial Pacific and to predict its time evolution is shown. The method is quite robust for predictions up to 6 months, and able to predict the onset of the 1997 warm event 15 months before its occurrence. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Univ Maryland, ESSIC, College Pk, MD 20742 USA. RP Ballabrera-Poy, J (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Mailcode 970, Greenbelt, MD 20771 USA. EM joaquim@neptune.gsfc.nasa.gov OI Ballabrera-Poy, Joaquim/0000-0002-1753-221X NR 46 TC 25 Z9 27 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 8 BP 1720 EP 1737 DI 10.1175/1520-0442(2001)014<1720:AOAROK>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 419XD UT WOS:000167973300003 ER PT J AU Kawamoto, K Nakajima, T Nakajima, TY AF Kawamoto, K Nakajima, T Nakajima, TY TI A global determination of cloud microphysics with AVHRR remote sensing SO JOURNAL OF CLIMATE LA English DT Article ID REFLECTED SOLAR-RADIATION; EFFECTIVE PARTICLE RADIUS; OPTICAL-THICKNESS; MARINE STRATOCUMULUS; BOUNDARY-LAYER; NOAA AVHRR; RETRIEVAL; PARAMETERS; SCATTERING; ALBEDO AB An algorithm is developed for determining the cloud optical thickness and effective particle radius simultaneously on a global scale using Advanced Very High Resolution Radiometer (AVHRR) multispectral radiance data. In the algorithm, the treatment of thermal radiation in Nakajima and Nakajima is improved by reformulating the thermal emission in the atmospheric layers. At the same time, the lookup table for thermal emission is parameterized in terms of the equivalent water vapor path in order to include the effect of various vertical water vapor profiles. The algorithm is applied to AVHRR radiance data corresponding to reported aircraft and balloon measurements of cloud microphysical parameters. A comparison shows a good agreement between in situ and satellite-retrieved values thus obtained. The algorithm is further applied to 4-month Global Area Coverage data of 1987 to generate global distributions of the cloud optical thickness and effective particle radius for every 0.5 degrees X 0.5 degrees box in a -60 degrees -60 degrees latitudinal region. Similarities and differences in the global features of the effective particle radius and the optical thickness are found as compared with the previous studies. C1 Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. Natl Space Dev Agcy Japan, Earth Observat Res Ctr, Tokyo, Japan. RP Kawamoto, K (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Mail Stop 420, Hampton, VA 23681 USA. RI Nakajima, Takashi/C-2747-2009; Nakajima, Teruyuki/H-2370-2013 OI Nakajima, Teruyuki/0000-0002-9042-504X NR 58 TC 111 Z9 112 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 9 BP 2054 EP 2068 DI 10.1175/1520-0442(2001)014<2054:AGDOCM>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 424UX UT WOS:000168253300009 ER PT J AU Cess, RD Zhang, MH Wielicki, BA Young, DF Zhou, XL Nikitenko, Y AF Cess, RD Zhang, MH Wielicki, BA Young, DF Zhou, XL Nikitenko, Y TI The influence of the 1998 El Nino upon cloud-radiative forcing over the Pacific warm pool SO JOURNAL OF CLIMATE LA English DT Article ID EARTHS ENERGY-BALANCE; BUDGET EXPERIMENT; CIRRUS CLOUDS; CLIMATE; REGIONS; MISSION AB Clouds cool the climate system by reflecting shortwave radiation and warm it by increasing the atmospheric greenhouse. Previous studies have shown that in tropical regions of deep convection there is a near cancellation between cloud-induced shortwave cooling and longwave warming. The present study investigates the possible influence of the 1998 El Nino upon this near cancellation for the tropical western Pacific's warm pool; this was accomplished by employing satellite radiometric measurements (Earth Radiation Budget Experiment, and Clouds and the Earth's Radiant Energy System). With the exclusion of the 1998 El Nino, this study also finds near cancellation between the shortwave and longwave cloud forcings and demonstrates that it refers to the average of different cloud types rather than being indicative of a single cloud type. The shortwave cooling slightly dominates the longwave warming, and there is considerable interannual variability in this modest dominance that appears attributable to interannual variability of tropopause temperature. For the strong 1998 El Nino, however, there is a substantially greater tendency toward net radiative cooling, and the physical mechanism for this appears to be a change in cloud vertical structure. For normal years, as well as for the weaker 1987 El Nino, high clouds dominate the radiation budget over the warm pool. In 1998, however, the measurements indicate the radiation budget is partially governed by middle-level clouds, thus explaining the net cooling over the warm pool during the 1998 El Nino as well as emphasizing differences between this event and the weaker 1987 El Nino. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Cess, RD (reprint author), SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. NR 21 TC 62 Z9 65 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 9 BP 2129 EP 2137 DI 10.1175/1520-0442(2001)014<2129:TIOTEN>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 424UX UT WOS:000168253300014 ER PT J AU Chang, FC Smith, EA AF Chang, FC Smith, EA TI Hydrological and dynamical characteristics of summertime droughts over US Great Plains SO JOURNAL OF CLIMATE LA English DT Article ID SEMI-ARID REGIONS; SEA-SURFACE TEMPERATURE; UNITED-STATES; NORTH-AMERICA; PRECIPITATION VARIABILITY; JULY CIRCULATION; HEIGHT FIELD; 1988 DROUGHT; SOLAR-CYCLE; HEAT WAVES AB A drought pattern and its time evolution over the U.S. Great Plains are investigated from time series of climate divisional monthly mean surface air temperature and total precipitation anomalies. The spatial pattern consists of correlated occurrences of high (low) surface air temperature and deficit (excess) rainfall. The center of maximum amplitude in rain fluctuation is around Kansas City; that of temperature is over South Dakota. Internal consistency between temperature and precipitation variability is the salient feature of the drought pattern. A drought index is used to quantify drought severity for the period 1895-1996. The 12 severest drought months (in order) during this period are June 1933, June 1988, July 1936, August 1983, July 1934, July 1901, June 1931, August 1947, July 1930, June 1936, July 1954, and August 1936. Hydrological conditions are examined using National Centers for Environmental Prediction (NCEP) reanalysis precipitable water (PW) and monthly surface observations from Kansas City, Missouri, and Bismarck, North Dakota, near the drought centers. This analysis explains why droughts exhibit negative surface relative humidity anomalies accompanied by larger than normal monthly mean daily temperature ranges and why maximum PWs are confined to a strip of about 10 degrees longitude from New Mexico and Arizona into the Dakotas and Minnesota. Dynamical conditions are examined using NCEP reanalysis sea level pressures and 500- and 200-mb geopotential heights. The analysis indicates a midtroposphere wave train with positive centers situated over the North Pacific, North America, and the North Atlantic, with negative centers in the southeastern Gulf of Alaska and Davis Strait. Above-normal sea level pressures over New Mexico, the North Atlantic, and the subtropical Pacific along with below-normal sea level pressures over the Gulf of Alaska eastward to Canada, Davis Strait, and Greenland are present during drought periods. The most prominent feature is the strong anticyclone over central North America. On a regional scale, midtropospheric westerly winds are weakened (or become easterly) south of a thermal heat low centered in South Dakota during drought episodes because of the north-south temperature reversal perturbation. The associated westward displaced Bermuda high leads to enhanced low-level warm flow into the Dakotas, thus helping to maintain the reversal in the meridional temperature gradient and the concomitant thermal wind reversal. Enhanced moisture transport from the Gulf of California into the western plains (part of the Great Basin monsoon process) results from the large-scale perturbation pressure pattern. Middle-upper level convergence maintains the water vapor strip east of the Rocky Mountains, while the Mississippi valley undergoes moisture cutoff from both this process and the westward shift in the Bermuda high. The strip of maximum PW then undergoes enhanced solar and infrared absorption that feeds back on the thermal heat low. Surface air temperatures warm while sinking motion balances middle-upper level radiative cooling around the Kansas City area. This is the dynamical coupling that leads to reduced surface relative humidities. The centers of high surface air temperature and deficit rainfall are dynamically consistent with patterns in geopotential heights, vertical velocities, and water vapor amounts. C1 Univ Alabama, Earth Syst Sci Ctr, Huntsville, AL 35899 USA. Univ Alabama, Global Hydrol & Climate Ctr, NASA, George C Marshall Space Flight Ctr, Huntsville, AL USA. RP Chang, FC (reprint author), No 12, Lane 220 Chung-Ho Rd, Chungli 320, Taiwan. NR 55 TC 12 Z9 15 U1 0 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 10 BP 2296 EP 2316 DI 10.1175/1520-0442(2001)014<2296:HADCOS>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 432YT UT WOS:000168724900008 ER PT J AU Schubert, SD Suarez, MJ Chang, YH Branstator, G AF Schubert, SD Suarez, MJ Chang, YH Branstator, G TI The impact of ENSO on extratropical low-frequency noise in seasonal forecasts SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; ROSSBY-WAVE DYNAMICS; EL-NINO; ANOMALIES; PATTERNS; VARIABILITY; CLIMATE; WINTER; FLOW; PREDICTABILITY AB This study examines the variability in forecasts of the January-February-March (JFM) mean extratropical circulation and how that variability is modulated by the El Nino-Southern Oscillation. The analysis is based on ensembles of seasonal simulations made with an atmospheric general circulation model (AGCM) forced with sea surface temperatures observed during the 1983 El Nino and 1989 La Nina events. The AGCM produces pronounced interannual differences in the magnitude of the extratropical seasonal mean noise (intraensemble JFM variability). The North Pacific, in particular, shows extensive regions in which the 1989 seasonal mean noise kinetic energy (SKE), which is dominated by a "Pacific-North American (PNA)-like'' spatial structure, is more than 2 times that of the 1983 forecasts. The larger SKE in 1989 is associated with a larger-than-normal barotropic conversion of kinetic energy from the mean Pacific jet to the seasonal mean noise. The generation of SKE by submonthly transients also shows substantial interannual differences, though these are much smaller than the differences in the mean flow conversions. An analysis of the generation of monthly mean noise kinetic energy and its variability suggests that the seasonal mean noise is predominantly a statistical residue of variability resulting from dynamical processes operating on monthly and shorter timescales. A stochastically forced barotropic model (linearized about the AGCM's 1983 and 1989 seasonal and ensemble mean states) is used to further assess the role of the basic state, submonthly transients, and tropical forcing in modulating the uncertainties in the seasonal AGCM forecasts. When forced globally with spatially white noise, the linear model generates much larger variance for the 1989 basic state, consistent with the AGCM results. The extratropical variability for the 1989 basic state is dominated by a single eigenmode and is strongly coupled with forcing over the tropical western Pacific and the Indian Ocean. Linear calculations that include forcing from the AGCM variance of the tropical forcing and submonthly transients show a small impact on the variability over the PNA region as compared with that of the basic-state differences. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Schubert, SD (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 910-3, Greenbelt, MD 20771 USA. NR 32 TC 17 Z9 17 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 10 BP 2351 EP 2365 DI 10.1175/1520-0442(2001)014<2351:TIOEOE>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 432YT UT WOS:000168724900011 ER PT J AU Parkinson, CL Rind, D Healy, RJ Martinson, DG AF Parkinson, CL Rind, D Healy, RJ Martinson, DG TI The impact of sea ice concentration accuracies on climate model simulations with the GISS GCM SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; SENSOR MICROWAVE IMAGER; ARCTIC CLIMATE; SENSITIVITY AB The Goddard Institute for Space Studies global climate model (GISS GCM) is used to examine the sensitivity of the simulated climate to sea ice concentration specifications in the type of simulation done in the Atmospheric Model Intercomparison Project (AMIP), with specified oceanic boundary conditions. Results show that sea ice concentration uncertainties of +/-7% can affect simulated regional temperatures by more than 6 degreesC, and biases in sea ice concentrations of +7% and -7% alter simulated annually averaged global surface air temperatures by -0.10 degrees and +0.17 degreesC, respectively, over those in the control simulation. The resulting 0.27 degreesC difference in simulated annual global surface air temperatures is reduced by a third, to 0.18 degreesC, when considering instead biases of +4% and -4%. More broadly, least squares fits through the temperature results of 17 simulations with ice concentration input changes ranging from increases of 50% versus the control simulation to decreases of 50% yield a yearly average global impact of 0.0107 degreesC warming for every 1% ice concentration decrease, that is, 1.07 degreesC warming for the full +50% to -50% range. Regionally and on a monthly average basis, the differences can be far greater, especially in the polar regions, where wintertime contrasts between the +50% and -50% cases can exceed 30 degreesC. However, few statistically significant effects are found outside the polar latitudes, and temperature effects over the nonpolar oceans tend to be under 1 degreesC, due in part to the specification of an unvarying annual cycle of sea surface temperatures. The +/-7% and +/-4% results provide bounds on the impact (on GISS GCM simulations making use of satellite data) of satellite-derived ice concentration inaccuracies, +/-7% being the current estimated average accuracy of satellite retrievals and +/-4% being the anticipated improved average accuracy for upcoming satellite instruments. Results show that the impact on simulated temperatures of imposed ice concentration changes is least in summer, encouragingly the same season in which the satellite accuracies are thought to be worst. Hence, the impact of satellite inaccuracies is probably less than the use of an annually averaged satellite inaccuracy would suggest. C1 NASA, Oceans & Ice Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY USA. RP Parkinson, CL (reprint author), NASA, Oceans & Ice Branch, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. RI Parkinson, Claire/E-1747-2012; Healy, Richard/J-9214-2015 OI Parkinson, Claire/0000-0001-6730-4197; Healy, Richard/0000-0002-5098-8921 NR 28 TC 33 Z9 36 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 12 BP 2606 EP 2623 DI 10.1175/1520-0442(2001)014<2606:TIOSIC>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 441PQ UT WOS:000169239100008 ER PT J AU Borovikov, A Rienecker, MM Schopf, PS AF Borovikov, A Rienecker, MM Schopf, PS TI Surface heat balance in the equatorial Pacific Ocean: Climatology and the warming event of 1994-95 SO JOURNAL OF CLIMATE LA English DT Article ID TROPICAL PACIFIC; SEASONAL CYCLE; MIXED-LAYER; FRESH-WATER; EL-NINO; TEMPERATURE; VARIABILITY; SIMULATION; RADIATION; MODEL AB The surface heat budget in the equatorial Pacific Ocean was investigated through ocean model simulations, both the climatological cycle and the case of the 1994-95 warm event. The dominant processes governing the seasonal cycle of sea surface temperature (SST) vary significantly across the basin. In the western Pacific the annual cycle of SST is primarily in response to net surface heat flux. In the central basin the magnitude of the zonal advection term is comparable to that of the net surface heat flux. In the eastern basin the role of zonal advection is reduced and the vertical mixing and advection are more important. The model estimate of the vertical mixing contribution to the mixed layer heat budget compared well with estimates obtained by analysis of observations using the same diagnostic vertical mixing scheme. During 1994-95 the largest positive SST anomaly was observed in the midbasin and was related initially to reduced latent heat flux due to weak surface winds and later to anomalous zonal advection. In the eastern Pacific where winds were not significantly anomalous throughout 1994-95, only a moderate warm surface anomaly was detected. This is in contrast to strong El Nino events where the SST anomaly is largest in the eastern basin. Overall, the balances inferred from the model forced by Special Sensor Microwave/Imager winds are consistent with the balances derived using tropical atmosphere-ocean moorings data and Reynolds SST. C1 NASA, Seasonal Interannual Predict Project, Oceans & Ice Branch, Lab Hydrospher Proc,Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Gen Sci Corp, SAIC, Greenbelt, MD 20771 USA. George Mason Univ, Inst Computat Sci & Informat, Fairfax, VA 22030 USA. RP Borovikov, A (reprint author), NASA, Seasonal Interannual Predict Project, Oceans & Ice Branch, Lab Hydrospher Proc,Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 29 TC 15 Z9 15 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 12 BP 2624 EP 2641 DI 10.1175/1520-0442(2001)014<2624:SHBITE>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 441PQ UT WOS:000169239100009 ER PT J AU Mo, KC Hakkinen, S AF Mo, KC Hakkinen, S TI Interannual variability in the tropical Atlantic and linkages to the Pacific SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; HEAT-FLUX ANOMALIES; SST VARIABILITY; NORTHERN OCEANS; OSCILLATION; CIRCULATION; SCALES; LATENT; ENSO AB The variability of sea surface temperature anomalies (SSTAs) in the tropical Atlantic is examined using data from 1900 to the present. SSTAs are filtered to focus on the interannual band with fluctuations less than 60 months. Both SSTAs over the northern tropical Atlantic (NTA) and the southern tropical Atlantic (STA) are associated with the El Nino-Southern Oscillation (ENSO) variability in the tropical Pacific. SSTAs over the STA are associated with the quasi-biennial component of ENSO with a timescale of 22-32 months, and SSTAs over the NTA are influenced by the low-frequency part of the ENSO signal with a timescale of 36-48 months. The ENSO influence is seasonally dependent. The strongest linkages occur in the spring of each hemisphere. In addition to ENSO, SSTAs in the north equatorial Atlantic are also modulated by the circulation and net heat flux anomalies associated with the North Atlantic oscillation (NAO). The atmospheric impact on the ocean is different in the STA and NTA regions. When the quasi-biennial signal is strong in the central Pacific during September-November, warm SSTAs excite the Pacific South American wave train extending from the Pacific to the South Atlantic. The associated wind-driven dynamics initiates the changes in the STA. The local net heat flux anomalies and ocean wave dynamics influence the location and the strength of the SSTA maximum. The SSTAs over the NTA region are driven by the local heat flux anomalies related to the trade wind changes associated with the low-frequency component of ENSO in the Pacific. The magnitudes of SSTAs depend on the phase of the NAO. The net heat flux anomalies associated with the NAO may enhance or diminish the impact of ENSO over the NTA region and modulate SSTAs in the North Atlantic. C1 NOAA, Climate Predict Ctr, NCEP, NWS, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mo, KC (reprint author), NOAA, Climate Predict Ctr, NCEP, NWS, 5200 Auth Rd, Camp Springs, MD 20746 USA. RI Hakkinen, Sirpa/E-1461-2012 NR 32 TC 40 Z9 41 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 12 BP 2740 EP 2762 DI 10.1175/1520-0442(2001)014<2740:IVITTA>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 441PQ UT WOS:000169239100016 ER PT J AU Lau, KM Wu, HT AF Lau, KM Wu, HT TI Principal modes of rainfall-SST variability of the Asian summer monsoon: A reassessment of the monsoon-ENSO relationship SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURES; 1997-98 EL-NINO; INDIAN-OCEAN; INTERANNUAL VARIABILITY; SOUTHERN OSCILLATION; BIENNIAL OSCILLATION; SYSTEM; TELECONNECTION; ANOMALIES; CLIMATE AB Using global rainfall and sea surface temperature (SST) data for the past two decades (1979-98), the covariability of the Asian summer monsoon (ASM) and El Nino-Southern Oscillation (ENSO) was investigated. The findings suggest three recurring rainfall-SST coupled modes. Characterized by a pronounced biennial variability, the first mode is associated with generally depressed rainfall over the western Pacific and the "Maritime Continent,'' stemming from the eastward shift of the Walker circulation during the growth phase of El Nino. The associated SST pattern consists of an east-west SST seesaw across the Pacific and another seesaw with opposite polarity over the Indian Ocean. The second mode is associated with a growing La Nino, comprising mixed, regional, and basin-scale rainfall and SST variability with abnormally warm water in the vicinity of the Maritime Continent and western Pacific. It possesses a pronounced low-level west Pacific anticyclone (WPA) near the Philippines and exhibits large subseasonal-scale variability. The third mode is associated with regional coupled ocean-atmosphere processes in the ASM region, having spatial and temporal variabilities that suggest extratropical linkages and interhemispheric interactions occurring on decadal timescales. Results indicate the importance of regional processes in affecting ASM rainfall variability. On the average, and over the ASM region as a whole, ENSO-related basin-scale SSTs can account for about 30% of the variability, and regional processes can account for an additional 20%. In individual years and over subregions, the percentages can be much higher or lower. In addition to the shift in the Walker circulation, it is found that the regional excitation of the WPA is important in determining the rainfall variability over south Asia and east Asia. Based on the results, a hypothesis is proposed that anomalous wind forcings derived from the WPA may be instrumental in inducing a biennial modulation to natural ENSO cycles. The causes of the 1997 and 1998 rainfall anomalies over the ASM subregions are discussed in the context of these results and in light of recent observations of long-term changes in the monsoon-ENSO relationship. C1 NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 34 TC 102 Z9 115 U1 0 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 13 BP 2880 EP 2895 DI 10.1175/1520-0442(2001)014<2880:PMORSV>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 451HR UT WOS:000169796600006 ER PT J AU Schubert, SD Wu, ML AF Schubert, SD Wu, ML TI Predictability of the 1997 and 1998 south Asian summer monsoon low-level winds SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE-TEMPERATURE; INDIAN MONSOON; RAINFALL VARIABILITY; EL-NINO; MODEL; CIRCULATION; ENSO; SENSITIVITY; PREDICTIONS; CONVECTION AB The predictability of the 1997 and 1998 south Asian summer monsoon winds is examined from an ensemble of 10 atmospheric general circulation model simulations with prescribed sea surface temperatures (SSTs) and soil moisture. The simulations have no memory of atmospheric initial conditions for the periods of interest. The model simulations show that the 1998 monsoon is considerably more predictable than the 1997 monsoon. During May and June of 1998 the predictability of the low-level wind anomalies is largely associated with a local response to anomalously warm Indian Ocean SSTs. Predictability increases late in the season (July and August) as a result of the strengthening of the anomalous Walker circulation and the associated development of easterly low-level wind anomalies that extend westward across India and the Arabian Sea. During these months the model is also the most skillful, with the analyses showing a similar late-season westward extension of the easterly wind anomalies. The model shows little predictability or skill in the monthly mean low-level winds over Southeast Asia during 1997. Predictable wind anomalies do occur over the western Indian Ocean and Indonesia; however, over the Indian Ocean the predictability is artificial, because the model is responding to SST anomalies that were wind driven. The reduced predictability in the low-level winds during 1997 appears to be the result of a weaker (as compared with 1998) simulated anomalous Walker circulation, and the reduced skill is associated with pronounced intraseasonal activity that is not captured well by the model. It is remarkable that the model does produce an ensemble mean Madden-Julian oscillation (MJO) response, though it is approximately in quadrature with, and much weaker than, the observed MJO anomalies during 1997. C1 Goddard Lab Atmospheres, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Schubert, SD (reprint author), Goddard Lab Atmospheres, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. NR 33 TC 9 Z9 9 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 15 BP 3173 EP 3191 DI 10.1175/1520-0442(2001)014<3173:POTASA>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 458VM UT WOS:000170216200001 ER PT J AU Gettelman, A Randel, WJ Massie, S Wu, F Read, WG Russell, JM AF Gettelman, A Randel, WJ Massie, S Wu, F Read, WG Russell, JM TI El Nino as a natural experiment for studying the tropical tropopause region SO JOURNAL OF CLIMATE LA English DT Article ID STRATOSPHERIC WATER-VAPOR; INTERANNUAL VARIABILITY; TROPOSPHERE EXCHANGE; UARS MLS; CIRCULATION; PACIFIC; OSCILLATION; FEATURES; HEIGHT; ENSO AB The interannual variability of the tropical tropopause region between 14 and 18 km is examined using observations of convection, winds, and tropopause temperatures from reanalyses and water vapor from satellites. This variability is compared to a simulation using the Community Climate Model version 3 (CCM3) general circulation model forced by observed sea surface temperatures. A coherent picture of the effect of the El Nino-Southern Oscillation (ENSO) on the tropopause region is presented in the NCEP-NCAR reanalyses and CCM3. ENSO modifies convection in the Tropics, and the temperature and circulation of the tropical tropopause region, in agreement with idealized models of tropical heating. CCM3 reproduces most details of these changes, but not the zonal mean temperature variations present in the analysis fields, which are not related to ENSO. ENSO also forces significant changes in observed and simulated water vapor fields. In the upper troposphere water vapor is at maximum near convection, while in the tropopause region water vapor is at minimum in the regions of convection and surrounding it. Convection, cirrus clouds, temperatures, and transport are all linked to describe the water vapor distribution and highlight the role of transport in the tropopause region. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Jet Prop Lab, Pasadena, CA USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Gettelman, A (reprint author), Natl Ctr Atmospher Res, Box 3000, Boulder, CO 80307 USA. RI Randel, William/K-3267-2016 OI Randel, William/0000-0002-5999-7162 NR 49 TC 40 Z9 42 U1 1 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 16 BP 3375 EP 3392 DI 10.1175/1520-0442(2001)014<3375:ENOAAN>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 464WF UT WOS:000170554200003 ER PT J AU Sud, YC Mocko, DM Walker, GK Kosgter, RD AF Sud, YC Mocko, DM Walker, GK Kosgter, RD TI Influence of land surface fluxes on precipitation: Inferences from simulations forced with four ARM-CART SCM datasets SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; RELAXED ARAKAWA-SCHUBERT; SINGLE-COLUMN MODELS; SEMI-ARID REGIONS; TROPICAL DEFORESTATION; JULY CIRCULATION; CLOUD ENSEMBLE; GCM SIMULATION; CLIMATE; SCALE AB Four different Atmospheric Radiation Measurement Program Cloud and Radiation Test Bed (ARM-CART) Single-Column Model (SCM) datasets were used to force an SCM in a number of simulations performed to study the influence of land surface fluxes on precipitation. The SCM employed Goddard Earth Observing System (GEOS-2) GCM physics, which includes a recent version of prognostic cloud scheme (Microphysics of Clouds with Relaxed Arakawa-Schubert), and a land model (Simplified Simple Biosphere Model) coupled to a highly resolved soil hydrological description in the vertical. The four ARM-CART datasets employed in these studies are referred as case 1, case 3, case 4, and case 8. The SCM simulation results broadly confirm the previous findings that an increase in the solar absorption and surface evaporation helps to increase the local rainfall, but they also reveal that the magnitude of the rainfall increase is strongly affected by the ability of the background circulation to promote moist convection. The simulated precipitation increase was as large as 50% of the evapotranspiration increase for case 1 that covered a relatively wet period. It was substantially reduced for cases 3 and 4 covering a normal rainfall period and became negligible for case 8, a dry case. A part of evaporation increase became horizontal divergence of water vapor; this would have the potential of increasing the precipitation downstream of the test region. For a particular background circulation, it was found that the evaporation-precipitation relationship, often defined as recycling ratio, is remarkably robust even for a large range of vegetation covers, soil types, and initial soil moistures. Notwithstanding the limitations of only one-way interaction (i.e., the large scale influencing the regional physics and not vice versa), the current SCM simulations show that recycling ratio is a function of the background circulation and not a regional and/or seasonal feature. Indeed, a vigorous biosphere can help to produce more rainfall under wet conditions but may do little to dislodge a large-scale drought. It is pointed out that even though these inferences are robust, they are prone to weaknesses of the SCM physics as well as the assumption of the large scale remaining unaffected by changes of moist processes. C1 NASA, Goddard Space Flight Ctr, Climat & Radiat Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Sud, YC (reprint author), NASA, Goddard Space Flight Ctr, Climat & Radiat Branch, Atmospheres Lab, Mail Code 913, Greenbelt, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 43 TC 8 Z9 8 U1 2 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 17 BP 3666 EP 3691 DI 10.1175/1520-0442(2001)014<3666:IOLSFO>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 474YH UT WOS:000171134200011 ER PT J AU Chen, TC Yen, MC Schubert, S AF Chen, TC Yen, MC Schubert, S TI Diurnal variation of pressure-heights: A vertical phase shift SO JOURNAL OF CLIMATE LA English DT Article ID SURFACE PRESSURE; SEMIDIURNAL TIDES AB A vertical phase shift of the diurnal harmonic of geopotential height S-1(Z) in the lower troposphere of low latitudes is shown by a comparison of diurnal harmonic of surface pressure at two surface stations that have an elevation difference close to 4 km. It is inferred from longitude-height cross sections of S-1(Z) that this vertical phase shift is caused by the differential response of the lower and mid-upper troposphere to the diurnal variation of radiative heating/cooling. C1 Iowa State Univ, Dept Geol & Atmospher Sci, Atmospher Sci Program, Ames, IA 50011 USA. Natl Cent Univ, Dept Atmospher Sci, Chungli 32054, Taiwan. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Chen, TC (reprint author), Iowa State Univ, Dept Geol & Atmospher Sci, Atmospher Sci Program, 3010 Agron Hall, Ames, IA 50011 USA. NR 18 TC 5 Z9 5 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 17 BP 3793 EP 3797 DI 10.1175/1520-0442(2001)014<3793:DVOPHA>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 474YH UT WOS:000171134200019 ER PT J AU Wang, B Wu, RG Lau, KM AF Wang, B Wu, RG Lau, KM TI Interannual variability of the Asian summer monsoon: Contrasts between the Indian and the western North Pacific-east Asian monsoons SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE-TEMPERATURE; TROPOSPHERIC BIENNIAL OSCILLATION; EL-NINO; EQUATORIAL PACIFIC; RAINFALL VARIABILITY; INTERDECADAL CHANGES; TROPICAL PACIFIC; ENSO; SYSTEM; IMPACT AB Analyses of 50-yr NCEP-NCAR reanalysis data reveal remarkably different interannual variability between the Indian summer monsoon (ISM) and western North Pacific summer monsoon (WNPSM) in their temporal-spatial structures, relationships to El Nino, and teleconnections with midlatitude circulations. Thus, two circulation indices are necessary, which measure the variability of the ISM and WNPSM, respectively. A weak WNPSM features suppressed convection along 10 degrees -20 degreesN and enhanced rainfall along the mei-yu/baiu front. So the WNPSM index also provides a measure for the east Asian summer monsoon. An anomalous WNPSM exhibits a prominent meridional coupling among the Australian high, cross-equatorial flows, WNP monsoon trough, WNP subtropical high, east Asian subtropical front, and Okhotsk high. The WNP monsoon has leading spectral peaks at 50 and 16 months, whereas the Indian monsoon displays a primary peak around 30 months. The WNPSM is weak during the decay of an El Nino, whereas the ISM tends to abate when an El Nino develops. Since the late 1970s, the WNPSM has become more variable, but its relationship with El Nino remained steady; in contrast, the ISM has become less variable and its linkage with El Nino has dramatically declined. These contrasting features are in part attributed to the differing processes of monsoon-ocean interaction. Also found is a teleconnection between a suppressed WNPSM and deficient summer rainfall over the Great Plains of the United States. This boreal summer teleconnection is forced by the heat source fluctuation associated with the WNPSM and appears to be established through excitation of Rossby wave trains and perturbation of the jet stream that further excites downstream optimum unstable modes. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Int Pacific Res Ctr, Honolulu, HI 96822 USA. Univ Hawaii Manoa, Dept Meteorol, Honolulu, HI 96822 USA. NASA, Climate & Radiat Branch, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Wang, B (reprint author), Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Int Pacific Res Ctr, 2525 Correa Rd, Honolulu, HI 96822 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 66 TC 429 Z9 484 U1 11 U2 117 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 20 BP 4073 EP 4090 DI 10.1175/1520-0442(2001)014<4073:IVOTAS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 478JX UT WOS:000171344200006 ER PT J AU Leroy, SS AF Leroy, SS TI The effects of orbital precession on remote climate monitoring SO JOURNAL OF CLIMATE LA English DT Article ID GRIDPOINT TEMPERATURE ANOMALIES; RADIOSONDE VALIDATION; PRECISION AB The effect of the diurnal cycle when monitoring the climate from low earth orbit is examined briefly. Equations are derived that relate the harmonics of the diurnal cycle to temporal sampling error and drift rates in that error. Special attention is given to nodal precession of satellite orbits. Using an insolated blackbody as a simple model for the diurnal cycle, roughly simulating subtropical desert surface temperature, the effects of orbital precession are examined numerically. From an initial configuration, wherein satellites are evenly spaced in nodal crossing time, minor differences in precession rates lead to biases proportional to the amplitude of the semidiurnal cycle and inversely to the square root of the number of satellites. Overall biases for a single mission can be dramatically reduced by flying in a formation wherein the satellites' orbits are evenly distributed in their equator-crossing times. To monitor surface temperature, it is suggested that at least six satellites be flown in formation and that their precession rates be controlled to well within 25 min. The tolerance for monitoring any other variable can be scaled according to the size of its semidiurnal cycle. C1 Danish Meteorol Inst, DK-2100 Copenhagen O, Denmark. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Leroy, SS (reprint author), Danish Meteorol Inst, Lyngbyvej 100, DK-2100 Copenhagen O, Denmark. NR 12 TC 6 Z9 6 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PY 2001 VL 14 IS 22 BP 4330 EP 4337 DI 10.1175/1520-0442(2001)014<4330:TEOOPO>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 488FB UT WOS:000171924600007 ER PT J AU Fenske, MT Vizzini, AJ AF Fenske, MT Vizzini, AJ TI The inclusion of in-plane stresses in delamination criteria SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article ID FREE-EDGE; INTERLAMINAR STRESSES; LAMINATED COMPOSITES; STRENGTH; SHEAR AB Delamination is characterized as the failure of the interply resin-rich region. The interply resin layers are modeled and the six component stress state is determined using a finite element analysis. The Modified von Mises Delamination Criterion using both the in-plane and interlaminar stresses is developed and applied to the average stress state within 1.75 ply thicknesses of the edge. The MVMDC shows good correlation to experimental data as well as to other criteria. The MVMDC is not sensitive to the thickness of the interply resin layer. Instead it is merely the presence of such a layer and the stresses that result in the layer that can indicate delamination failure of a laminate. Thus consideration of the full stress state in the failure of the interply resin layer is valid and indicates the potential for interaction between the in-plane loading and delamination. C1 Univ Maryland, NASA, Goddard Space Flight Ctr, Dept Aerosp Engn, College Pk, MD 20742 USA. RP Fenske, MT (reprint author), Univ Maryland, NASA, Goddard Space Flight Ctr, Dept Aerosp Engn, College Pk, MD 20742 USA. NR 49 TC 17 Z9 18 U1 1 U2 3 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 2001 VL 35 IS 15 BP 1325 EP 1342 DI 10.1177/002199801772662541 PG 18 WC Materials Science, Composites SC Materials Science GA 464YK UT WOS:000170560800001 ER PT J AU Fleming, DC AF Fleming, DC TI Delamination modeling of composites for improved crash analysis SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article; Proceedings Paper CT American-Society-of-Composites 13th Annual Technical Conference on Composite Materials CY SEP 21-23, 1998 CL BALTIMORE, MARYLAND SP Amer Soc Composites ID ENERGY-ABSORPTION CAPABILITY; BONDED FIBER COMPOSITES; HIGH-RATES; TUBES; PREDICTION; FAILURE AB Modeling of crashworthy composite structures is limited by the inability of current generations of finite element crash codes to effectively model certain critical failure modes, such as delamination. Previous efforts to model delamination and debonding failure modes using crash codes have typically relied on ad hoc failure criteria and quasistatic fracture data. Improvements to these modeling procedures can be made by using an approach based on fracture mechanics. Finite element predictions of delamination growth using the virtual crack closure technique are implemented using the finite element crash code MSC/DYTRAN and compared with other methods of modeling delamination in finite element crash analyses. Computational results for composite double cantilever beam specimens are compared with experimental results from the literature. This investigation demonstrates the potential for improving the crash modeling of composites through improved delamination modeling. Further developments to this approach may result in improved analytical tools that can be used to model delamination using current generation crash codes. C1 Florida Inst Technol, Dept Mech & Aerosp Engn, Melbourne, FL 32901 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Fleming, DC (reprint author), Florida Inst Technol, Dept Mech & Aerosp Engn, 150 W Univ Blvd, Melbourne, FL 32901 USA. OI Fleming, David/0000-0002-3395-9432 NR 23 TC 9 Z9 10 U1 0 U2 2 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 2001 VL 35 IS 19 BP 1777 EP 1792 PG 16 WC Materials Science, Composites SC Materials Science GA 485QA UT WOS:000171764800005 ER PT J AU Shapiro, BE AF Shapiro, BE TI Osmotic forces and gap junctions in spreading depression: A computational model SO JOURNAL OF COMPUTATIONAL NEUROSCIENCE LA English DT Review DE spreading depression; neuronal volume; osmosis; gap junctions; potassium ID HIPPOCAMPAL PYRAMIDAL NEURONS; ACTIVATED POTASSIUM CHANNELS; BRAIN IN-SITU; RAT-BRAIN; CA2+ CHANNELS; RECEPTOR CHANNELS; EXTRACELLULAR-SPACE; APICAL DENDRITES; CO-TRANSPORT; K+ CURRENTS AB In a computational model of spreading depression (SD), ionic movement through a neuronal syncytium of cells connected by gap junctions is described electrodiffusively. Simulations predict that SD will not occur unless cells are allowed to expand in response to osmotic pressure gradients and K+ is allowed to move through gap junctions. SD waves of [K+](out) approximate to 25 to approximate to 60 mM moving at approximate to2 to approximate to 18 mm/min are predicted over the range of parametric values reported in gray matter, with extracellular space decreasing up to approximate to 50%. Predicted waveform shape is qualitatively similar to laboratory reports. The delayed-rectifier, NMDA, BK, and Na+ currents are predicted to facilitate SD, while SK and A-type K+ currents and glial activity impede SD. These predictions are consonant with recent findings that gap junction poisons block SD and support the theories that cytosolic diffusion via gap junctions and osmotic forces are important mechanisms underlying SD. C1 CALTECH, Jet Prop Lab, Machine Learning Syst Grp, Pasadena, CA 91109 USA. RP Shapiro, BE (reprint author), CALTECH, Jet Prop Lab, Machine Learning Syst Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 105 TC 52 Z9 53 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0929-5313 J9 J COMPUT NEUROSCI JI J. Comput. Neurosci. PD JAN PY 2001 VL 10 IS 1 BP 99 EP 120 DI 10.1023/A:1008924227961 PG 22 WC Mathematical & Computational Biology; Neurosciences SC Mathematical & Computational Biology; Neurosciences & Neurology GA 417XJ UT WOS:000167860500006 PM 11316343 ER PT J AU Watson, AB Hu, J McGowan, JF AF Watson, AB Hu, J McGowan, JF TI Digital video quality metric based on human vision SO JOURNAL OF ELECTRONIC IMAGING LA English DT Article ID MASKING; MODEL AB The growth of digital video has given rise to a need for computational methods for evaluating the visual quality of digital video. We have developed a new digital video quality metric, which we call DVQ (digital video quality) [A. B. Watson, in Human Vision, Visual Processing, and Digital Display VIII, Proc. SPIE 3299, 139-147 (1993)]. Here, we provide a brief description of the metric, and give a preliminary report on its performance. DVQ accepts a pair of digital video sequences, and computes a measure of the magnitude of the visible difference between them. The metric is based on the discrete cosine transform. It incorporates aspects of early visual processing, including light adaptation, luminance, and chromatic channels; spatial and temporal filtering; spatial frequency channels; contrast masking; and probability summation. It also includes primitive dynamics of light adaptation and contrast masking. We have applied the metric to digital video sequences corrupted by various typical compression artifacts, and compared the results to quality ratings made by human observers. (C) 2001 SPIE and IS&T. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Watson, AB (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 24 TC 210 Z9 224 U1 0 U2 5 PU I S & T - SOC IMAGING SCIENCE TECHNOLOGY PI SPRINGFIELD PA 7003 KILWORTH LANE, SPRINGFIELD, VA 22151 USA SN 1017-9909 J9 J ELECTRON IMAGING JI J. Electron. Imaging PD JAN PY 2001 VL 10 IS 1 BP 20 EP 29 DI 10.1117/1.1329896 PG 10 WC Engineering, Electrical & Electronic; Optics; Imaging Science & Photographic Technology SC Engineering; Optics; Imaging Science & Photographic Technology GA 400ZJ UT WOS:000166902300004 ER PT J AU Saleeb, AF Arnold, SM AF Saleeb, AF Arnold, SM TI A general time dependent constitutive model: Part I - Theoretical developments SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article DE viscoelasticity; hereditary behavior; TIMETAL 21S; nonisothermal deformation; multiaxial; thermodynamics ID FRACTIONAL CALCULUS; VISCOELASTICITY; BEHAVIOR AB Using an internal-variable formalism as a starting point, we describe the viscoelastic complement of a previously-developed viscoplasticity formulation of the complete potential structure type. It is mainly motivated by experimental evidence for the presence of rate/time effects in the so-called quasilinear, reversible, material response range. Several possible generalizations are described, in the general format of hereditary-integral representations for nonequilibrium, stress-type, rate variables, both for isotropic as well as anisotropic materials. In particular, thorough discussions are given on the important issues of thermodynamic admissibility requirements for such general descriptions, resulting in a set of explicit mathematical constraints on the associated kernel (relaxation and creep compliance) functions. In addition, a number of explicit, integrated forms are derived, under stress and strain control to facilitate the parametric and qualitative response characteristic studies reported here as well as to help identify critical factors in the actual experimental characterizations from test data that will be reported in Part II. C1 Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Saleeb, AF (reprint author), Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. NR 43 TC 7 Z9 7 U1 1 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 51 EP 64 DI 10.1115/1.1288595 PG 14 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 430KF UT WOS:000168572500007 ER PT J AU Arnold, SM Saleeb, AF Castelli, MG AF Arnold, SM Saleeb, AF Castelli, MG TI A general time dependent constitutive model: Part II - Application to a titanium alloy SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article DE viscoelasticity; hereditary behavior; TIMETAL 21S; nonisothermal deformation; experimental testing AB Given the mathematical framework and specific viscoelastic model in Part I our primary goal in this second part is focused on model characterization and assessment for the specific titanium alloy. TIMETAL 21S. The model is motivated by experimental evidence suggesting the presence of significant rate/time effects in the so-called quasilinear, reversible, material response range. An explanation of the various experiments performed and their corresponding results are also included. Finally, model correlations and predictions are presented for a wide temperature range. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Univ Akron, Dept Civil Engn, Akron, OH 44325 USA. NYMA Inc, Engn Serv Div, Brook Pk, OH 44142 USA. RP Arnold, SM (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 7 Z9 7 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 65 EP 73 DI 10.1115/1.1288366 PG 9 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 430KF UT WOS:000168572500008 ER PT J AU Huyse, L Maes, MA AF Huyse, L Maes, MA TI Random field modeling of elastic properties using homogenization SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article ID DISCRETE NUMERICAL-MODEL; PLANAR DELAUNAY NETWORKS; GRANULAR ASSEMBLIES; LINEAR ELASTICITY; PARTICLE MODEL; FRACTURE; COMPOSITES; SIMULATION; AGGREGATE; MECHANICS AB This paper addresses the random field characterization of elastic properties. Consistent random held properties of a continuum are derived from a simple stochastic micromechanical model of the continuum. Existing displacement-based techniques to homogenize the discrete microstructure are discussed and a new force-based technique is introduced. The stochastic features of a micromechanically consistent continuum can be considerably different from those based on a straightforward randomization of deterministic constitutive laws. Examples indicate the relevance for structural reliability. The impact of uncertainties associated with selecting micromechanical models is assessed. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Calgary, Dept Civil Engn, Calgary, AB T2N 1N4, Canada. RP Huyse, L (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 37 TC 27 Z9 27 U1 1 U2 3 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD JAN PY 2001 VL 127 IS 1 BP 27 EP 36 DI 10.1061/(ASCE)0733-9399(2001)127:1(27) PG 10 WC Engineering, Mechanical SC Engineering GA 383FQ UT WOS:000165872800004 ER PT J AU Davis, MW Olla, BL Schreck, CB AF Davis, MW Olla, BL Schreck, CB TI Stress induced by hooking, net towing, elevated sea water temperature and air in sablefish: lack of concordance between mortality and physiological measures of stress SO JOURNAL OF FISH BIOLOGY LA English DT Article DE bycatch; capture; physiology; temperature ID COHO SALMON; NORTH-SEA; FISH; DURATION; CORTISOL; SURVIVAL AB In a series of laboratory studies designed to simulate bycatch processes. sablefish Anoplopoma fimbria were either hooked for up to 24 h or towed in a net for 4 h and then subjected to an abrupt transfer to elevated sea water temperature and air. Mortality did not result from hooking or net towing followed by exposure to air, but increased for both capture methods as fish were exposed to elevated temperatures, reflecting the magnifying effect of elevated temperature on mortality. Hooking and exposure to air resulted in increased plasma cortisol and lactate concentrations, while the combination of hooking and exposure to elevated temperature and air resulted in increased lactate and potassium concentrations. In fish that were towed in a net and exposed to air. cortisol, lactate. potassium and sodium concentrations increased. but when subjected to elevated temperature and air, no further increases occurred above the concentrations induced by net towing and air, suggesting a possible maximum of the physiological stress response. The results suggest that caution should be exercised when using physiological measures to quantify stress induced by capture and exposure to elevated temperature and air. that ultimately result in mortality, since the connections between physiological stress and mortality in bycatch processes remain to be fully understood. C1 Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. Oregon State Univ, US Geol Survey, Dept Fisheries & Wildlife, Oregon Cooperat Fishery Res Unit, Corvallis, OR 97331 USA. RP Davis, MW (reprint author), Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. NR 32 TC 63 Z9 66 U1 4 U2 13 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JAN PY 2001 VL 58 IS 1 BP 1 EP 15 DI 10.1006/jfbi.2000.1399 PG 15 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 397FL UT WOS:000166682600001 ER PT J AU Webber, WR Lockwood, JA McDonald, FB Heikkila, B AF Webber, WR Lockwood, JA McDonald, FB Heikkila, B TI Using transient decreases of cosmic rays observed at Voyagers 1 and 2 to estimate the location of the heliospheric termination shock SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID OUTER HELIOSPHERE; FORBUSH DECREASE; INTENSITY; MISSIONS AB We have examined the intensity-time profiles of outward moving transient decreases of anomalous and galactic cosmic rays observed by Voyager 1 (V1) and Voyager 2 (V2) in 1998 and 1999 in the outer heliosphere. The goal of this study is to compare these intensity-time profiles with those obtained by le Roux and Fichtner [1999] using numerical simulations of the time-dependent cosmic ray modulation produced by the passage of large global merged interaction regions. Their calculations show that when these interaction regions reach the heliospheric termination shock, they weaken rapidly causing the intensity of both galactic and anomalous cosmic rays to increase rapidly. They suggest using this time of rapid increase and the propagation times of these events to determine the location of the termination shock. Three outward propagating transient decreases were observed during the 1998-1999 time period. Because of local temporal variations the first two events did not exhibit a le Roux-Fichtner type of rapid recovery. However, the third event starting on day 50 of 1999 at V1 exhibited a very sharply defined intensity-time profile with a very rapid recovery starting on day 88 +/- 3 of 1999 that was observed in three energy channels on V1. From this time delay we are able to determine that the termination shock was 9.5-10.7 AU beyond V1 or at a distance of 82.6-83.8 AU at this time. The intensity-time profile at V2 was less sharp, but the rapid recovery that was observed occurred at the same time (+/-5 days) as that at V1, thus confirming the conclusions from the V1 data. At its present outward speed of 3.6 AU yr(-1), V1 would be expected to encounter the termination shock at this location as early as the last quarter of 2001. C1 New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Webber, WR (reprint author), New Mexico State Univ, Dept Astron, MSC 45000,POB 30001, Las Cruces, NM 88003 USA. NR 21 TC 16 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 2001 VL 106 IS A1 BP 253 EP 260 DI 10.1029/2000JA000285 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391WQ UT WOS:000166379600022 ER PT J AU Raeder, J McPherron, RL Frank, LA Kokubun, S Lu, G Mukai, T Paterson, WR Sigwarth, JB Singer, HJ Slavin, JA AF Raeder, J McPherron, RL Frank, LA Kokubun, S Lu, G Mukai, T Paterson, WR Sigwarth, JB Singer, HJ Slavin, JA TI Global simulation of the Geospace Environment Modeling substorm challenge event SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; 3-DIMENSIONAL MHD SIMULATION; IONOSPHERIC ELECTRIC-FIELDS; ALIGNED CURRENTS; PLASMA SHEET; SOLAR-WIND; SYNCHRONOUS ALTITUDE; AURORAL ACTIVITY; COUPLING MODEL; MAGNETOSPHERE AB We use a global model of Earth's magnetosphere and ionosphere to simulate the Geospace Environment Modeling (GEM) substorm challenge event of November 24, 1996. We compare our results to International Monitor for Auroral Geomagnetic Effects (IMAGE) ground magnetometer data, assimilative mapping of ionospheric electrodynamics (AMIE) polar cap potential and field aligned current patterns, Polar Visible Imaging System (VIS) estimates of the polar cap magnetic flux, GOES 8 geosynchronous magnetometer data, IMP 8 magnetometer data, and Geotail plasma and magnetic field data. We find generally good agreement between the simulation and the data. The modeled evolution of this substorm generally follows the phenomenological near-Earth neutral line model. However, reconnection in the tail is very localized, which makes establishing a causal relation between tail dynamics and auroral dynamics difficult, if not impossible. We also find that the model results critically depend on the parameterization of auroral Hall and Pedersen conductances and anomalous resistivity in the magnetosphere. For many combinations of parameters that enter these parameterizations, no substorm develops in the model, but instead the magnetosphere enters a steady convection mode. The main deviation of the model from the data is excessive convection, which leads to a strong, driven westward electrojet in the growth phase, only partial tail loading, and a reduced recovery phase. Possible remedies are a better model for auroral conductances, an improved anomalous resistivity model, and a more realistic treatment of the ring current. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Nagoya Univ, Solar Terr Environm Lab, Aichi 442, Japan. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Raeder, J (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, 405 Hilgard Ave, Los Angeles, CA 90095 USA. RI Lu, Gang/A-6669-2011; Paterson, William/F-5684-2012; Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 67 TC 150 Z9 155 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 2001 VL 106 IS A1 BP 381 EP 395 DI 10.1029/2000JA000605 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391WQ UT WOS:000166379600032 ER PT J AU Sigsbee, K Cattell, CA Mozer, FS Tsuruda, K Kokubun, S AF Sigsbee, K Cattell, CA Mozer, FS Tsuruda, K Kokubun, S TI Geotail observations of low-frequency waves from 0.001 to 16 Hz during the November 24, 1996, Geospace Environment Modeling substorm challenge event SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD VARIATIONS; PLASMA SHEET BOUNDARY; ELECTRIC-FIELDS; MAGNETOTAIL; PULSATIONS; MAGNETOSPHERE; RECONNECTION; TURBULENCE; ONSETS; FLOW AB We present observations of low-frequency waves from 0.001 Hz up to the lower hybrid frequency during the time periods corresponding to the growth, expansion, and recovery phases of a substorm that occurred from similar to 2100 to 2310 UT on November 24, 1996, while Geotail was located in the magnetotail at X-GSE similar to 25 R-E and 0100 LT. Large-amplitude waves near the lower hybrid frequency were observed when large-scale density and magnetic field gradients were present during thinning of the plasma sheet at substorm onset and the beginning of the recovery phase. Later in the recovery phase, waves near the lower hybrid frequency were observed close to the neutral sheet in localized areas with strong small-scale density and magnetic field gradients. Fluctuations of the electric and magnetic fields near the ion gyrofrequency were also observed during this event; however, the amplitudes were smaller than those often observed in the near tail in association with substorms. Compressional fluctuations of the magnetic field in the Pi2 frequency range were observed close to substorm onset. Although Geotail was not in the region considered in recent studies of Pi2 pulsations, it may still be possible that the magnetic field fluctuations observed by Geotail during the November 24, 1996, substorm are related to this phenomenon since little is known about propagation of the compressional pulses and generation of the waves. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Nagoya Univ, Solar Terr Environm Lab, Aichi 442, Japan. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. RP NASA, Goddard Space Flight Ctr, Code 696, Greenbelt, MD 20771 USA. EM ksigsbee@belka.space.umn.edu OI Sigsbee, Kristine/0000-0001-8727-380X NR 26 TC 15 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 2001 VL 106 IS A1 BP 435 EP 445 DI 10.1029/2000JA900090 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 391WQ UT WOS:000166379600036 ER PT J AU Schmeltz, M Rignot, E MacAyeal, DR AF Schmeltz, M Rignot, E MacAyeal, DR TI Ephemeral grounding as a signal of ice-shelf change SO JOURNAL OF GLACIOLOGY LA English DT Article ID RADAR INTERFEROMETRY; WEST ANTARCTICA; STREAM; FILCHNER; IMAGERY; GLACIER; MOTION; TIDES; SEA AB Interferometric synthetic aperture radar (InSAR) observations of ice-shelf tidal deformation reveal the wide transition between grounded and floating ice as well as local areas where the ice shelf is only grounded at low tide, a condition that we call ephemeral grounding. Ephemeral grounding creates a subtle, local disturbance on the vertical motion field of the ice-shelf surface in response to changes in oceanic tide which is detected with millimetric precision using InSAR. These ice-shelf features are, however, not expected to produce a noticeable disturbance on the ice-shelf velocity field. To illustrate the influence of ephemeral grounding on ice-shelf creep flow, we use a finite-element model in which ephemeral grounding is incorporated through a variable basal friction coefficient. The results show that while ice rises (permanently grounded areas) have a pronounced influence on the ice-shelf velocity field, areas of ephemeral grounding have a vanishingly small influence. What is thus of most interest is the capacity for observations of ephemeral grounding to reveal subtle changes in ice-shelf thickness over time. We discuss an example in the Thwaites Glacier area, West Antarctica, where multi-year data show how ice rises become ephemeral grounding and subsequently disappear. This result is consistent with the grounding-line retreat and ice thinning of Thwaites Glacier. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. RP Schmeltz, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Rignot, Eric/A-4560-2014; OI Rignot, Eric/0000-0002-3366-0481; MacAyeal, Douglas/0000-0003-0647-6176 NR 21 TC 20 Z9 20 U1 2 U2 2 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 2001 VL 47 IS 156 BP 71 EP 77 DI 10.3189/172756501781832502 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 466WM UT WOS:000170669200008 ER PT J AU Rignot, E AF Rignot, E TI Evidence for rapid retreat and mass loss of Thwaites Glacier, West Antarctica SO JOURNAL OF GLACIOLOGY LA English DT Article ID SATELLITE-RADAR INTERFEROMETRY; HINGE-LINE MIGRATION; ICE-SHEET; PETERMANN-GLETSCHER; GREENLAND; VELOCITY; BALANCE; STREAM; IMAGE; NORTH AB Thwaites Glacier, the second largest ice stream in West Antarctica, drains an area of 166500 +/- 2000 km(2) which accumulates 55 +/- 5 Gt a(-1) (or 60 +/- 6 km(3) ice a(-1)) into the Amundsen Sea, unrestrained by an ice shelf. Using interferometric synthetic-aperture radar (InSAR) data collected by the European Remote-sensing Satellites (ERS-1 and -2) in 1996, an output flux of 71 +/- 7 Gta(-1) (or 77 +/- 8 km(3) ice a(-1)) is estimated at the grounding line, where ice thickness is deduced from hydrostatic equilibrium. A similar flux, 70 +/- 7 Gt a(-1) (or 76 +/- 8 km(3) ice a(-1)), is obtained at a gate located 20 km upstream, where ice thickness was measured in 1978 by ice-sounding radar. Total accumulation in between the two gates is 1.6 Gt a(-1), or 1.8 km(3) ice a(-1). Ice discharge therefore exceeds mass accumulation by 30 +/- 15%, and Thwaites Glacier must be thinning and retreating at present. The InSAR data show that the glacier floating ice tongue exerts no back pressure on the inland ice, calves into tabular icebergs along a significant fraction of its grounding line, and has a grounding-line thickness which exceeds a prior-calculated limit for stability. Glacier thinning is confirmed at the coast by the detection of a 1.4 +/- 0.2 km retreat of its grounding line between 1992 and 1996 with InSAR, which implies 3.2 +/- 0.6 in ice a(-1) thinning at the glacier center and less near the sides. These results complement the decimeter-scale annual surface lowering observed with satellite radar altimetry several hundred kin inland of the grounding line. The magnitude of ice thinning estimated at the coast, however, rules out temporal changes in accumulation as the explanation for surface lowering. Ice thinning must be due to changes in ice flow. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 38 TC 57 Z9 58 U1 2 U2 19 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 2001 VL 47 IS 157 BP 213 EP 222 DI 10.3189/172756501781832340 PG 10 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 503DU UT WOS:000172783800006 ER PT J AU Price, SF Bindschadler, RA Hulbe, CL Joughin, IR AF Price, SF Bindschadler, RA Hulbe, CL Joughin, IR TI Post-stagnation behavior in the upstream regions of Ice Stream C, West Antarctica SO JOURNAL OF GLACIOLOGY LA English DT Article ID SATELLITE IMAGERY; BASAL MECHANICS; MASS-BALANCE; RADAR; FLOW; VELOCITY; SHEET; CONFIGURATION AB The region where two active tributaries feed into the now stagnant Ice Stream C (ISC), West Antarctica, is thickening. In this region, we observe a correlation between faster ice flow (the tributaries) and elevated topography. We conclude that stagnation of ISC resulted in compression and thickening along the tributaries, eventually forming a "bulge" on the ice-sheet surface. Modern hydraulic potential gradients would divert basal meltwater from ISC to Ice Stream B (ISB). These gradients are primarily controlled by the bulge topography, and so likely formed subsequent to trunk stagnation. As such, we argue against "water piracy" as being the cause for ISCs stagnation. Kinematic-wave theory suggests that thickness perturbations propagate downstream over time, but that kinematic-wa-ve speed decreases near the stagnant trunk. This and modest diffusion rates combine to trap most of the tributary-fed ice in the bulge region. Using interferometric synthetic aperture radar velocity measurements, we observe that half of the ice within ISC's southern tributary flows into ISB. That flow pattern and other observations of non-steady flow in the region likely result from stagnation-induced thickening along upper ISC combined with a longer period of thinning on upper ISB. If current trends in thickness change continue, more ice from upper ISC will be diverted to ISB. C1 SAIC Gen Sci Corp, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST Ctr, Oceans & Ice Branch, NASA,Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Price, SF (reprint author), Univ Washington, Dept Earth & Space Sci, Box 351650,Johnson Hall,Room 63, Seattle, WA 98195 USA. RI Joughin, Ian/A-2998-2008; Price, Stephen /E-1568-2013 OI Joughin, Ian/0000-0001-6229-679X; Price, Stephen /0000-0001-6878-2553 NR 40 TC 36 Z9 37 U1 1 U2 6 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 2001 VL 47 IS 157 BP 283 EP 294 DI 10.3189/172756501781832232 PG 12 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 503DU UT WOS:000172783800013 ER PT J AU Nghiem, SV Steffen, K Kwok, R Tsai, WY AF Nghiem, SV Steffen, K Kwok, R Tsai, WY TI Detection of snowmelt regions on the Greenland ice sheet using diurnal backscatter change SO JOURNAL OF GLACIOLOGY LA English DT Article ID COMPLEX-DIELECTRIC-CONSTANT; ENERGY-BALANCE; MICROWAVE; FREQUENCIES; AVHRR AB Snowmelt regions on Greenland ice are mapped daily with the SeaWinds wideswath Ku-band (13.4 GHz) scatterometer on the QuikSCAT satellite. The approach exploits the high temporal resolution of SeaWinds/QuikSCAT data for the melt mapping using diurnal backscatter change independent of the absolute calibration. The results reveal several pronounced melting and refreezing events, and effects of topography are evident in the melt patterns. The spatial resolution is sufficient to identify melt features on the Sukkertoppen Iskappe west of the main ice sheet. An anomalous warming event, caused by downward mixing of warm air, is detected in late September 1999 over the west flank of the southern Greenland ice sheet. Time-series images of melt regions are presented over the period from summer to the fall freeze-up. The satellite observations are verified with in situ measurements from the Greenland Climate Network stations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Dr, Pasadena, CA 91109 USA. RI Kwok, Ron/A-9762-2008; Steffen, Konrad/C-6027-2013 OI Kwok, Ron/0000-0003-4051-5896; Steffen, Konrad/0000-0001-8658-1026 NR 26 TC 41 Z9 43 U1 1 U2 8 PU CAMBRIDGE UNIV PRESS PI CAMBRIDGE PA EDINBURGH BLDG, SHAFTESBURY RD, CB2 8RU CAMBRIDGE, ENGLAND SN 0022-1430 EI 1727-5652 J9 J GLACIOL JI J. Glaciol. PY 2001 VL 47 IS 159 BP 539 EP 547 DI 10.3189/172756501781831738 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 546BT UT WOS:000175252600002 ER PT J AU Waszak, MR AF Waszak, MR TI Robust multivariable flutter suppression for Benchmark Active Control Technology wind-tunnel model SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID DESIGN AB The Benchmark Active Controls Technology project is part of NASA Langley Research Center's Benchmark Models Program for studying transonic aeroelastic phenomena. In January 1996, the Benchmark Active Controls Technology wind-tunnel model was used to successfully demonstrate the application of robust multivariable control design methods (H-infinity, and mu -synthesis) to flutter suppression. This paper addresses the design and experimental evaluation of robust multivariable flutter suppression control laws with particular attention paid to the degree to which stability and performance robustness was achieved. C1 NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23681 USA. RP Waszak, MR (reprint author), NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23681 USA. NR 13 TC 45 Z9 48 U1 0 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 2001 VL 24 IS 1 BP 147 EP 153 DI 10.2514/2.4694 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 391LT UT WOS:000166358000023 ER PT J AU Haley, P Soloway, D AF Haley, P Soloway, D TI Generalized predictive control for active flutter suppression SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Experimental results of a transonic wind-tunnel test that demonstrate the use of generalized predictive control for flutter suppression in a subsonic wind-tunnel vying model are presented. The generalized predictive control algorithm is based on the minimization of a suitable cost function over finite costing and control horizons. The cost function minimizes not only the sum of the mean square output of the plant predictions, but also the weighted square rate of change of the control input with its input constraints. An additional term was added to the cost function to compensate for dynamics of the wing model that cause it to be invariant to low input frequencies. This characteristic results in a control surface that drifts within the specified input constraints. The augmentation to the cost function that penalizes this low-frequency drift is derived and demonstrated. The initial validation of the controller uses a linear plant predictor model for the computation of the control inputs. Simulation results of the closed-loop system that were used to determine nominal ranges for the tuning parameters are presented. The generalized predictive controller based on the linear predictor model successfully suppressed the flutter for all testable Mach numbers and dynamic pressures in the transonic region in both simulation and wind-tunnel testing. The results confirm that the generalized predictive controller is robust to modeling errors. C1 NASA, Langley Res Ctr, Dynam & Control Branch Airborne Syst Competency, Hampton, VA 23681 USA. NASA, Ames Res Ctr, Nero Engn & Smart Syst Computat Sci Div, Moffett Field, CA 94035 USA. RP Haley, P (reprint author), NASA, Langley Res Ctr, Dynam & Control Branch Airborne Syst Competency, MS 132, Hampton, VA 23681 USA. NR 11 TC 5 Z9 6 U1 1 U2 7 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 2001 VL 24 IS 1 BP 154 EP 159 DI 10.2514/2.4696 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 391LT UT WOS:000166358000024 ER PT J AU Nykanen, DK Foufoula-Georgiou, E Lapenta, WM AF Nykanen, DK Foufoula-Georgiou, E Lapenta, WM TI Impact of small-scale rainfall variability on larger-scale spatial organization of land-atmosphere fluxes SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID MULTICOMPONENT DECOMPOSITION; SOIL-MOISTURE; MODEL; SENSITIVITY; FIELDS; RESOLUTION; SIMULATION; FLOODS; BASIN AB A coupled modeling framework is used in this study to investigate the effect of subgrid-scale rainfall variability on the spatial structure of the evolving storm and on other surface variables and water and energy fluxes. The Fifth-Generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model coupled with the Biosphere-Atmosphere Transfer Scheme is combined with a dynamical/statistical scheme for statistically downscaling rainfall. Model simulations with and without including subgrid-scale rainfall variability are compared at the grid scale to quantify the propagation of small-scale rainfall heterogeneities through the nonlinear land-atmosphere system. It was found that including subgrid-scale rainfall variability (here on the order of 3 km) affects the spatial organization of the storm system itself, surface temperature, soil moisture, and sensible and latent heat fluxes. These effects were found to occur at spatial scales much larger than the scale at which rainfall variability was prescribed, illustrating the pronounced nonlinear spatial dynamics of the land-atmosphere system and its important role on hydrometeorological predictions. C1 Univ Minnesota, Dept Civil Engn, St Anthony Falls Lab, Minneapolis, MN USA. NASA, MSFC, Global Hydrol & Climate Ctr, Huntsville, AL 35812 USA. RP Nykanen, DK (reprint author), Michigan Technol Univ, Dept Civil & Environm Engn, 1400 Townsend Dr, Houghton, MI 49931 USA. NR 37 TC 25 Z9 26 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 2 BP 105 EP 121 DI 10.1175/1525-7541(2001)002<0105:IOSSRV>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 418AT UT WOS:000167868200001 ER PT J AU Baker, RD Lynn, BH Boone, A Tao, WK Simpson, J AF Baker, RD Lynn, BH Boone, A Tao, WK Simpson, J TI The influence of soil moisture, coastline curvature, and land-breeze circulations on sea-breeze-initiated precipitation SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID LAYER CONVERGENCE LINES; BOUNDARY-LAYER; DEEP CONVECTION; MESOSCALE CIRCULATIONS; SOUTH FLORIDA; SURFACE PARAMETERIZATION; RAINFALL FEEDBACK; MODEL; SENSITIVITY; SIMULATIONS AB Idealized numerical simulations of Florida convection are performed with a coupled atmosphere-land surface model to identify the roles of initial soil moisture, coastline curvature, and land-breeze circulations on sea-breeze-initiated precipitation. The 3D Goddard Cumulus Ensemble cloud-resolving model is coupled with the Goddard Parameterization for Land-Atmosphere-Cloud Exchange land surface model, thus providing a tool to simulate more realistically land surface-atmosphere interaction and convective initiation. Eight simulations are conducted with either straight or curved coastlines, initially homogeneous soil moisture or initially variable soil moisture, and initially homogeneous horizontal winds or initially variable horizontal winds (land breezes). An additional simulation is performed to assess the role of Lake Okeechobee on convective development. All model simulations capture the diurnal evolution and general distribution of sea-breeze-initiated precipitation over central Florida. The distribution of initial soil moisture influences the timing and location of subsequent precipitation. Soil moisture acts as a moisture source for the atmosphere, increases the convectively available potential energy, and thus preferentially focuses heavy precipitation over existing wet soil. Soil moisture-induced mesoscale circulations do not produce heavy precipitation. Coastline curvature has a major impact on the timing and location of precipitation. Earlier low-level convergence occurs inland of convex coastlines, and subsequent heavy precipitation occurs earlier in simulations with curved coastlines. Early-morning land breezes influence the timing of precipitation by modifying low-level convergence. Because of nonlinear interaction between coastline curvature and soil moisture, the highest peak accumulated rainfall and highest peak rain rates occur in simulations with both coastline curvature and initial soil moisture variations. Lake Okeechobee influences the timing and location of precipitation because of strong lake-breeze circulations. C1 NASA, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY USA. Meteo France, Ctr Natl Rech Meteorol, Toulouse, France. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Baker, RD (reprint author), Austin Coll, Dept Phys, 900 N Grand Ave, Sherman, TX 75090 USA. NR 48 TC 71 Z9 77 U1 2 U2 23 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 2 BP 193 EP 211 DI 10.1175/1525-7541(2001)002<0193:TIOSMC>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 418AT UT WOS:000167868200006 ER PT J AU Stieglitz, M Ducharne, A Koster, R Suarez, M AF Stieglitz, M Ducharne, A Koster, R Suarez, M TI The impact of detailed snow physics on the simulation of snow cover and subsurface thermodynamics at continental scales SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID GENERAL-CIRCULATION MODELS; ATMOSPHERE TRANSFER SCHEME; CATCHMENT-BASED APPROACH; SUMMER MONSOON RAINFALL; LAND-SURFACE PROCESSES; ARCTIC TUNDRA; APPARENT RELATIONSHIP; CARBON-DIOXIDE; INDIAN MONSOON; ENERGY-BALANCE AB The three-layer snow model of Lynch-Stieglitz is coupled to the global catchment-based land surface model of the National Aeronautics and Space Administration's Seasonal to Interannual Prediction Project, and the combined models are used to simulate the growth and ablation of snow cover over the North American continent for the period of 1987-88. The various snow processes included in the three-layer model, such as snow melting and refreezing, dynamic changes in snow density, and snow insulating properties, are shown (through a comparison with the corresponding simulation using a much simpler snow model) to lead to an improved simulation of ground thermodynamics on the continental scale. This comparison indicates that the three-layer model, originally developed and validated at small experimental catchments, does indeed capture the important snow processes that control the growth and the ablation of continental-scale snowpack and its snow insulation capabilities. C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Univ Paris 06, UMR Sisyphe, Paris, France. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Stieglitz, M (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Route 9W, Palisades, NY 10964 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 70 TC 72 Z9 72 U1 2 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 3 BP 228 EP 242 DI 10.1175/1525-7541(2001)002<0228:TIODSP>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 447DQ UT WOS:000169554900002 ER PT J AU Basist, A Williams, C Grody, N Ross, TF Shen, S Chang, ATC Ferraro, R Menne, MJ AF Basist, A Williams, C Grody, N Ross, TF Shen, S Chang, ATC Ferraro, R Menne, MJ TI Using the special sensor microwave imager to monitor surface wetness SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID SOIL-MOISTURE; SNOW COVER; SSM/I; TEMPERATURE; VEGETATION; BASIN AB The frequencies flown on the Special Sensor Microwave Imager (SSM/I) are sensitive to liquid water near the earth's surface. These frequencies are primarily atmospheric window channels, which receive the majority of their radiation from the surface. Liquid water near the surface depresses the emissivity as a function of wavelength. The relationship between brightness temperatures at different frequencies is used to dynamically derive the amount of liquid water in each SSM/I observation at 1/3 degrees resolution. These data are averaged at 1 degrees resolution throughout the globe for each month during the period of 1992-97, and the 6-yr monthly means and the monthly anomalies of the wetness index are computed from this base period. To quantify the relationship between precipitation and surface wetness, these anomalies are compared with precipitation anomalies derived from the Global Precipitation Climate Program. The analysis was performed for six agricultural regions across six continents. There is generally a good correspondence between the two variables. The correlation generally increases when the wetness index is compared with precipitation anomalies accumulated over a 2-month period. These results indicate that the wetness index has a strong correspondence to the upper layer of the soil moisture in many cultivated areas of the world. The region in southeastern Australia had the best relationship, with a correlation coefficient of 0.76. The Sahel, France, and Argentina showed that the wetness index had memory of precipitation anomalies from the previous months. The memory is shorter for southeastern Australia and central China. The weakest correlations occurred over the southeastern United States, where the surface is covered by dense vegetation. The unique signal, strengths, and weaknesses of the wetness index in each of the six study regions are discussed. C1 NOAA, Natl Climat Data Ctr, NESDIS, Asheville, NC 28801 USA. NOAA, Atmospher Res & Applicat Div, Off Res & Applicat, NESDIS, Camp Springs, MD USA. Univ Alberta, Dept Math, Edmonton, AB, Canada. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Basist, A (reprint author), NOAA, Natl Climat Data Ctr, NESDIS, 151 Patton Ave,Rm 120, Asheville, NC 28801 USA. RI Ferraro, Ralph/F-5587-2010 OI Ferraro, Ralph/0000-0002-8393-7135 NR 28 TC 30 Z9 31 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 3 BP 297 EP 308 DI 10.1175/1525-7541(2001)002<0297:UTSSMI>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 447DQ UT WOS:000169554900006 ER PT J AU Walker, JP Willgoose, GR Kalma, JD AF Walker, JP Willgoose, GR Kalma, JD TI One-dimensional soil moisture profile retrieval by assimilation of near-surface measurements: A simplified soil moisture model and field application SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID WATER; HYDROLOGY; PARAMETERIZATION; VEGETATION; TERRAIN AB The Kalman filter assimilation technique is applied to a simplified soil moisture model for retrieval of the soil moisture profile from near-surface soil moisture measurements. First, the simplified soil moisture model is developed, based on an approximation to the Buckingham-Darcy equation. This model is then used in a 12-month one-dimensional field application, with updating at 1-, 5-, 10-, and 20- day intervals. The data used are for the Nerrigundah field site, New South Wales, Australia. This study has identified (i) the importance of knowing the depth over which the near-surface soil moisture measurements are representative (i.e., observation depth), (ii) soil porosity and residual soil moisture content as the most important soil parameters for correct retrieval of the soil moisture profile, (iii) the importance of a soil moisture model that represents the dominant soil physical processes correctly, and (iv) an appropriate forecasting model as far more important than the temporal resolution of near-surface soil moisture measurements. Although the soil moisture model developed here is a good approximation to the Richards equation, it requires a root water uptake term or calibration to an extreme drying event to model extremely dry periods at the field site correctly. C1 Univ Newcastle, Dept Civil Surveying & Environm Engn, Callaghan, NSW, Australia. RP Walker, JP (reprint author), Hydrol Sci Branch, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI Willgoose, Garry/A-1492-2008 OI Willgoose, Garry/0000-0001-5175-4935 NR 30 TC 69 Z9 69 U1 2 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 4 BP 356 EP 373 DI 10.1175/1525-7541(2001)002<0356:ODSMPR>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 461ZQ UT WOS:000170394100003 ER PT J AU Crawford, TM Stensrud, DJ Mora, F Merchant, JW Wetzel, PJ AF Crawford, TM Stensrud, DJ Mora, F Merchant, JW Wetzel, PJ TI Value of incorporating satellite-derived land cover data in MM5/PLACE for simulating surface temperatures SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID NUMERICAL WEATHER PREDICTION; LEAF-AREA INDEX; SOIL-MOISTURE; NOAA-AVHRR; BOUNDARY-LAYER; GLOBAL CHANGE; MODEL; VEGETATION; PARAMETERIZATION; SENSITIVITY AB The Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) module is used within the Fifth-Generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) to determine the importance of individual land surface parameters in simulating surface temperatures. Sensitivity tests indicate that soil moisture and the coverage and thickness of green vegetation [as manifested by the values of fractional green vegetation coverage (fVEG) and leaf area index (LAI)] have a large effect on the magnitudes of surface sensible heat fluxes. The combined influence of LAI and fVEG is larger than the influence of soil moisture on the partitioning of the surface energy budget. Values for fVEG, albedo, and LAI, derived from 1-km-resolution Advanced Very High Resolution Radiometer data, are inserted into PLACE, and changes in model-simulated 1.5-m air temperatures in Oklahoma during July of 1997 are documented. Use of the land cover data provides a clear improvement in afternoon temperature forecasts when compared with model runs with monthly climatological values for each land cover type. However, temperature forecasts from MM5 without PLACE are significantly more accurate than those with PLACE, even when the land cover data are incorporated into the model. When only the temperature observations above 37 degreesC are analyzed, however, the simulations from the high-resolution land cover dataset with PLACE significantly outperform MM5 without PLACE. Previous land surface models have simply used (at best) climatological values of these crucial land cover parameters. The ability to improve model simulations of surface energy fluxes and the resultant temperatures in a diagnostic sense provides promise for future attempts at ingesting satellite-derived land cover data into numerical models. These model improvements would likely be most helpful in predictions of extreme temperature events (during drought or extremely wet conditions) for which current numerical weather prediction models often perform poorly. The potential value of real-time land cover information for model initialization is substantial. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Nebraska, Ctr Adv Land Management Informat Technol, Lincoln, NE USA. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Stensrud, DJ (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 56 TC 40 Z9 43 U1 3 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 5 BP 453 EP 468 DI 10.1175/1525-7541(2001)002<0453:VOISDL>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 478MC UT WOS:000171349100002 ER PT J AU Koster, RD Suarez, MJ AF Koster, RD Suarez, MJ TI Soil moisture memory in climate models SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID LAND-ATMOSPHERE SYSTEM; SURFACE SCHEMES; SCALES; PREDICTABILITY; PRECIPITATION; PERSISTENCE AB Water balance considerations at the soil surface lead to an equation that relates the autocorrelation of soil moisture in climate models to 1) seasonality in the statistics of the atmospheric forcing, 2) the variation of evaporation with soil moisture, 3) the variation of runoff with soil moisture, and 4) correlation between the atmospheric forcing and antecedent soil moisture, as perhaps induced by land-atmosphere feedback. Geographical variations in the relative strengths of these factors, which can be established through analysis of model diagnostics, lead to geographical variations in simulated soil moisture memory. The use of the equation to characterize controls on soil moisture memory is demonstrated with data from the modeling system of the National Aeronautics and Space Administration Seasonal-to-Interannual Prediction Project. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Koster, RD (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Code 974, Greenbelt, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 21 TC 180 Z9 185 U1 5 U2 27 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PY 2001 VL 2 IS 6 BP 558 EP 570 DI 10.1175/1525-7541(2001)002<0558:SMMICM>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 503MF UT WOS:000172801700002 ER PT J AU Crucian, BE Stowe, RP Pierson, DL Sams, CF AF Crucian, BE Stowe, RP Pierson, DL Sams, CF TI Routine detection of Epstein-Barr virus specific T-cells in the peripheral blood by flow cytometry SO JOURNAL OF IMMUNOLOGICAL METHODS LA English DT Article ID CYTOKINE EXPRESSION; ACUTE INFECTION; IMMUNODEFICIENCY; FREQUENCIES; ACTIVATION; STRESS; CD4+ AB The ability to detect cytomegalovirus-specific T-cells (CD4(+)) in the peripheral blood by flow cytometry has been recently described by Picker et al. In this method, cells are incubated with viral antigen and responding (cytokine producing) T-cells are then identified by how cytometry. To date, this technique has not been reliably used to detect Epstein-Barr virus (EBV)-specific T-cells primarily due to the superantigen/mitogenic properties of the virus which non-specifically activate T-cells. By modifying culture conditions under which the antigens are presented, we have overcome this limitation and developed an assay to detect and quantitate EBV-specific T-cells. The detection of cytokine producing T-cells by Row cytometry requires an extremely strong signal (such as culture in the presence of PMA and ionomycin). Our data indicate that in modified culture conditions (early removal of viral antigen) the non-specific activation of T-cells by EBV is reduced, but antigen presentation will continue uninhibited. Using this method. EBV-specific T-cells may be legitimately detected using flow cytometry. No reduction in the numbers of antigen-specific T-cells was observed by the early removal of target antigen when verified using cytomegalovirus antigen (a virus with no non-specific T-cell activation properties). In EBV-seropositive individuals, the phenotype of the EBV-specific cytokine producing T-cells was evaluated using four-color flow cytometry and found to be CD45(+), CD3(+), CD4(+), CD45RA(-), CD69(+), CD25(-). This phenotype indicates the stimulation of circulating previously unactivated memory T-cells. No cytokine production was observed in CD4(+) T-cells from EBV-seronegative individuals, confirming the specificity of this assay. In addition, the use of four color cytometry (CD45, CD3, CD69, IFN gamma /IL-2) allows the total quantitative assessment of EBV-specific T-cells while monitoring the interference of EBV non-specific mitogenic activity. This method may have significant utility for the monitoring of the immune response to latent virus infection/reactivation. (C) 2001 Elsevier Science B.V. All rights reserved. C1 NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Wyle Labe, Cell & Mol Res Labs, Houston, TX USA. Univ Texas, Med Branch, Dept Pathol, Galveston, TX 77550 USA. RP Sams, CF (reprint author), NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Mail Code SD3, Houston, TX 77058 USA. NR 19 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1759 J9 J IMMUNOL METHODS JI J. Immunol. Methods PD JAN 1 PY 2001 VL 247 IS 1-2 BP 35 EP 47 DI 10.1016/S0022-1759(00)00326-4 PG 13 WC Biochemical Research Methods; Immunology SC Biochemistry & Molecular Biology; Immunology GA 393EA UT WOS:000166455200005 PM 11150535 ER PT J AU Hunter, SL AF Hunter, SL TI Ergonomic evaluation of manufacturing system designs SO JOURNAL OF MANUFACTURING SYSTEMS LA English DT Article DE manufacturing system design; ergonomics; lean production; cellular manufacturing; physiology; 3-D simulation AB Using high-level, 3-D computer graphics simulation and other engineering analysis tools, this research investigates the ergonomic advantages of one manufacturing system design over another. The designs compared are lean manufacturing (manufacturing cells) and the functional (job shop) design. Simulation models based on an actual manufacturing cell and its workers are used to generate corresponding functional workstations with identically modeled workers. Three ergonomic areas-kilocalorie expenditure, potential for harmful postures, and potential for repetitive motion disorders-are analyzed from simulated and monitored data on energy expenditure, postures, repetitive motion, and other processing functions, such as cycle time. Initial research indicates a substantially lower risk from work-related injuries when using the cellular manufacturing design rather than the functional job shop design; thus, the design of the manufacturing system may inherently reduce or eliminate physiological problems before they develop. In addition, 3-D simulation software with ergonomic analysis functions is shown to be an extremely effective tool for the manufacturing system designer and the ergonomist. C1 Mississippi State Univ, Forest Prod Lab, Starkville, MS 39759 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Hunter, SL (reprint author), Mississippi State Univ, Forest Prod Lab, Starkville, MS 39759 USA. NR 12 TC 5 Z9 5 U1 1 U2 9 PU SOC MANUFACTURING ENGINEERS PI DEARBORN PA ONE SME DRIVE, PO BOX 930, DEARBORN, MI 48121-0930 USA SN 0278-6125 J9 J MANUF SYST JI J. Manuf. Syst. PY 2001 VL 20 IS 6 BP 429 EP 444 DI 10.1016/S0278-6125(01)80062-5 PG 16 WC Engineering, Industrial; Engineering, Manufacturing; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 578DP UT WOS:000177102400006 ER PT J AU Troeger, LP Domack, MS AF Troeger, LP Domack, MS TI Microstructure and mechanical property characterization of Al-Cu-Mg-Ag alloy C415 shear formed cylinders SO JOURNAL OF MATERIALS PROCESSING & MANUFACTURING SCIENCE LA English DT Article AB Successful application of the shear forming method for production of large seamless cylinders can reduce production costs and increase the reliability of aerospace structural components through the reduction of material scrap and part count and the minimization of joints. The current research evaluates the applicability of shear forming to the Al-Cu-Nlg-Ag alloy C415, developed for airframe structure. The processing-microstructure-property relationships, are investigated for lab-scale shear formed C415 cylinders which had undergone various amounts of shear-forming strain. The grain structure, texture, and mechanical properties developed during and after shear forming are evaluated and compared with C415-T8 sheet. The cylinders exhibited a primarily recrystallized grain structure and weak texture. The grain size was fairly uniform through the thickness for low levels of shear-forming strain, However, at higher levels of strain, a bimodal grain size distribution developed. Room-temperature T8 yield and ultimate tensile strengths were comparable to C415-T8 sheet. C1 NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 1062-0656 J9 J MATER PROCESS MANU JI J. Mater. Process. Manuf. Sci. PD JAN PY 2001 VL 9 IS 3 BP 180 EP 204 DI 10.1106/6MME-UYUL-D9GG-7VYX PG 25 WC Materials Science, Multidisciplinary SC Materials Science GA 552VG UT WOS:000175640300002 ER PT J AU Troeger, LP Wagner, JA AF Troeger, LP Wagner, JA TI Microstructure and mechanical property characterization of shear formed Al-Li alloy 2195 for launch vehicle applications SO JOURNAL OF MATERIALS PROCESSING & MANUFACTURING SCIENCE LA English DT Article AB Advanced manufacturing processes such as near-net-shape forming can reduce production costs and increase the reliability of launch vehicle and airframe structural components through the reduction of material scrap and part count and the minimization of structural joints. The current research is an investigation of the evolution of grain structure, texture, and tensile properties of shear formed Al-Li alloy 2195 cylinders for launch vehicle applications. The cylinders were characterized after various amounts of shear-forming strain using optical metallographic techniques, orientation distribution function (ODF) analysis and standard tensile tests. The cylinders exhibited a fairly homogeneous microstructure and nearly random texture for low levels of shear forming strain. The grain structure became increasingly inhomogeneous as shear-forming strain increased, accompanied by an increase in overall texture intensity and the development of an FCC-type deformation texture. The tensile strength increased with shear-fort-ning strain, while the ductility decreased. It is emphasized that these results are for the first full-scale shear formed Al-Li test article. As such, the microstructure and propel-ties have not yet been optimized through modifications to the shear-forming and secondary processing parameters. C1 NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 1062-0656 J9 J MATER PROCESS MANU JI J. Mater. Process. Manuf. Sci. PD JAN PY 2001 VL 9 IS 3 BP 205 EP 222 DI 10.1106/W850-RPV0-J1D1-2HGL PG 18 WC Materials Science, Multidisciplinary SC Materials Science GA 552VG UT WOS:000175640300003 ER PT J AU Coon, DN Calomino, AM AF Coon, DN Calomino, AM TI Monte Carlo simulation of fatigue of a fibre tow undergoing chemical reaction SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID SILICON-CARBIDE-FIBER; GLASS-CERAMIC COMPOSITES; MATRIX COMPOSITE; TEMPERATURE FATIGUE; STRENGTH; DEGRADATION; MECHANISMS; TENSILE AB Monte Carlo simulation has been used to model environmental attack of a fibre tow, and suggested that such attack could lead to fatigue-type behaviour under static load conditions. The system was assumed to be fibre dominated with the presence of matrix cracks relaxing stress in the matrix and providing a path for environmental species to reach the fibres. Lifetime under load was related to the fibre-environment reaction rate and distribution of forces from broken fibres. Fatigue exponents ranging from 1.0 to 1.5 were predicted for selected reaction rates at stress levels less than 140 MPa. Simulation results were compared with literature data, and predicted fatigue exponents were substantially lower than those observed experimentally. This result could suggest that fibre-environment chemical reaction was not the sole mechanism operable in experiments. However, it was suggested that a stress dependent reaction rate could be used to improve the correlation between the simulation and experimental results. (C) 2001 Kluwer Academic Publishers. C1 Univ Wyoming, Laramie, WY 82071 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Coon, DN (reprint author), Univ Wyoming, Laramie, WY 82071 USA. NR 40 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PY 2001 VL 36 IS 11 BP 2597 EP 2605 DI 10.1023/A:1017931906352 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 434VW UT WOS:000168837400002 ER PT J AU Chernov, AA AF Chernov, AA TI Crystal growth science between the centuries SO JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS LA English DT Article; Proceedings Paper CT Annual Conference of the British-Association-for-Crystal-Growth (BACG) CY SEP, 2000 CL UNIV MANCHESTER, INST SCI TECH, MANCHESTER, ENGLAND SP British Assoc Crystal Growth HO UNIV MANCHESTER, INST SCI TECH ID SURFACE-MORPHOLOGY; LYSOZYME CRYSTALS; MELT INTERFACE; STEP; KINETICS; FACE; STABILITY; CRYSTALLIZATION; INSTABILITY; TRANSITION AB The major framework of crystal growth concepts and technologies was built during the 20th century. This solid framework, however, does not have enough predictive power. The lack of fundamental constants, multi-parametric experimental conditions, and complex chemistry in many systems remain obstacles to the quantitative confrontation of many key concepts with experiment, to make them predictive and to develop these concepts further. In addition, at least several generic issues should be addressed. For instance, the BCF theory is based on the assumption that thermodynamic fluctuations at steps are fast enough to generate a sufficient density of kinks for growth. However, for strongly polygonized steps this is not always the case. Also, for these steps, the Gibbs-Thomson relationship may be valid only within a very low supersaturation range. These problems are considered here. The Kossel model should be generalized for the lattices of which unit cells include several, say, n identical molecules, atoms, or ions in crystallographically inequivalent positions. In this case, only the unit cell as a whole makes a self-reproducible kink while the building blocks in the liquid or gas are the component molecules, atoms or ions. Because of this, the driving force for crystallization takes the same form as that in a system of n components. Therefore even the kink rate is proportional to C-n-C-e(n) rather than to C-C-e where C and C-e are actual and equilibrium concentrations, respectively. Finally, the challenges of biomacromolecular crystallization are discussed. (C) 2001 Kluwer Academic Publishers. C1 NASA, Univ Space Res Assoc, George C Marshall Space Flight Ctr, Huntsville, AL 35806 USA. RP Chernov, AA (reprint author), NASA, Univ Space Res Assoc, George C Marshall Space Flight Ctr, 4950 Corp Dr,Suite 100, Huntsville, AL 35806 USA. NR 70 TC 46 Z9 46 U1 1 U2 17 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0957-4522 J9 J MATER SCI-MATER EL JI J. Mater. Sci.-Mater. Electron. PY 2001 VL 12 IS 8 BP 437 EP 449 DI 10.1023/A:1011839431276 PG 13 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 473TJ UT WOS:000171063900004 ER PT J AU Drouin, BJ Miller, CE Muller, HSP Cohen, EA AF Drouin, BJ Miller, CE Muller, HSP Cohen, EA TI The rotational spectra, isotopically independent parameters, and interatomic potentials for the X-1 (2)Pi(3/2) and X-2 (2)Pi(1/2) states of BrO SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ELECTRON RESONANCE SPECTRA; DIATOMIC-MOLECULES; MICROWAVE SPECTROSCOPY; INFRARED MEASUREMENTS; LASER SPECTROSCOPY; AB-INITIO; TRANSITION; CLO; IO; ABSORPTION AB Observations of the rotational spectrum of BrO have been extended to include vibrational levels up to v = 8 in the X-1 (2)Pi (3/2) and v = 7 in the X-2 (2)Pi (1/2) states. The rotational spectra of isotopically enriched (BrO)-O-18, X-1, v = 0, 1 and X-2, v = 0 have been observed as well. The spectra of all four isotopic species have been fit to a Hamiltonian in which the parameters have fixed isotopic ratios. An extensive set of isotopically independent parameters has been determined. Interatomic potentials have been derived for both the X-1 and X-2 states. The hyperfine constants and their vibrational dependencies have been determined more precisely and several of them have been determined for the first time. These are interpreted in terms of the electronic structure of the molecule. The isotope relations among the constants have provided a means of decorrelating the electron spin-rotation constant gamma from the fine-structure centrifugal distortion constant, A(D), and have allowed the first determination of an effective value for gamma. (C) 2001 Academic Press. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Haverford Coll, Dept Chem, Haverford, PA 19041 USA. RP Drouin, BJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 49 TC 52 Z9 52 U1 1 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JAN PY 2001 VL 205 IS 1 BP 128 EP 138 DI 10.1006/jmsp.2000.8252 PG 11 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 393YM UT WOS:000166497300018 ER PT J AU Wang, LP Koblinsky, CJ Howden, S AF Wang, LP Koblinsky, CJ Howden, S TI Annual Rossby wave in the southern Indian Ocean: Why does it "appear" to break down in the middle ocean? SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SHALLOW-WATER SIMULATIONS; SEA-LEVEL VARIATIONS; NORTH PACIFIC OCEAN; SEASONAL-VARIATIONS; CIRCULATION MODEL; EL-NINO; GEOSAT; THROUGHFLOW; ALTIMETRY; VARIABILITY AB Using both altimetry data (TOPEX/Poseidon and Geosat) and Levitus climatology and a linear reduced-gravity model, the authors studied the annual Rossby waves in the southern Indian Ocean from 19 degrees to 9 degreesS. The most striking feature from the data analysis is that the westward phase propagation of the annual variability appears to break up in the midocean, which results in two local maxima for annual variability in both the sea level and the depth of the 18 degreesC isotherm, with one in the eastern basin and the other in the western basin. Separating the two maxima is a midocean minimum. Decomposition of the annual variability into Rossby waves and localized response indicates that the two local maxima of the annual variability simply result from the constructive interference between the localized response and the Rossby waves in the eastern and western basin. On the other hand, the midocean local minimum results from the destructive interference between the Rossby waves and the localized response. Modeling results suggest that the bulk of the annual variability in the study domain is driven by wind forcing, while forcing by throughflow through eastern boundary radiation is of minor importance. Dissipation is found to have a much greater impact on the Rossby waves than on the local response. C1 Univ Maryland, ESSIC, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Ocean & Ice Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Wang, LP (reprint author), Univ Maryland, ESSIC, College Pk, MD 20742 USA. NR 35 TC 25 Z9 26 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 1 BP 54 EP 74 DI 10.1175/1520-0485(2001)031<0054:ARWITS>2.0.CO;2 PG 21 WC Oceanography SC Oceanography GA 393ND UT WOS:000166475800004 ER PT J AU Chen, W Banner, ML Walsh, EJ Jensen, JB Lee, SH AF Chen, W Banner, ML Walsh, EJ Jensen, JB Lee, SH TI The Southern Ocean Waves Experiment. Part II: Sea surface response to wind speed and wind stress variations SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID PLANETARY BOUNDARY-LAYER; SYNTHETIC-APERTURE RADAR; ROLL VORTICES; NUMBER SPECTRA; TURBULENCE; SATELLITE; WATER; AIRCRAFT; IMAGERY AB The Southern Ocean Waves Experiment (SOWEX) was an international collaborative air-sea interaction experiment in which a specially instrumented meteorological research aircraft simultaneously gathered marine boundary-layer atmospheric turbulence data and sea surface roughness data over the Southern Ocean, particularly for gale-force wind conditions. In this paper analysis and findings are presented on key aspects of the coupled variability of the wind field, the wind stress, and the underlying sea surface roughness. This study complements the overview, methodology, and mean results published in Part I. Weakly unstable atmospheric stratification conditions prevailed during SOWEX, with wind speeds ranging from gale force to light and variable. Throughout the SOWEX observational period, the wind field was dominated by large-scale atmospheric roll-cell structures, whose height scale was comparable with the thickness of the marine atmospheric boundary layer (MABL). Well above the sea surface, these coherent structures provide the dominant contribution to the downward momentum flux toward the sea surface. Closer to the sea surface, these organized large-scale structures continued to make significant contributions to the downward momentum flux, even within a few tens of meters of the sea surface. At the minimum aircraft height, typical cumulative stress cospectra indicated that 10-km averages along crosswind tracks appeared adequate to close the stress cospectrum. Nevertheless, a large-scale spatial inhomogeneity in the wind stress vector was observed using 10- and 20-km spatial averaging intervals on one of the strongest wind days when the mean wind field was close to being spatially uniform. This indicates a departure from the familiar drag coefficient relationship and implies large-scale transverse modulations in the MABL with an effective horizontal to vertical aspect ratio of around 20. A high visual correlation was found between mean wind speed variations and collocated sea-surface mean square slope (mss) variations, averaged over 1.9 km. A comparable plot of the 10-km running average of the downward momentum flux, observed at heights from 30 to 90 m, showed appreciably lower visual correlation with the wind speed variations and mss variations. The 10-20 km averaging distance needed to determine the wind stress was larger than the local scale of variation of the mss roughness variations. It also exceeded the scale of the striations often observed in synthetic aperture radar imagery under unstable atmospheric conditions and strong wind forcing. This highlights an overlooked intrinsic difficulty in using the friction velocity as the wind parameter in models of the wind wave spectrum, especially for the short wind wave scales. C1 Univ New S Wales, Sch Math, Sydney, NSW 2052, Australia. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Wallops Island, VA 23337 USA. CSIRO Atmospher Res, Aspendale, Vic, Australia. RP Banner, ML (reprint author), Univ New S Wales, Sch Math, Sydney, NSW 2052, Australia. RI Jensen, Jorgen/C-9211-2009; OI Banner, Michael/0000-0002-0799-5341 NR 35 TC 12 Z9 12 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 1 BP 174 EP 198 DI 10.1175/1520-0485(2001)031<0174:TSOWEP>2.0.CO;2 PG 25 WC Oceanography SC Oceanography GA 393ND UT WOS:000166475800011 ER PT J AU Nakamura, M Chao, Y AF Nakamura, M Chao, Y TI Diagnoses of an eddy-resolving Atlantic Ocean model simulation in the vicinity of the Gulf Stream. Part I: Potential vorticity SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID QUASI-GEOSTROPHIC OCEAN; NORTH-ATLANTIC; GENERAL-CIRCULATION; HORIZONTAL RESOLUTION; BOUNDARY CURRENTS; CAPE HATTERAS; DYNAMICS; EDDIES; THERMOCLINE; ANOMALIES AB Output of an eddy-resolving model of the North Atlantic is diagnosed in the vicinity of the Gulf Stream (GS), using quasigeostrophic potential vorticity (QGPV), Ertel's potential vorticity (PV), and particle trajectories. Time series of QGPV show strong input of QGPV by the GS in the top 1000 m of the model ocean. Vigorous wave motions are observed in the vicinity of the model GS, mixing QGPV in the region. The time-mean horizontal QGPV structures show qualitative similarity to those of large-scale climatological PV calculated from hydrographic data by Keffer and that of Lozier. The top 1000 m of the model ocean is characterized by a tongue or an elongated island of high mean QGPV along the GS. It is demonstrated that the tongue is a product of strong QGPV input by the GS, vigorous mixing by eddies, and dissipation of QGPV along the path of the GS. At the intermediate depths, 1000-2500 m, a large region of nearly homogenized mean PV or weakly varying mean QGPV is found to the west of the Mid-Atlantic Ridge. It is located undernearth a region of strong near-surface eddy activity and is in qualitative agreement with a deep and large pool of nearly homogenized PV recently found by Lozier. Below the pool of nearly homogenized PV or weakly varying QGPV, the mean PV and QGPV show substantial horizontal gradient and some vertical gradient at deep levels. This structure is in qualitative agreement with results of idealized model experiments and a theory of baroclinic neutrality of the midlatitude atmosphere proposed by Lindzen that may well apply to this oceanic region of strong baroclinic wave activity. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Mail Stop 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM moto@pacific.jpl.nasa.gov NR 54 TC 7 Z9 7 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 EI 1520-0485 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 2 BP 353 EP 378 DI 10.1175/1520-0485(2001)031<0353:DOAERA>2.0.CO;2 PG 26 WC Oceanography SC Oceanography GA 404RH UT WOS:000167114100004 ER PT J AU Fu, LL Cheng, B Qiu, B AF Fu, LL Cheng, B Qiu, B TI 25-day period large-scale oscillations in the argentine basin revealed by the TOPEX/Poseidon altimeter SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID DRIVEN CURRENT FLUCTUATIONS; SATELLITE ALTIMETRY; SOUTHWESTERN ATLANTIC; MALVINAS CURRENTS; NORTH-ATLANTIC; SOUTH-ATLANTIC; VARIABILITY; PACIFIC; CIRCULATION; OCEAN AB The measurement of the global sea surface height made by the TOPEX/Poseidon satellite has provided the first synoptic view of large-scale oceanic variability at intraseasonal scales from weeks to months. Areas of significant intraseasonal variability were found primarily in the Tropics and the high-latitude oceans, the Southern Ocean in particular. The focus of the paper is the finding of large-scale oscillations at a period of 25 days in the Argentine Basin of the South Atlantic Ocean. These oscillations exhibit a dipole pattern of counterclockwise rotational propagation centered at 45 degreesS, 317 degreesE over the Zapiola Rise. The scale of the dipole is about 1000 km. The peak-to-trough amplitude is on the order of 10 cm. The amplitude of these oscillations has large seasonal-to-interannual variations. These oscillations are shown to be associated with a free barotropic mode of the basin as a solution to a linearized barotropic vorticity equation. Closed f/H contours provide a mechanism for the confinement of the waves to the topographic feature of the Zapiola Rise. Results from a numerical model simulation reproduced the patterns of the observed oscillations. The resultant mass transport variability is on the order of 50 Sv (Sv = 10(6) m(3) s(-1)). Deep current meters in the Argentine Basin reveal signals consistent with the altimetry observations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. RP Fu, LL (reprint author), CALTECH, Jet Prop Lab, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Qiu, Bo/D-9569-2017 NR 36 TC 34 Z9 35 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 2 BP 506 EP 517 DI 10.1175/1520-0485(2001)031<0506:DPLSOI>2.0.CO;2 PG 12 WC Oceanography SC Oceanography GA 404RH UT WOS:000167114100012 ER PT J AU Canuto, VM Howard, A Cheng, Y Dubovikov, MS AF Canuto, VM Howard, A Cheng, Y Dubovikov, MS TI Ocean turbulence. Part I: One-point closure model - Momentum and heat vertical diffusivities SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID GENERAL-CIRCULATION MODEL; LARGE-EDDY SIMULATION; MIXED-LAYER; DYNAMICAL MODEL; BOUNDARY-LAYER; ENERGY-MODEL; GEOPHYSICAL FLOWS; SHEAR; DISSIPATION; BUOYANCY AB Ocean mixing processes have traditionally been formulated using one-point turbulence closure models, specifically the Mellor and Yamada (MY) models, which were pioneered in geophysics using 1980 state-of-the-art turbulence modeling. These models have been widely applied over the years, but the underlying core physical assumptions have hardly improved since the 1980s; yet, in the meantime, turbulence modeling has made sufficient progress to allow four improvements to be made. 1) The value of Ri(cr). MY-type models yield a low value for the critical Richardson number, Ri(cr) = 0.2 (the result of linear stability is Ri(cr) = 1/ 4). On the other hand, nonlinear stability analysis, laboratory measurements, direct numerical simulation, large eddy simulation, and mixed layer studies indicate that Ri(cr) similar to1. The authors show that by improving the closure for the pressure correlations, the result Ri(cr) similar to 1 naturally follows. 2) Nonlocal, third-order moments (TOMs). The downgradient approximation used in all models thus far seriously underestimates the TOMs. A new expression that includes both stratification and shear is presented here for the first time. It is obtained by solving the dynamic equations for the third-order moments. 3) Rotation. The MY-type models with rotation assume that the latter does not affect turbulence, specifically, neither the pressure correlations nor the rate of dissipation of turbulent kinetic energy. Recent studies show that both quantities are affected. 4) Mixing below the mixed layer. Thus far, the momentum and heat diffusivities below the mixed layer have been treated as adjustable parameters. A new model that allows use of the same turbulence model throughout the ocean depth is proposed. A new model is presented that includes 1), 2), and 4). Rotation will be dealt with in a subsequent paper. The new model is fully algebraic and easy to use in an ocean code. The new model is used in an OGCM, and the predicted global temperature and salinity profiles are compared with those of the KPP model and Levitus data. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 60 TC 282 Z9 292 U1 2 U2 20 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 6 BP 1413 EP 1426 DI 10.1175/1520-0485(2001)031<1413:OTPIOP>2.0.CO;2 PG 14 WC Oceanography SC Oceanography GA 443UR UT WOS:000169360500002 ER PT J AU Wright, CW Walsh, EJ Vandemark, D Krabill, WB Garcia, AW Houston, SH Powell, MD Black, PG Marks, FD AF Wright, CW Walsh, EJ Vandemark, D Krabill, WB Garcia, AW Houston, SH Powell, MD Black, PG Marks, FD TI Hurricane directional wave spectrum spatial variation in the open ocean SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article AB The sea surface directional wave spectrum was measured for the first time in all quadrants of a hurricane's inner core over open water. The NASA airborne scanning radar altimeter (SRA) carried aboard one of the NOAA WP-3D hurricane research aircraft at 1.5-km height acquired the open-ocean data on 24 August 1998 when Bonnie, a large hurricane with 1-min sustained surface winds of nearly 50 m s(-1), was about 400 km east of Abaco Island, Bahamas. The NOAA aircraft spent more than five hours within 180 km of the eye and made five eye penetrations. Grayscale coded images of Hurricane Bonnie wave topography include individual waves as high as 19 m peak to trough. The dominant waves generally propagated at significant angles to the downwind direction. At some positions, three different wave fields of comparable energy crossed each other. Partitioning the SRA directional wave spectra enabled determination of the characteristics of the various components of the hurricane wave field and mapping of their spatial variation. A simple model was developed to predict the dominant wave propagation direction. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. USA, Engineer Res & Dev Ctr, Vicksburg, MS USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Wright, CW (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Code 972, Wallops Isl, VA 23337 USA. RI Marks, Frank/A-5733-2011; Powell, Mark/I-4963-2013 OI Marks, Frank/0000-0003-0371-5514; Powell, Mark/0000-0002-4890-8945 NR 19 TC 78 Z9 80 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 8 BP 2472 EP 2488 DI 10.1175/1520-0485(2001)031<2472:HDWSSV>2.0.CO;2 PG 17 WC Oceanography SC Oceanography GA 461ZR UT WOS:000170394200032 ER PT J AU Chao, Y Lozier, MS AF Chao, Y Lozier, MS TI Evaluation of North Atlantic property field simulations at 1/6 degrees SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID GLOBAL OCEAN CIRCULATION; NUMERICAL-SIMULATION; MODEL; WATER; RESOLUTION; SECTION; EQUATOR; EDDIES; SYSTEM AB One way to measure the skill of an ocean general circulation model is to evaluate its ability to simulate observed property distributions. Pressure, temperature, and salinity distributions generated by a 1/6 degrees Atlantic Ocean general circulation model are compared with climatological fields on three potential density surfaces, representative of the upper, middepth, and deep ocean waters. The upper ocean property fields are relatively well simulated, a testimony to the model's ability to generally reproduce the wind-driven circulation in the North Atlantic. However, in the middepth and deep ocean, where wind forcing is negligible and buoyant flows associated with deep-water formation play a major role in establishing property distributions, the fields are poorly represented in the 1/6 degrees Atlantic Ocean model. The comparison between the observed and modeled fields indicates several model deficiencies in the representation of intermediate and deep waters and their pathways. Possible model improvements to reduce the mismatch between model and data are proposed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Duke Univ, Durham, NC USA. RP Chao, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-323, Pasadena, CA 91109 USA. NR 36 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PY 2001 VL 31 IS 11 BP 3200 EP 3213 DI 10.1175/1520-0485(2001)031<3200:EONAPF>2.0.CO;2 PG 14 WC Oceanography SC Oceanography GA 487NK UT WOS:000171881400005 ER PT J AU Krizek, DT Middleton, EM Sandhu, RK Kim, MS AF Krizek, DT Middleton, EM Sandhu, RK Kim, MS TI Evaluating UV-B effects and EDU protection in cucumber leaves using fluorescence images and fluorescence emission spectra SO JOURNAL OF PLANT PHYSIOLOGY LA English DT Article DE blue, green, red and far-red fluorescence; cucumber (Cucumis sativus L.); EDU; fluorescence imaging; fluorescence ratios red/green; blue/far-red; UV/blue; far-red/red; plant stress; UV-B ID CHLOROPHYLL FLUORESCENCE; RATIO F690/F730; SOYBEAN LEAVES; PISUM-SATIVUM; PLANT-LEAVES; GROWTH; PHOTOSYNTHESIS; STRESS; OZONE; ETHYLENEDIUREA AB A newly developed laboratory fluorescence imaging system was used to obtain fluorescence images (Flmage) of freshly excised cucumber (Cucumis sativus L.) leaves in spectral bands centered in the blue (F450), green (F550), red (F680), and far-red (F730) spectral regions that resulted from a broad-band (300-400 nm) excitation source centered at 360 nm. Means of relative fluorescence intensities (RFI) from these spectral fluorescence images were compared with spectral fluorescence emission data obtained from excitation wavelengths at 280 nm (280EX, 300-550 nm) and 380 nm (380EX, 400-800 nm) of dimethyl sulfoxide (DMSO) extracts from these leaves. All three fluorescence data types (Flmage, 280EX, 380 EX) were used to assess ultraviolet-B (UV-B, 280-320 nm) induced physiological changes and the possible use of N-[2-(2-oxo-1-imidazolidinyl) ethyl]-N'-phenylurea (EDU or ethylenediurea) as a chemical protectant against UV-B damage. Plants exhibited well known foliar growth and pigment responses to UV-B exposure (e.g., increased UV-B absorbing compounds and decreased leaf area, chlorophyll a content; and and lower chlorophyll a/b and chlorophyll/carotenoid pigment ratios). Since EDU alone had no effect on foliar variables, there was no evidence that EDU afforded protection against UV-B. Instead, EDU augmented some UV-B effects when provided in conjunction with UV-B irradiation (e.g., reductions in the chlorophyll/carotenoid ratio, total photosynthetic pigments, and chlorophyll b content). Relative fluorescence intensities (RFI) in the longer visible wavelengths (green, red, and far-red) were uncorrelated for comparisons between the Flmage and 380EX data sets. However, blue and green RFI were significantly correlated (0.8>r>0.6; P<0.002) for comparisons between Flmage and 280EX data sets. UV-B treatment caused an increase in blue RFI (e.g., F450) in both images and 280EX measurements. One explanation is that the UV-B excitation of both 280EX and Flmage stimulates processes that produce excess blue fluorescence The molecules that produce the excess blue fluorescence in both the 280EX and the Flmage data are different electron transfer agents that operate in parallel. For Flmage, the UV excitation penetrates leaf surface layers to stimulate fluorescence from compounds in mesophyll and epidermal tissues las occurs for the extracts of leaf discs),whereas emissions captured at longer, less energetic wavelengths, were primarily from the epidermal layer UV-B irradiated leaves showed much greater heteorgeneity of RFI in both the green (F550(Flmag)) and the red (F680(Flmag)) bands than unirradiated leaves; this was true irrespective of EDU treatment. Although qualitative responses in individual bands differed between Flmage and 380EX data, similar results were obtained in the detection of UV-B induced effects when the red/green and blue/far-red fluorescence ratios of these data were compared. The red/green ratio (either F680/F550(Flmage) or F675/F525(380EX)) was lower for UV-B exposed plants in both images and 380EX data. UV-B exposure also significantly enhanced the blue/far-red ratio of images (F450/F740(Flmage)) and the comparable 380EX ratio (F450/F730(380EX)) for the combined UV-B/EDU group, The far-red/red ratios were not useful in separating treatment effects in images or 380EX. Although comparable ratios were not available in 280EX data, the UV/blue ratio (F315/F420(280EX)) was substantially reduced by UV-B exposure and was inversely related to total photosynthetic pigment content. These findings suggest that the red/green ratio (Flmage, 380EX) and the UV/blue ratio (280EX) may be as useful as the blue/far-red ratio (380EX) reported previously in detection of UV-B stress. Furthermore, the results support the validity of the imaging technique as a non-destructive diagnostic tool for assessing UV-8 stress damage in plants. C1 USDA ARS, Climate Stress Lab, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Troy State Univ, Dept Environm Anal & Management, Troy, AL 36092 USA. RP Krizek, DT (reprint author), USDA ARS, Climate Stress Lab, Beltsville, MD 20705 USA. EM dkrizek@asrr.arsusda.gov RI Strid, Ake/E-5309-2012 OI Strid, Ake/0000-0003-3315-8835 NR 46 TC 12 Z9 14 U1 2 U2 17 PU ELSEVIER GMBH, URBAN & FISCHER VERLAG PI JENA PA OFFICE JENA, P O BOX 100537, 07705 JENA, GERMANY SN 0176-1617 J9 J PLANT PHYSIOL JI J. Plant Physiol. PD JAN PY 2001 VL 158 IS 1 BP 41 EP 53 DI 10.1078/0176-1617-00226 PG 13 WC Plant Sciences SC Plant Sciences GA 401PY UT WOS:000166938400006 ER PT J AU Wehrmeyer, JA Cramer, JM Eskridge, RH Dobson, CC AF Wehrmeyer, JA Cramer, JM Eskridge, RH Dobson, CC TI Development of ultraviolet Raman diagnostics for rocket engine injector analysis SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 33rd Joint Propulsion Conference and Exhibit CY JUL 06-09, 1997 CL SEATTLE, WA SP Amer Inst Aeronaut & Astronaut, ASME, SAE, ASEE ID SCATTERING; FLAME; OZONE AB The development of a laser-based combustion diagnostics system and its application to the analysis of a high-pressure rocket engine injector flowfield are described, One dimensionally spatially resolved (linewise), multispecies, single-pulse images are obtained with an imaging spectrograph/digital camera detection setup that images spontaneous vibrational Raman light scattering caused by a pulsed ultraviolet laser, used to enhance Raman signal strength by the inverse fourth power of laser wavelength scaling for Raman scattering cross sections. These images provide temporally and spatially resolved qualitative information about the presence of gaseous major species (water vapor and molecular hydrogen, nitrogen, and oxygen) during a hot-fire, high-pressure (6.04-MPa) test of a single-element liquid oxygen/gaseous hydrogen swirled injector operating at a high oxidizer/fuel mixture ratio (100) in a test article pressurized by a nitrogen coflow. Raman images, taken every 40 ms, are generally uncorrelated with respect to each other during the constant pressure, main-stage portion of the test, but occasionally temporally adjacent image pairs are correlated, suggesting large-scale motion in the dow, possibly from transverse movements of the reactant jet within the diluent coflow. Simultaneous measurements of major species show unburnt ignitor gas (hydrogen) during the startup transient and excess diluent (nitrogen) during the shutdown transient, along with significant variations in the oxygen/nitrogen ratio during the test. Stimulated Raman and ozone production problems are investigated. C1 NASA, George C Marshall Space Flight Ctr, Prop Lab, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. RP Vanderbilt Univ, Dept Mech Engn, Box 1592 Stn B, Nashville, TN 37235 USA. NR 24 TC 5 Z9 5 U1 0 U2 0 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 EI 1533-3876 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 2001 VL 17 IS 1 BP 27 EP 34 DI 10.2514/2.5703 PG 8 WC Engineering, Aerospace SC Engineering GA 393FG UT WOS:000166458100003 ER PT J AU Gorrell, SE Copenhaver, WW Chriss, RM AF Gorrell, SE Copenhaver, WW Chriss, RM TI Upstream wake influences on the measured performance of a transonic compressor stage SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID ROTOR AB The influence of an upstream wake on the performance of a downstream compressor stage with transonic inlet conditions is studied. Experimental results from fixed plane compressor exit instrumentation show that deep wakes, representative of heavily loaded stator wakes, persist further downstream than anticipated. The influences of the upstream wakes are aliased into a typical stator pitch held, thus magnifying their "true" influence. Results also show that reducing the axial spacing between the upstream stator blade-row and downstream rotor blade-row reduced the overall performance suggesting that mechanisms other than wake recovery are present for this compressor. This change in performance was determined to be associated with the upstream stator wakes. The work presented herein shows that the stator/rotor interaction is significant and should be accounted for in the design, testing, and analysis of transonic axial compressors. C1 USAF, Res Lab, Prop Directorate, Wright Patterson AFB, OH 45433 USA. NASA, John H Glenn Res Ctr, Res & Technol Directorate, Cleveland, OH 44135 USA. RP Gorrell, SE (reprint author), USAF, Res Lab, Prop Directorate, Wright Patterson AFB, OH 45433 USA. NR 13 TC 19 Z9 20 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 2001 VL 17 IS 1 BP 43 EP 48 DI 10.2514/2.5705 PG 6 WC Engineering, Aerospace SC Engineering GA 393FG UT WOS:000166458100005 ER PT J AU Patnaik, SN Guptill, JD Hopkins, DA Lavelle, TM AF Patnaik, SN Guptill, JD Hopkins, DA Lavelle, TM TI Optimization for aircraft engines with regression and neural-network analysis approximators SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The NASA Engine Performance Program (NEPP) can configure and analyze almost any type of gas-turbine engine that can be generated through the interconnection of a set of standard physical components, In addition, the code can optimize engine performance by changing adjustable variables under a set of constraints, For engine-cycle problems at certain operating points, the NEPP code can encounter difficulties: nonconvergence in Powell's optimization algorithm and deficiencies in the Newton-Raphson solver during engine balancing. A project was undertaken to correct the deficiencies, Nonconvergence was avoided through a cascade optimization strategy. Deficiencies associated with engine balancing were eliminated through neural-network and linear-regression methods. An approximation-interspersed cascade strategy was used to optimize engine operation over the Right envelope. Replacement of Powell's algorithm by the cascade strategy improved the optimization segment of the NEPP code. The performance of the linear-regression and neural-network methods as alternate engine analyzers was found to be satisfactory. The paper illustrates the results and insights gained from the improved version of the NEPP code considering two examples: a supersonic mixed-flow turbofan engine and a subsonic waverotor-topped engine. C1 NASA, John H Glenn Res Ctr Lewis Field, Computat Sci Branch, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Brookpark, OH 44142 USA. NASA, John H Glenn Res Ctr Lewis Field, Machine Dynam Branch, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr Lewis Field, Prop Syst Anal Off, Cleveland, OH 44135 USA. RP NASA, John H Glenn Res Ctr Lewis Field, Computat Sci Branch, MS 49-8, Cleveland, OH 44135 USA. NR 19 TC 3 Z9 3 U1 1 U2 1 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 EI 1533-3876 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 2001 VL 17 IS 1 BP 85 EP 92 DI 10.2514/2.5711 PG 8 WC Engineering, Aerospace SC Engineering GA 393FG UT WOS:000166458100011 ER PT J AU Korte, JJ Salas, AO Dunn, HJ Alexandrov, NM Follett, WW Orient, GE Hadid, AH AF Korte, JJ Salas, AO Dunn, HJ Alexandrov, NM Follett, WW Orient, GE Hadid, AH TI Multidisciplinary approach to linear aerospike nozzle design SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 34th Joint Propulsion Conference and Exhibit CY JUL 12-15, 1998 CL CLEVELAND, OHIO SP AIAA, ASME, SAE, ASEE AB A model of a linear aerospike rocket nozzle that consists of coupled aerodynamic and structural analyses has been developed. A nonlinear computational fluid dynamics code is used to calculate the aerodynamic thrust, and a three-dimensional finite element model is used to determine the structural response and weight. The model will be used to demonstrate multidisciplinary design capabilities for relevant engine concepts, assess performance of various multidisciplinary design approaches, and provide a guide for future application development. In this study, the multidisciplinary design problem is formulated using the multidisciplinary feasible strategy, The results For the multidisciplinary feasible formulation are presented with comparisons against sequential aerodynamic and structural designs. Significant improvements are demonstrated by using a multidisciplinary approach in comparison with the single-discipline design strategy. C1 NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23681 USA. Boeing N Amer, Rocketdyne Div, Canoga Park, CA 91309 USA. RP Korte, JJ (reprint author), NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Mail Stop 159, Hampton, VA 23681 USA. NR 27 TC 8 Z9 8 U1 1 U2 8 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 2001 VL 17 IS 1 BP 93 EP 98 DI 10.2514/2.5712 PG 6 WC Engineering, Aerospace SC Engineering GA 393FG UT WOS:000166458100012 ER PT J AU Rai, MM Madavan, NK AF Rai, MM Madavan, NK TI Application of artificial neural networks to the design of turbomachinery airfoils SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT 36th Aerospace Sciences Meeting and Exhibit CY JAN 12-15, 1998 CL RENO, NEVADA AB The feasibility of applying artificial neural networks to the aerodynamic design of turbomachinery airfoils is investigated. The design process involves defining a target pressure distribution, computing several flows to adequately populate the design space in the vicinity of the target, training the neural network with this data, and, finding a design that has a pressure distribution that is closest to the target. The last step is carried out using the network as a function evaluator. This design process is tested using an established how simulation procedure, a simple two-layer feedforward network and a conjugate gradient optimization technique, Results are presented for some validation tests as well as a complete design effort where the pressure distribution from a modern Pratt and Whitney turbine was used as a target. These results are very encouraging and clearly warrant further development of the process for full three-dimensional design. C1 NASA, Ames Res Ctr, Informat Sci & Technol Directorate, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Numer Aerosp Simulat Syst Div, Moffett Field, CA 94035 USA. RP Rai, MM (reprint author), NASA, Ames Res Ctr, Informat Sci & Technol Directorate, M-S 269-1, Moffett Field, CA 94035 USA. NR 15 TC 12 Z9 12 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 2001 VL 17 IS 1 BP 176 EP 183 DI 10.2514/2.5725 PG 8 WC Engineering, Aerospace SC Engineering GA 393FG UT WOS:000166458100023 ER PT J AU Devi, VM Benner, DC Smith, MAH Rinsland, CP AF Devi, VM Benner, DC Smith, MAH Rinsland, CP TI Measurements of air-broadened width and air-induced shift coefficients and line mixing in the v(6) band of (CH3D)-C-12 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE methane; monodeuterated methane; infrared spectra; Fourier transform infrared (FTIR) spectroscopy; spectral lineshape ID DIODE-LASER MEASUREMENTS; 6-10 MU-M; TEMPERATURES RELEVANT; SPECTRAL REGION; INFRARED BANDS; CH3D; INTENSITIES; ABSORPTION; CM(-1); (H2O)-O-16 AB Air-broadening and shift coefficients for more than 680 transitions in the 1040-1410 cm(-1) spectral region of the nu(6) perpendicular band of (CH3)-C-12 D have been measured. Values have been obtained from analysis of 11 room temperature absorption spectra recorded at 0.005 cm(-1) resolution with the McMath-Pierce Fourier transform spectrometer located on Kitt Peak National Solar Observatory and retrieved using a multispectrum nonlinear least-squares fitting technique. The measured broadening coefficients range from 0.016 to 0.077 cm(-1) atm(-1) at 296 K for transitions up to J" = 17 and K"=15, including 34 forbidden lines with 2 less than or equal to Delta K less than or equal to 4. The corresponding pressure-induced shift coefficients vary from -0.012 to + 0.008 cm(-1) atm(-1), and the majority of these are negative. Within each J series in the P-P and R-R subbands, the J" = K" land J' = K') transition exhibited the smallest broadening coefficient. In the PQ sub-band, the J" = K" transition in each J series of lines had the largest positive pressure-shift coefficient while the largest negative pressure-shift coefficients were associated with the J' = K' lines in the (R)Q sub-band. Subsets of the air-broadened width coefficients vary somewhat smoothly as a function of the rotational quanta, and this behavior has been modeled to +/- 8% using empirical expressions. Finally, Line mixing effects were observed for the first time in several of the K" = 3 (A(+)A(-)) split components in the P-P, (P)Q, R-P, P-R, (R)Q and R-R sub-band transitions, and values for off-diagonal relaxation matrix coefficients were determined. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 31 TC 15 Z9 15 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JAN 1 PY 2001 VL 68 IS 1 BP 1 EP 41 DI 10.1016/S0022-4073(00)00019-4 PG 41 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 354MR UT WOS:000089334700001 ER PT J AU Lyapustin, AI Muldashev, TZ AF Lyapustin, AI Muldashev, TZ TI Solution for atmospheric optical transfer function using spherical harmonics method SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE radiative transfer; inhomogeneous surface; 3D effects; optical transfer function AB This paper presents a numerical algorithm for computation of atmospheric optical transfer function (OTF) for the problem with Lambertian reflectance. OTF is a Fourier transform of the atmospheric point spread function, and it describes photon transport over a spatially non-uniform surface. The boundary-value problem for OTF is obtained from the 3D radiative transfer problem linearized in the spatial albedo variation. This problem is then solved with an efficient SVD modification of the spherical harmonics method with the smoothing procedure of the source function integration. This combination allowed us to develop a fast stable algorithm allowing calculations in arbitrary directions for vertically inhomogeneous atmosphere with arbitrary optical thickness and scattering function. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, UMBC, Greenbelt, MD 20771 USA. Space Res Inst, Alma Ata, Kazakhstan. RP Lyapustin, AI (reprint author), NASA, Goddard Space Flight Ctr, UMBC, Mailcode 920, Greenbelt, MD 20771 USA. RI Lyapustin, Alexei/H-9924-2014 OI Lyapustin, Alexei/0000-0003-1105-5739 NR 16 TC 9 Z9 10 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JAN 1 PY 2001 VL 68 IS 1 BP 43 EP 56 DI 10.1016/S0022-4073(00)00013-3 PG 14 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 354MR UT WOS:000089334700002 ER PT J AU Platnick, S AF Platnick, S TI A superposition technique for deriving mean photon scattering statistics in plane-parallel cloudy atmospheres SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE cloud remote sensing; multiple scattering; scattering statistics; adding/doubling method of technique; photon diffusion AB Photon transport in a multiple scattering medium is critically dependent on scattering statistics, in particular the average number of scatterings. A superposition technique is derived to accurately determine the average number of scatterings encountered by reflected and transmitted photons within arbitrary layers in plane-parallel, vertically inhomogeneous clouds. As expected, the resulting scattering number profiles are highly dependent on cloud particle absorption and solar/viewing geometry. The technique uses efficient adding and doubling radiative transfer procedures, avoiding traditional time-intensive Monte Carlo methods. Derived superposition formulae are applied to a variety of geometries and cloud models, and selected results are compared with Monte Carlo calculations. Cloud remote sensing techniques that use solar reflectance or transmittance measurements generally assume a homogeneous plane-parallel cloud structure. The scales over which this assumption is relevant, in both the vertical and horizontal, can be obtained from the superposition calculations. Though the emphasis is on photon transport in clouds, the derived technique is applicable to any multiple scattering plane-parallel radiative transfer problem, including arbitrary combinations of cloud, aerosol, and gas layers in the atmosphere. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Platnick, S (reprint author), NASA, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. RI Platnick, Steven/J-9982-2014 OI Platnick, Steven/0000-0003-3964-3567 NR 14 TC 13 Z9 13 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JAN 1 PY 2001 VL 68 IS 1 BP 57 EP 73 DI 10.1016/S0022-4073(00)00015-7 PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 354MR UT WOS:000089334700003 ER PT J AU Platnick, S AF Platnick, S TI Approximations for horizontal photon transport in cloud remote sensing problems SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID MARINE STRATOCUMULUS AB The effect of horizontal photon transport within real-world clouds can be of consequence to remote sensing problems based on plane-parallel cloud models. In this paper, analytic approximations for the root-mean-square horizontal displacement of reflected and transmitted photons, relative to the incident cloud-top location, are derived for plane-parallel cloud layers. With anisotropic scattering, separate approximations are needed depending on the order of scattering. When sufficient numbers of photon scatterings occur, an approximation based on random walk theory (photon diffusion) is applicable; when scattering numbers are relatively small, a modification to the diffusion result is used. The resulting formulae are a function of the average number of photon scatterings, as well as particle asymmetry parameter and single scattering albedo. In turn, the average number of scatterings from plane-parallel, vertically inhomogeneous cloud layers can be determined from efficient adding/doubling radiative transfer procedures. The transport approximations are applied to liquid water clouds for typical remote sensing solar spectral bands, involving both conservative and non-conservative scattering. Results compare well with Monte Carlo calculations. Though the emphasis is on horizontal photon transport in terrestrial clouds, the derived approximations are applicable to general anisotropic, multiple scattering, plane-parallel radiative transfer problems. Approximations useful for three-dimensional transport are also given. The complete horizontal transport probability distribution can be described with an analytic distribution specified by the root-mean-square and average radial displacement values. However, it is shown empirically that the average displacement can be reasonably inferred from the root-mean-square value. An estimate for the horizontal transport distribution can then be made from the root-mean-square photon displacement alone. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Platnick, S (reprint author), NASA, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. RI Platnick, Steven/J-9982-2014 OI Platnick, Steven/0000-0003-3964-3567 NR 22 TC 20 Z9 21 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JAN 1 PY 2001 VL 68 IS 1 BP 75 EP 99 DI 10.1016/S0022-4073(00)00016-9 PG 25 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 354MR UT WOS:000089334700004 ER PT J AU Gan, YX Aglan, H Faughnan, P Bryan, C AF Gan, YX Aglan, H Faughnan, P Bryan, C TI Fatigue fracture mechanisms of particle and fiber filled PTFE composites SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article DE fatigue behaviors; fracture surface analysis; short fiber and particle filled PTFE composites ID CARBON-FIBRE/POLYMER COMPOSITES; METAL-MATRIX COMPOSITE; STRAIN-CONTROLLED MODE; REINFORCED MATERIALS; ELEVATED-TEMPERATURE; INTERFACE; POLYMERS; DAMAGE; STRESS; INTERPHASE AB The effect of filler type on the fatigue fracture mechanisms of polytetrafluoroethylene (PTFE) composites was studied. The two composites were a silica particle filled PTFE (Garlock 3502(TM) ) and a glass fiber filled PTFE (Garlock 8573(TM) ). Tension-tension fatigue crack propagation tests were conducted on both materials at room temperature at a frequency of 3 Hz. The maximum stress was 6 MPa and the ratio of minimum load to maximum load was 0.1. It was found that the fatigue lifetime of the particle filled PTFE is approximately four times higher than that of the fiber filled PTFE. The fatigue data also revealed that the crack speed of the particle filled composite is always lower than that of the short fiber filled composite. Microscopic analysis on representative fracture surface of each material was performed to identify different fracture surface features. The three fracture regions, crack initiation, stable crack growth and unstable crack growth were examined. In the first region, both composites displayed extensive plastic deformation and severe debonding at the filler/matrix interface. In the second region, stable crack propagation, torn ligament bundles, fibrillation and debonded fillers are the main fracture surface features. The fracture surface of the fiber filled PTFE in the unstable crack propagation region has a more smooth appearance with extensive fiber pull-out. This indicates a fast fracture process and a brittle fracture mechanism dominating this region. The third region of the fracture surface for the particle filled PTFE displayed more severe matrix deformation. The particle filled PTFE displayed more intensive fibrillation in the second region than the fiber filled PTFE, indicating more damage formation and thus higher energy consumption in the stable crack propagation stage. Consequently, the crack speed of the particle filled PTFE is lower than that of the fiber filled PTFE composite. C1 Tuskegee Univ, Dept Mech Engn, Tuskegee, AL 36088 USA. NASA, John F Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Aglan, H (reprint author), Tuskegee Univ, Dept Mech Engn, Tuskegee, AL 36088 USA. NR 46 TC 5 Z9 5 U1 1 U2 14 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PY 2001 VL 20 IS 9 BP 766 EP 785 DI 10.1106/UH1Q-YMU2-E9QU-A5VX PG 20 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 445RM UT WOS:000169471000003 ER PT J AU Zoby, EV AF Zoby, EV TI Journal support SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Zoby, EV (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 2001 VL 38 IS 1 BP 1 EP 1 PG 1 WC Engineering, Aerospace SC Engineering GA 400RP UT WOS:000166885700001 ER PT J AU Glass, DE Dilley, AD Kelly, HN AF Glass, DE Dilley, AD Kelly, HN TI Numerical analysis of convection/transpiration cooling SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 9th International Space Planes and Hypersonic Systems and Technologies Conference CY NOV 01-05, 1999 CL NORFOLK, VIRGINIA SP Amer Inst Aeronaut & Astronaut AB An innovative concept utilizing the natural porosity of refractory-composite materials and hydrogen coolant to provide convective and transpiration cooling and oxidation protection has been numerically studied for surfaces exposed to a high-heat-flux, high-temperature environment such as hypersonic vehicle engine combustor walls. A boundary-layer code and a porous media finite difference code were utilized to analyze the effect of convection and transpiration cooling on surface heat flux and temperature. The boundary-layer code determined that transpiration flow is able to provide blocking of the surface heat flux only if it is above a minimum level due to heat addition from combustion of the hydrogen transpirant. The porous media analysis indicated that cooling of the surface is attained with coolant flow rates that are in the same range as those required for blocking. C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Glass, DE (reprint author), NASA, Langley Res Ctr, MS 396, Hampton, VA 23681 USA. NR 9 TC 17 Z9 20 U1 1 U2 14 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 2001 VL 38 IS 1 BP 15 EP 20 DI 10.2514/2.3666 PG 6 WC Engineering, Aerospace SC Engineering GA 400RP UT WOS:000166885700003 ER PT J AU Tajmar, M Wang, J AF Tajmar, M Wang, J TI Three-dimensional numerical simulation of field-emission-electric-propulsion backflow contamination SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID ION AB A three-dimensional full particle particle-in-cell with Monte Carlo collision simulation model is developed to study charge-exchange ion backflow from a field-emission-electric-propulsion thruster using liquid cesium as a propellant, Contamination from backflow of low-energy charge-exchange ions generated in the plume is an important spacecraft integration issue. Simulations show that the backflow ion current is on the order of 0.01% of the total emitting current under typical thruster operating conditions, Nearly all charge-exchange ions are collected by the accelerator electrode close to the emitter. Operating a held emission thruster at lower neutral flux, lower emitter current, or higher emitter potentials helps to reduce the backflow current and possible spacecraft contamination. The operation of a neutralizer does not have a significant effect on the backflow current under typical space plasma environments. A semi-analytical expression is also derived for quick estimations of the field emission thruster backflow current. C1 Austrian Res Ctr Seibersdorf, Space Propuls Grp, A-2444 Seibersdorf, Austria. CALTECH, Jet Prop Lab, Adv Propuls Technol Grp, Engn Staff, Pasadena, CA 91109 USA. RP Tajmar, M (reprint author), Austrian Res Ctr Seibersdorf, Space Propuls Grp, A-2444 Seibersdorf, Austria. EM martin.tajmar@arcs.ac.at; joseph.j.wang@jpl.nasa.gov OI Tajmar, Martin/0000-0002-7406-7588 NR 15 TC 5 Z9 5 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 2001 VL 38 IS 1 BP 69 EP 78 DI 10.2514/2.3656 PG 10 WC Engineering, Aerospace SC Engineering GA 400RP UT WOS:000166885700010 ER PT J AU Boltz, FW AF Boltz, FW TI Miniature launch vehicles for very small payloads SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article C1 NASA, Ames Res Ctr, Aeronaut Div, Moffett Field, CA 94035 USA. RP Boltz, FW (reprint author), NASA, Ames Res Ctr, Aeronaut Div, Moffett Field, CA 94035 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 2001 VL 38 IS 1 BP 126 EP 128 DI 10.2514/2.3664 PG 3 WC Engineering, Aerospace SC Engineering GA 400RP UT WOS:000166885700018 ER PT J AU Booth, ER McCluer, M Tadghighi, H AF Booth, ER McCluer, M Tadghighi, H TI Acoustic characteristics of an isolated tiltrotor model in the DNW SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB An acroacoustic wind funnel test was conducted using a scaled isolated tiltrotor model consisting of a single rotor and nacelle. Acoustic data were acquired using an in-flow microphone wing traversed beneath the model to map the directivity of the near-field acoustic radiation of the rotor for a parametric variation of rotor angle-of-attack, tunnel speed, and rotor thrust. Acoustic metrics were examined to show trends of impulsive noise for the parametric variations. BVISPL maximum noise levels were found to increase with angle-of-attack (alpha) for constant advance ratio (mu) and thrust coefficient (C-r), although the maximum BVI levels were found at much higher alpha than for a typical helicopter. BVISPL levels were found to increase with mu for constant alpha and C-T. BVISPL was found to decrease with increasing C-T for constant alpha and mu, although BVISPL increased with thrust for a constant wake geometry. Acoustic metrics: were also scaled for M-tip to show simple power law scaling could be used to correct acoustic metrics for small M-tip excursions. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Boeing Co, Mesa, AZ USA. RP Booth, ER (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JAN PY 2001 VL 46 IS 1 BP 72 EP 80 PG 9 WC Engineering, Aerospace SC Engineering GA 466UN UT WOS:000170664700007 ER PT J AU Dunham, DW Roberts, CE AF Dunham, DW Roberts, CE TI Stationkeeping techniques for libration-point satellites SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AIAA/AAS Astrodynamics Specialists Conference CY AUG 10-12, 1998 CL BOSTON, MASSACHUSETTS SP Amer Inst Aeronaut & Astronaut, AAS ID HALO ORBITS AB Orbits about collinear libration points are unstable, requiring stationkeeping maneuvers to maintain. Several different methods for calculating libration-point orbit stationkeeping maneuvers have been proposed. A tight control technique was used by the third International Sun-Earth Explorer (ISEE-3), the first libration-point mission. An easily-implemented "orbital energy balancing" loose control strategy was developed later and has been used successfully by the Solar Heliospheric Observatory (SOHO) and Advanced Composition Explorer (ACE). For SOHO, this loose control has resulted in station-keeping DeltaV costs of just over 2 m/sec per year with maneuvers performed about four times a year, an improvement of almost a factor of four over ISEE-3's tight control. Part of the gain probably results from better trajectory determinations from improved radiometric tracking data for SOHO. All three missions, especially SOHO, have had operational mishaps that have resulted in temporary expenditures of fuel that were much larger than expected, but in spite of these, it appears that the spacecraft can be kept in their designed halo orbits for periods longer than planned before launch. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RP Dunham, DW (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 32 TC 36 Z9 39 U1 1 U2 1 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JAN-MAR PY 2001 VL 49 IS 1 BP 127 EP 144 PG 18 WC Engineering, Aerospace SC Engineering GA 504CH UT WOS:000172839300008 ER PT J AU Franz, H Sharer, P Ogilvie, K Desch, M AF Franz, H Sharer, P Ogilvie, K Desch, M TI WIND nominal mission performance and extended mission design SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AIAA/AAS Astrodynamics Specialists Conference CY AUG 10-12, 1998 CL BOSTON, MASSACHUSETTS SP Amer Inst Aeronaut & Astronaut, AAS AB On November 1, 1994, the National Aeronautics and Space Administration launched the Interplanetary Physics Laboratory, or WIND spacecraft, as part of the Global Geospace Science program on a three-year mission to monitor the solar wind upstream of the Earth. The baseline mission design included a two-year dayside double lunar swingby orbit, followed by one year in a small-amplitude halo orbit at the Sun-Earth interior libration point, Lt. During operations, the double lunar swingby phase was expanded to three years. Execution of WIND's seventeenth successful lunar flyby in October 1997, sending the spacecraft into an eight-month "halo orbit" loop of the double lunar swingby, marked the completion of the nominal mission phase and the inauguration of the extended mission. The extended mission design, which continues to evolve, has comprised various orbital phases and concepts, including the backflip, nightside double lunar swingby, deep-tail excursion, lunar orbit, high-inclination "petal" orbit, and Earth return trajectory, in the pursuit of new science objectives. This paper provides an overview of the original mission design and describes the evolution of both nominal and extended mission phases during WIND's operational lifetime. The powerful mission design techniques that allowed accomplishment of a successful mission are discussed. Some of these techniques were first validated during flight of the International Sun Earth Explorer-3 (ISEE-3), while others constitute a novel approach to mission design implementation. Finally, WIND's performance is summarized from both mission design and science perspectives. C1 NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Franz, H (reprint author), NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RI Franz, Heather/F-3508-2012 NR 17 TC 14 Z9 17 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JAN-MAR PY 2001 VL 49 IS 1 BP 145 EP 167 PG 23 WC Engineering, Aerospace SC Engineering GA 504CH UT WOS:000172839300009 ER PT J AU Lo, MW Williams, BG Bollman, WE Han, DS Hahn, YS Bell, JL Hirst, EA Corwin, RA Hong, PE Howell, KC Barden, B Wilson, R AF Lo, MW Williams, BG Bollman, WE Han, DS Hahn, YS Bell, JL Hirst, EA Corwin, RA Hong, PE Howell, KC Barden, B Wilson, R TI Genesis mission design SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AIAA/AAS Astrodynamics Specialists Conference CY AUG 10-12, 1998 CL BOSTON, MASSACHUSETTS SP Amer Inst Aeronaut & Astronaut, AAS AB The Genesis spacecraft will collect solar wind samples from a halo orbit about the Sun-Earth L1 point for two years, returning those samples to Earth in 2003 for analysis and examination. The solar wind will imbed itself into a set of ultra-pure material collectors that will be deployed throughout the collection phase of the mission. Analysis of the samples collected by the mission will contribute to our understanding of the origins of the solar system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lockheed Martin Astronaut, Denver, CO 80201 USA. Purdue Univ, W Lafayette, IN 47907 USA. RP Lo, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 55 Z9 60 U1 1 U2 2 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JAN-MAR PY 2001 VL 49 IS 1 BP 169 EP 184 PG 16 WC Engineering, Aerospace SC Engineering GA 504CH UT WOS:000172839300010 ER PT J AU Smith, SA DelGenio, AD AF Smith, SA DelGenio, AD TI Analysis of aircraft, radiosonde, and radar observations in cirrus clouds observed during FIRE II: The interactions between environmental structure, turbulence, and cloud microphysical properties SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-TRANSFER; ICE CLOUDS; SIZE SPECTRA; MODEL; PARAMETERIZATION; STRATOCUMULUS AB Ways to determine the turbulence intensity and the horizontal variability in cirrus clouds have been investigated using First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment II aircraft, radiosonde, and radar data. Higher turbulence intensities were found within some, but not all, of the neutrally stratified layers. It was also demonstrated that the stability of cirrus layers with high extinction values decreases in time, possibly as a result of radiative destabilization. However, these features could not be directly related to each other in any simple manner. A simple linear relationship was observed between the amount of horizontal variability in the ice water content and its average value. This was also true for the extinction and ice crystal number concentrations. A relationship was also suggested between the variability in cloud depth and the environmental stability across the depth of the cloud layer, which requires further investigation. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, New York, NY USA. RP DelGenio, AD (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Del Genio, Anthony/D-4663-2012 OI Del Genio, Anthony/0000-0001-7450-1359 NR 27 TC 11 Z9 11 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 5 BP 451 EP 461 DI 10.1175/1520-0469(2001)058<0451:AOARAR>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 402AX UT WOS:000166964400003 ER PT J AU Sassen, K Campbell, JR AF Sassen, K Campbell, JR TI A midlatitude cirrus cloud climatology from the facility for atmospheric remote sensing. Part I: Macrophysical and synoptic properties SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE PROPERTIES; OPTICAL-PROPERTIES; OCTOBER 1986; ISCCP; LIDAR; FIRE; ICE; MICROPHYSICS; WINTER AB A uniquely extensive high cloud dataset has been collected from the University of Utah Facility for Atmospheric Remote Sensing in support of the First (ISCCP) International Satellite Cloud Climatology Project Regional Experiment extended time observations satellite validation effort. Here in Part I of a series of papers examining the climatological properties of the cirrus clouds studied over Salt Lake City, Utah, similar to 2200 h of data collected from 1986-96 is used to create a subset of 1389 hourly polarization ruby (0.694 mum) lidar measurements of cloud layer heights. These data were obtained within +/-3 h of the local 0000 UTC National Weather Service radiosonde launches to provide reliable cloud temperature, pressure, and wind data. Future parts of this series will consider the inferred cirrus cloud microphysical and radiative properties. In addition to describing the cirrus macrophysical properties in terms of their yearly, seasonal, and monthly means and variabilities, the synoptic weather patterns responsible for the cirrus are characterized. The strong linkage between cirrus and weather is controlled by upper-air circulations mainly related to seasonally persistent intermountain region ridge/trough systems. The cloud-top heights of cirrus usually associated with jet streams tend to approach the local tropopause, except during the summer season due to relatively weak monsoonal convective activity. Although a considerable degree of variability exists, 10-yr average values for cirrus cloudbase/top properties are 8.79/11.2 km, 336.3/240.2 mb, -34.4 degrees/-53.9 degreesC, 16.4/20.2 m s(-1), and 276.3 degrees /275.7 degrees wind direction. The average cirrus layer physical thickness for single and multiple layers is 1.81 km. Estimates of cloud optical thickness tau based on a "thin'' (i.e., bluish) visual appearance suggest that tau less than or similar to 0.3 occur similar to 50% of the time for detected cirrus, implying that the cirrus in the region of study may be too tenuous to be effectively sampled using current satellite methods. The global representativeness of this extended cirrus cloud study is discussed. C1 Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Sassen, K (reprint author), Univ Utah, Dept Meteorol, 135 S 1460 E,819 WBB, Salt Lake City, UT 84112 USA. RI Campbell, James/C-4884-2012 OI Campbell, James/0000-0003-0251-4550 NR 33 TC 99 Z9 105 U1 2 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 5 BP 481 EP 496 DI 10.1175/1520-0469(2001)058<0481:AMCCCF>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 402AX UT WOS:000166964400005 ER PT J AU Gerber, H Jensen, JB Davis, AB Marshak, A Wiscombe, WJ AF Gerber, H Jensen, JB Davis, AB Marshak, A Wiscombe, WJ TI Spectral density of cloud liquid water content at high frequencies SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID STRATOCUMULUS CLOUDS; MARINE STRATOCUMULUS; SIZE DISTRIBUTION; CUMULUS; PARAMETERIZATION; INTERMITTENCY; DISTRIBUTIONS; CONDENSATION; MICROPHYSICS; CENTIMETER AB Aircraft measurements of liquid water content (LWC) made at sampling frequencies of 1 and 2 kHz with a particle volume monitor (PVM) probe from horizontal traverses in stratocumulus clouds during the Southern Ocean Cloud Experiment and cumulus clouds during the Small Cumulus Microphysics Study are described. The spectral density of the LWC measurements is calculated and compared to the -5/3 scaling law. The effect of PVM sampling noise is found to be small in most cases. Most measurements follow approximately the -5/3 law until cloud scales decrease below about 5 m in length. Below this length LWC variance can exceed that predicted by the -5/3 law. It is suggested that the enhanced LWC variance at small scales is related to entrainment of environmental air into the clouds, which changes primarily the droplet concentration. C1 Gerber Sci Inc, Reston, VA 20190 USA. CSIRO Atmospher Res, Aspendale, Vic, Australia. Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, Los Alamos, NM USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Gerber, H (reprint author), Gerber Sci Inc, 1643 Bentana Way, Reston, VA 20190 USA. EM gerber.gsi@erols.com RI Jensen, Jorgen/C-9211-2009; Wiscombe, Warren/D-4665-2012; Marshak, Alexander/D-5671-2012 OI Wiscombe, Warren/0000-0001-6844-9849; NR 35 TC 29 Z9 29 U1 2 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 5 BP 497 EP 503 DI 10.1175/1520-0469(2001)058<0497:SDOCLW>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 402AX UT WOS:000166964400006 ER PT J AU Lynn, BH Tao, WK Abramopoulos, F AF Lynn, BH Tao, WK Abramopoulos, F TI A parameterization for the triggering of landscape-generated moist convection. part I: Analysis of high-resolution model results SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID AVERAGED SURFACE FLUXES; BOUNDARY-LAYER; LAND-SURFACE; MESOSCALE CIRCULATIONS; TURBULENCE STRUCTURE; AIRCRAFT OBSERVATIONS; DEEP CONVECTION; SCALE; CUMULUS; IMPACT AB To develop a parameterization for the triggering of moist convection by landscape-generated mesoscale circulations, a set of relatively high-resolution three-dimensional (3D) simulations was produced. These simulations modeled the development of landscape generated mesoscale circulations that triggered moist convection over west-to-east dry patches. No clear relationship existed between average patch size and average rainfall. Rather, rainfall averaged over the area of individual patches varied linearly with the size of these patches. Thus, cumulus parameterization schemes need to account for a population of clouds (over individual patches) within each domain of a large-scale atmospheric model (i.e., numerical weather prediction and global circulation models). It is demonstrated that mesoscale perturbations in velocity, temperature, and moisture need to be included in triggering functions when evaluating whether moist convection will occur. Yet, the largest patches did not always produce the largest mesoscale perturbations. Instead, the size of the perturbations depended upon the ratio of the local radius of deformation to patch size, the gradient of soil moisture between patches, as well as large-scale environmental conditions such as wind, stability, and specific humidity. These perturbations can be used to improve the representation of triggering functions associated with moist convection over landscape patches. Appropriate dimensionless numbers that can be used in a parameterization for the mesoscale perturbations are identified. C1 Columbia Univ, Ctr Climate Syst Res, New York, NY USA. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. NASA, Goddard Inst Space Studies, Sci Syst & Applicat Inc, New York, NY 10025 USA. RP Lynn, BH (reprint author), Hebrew Univ Jerusalem, Dept Atmospher Sci, IL-91904 Jerusalem, Israel. NR 51 TC 14 Z9 14 U1 2 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 6 BP 575 EP 592 DI 10.1175/1520-0469(2001)058<0575:APFTTO>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 406JD UT WOS:000167210400004 ER PT J AU Lynn, BH Tao, WK AF Lynn, BH Tao, WK TI A parameterization for the triggering of landscape-generated moist convection. part II: Zero-order and first-order closure SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CUMULUS; MODELS; LAND; VARIABILITY; SIMULATIONS; WEATHER; CLIMATE; ENERGY; FLUXES; CLOUDS AB To improve the triggering of clouds over landscape heterogeneity, it is suggested that the forcing by mesoscale circulations generated by landscape patches be included. For this purpose, it is suggested that a relatively simple zero-order closure be used to obtain a triggering parcel's mesoscale perturbation vertical velocity, potential temperature, and specific humidity. In combination with a turbulent fluctuation averaged over a parcel area, one can obtain a parcel's (total) velocity, temperature, and moisture. The authors used similarity theory to parameterize the mesoscale perturbations, using a dataset generated by a three-dimensional, high-resolution cumulus ensemble model with west-to-east land surface patches. Alternatively, the authors used one-dimensional budget equations that contain mesoscale and turbulent fluctuations (and source terms) to obtain the vertical profile of potential temperature and specific humidity within a triggering parcel. Here, it is suggested that first-order closure be used; these equations with first-order closure should provide more realistic profiles of temperature and moisture within a triggering parcel than with the zero-order scheme above. This is especially the case when moist (cloud) processes occur. An analysis of the model-produced dataset indicated that parameterizations for two terms needed to be developed to close the budget equations: the vertical flux of the mesoscale temperature and moisture. Similarity theory is used to parameterize these fluxes. C1 Columbia Univ, Ctr Climate Syst Res, New York, NY USA. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Lynn, BH (reprint author), Hebrew Univ Jerusalem, Dept Atmospher Sci, IL-91904 Jerusalem, Israel. NR 24 TC 11 Z9 11 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 6 BP 593 EP 607 DI 10.1175/1520-0469(2001)058<0593:APFTTO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 406JD UT WOS:000167210400005 ER PT J AU Peng, L Sui, CH Lau, KM Tao, WK AF Peng, L Sui, CH Lau, KM Tao, WK TI Genesis and evolution of hierarchical cloud clusters in a two-dimensional cumulus-resolving model SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID TROPICAL INTRASEASONAL OSCILLATION; FORCED GRAVITY-WAVES; DENSITY CURRENTS; WESTERN PACIFIC; SQUALL LINES; SHEAR FLOWS; ANELASTIC APPROXIMATION; MESOSCALE PROCESSES; CONVECTION SCHEMES; DEEP CONVECTION AB A two-dimensional cloud ensemble model is integrated over a basin-scale domain with prescribed sea surface temperature (SST), to study the formation and evolution of cloud clusters over a large-scale warm pool. Neither a basic zonal flow is prescribed nor is a single perturbation initially given. The results show that deep convective clouds appear in hierarchical clustered patterns and are limited to the area of warm SST above 28 degreesC. The most fundamental cloud cluster in the model has a horizontal scale of a few hundred kilometers, in which new cumulus clouds are generated at the leading edge of a propagating surface cold-air pool-the "gust front.'' It may last for days and propagate for a long distance if the background flow is broad and persistent as is the case in the low-level convergence zone of the SST-induced background flow. The largest hierarchical propagating cloud systems in the model have horizontal scales up to 3000 km and consist of up to four cloud clusters that are generally of gust front type. The constituent cloud clusters are generated intermittently and have life spans of 12-36 h. The internal heating of the constituent clusters collectively induces an overall troposphere-deep gravity wave. The overall wave travels in the direction of the tropospheric deep shear at a speed determined by the thermodynamic asymmetry in the wave created by the transition from warm and moist incoming air in the front to drier and cooler air in the rear. The development of new cumulus clusters in the front region of the hierarchical system is due to the combined effect of the overall wave and the gravity waves excited by the constituent clusters on the lower-tropospheric stability. When there are no interruptions from outside the cloud system, new cloud clusters developed intermittently from shallow disturbances hundreds of kilometers ahead of the existing deep convection. The resulting hierarchical cloud pattern resembles the observed equatorial super cloud cluster (SCC) in the time-longitude diagram. However, the life spans of the constituent clusters of the system are shorter than that in the observed SCC. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Space Applicat Corp, Vienna, VA USA. RP Sui, CH (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Mail Code 913, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012; OI Lau, William /0000-0002-3587-3691; SUI, CHUNG-HSIUNG/0000-0003-2842-5660 NR 42 TC 14 Z9 14 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 8 BP 877 EP 895 DI 10.1175/1520-0469(2001)058<0877:GAEOHC>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 414NV UT WOS:000167673700008 ER PT J AU Varnai, T Marshak, A AF Varnai, T Marshak, A TI Statistical analysis of the uncertainties in cloud optical depth retrievals caused by three-dimensional radiative effects SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID BOUNDARY-LAYER CLOUDS; RADIANCE MEASUREMENTS; MARINE STRATOCUMULUS; SATELLITE; VARIABILITY; FLUXES; ALBEDO AB This paper presents a simple yet general approach to estimate the uncertainties that arise in satellite retrievals of cloud optical depth when the retrievals use one-dimensional radiative transfer theory for heterogeneous clouds that have variations in all three dimensions. For the first time, preliminary error bounds are set to estimate the uncertainty of cloud optical depth retrievals. These estimates can help us better understand the nature of uncertainties that three-dimensional effects can introduce into retrievals of this important product of the Moderate Resolution Imaging Spectroradiometer instrument. The probability distribution of resulting retrieval errors is examined through theoretical simulations of shortwave cloud reflection for a set of cloud fields that represent the variability of stratocumulus clouds. The results are used to illustrate how retrieval uncertainties change with observable and known parameters, such as solar elevation or cloud brightness. Furthermore, the results indicate that a tendency observed in an earlier study-clouds appearing thicker for oblique sun-is indeed caused by three-dimensional radiative effects. C1 NASA, Goddard Space Flight Ctr, Joint Ctr Earth Syst Technol, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Greenbelt, MD USA. RP Varnai, T (reprint author), NASA, Goddard Space Flight Ctr, Joint Ctr Earth Syst Technol, Code 913, Greenbelt, MD 20771 USA. RI Marshak, Alexander/D-5671-2012 NR 38 TC 39 Z9 39 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 12 BP 1540 EP 1548 DI 10.1175/1520-0469(2001)058<1540:SAOTUI>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 433HB UT WOS:000168753200005 ER PT J AU Xu, KM Randall, DA AF Xu, KM Randall, DA TI Updraft and downdraft statistics of simulated tropical and midlatitude cumulus convection SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID AVAILABLE POTENTIAL-ENERGY; VERTICAL VELOCITY CHARACTERISTICS; TOGA-COARE; NUMERICAL-SIMULATION; CONTINENTAL CLOUDS; SUPERCELL THUNDERSTORM; EXPLICIT SIMULATION; OCEANIC CONVECTION; PHASE-III; GATE AB This paper presents a detailed analysis of updraft and downdraft statistics of simulated tropical oceanic and midlatitude continental cumulus convection, with an emphasis on the individual terms in the vertical momentum budget. Strong convective cores with absolute vertical velocities over 1 m s(-1) and total condensate mixing ratios over 0.1 g kg(-1) are sampled from several long-term simulations, driven by the observed large-scale advective forcings over the eastern Atlantic and Oklahoma regions. The median updraft and downdraft velocities are weakly dependent upon height, but the 90th percentile of the updraft velocity varies strongly with height, with a maximum in the middle troposphere. The median updraft thermal buoyancies are only about 0.5 K higher than those of downdrafts. As in aircraft measurements, positive thermal buoyancies exist for more than half of downdraft cores, and negative thermal buoyancies exist for a significant number of updrafts. The existence of the nonhydrostatic pressure gradients can explain such a surprising result first obtained from aircraft measurements. On the other hand, the largest differences between tropical and midlatitude convection occur in the strongest 10% of the drafts, not in the median drafts. For updrafts, the difference is related to the larger thermal buoyancy and relatively smaller condensate mixing ratio in midlatitudes, in addition to the larger dynamic triggering in the subcloud layer. The larger dynamic effects of the nonhydrostatic pressure gradient forces are responsible for the larger downdraft velocities in midlatitudes, in addition to the drier environments. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Xu, KM (reprint author), NASA, Langley Res Ctr, Radiat & Aerosols Branch, Mail Stop 420, Hampton, VA 23681 USA. EM k.m.xu@larc.nasa.gov RI Xu, Kuan-Man/B-7557-2013; Randall, David/E-6113-2011 OI Xu, Kuan-Man/0000-0001-7851-2629; Randall, David/0000-0001-6935-4112 NR 51 TC 45 Z9 46 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 13 BP 1630 EP 1649 DI 10.1175/1520-0469(2001)058<1630:UADSOS>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 450UK UT WOS:000169762400002 ER PT J AU Stevens, B Ackerman, AS Albrecht, BA Brown, AR Chlond, A Cuxart, J Duynkerke, PG Lewellen, DC Macvean, MK Neggers, RAJ Sanchez, E Siebesma, AP Stevens, DE AF Stevens, B Ackerman, AS Albrecht, BA Brown, AR Chlond, A Cuxart, J Duynkerke, PG Lewellen, DC Macvean, MK Neggers, RAJ Sanchez, E Siebesma, AP Stevens, DE TI Simulations of trade wind cumuli under a strong inversion SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERIC BOUNDARY-LAYER; LARGE-EDDY SIMULATION; FRACTIONAL CLOUDINESS; CONVECTION; PARAMETERIZATION; PARAMETRIZATION; MODEL; MASS AB The fifth intercomparison of the Global Water and Energy Experiment Cloud System Studies Working Group 1 is used as a vehicle for better understanding the dynamics of trade wind cumuli capped by a strong inversion. The basis of the intercomparison is 10 simulations by 7 groups. These simulations are supplemented by many further sensitivity studies, including some with very refined grid meshes. The simulations help illustrate the turbulent dynamics of trade cumuli in such a regime. In many respects the dynamics are similar to those found in many previous simulations of trade cumuli capped by weaker inversions. The principal differences are the extent to which the cloud layer is quasi-steady in the current simulations, evidence of weak countergradient momentum transport within the cloud layer, and the development and influence of an incipient stratiform cloud layer at the top of the cloud layer. Although many elements of the turbulent structure (including the wind profiles, the evolution of cloud-base height, the statistics of the subcloud layer, and the nature of mixing in the lower and middle parts of the cloud layer) are robustly predicted, the representation of the stratiform cloud amount by the different simulations is remarkably sensitive to a number of factors. Chief among these are differences between numerical algorithms. These sensitivities persist even among simulations on relatively refined grid meshes. Part of this sensitivity is attributed to a physically realistic positive radiative feedback, whereby a propensity toward higher cloud fractions in any given simulation is amplified by longwave radiative cooling. The simulations also provide new insight into the dynamics of the transition layer at cloud base. In accord with observations, the simulations predict that this layer is most identifiable in terms of moisture variances and gradients. The simulations help illustrate the highly variable (in both height and thickness) nature of the transition layer, and we speculate that this variability helps regulate convection. Lastly the simulations are used to help evaluate simple models of trade wind boundary layers. In accord with previous studies, mass-flux models well represent the dynamics of the cloud layer, while mixing-length models well represent the subcloud layer. The development of the stratiform cloud layer is not, however, captured by the mass-flux models. The simulations indicate that future theoretical research needs to focus on interface rules, whereby the cloud layer is coupled to the subcloud layer below and the free atmosphere above. Future observational studies of this regime would be of most benefit if they could provide robust cloud statistics as a function of mean environmental conditions. C1 Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Met Off, Bracknell, Berks, England. Max Planck Inst Meteorol, Hamburg, Germany. Inst Nacl Meteorol, Madrid, Spain. Inst Marine & Atmospher Res, Utrecht, Netherlands. W Virginia Univ, MAE Dept, Morgantown, WV 26506 USA. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Stevens, B (reprint author), Univ Calif Los Angeles, Dept Atmospher Sci, 405 Hilgard Ave,Box 951565, Los Angeles, CA 90095 USA. RI Lewellen, David/B-1453-2008; Ackerman, Andrew/D-4433-2012; Stevens, Bjorn/A-1757-2013; Sanchez, Enrique/L-5086-2014 OI Ackerman, Andrew/0000-0003-0254-6253; Stevens, Bjorn/0000-0003-3795-0475; Sanchez, Enrique/0000-0002-7720-4437 NR 31 TC 154 Z9 157 U1 0 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 14 BP 1870 EP 1891 DI 10.1175/1520-0469(2001)058<1870:SOTWCU>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 450UL UT WOS:000169762500003 ER PT J AU Waliser, DE Zhang, ZZ Lau, KM Kim, JH AF Waliser, DE Zhang, ZZ Lau, KM Kim, JH TI Interannual sea surface temperature variability and the predictability of tropical intraseasonal variability SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MADDEN-JULIAN OSCILLATION; OUTGOING LONGWAVE RADIATION; GENERAL-CIRCULATION MODELS; AUSTRALIAN SUMMER MONSOON; LARGE-SCALE ENVIRONMENT; CUMULUS CLOUD ENSEMBLE; EL-NINO; BIOSPHERE MODEL; TIME SCALES; PREDICTION AB The objective of this study is to examine the relationship between interannual SST variability and the activity and predictability of tropical intraseasonal variability (TISV). A 10-yr simulation forced by climatological SSTs and a 10-member 10-yr (1979-88) ensemble of simulations forced by observed SSTs from the NASA Goddard Laboratory for the Atmospheres GCM coupled to a weakly interacting slab ocean mixed layer are analyzed. The climatological simulation provides a measure of the natural variability associated with TISV, while the observed SST simulations provide an indication of how externally imposed SST anomalies modify this variability. Analysis is conducted on both the eastward-propagating (winter mode) and northeastward-propagating (summer mode) forms of TISV. Indices of TISV are constructed from the amplitude time series of the leading EOFs of intraseasonally bandpassed model precipitation and 850-hPa zonal wind. Analysis of the TISV activity indices from the climatological SST simulation shows that considerable natural variability exists for both the winter and summer TISV modes. Based on the TISV indices constructed, the internal variability of TISV is about 50% of the mean signal. Moreover, the interannual standard deviation in TISV activity from the climatological SST simulation ranges from about the same size to about twice the standard deviation associated with the seasonal evolution of TISV activity. A ratio between an estimate of the externally forced TISV variability in the observed SST simulations to an estimate of natural TISV variability from the climatological SST simulations is constructed to give a measure of TISV predictability. While these predictability values exhibit some seasonal dependence, on average they suggest little to no predictability associated with interannual TISV variations for either the winter or summer TISV mode. However, the ensemble does demonstrate significantly enhanced predictability of the summer TISV mode during the 1982/83 winter. This same characteristic was found during the 1997/98 winter in a second 10-member ensemble that was conducted for the period September 1996 to August 1998. In each of these cases, the ensemble means exhibited a decrease in TISV activity, a feature that is also echoed in the observations. Thus, under very specific circumstances, anomalous SST may have some predictable influence over the level of TISV activity, at least for the summer mode. In addition, the simulations show evidence that generalized intraseasonal variance (i.e., no constraint on spatial structure) displays some predictable characteristics over the central and eastern equatorial Pacific in association with ENSO-related SST anomalies. Considerations of the use of the ocean mixed layer coupling in the context of the above study are discussed as well as the agreement between the observed levels of TISV activity for the periods modeled and the levels simulated by the GCM ensemble. C1 SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. Space Applicat Corp, Vienna, VA USA. RP Waliser, DE (reprint author), SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Endeavour Hall 205, Stony Brook, NY 11794 USA. EM waliser@terra.msrc.sunysb.edu RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 61 TC 14 Z9 14 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 17 BP 2596 EP 2615 DI 10.1175/1520-0469(2001)058<2596:ISSTVA>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 474XY UT WOS:000171133200009 ER PT J AU Chao, WC Chen, BD AF Chao, WC Chen, BD TI Multiple quasi equilibria of the ITCZ and the origin of monsoon onset. Part II: Rotational ITCZ attractors SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SOLAR-RADIATION; PARAMETERIZATION; CONVECTION; CLIMATE; MODELS; GCM AB Chao's numerical and theoretical work on multiple quasi equilibria of the intertropical convergence zone (ITCZ) and the origin of monsoon onset is extended to solve two additional puzzles. One is the highly nonlinear dependence on latitude of the "force'' acting on the ITCZ due to the earth's rotation, which makes the multiple quasi equilibria of the ITCZ and monsoon onset possible. The other is the dramatic difference in such dependence when different cumulus parameterization schemes are used in a model. Such a difference can lead to a switch between a single ITCZ at the equator and a double ITCZ, when a different cumulus parameterization scheme is used. Sometimes one of the double ITCZ can diminish and only the other remains strong, but still this can mean different latitudinal locations for the single ITCZ. A single idea based on two off-equator attractors for the ITCZ symmetric with respect to the equator, due to the earth's rotation, and the dependence of the strength and size of these attractors on the cumulus parameterization scheme solves both puzzles. The origin of these rotational attractors, explained in Part I, is further discussed. Each attractor exerts on the ITCZ a force of simple shape in latitude; but the sum gives a shape highly varying in latitude. Also the strength and the domain of influence of each attractor vary when change is made in the cumulus parameterization. This gives rise to the high sensitivity of the force shape to cumulus parameterization. Numerical results, of experiments using Goddard's GEOS GCM, supporting this idea are presented. It is also found that the model results are sensitive to changes outside of the cumulus parameterization. The significance of this study to El Nino forecast and to tropical forecast in general is discussed. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD USA. RP Chao, WC (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Mail Code 913, Greenbelt, MD 20771 USA. NR 20 TC 14 Z9 15 U1 0 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 18 BP 2820 EP 2831 DI 10.1175/1520-0469(2001)058<2820:MQEOTI>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 474YF UT WOS:000171133900009 ER PT J AU Kato, S Mace, GG Clothiaux, EE Liljegren, JC Austin, RT AF Kato, S Mace, GG Clothiaux, EE Liljegren, JC Austin, RT TI Doppler cloud radar derived drop size distributions in liquid water stratus clouds SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-TRANSFER; AIRCRAFT OBSERVATIONS; ATMOSPHERIC RADIATION; STRATOCUMULUS CLOUDS; MICROWAVE RADIOMETER; STRATIFORM CLOUDS; CLIMATE MODELS; BOUNDARY-LAYER; SCATTERING; PARAMETERIZATION AB A cloud particle size retrieval algorithm that uses radar reflectivity factor and Doppler velocity obtained by a 35-GHz Doppler radar and liquid water path estimated from microwave radiometer radiance measurements is developed to infer the size distribution of stratus cloud particles. Assuming a constant, but unknown, number concentration with height, the algorithm retrieves the number concentration and vertical profiles of liquid water content and particle effective radius. A novel aspect of the retrieval is that it depends upon an estimated particle median radius vertical profile that is derived from a statistical model that relates size to variations in particle vertical velocity; the model posits that the median particle radius is proportional to the fourth root of the particle velocity variance if the radii of particles in a parcel of zero vertical velocity is neglected. The performance of the retrieval is evaluated using data from two stratus case study days 1.5 and 8.0 h in temporal extent. Aircraft in situ microphysical measurements were available on one of the two days and the retrieved number concentrations and effective radii are consistent with them. The retrieved liquid water content and effective radius increase with height for both stratus cases, which agree with earlier studies. Error analyses suggest that the error in the liquid water content vanishes and the magnitudes of the fractional error in the effective radius and shortwave extinction coefficient computed from retrieved cloud particle size distributions are half of the magnitudes of the fractional error in the estimated cloud particle median radius if the fractional error in the median radius is constant with height. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Kato, S (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 33 TC 17 Z9 17 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 19 BP 2895 EP 2911 DI 10.1175/1520-0469(2001)058<2895:DCRDDS>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 478LD UT WOS:000171346900004 ER PT J AU Barker, HW Marshak, A AF Barker, HW Marshak, A TI Inferring optical depth of broken clouds above green vegetation using surface solar radiometric measurements SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID BOUNDARY-LAYER CLOUDS; INDEPENDENT PIXEL APPROXIMATION; RADIATIVE-TRANSFER; ALBEDO; STRATOCUMULUS; SATELLITE; FLUXES; PARAMETERIZATION; DISTRIBUTIONS; ABSORPTION AB A method for inferring cloud optical depth tau is introduced and assessed using simulated surface radiometric measurements produced by a Monte Carlo algorithm acting on fields of broken, single-layer, boundary layer clouds derived from Landsat imagery. The method utilizes a 1D radiative transfer model and time series of zenith radiances and irradiances measured at two wavelengths, lambda (1) and lambda (2), from a single site with surface albedos alpha (lambda1) < (lambda2). Assuming that clouds transport radiation in accordance with 1D theory And have spectrally invariant optical properties, inferred optical depths tau' are obtained through cloud-base reflectances that are approximated by differencing spectral radiances and estimating upwelling fluxes at cloud base. When initialized with suitable values of alpha (lambda1), alpha (lambda2), and cloud-base altitude h, this method performs well at all solar zenith angles. Relative mean bias errors for tau' are typically less than 5% for these cases. Relative variances for tau' for given values of inherent tau are almost independent of inherent tau and are <50%. Errors due to neglect of net horizontal transport in clouds yield sight, but systematic, overestimates for less than or equal to5 and underestimates for larger tau. Frequency distributions and power spectra for retrieved and inherent tau are often in excellent agreement. Estimates of tau depend weakly on errors in h, especially when h is overestimated. Also, they are almost insensitive to errors in surface albedo when alpha (lambda1) is underestimated and alpha (lambda2) overestimated. Reversing the sign of these errors leads to overestimation of tau, particularly large tau. In contrast, the conventional method of using only surface irradiance yields almost entirely invalid results when clouds are broken. Those results are shown only for surfaces resembling green vegetation (i.e., alpha (lambda1) << alpha (lambda2)), the performance of this method depends little on the values of alpha (lambda1), and alpha (lambda2). Thus, if radiometric data have sufficient signal-to-noise ratios and suitable wavelengths can be found, this method should yield reliable estimates for tau for broken clouds above many surface types. C1 Environm Canada, Downsview, ON, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barker, HW (reprint author), Meteorol Serv Canada, Cloud Phys Res Div ARMP, 4905 Dufferin St, Toronto, ON M3H 5T4, Canada. RI Marshak, Alexander/D-5671-2012 NR 32 TC 20 Z9 20 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 20 BP 2989 EP 3006 DI 10.1175/1520-0469(2001)058<2989:IODOBC>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 478LF UT WOS:000171347100002 ER PT J AU Ustinov, EA AF Ustinov, EA TI Adjoint sensitivity analysis of atmospheric dynamics: Application to the case of multiple observables SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GLOBAL INVERSE MODEL; NON-LINEAR SYSTEMS; WEIGHTING FUNCTIONS; TRANSPORT; EQUATION AB The matrix approach to the adjoint sensitivity analysis of atmospheric models with multiple observables is presented. The approach is developed as a straightforward generalization of the scalar case originally devised by Marchuk in the 1960s for applications in atmospheric remote sensing based on the use of the adjoint equation of radiative transfer. According to the commonly accepted viewpoint, the solution of the adjoint problem corresponding to the forward problem formulated with respect to an n vector of variables, is also an n vector. It is shown that in the general case of m observables this adjoint solution should have the form of an n x m matrix. Then, the m x N matrix of sensitivities of m observables to N model parameters can be directly evaluated from the single matrix adjoint solution rather than from multiple vector adjoint solutions computed for each of m observables. Potentially, this can provide appreciable savings of computer time. A general operator-matrix presentation of the approach is given and its application to the sensitivity analysis of a simple zero-dimensional radiative balance model with two field variables and two observables is considered. The results are validated by numerical experiments. C1 CALTECH, Jet Prop Lab, CIT, Pasadena, CA 91109 USA. RP Ustinov, EA (reprint author), CALTECH, Jet Prop Lab, CIT, Mail Stop 169-237,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Ustinov, Eugene/D-1350-2015 OI Ustinov, Eugene/0000-0003-0227-4286 NR 19 TC 4 Z9 4 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 21 BP 3340 EP 3348 DI 10.1175/1520-0469(2001)058<3340:ASAOAD>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 489QC UT WOS:000172002000015 ER PT J AU Chao, WC Chen, B AF Chao, WC Chen, B TI The origin of monsoons SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ASIAN SUMMER MONSOON; GENERAL-CIRCULATION; SOLAR-RADIATION; TIBETAN PLATEAU; MODEL; PARAMETERIZATION; PREDICTION; CLIMATE; ONSET AB The monsoon is interpreted as an intertropical convergence zone (ITCZ) substantially away (more than 10 degrees) from the equator and the existence of the ITCZ does not have to rely on land-sea contrast. Land-sea contrast can provide a favorable longitudinal location for the ITCZ but this role can be replaced by sea surface temperature contrast in the longitudinal direction. Thus, the interpretation of the monsoon presented herein differs from the long-held fundamental belief that its basic cause is land-sea thermal contrast on the continental scale in the sense that the existence of landmass is not considered a necessary condition for monsoons. Through general circulation model experiments, support has been found for this interpretation. The Asian and Australian summer monsoon circulations are largely intact in an experiment in which Asia, maritime continent, and Australia are replaced by ocean with sea surface temperature (SST) taken from that of the surrounding oceans. Thus, in these areas land-sea contrast is not a necessary condition for monsoon. This also happens to the Central American summer monsoon. The same thing can also be said about the African and South American summer monsoons, if these continents are replaced by ocean of sufficiently high SST. It is also shown that in the Asian monsoon the change resulting from such replacement is due more to the removal of topography than to the removal of land-sea contrast. In the Asian and Australian winter monsoons land-sea contrast also plays only a minor role. The origin of the ITCZs and their latitudinal locations have been previously interpreted by Chao. The circulation associated with an off-equator ITCZ, previously interpreted by Chao and Chen through a modified Gill solution and briefly described in this paper, explains the monsoon circulation. The longitudinal location of the ITCZ is determined by the distribution of surface conditions. ITCZs favor locations of high SST as in the western Pacific and Indian oceans, or tropical landmass, due to land-sea contrast, as in tropical Africa and South America. Thus, the role of landmass, when it is important, in the origin of monsoons can be replaced by ocean of sufficiently high SST. Furthermore, the ITCZ circulation extends into the tropics in the other hemisphere to give rise to the winter monsoon circulation there. Also through the equivalence of land-sea contrast and high SST, it is argued that the basic monsoon onset mechanism proposed by Chao is valid for all monsoons. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21228 USA. RP Chao, WC (reprint author), NASA, Atmospheres Lab, Goddard Space Flight Ctr, Mail Code 913, Greenbelt, MD 20771 USA. NR 29 TC 76 Z9 90 U1 3 U2 24 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 22 BP 3497 EP 3507 DI 10.1175/1520-0469(2001)058<3497:TOOM>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 488FC UT WOS:000171924700009 ER PT J AU Kato, S Smith, GL Barker, HW AF Kato, S Smith, GL Barker, HW TI Gamma-weighted discrete ordinate two-stream approximation for computation of domain-averaged solar irradiance SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID BOUNDARY-LAYER CLOUDS; RADIATIVE-TRANSFER; SCATTERING ATMOSPHERES; MULTIPLE-SCATTERING; HEATING RATES; PARAMETERIZATION; FLUXES; ALGORITHM; MEDIA AB An algorithm is developed for the gamma-weighted discrete ordinate two-stream approximation that computes profiles of domain-averaged shortwave irradiances for horizontally inhomogeneous cloudy atmospheres. The algorithm assumes that frequency distributions of cloud optical depth at unresolved scales can be represented by a gamma distribution though it neglects net horizontal transport of radiation. This algorithm is an alternative to the one used in earlier studies that adopted the adding method. At present, only overcast cloudy layers are permitted. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Environm Canada, Downsview, ON, Canada. RP NASA, Langley Res Ctr, Mail Stop 420,21 Langley Blvd,B1250, Hampton, VA 23681 USA. EM s.kato@larc.nasa.gov NR 20 TC 9 Z9 9 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PY 2001 VL 58 IS 24 BP 3797 EP 3803 DI 10.1175/1520-0469(2001)058<3797:GWDOTS>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 500HP UT WOS:000172621200009 ER PT J AU Xie, W Pan, WP Chuang, KC AF Xie, W Pan, WP Chuang, KC TI Thermal degradation study of polymerization of monomeric reactants (PMR) polyimides SO JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY LA English DT Article DE degradation; polyimide; thermal analysis AB A novel PMR polyimides (TMBZ-15) based on substituted benzidines is examined and compared to state-of-the-art PMR-15. The mechanism for the thermal decomposition of two specific PMR polyimides is obtained using TG/FTIR/MS techniques. In order to verify the pathway of polyimide degradation, a pyrolysis/GC-MS technique was employed to evaluate the organic degradation products, particularly the larger components that are destroyed in traditional TG/MS. A proposed degradation mechanism involves two main stages of decomposition, each of which produce a variety of products. The first group includes aromatic hydrocarbons, aromatic amines and nitriles, which correspond to partial fragments of polymer chains. The second group consists largely of fluorene, naphthalene and phenanthrene, which are attributed to the isomerization, rearrangements and cyclizations of the aforementioned pyrolyzates at high temperature. C1 Western Kentucky Univ, Dept Chem, Thermal Anal lab, Bowling Green, KY 42101 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Xie, W (reprint author), Western Kentucky Univ, Dept Chem, Thermal Anal lab, Bowling Green, KY 42101 USA. NR 6 TC 19 Z9 20 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1418-2874 J9 J THERM ANAL CALORIM JI J. Therm. Anal. PY 2001 VL 64 IS 2 BP 477 EP 485 DI 10.1023/A:1011566127251 PG 9 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 432EQ UT WOS:000168679600007 ER PT J AU Park, C Jaffe, RL Partridge, H AF Park, C Jaffe, RL Partridge, H TI Chemical-kinetic parameters of hyperbolic Earth entry SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 38th Aerospace Sciences Meeting and Exhibit CY JAN 10-15, 2000 CL RENO, NEVADA SP Amer Inst Aeronatu & Astronaut ID TRANSPORT CROSS-SECTIONS; ENERGY ELECTRON-SCATTERING; THERMAL RATE CONSTANTS; VISCOUS SHOCK-LAYER; COLLISION INTEGRALS; SURFACES; HYDROGEN; NITROGEN AB Chemical-kinetic parameters governing the Row in the shock layer over a heat shield of a blunt body entering Earth's atmosphere from a hyperbolic orbit are derived. By the use of the assumption that the heat shield is made of carbon phenolic and by allowing for an arbitrary rate of pyrolysis-gas injection, chemical reactions occurring in the shock layer are postulated, and the collision integrals governing the transport properties, the rate coefficients of the reactions, and the parameters needed for the bifurcation model and for the finite-rate kinetic wall boundary conditions are determined using the best available techniques. Sample flowfield calculations are performed using this set of parameters to show that the heating and surface removal rates are substantially smaller than calculated using the existing set of such parameters and traditional assumptions of gas-surface equilibrium and quasi-steady-state ablation. C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. Eloret Corp, Computat Chem Branch, Moffett Field, CA 94085 USA. RP Park, C (reprint author), NASA, Ames Res Ctr, Space Technol Div, Mail Stop 229-1, Moffett Field, CA 94035 USA. NR 51 TC 113 Z9 123 U1 1 U2 10 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 2001 VL 15 IS 1 BP 76 EP 90 DI 10.2514/2.6582 PG 15 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 396RX UT WOS:000166651300010 ER PT J AU Sakai, T Tsuru, T Sawada, K AF Sakai, T Tsuru, T Sawada, K TI Computation of hypersonic radiating flowfield over a blunt body SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 37th Aerospace Sciences Meeting and Exhibit CY JAN 11-14, 1999 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut ID ENTRIES; EARTH AB A numerical method for calculating a strongly radiating axisymmetric flowfield is developed, Radiative transfer is treated one, two, and three dimensionally. Radiative heat flux is evaluated using a model developed earlier that combines Planck, Rosseland, and gray-gas models. The Row solution is obtained with a fully implicit time-marching method using a full block matrix inversion. To show its robustness the method is applied to calculate the environment of a blunt body Eying at the velocity of 16 km/s, The results show that the multidimensional radiative transport calculation is different from the one-dimensional calculation. The computational costs for the method are given for each method of radiative transfer calculations. The method is also tested For an experiment conducted in a ballistic range. The calculated radiative heat flux values are lower than the measured value by a factor of at least four. C1 Tohoku Univ, Dept Aeronaut & Space Engn, Sendai, Miyagi 9808579, Japan. RP Sakai, T (reprint author), NASA, Ames Res Ctr, Reacting Flow Environm Branch, Mail Stop 230-2, Moffett Field, CA 94035 USA. NR 21 TC 6 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 2001 VL 15 IS 1 BP 91 EP 98 DI 10.2514/2.6583 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 396RX UT WOS:000166651300011 ER PT J AU Sakai, T Sawada, K AF Sakai, T Sawada, K TI Calculation of nonequilibrium radiation from a blunt-body shock layer SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA 38th Aerospace Sciences Meeting and Exhibit CY JAN 10-15, 2000 CL RENO, NEVADA SP Amer Inst Aeronatu & Astronaut ID CHEMICAL-KINETIC PROBLEMS; FUTURE NASA MISSIONS; FLOWFIELD; ENTRIES AB A numerical method is developed for calculating the radiating axisymmetric flowfield accounting for nonequilibrium thermochemistry, Solutions of the Row with radiation are obtained in a fully coupled manner using a fully implicit time-marching method through a full block-matrix inversion. The method is used in calculating the radiation from the blunt-body shock layer in both air and carbon-containing airflows, The calculated results are compared with the experimental data obtained in a ballistic range at flight speeds of up to 13.4 km/s, For aluminum models, which do not ablate, the experimentally observed spectral features are qualitatively reproduced by the calculation, which assumes the shock layer to contain only the air species. For polycarbonate models, which ablate, additionally carbonaceous species must be included in the calculation in order to bring about qualitative agreement. Quantitative agreement is obtained for the ablating models only by accounting additionally for a blackbody radiation, produced possibly by spalled carbon particles. C1 Tohoku Univ, Dept Aeronaut & Space Engn, Sendai, Miyagi 9808579, Japan. RP Sakai, T (reprint author), NASA, Ames Res Ctr, Reacting Flow Environm Branch, Mail Stop 230-2, Moffett Field, CA 94035 USA. NR 23 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 2001 VL 15 IS 1 BP 99 EP 105 DI 10.2514/2.6584 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 396RX UT WOS:000166651300012 ER PT J AU Kirkpatrick, AW Dulchavsky, SA Boulanger, BR Campbell, MR Hamilton, DR Dawson, DL Williams, DR AF Kirkpatrick, AW Dulchavsky, SA Boulanger, BR Campbell, MR Hamilton, DR Dawson, DL Williams, DR TI Extraterrestrial resuscitation of hemorrhagic shock: Fluids SO JOURNAL OF TRAUMA-INJURY INFECTION AND CRITICAL CARE LA English DT Review ID HYPERTONIC SALINE RESUSCITATION; 7.5-PERCENT SODIUM-CHLORIDE; LACTATED RINGERS SOLUTION; SEVERE HEAD-INJURY; TRAUMA PATIENTS; IN-SPACE; SIMULATED MICROGRAVITY; BAROREFLEX CONTROL; MULTICENTER TRIAL; HYPOVOLEMIC SHOCK C1 Vancouver Hosp & Hlth Sci Ctr, Trauma Serv, Vancouver, BC V5Z 1L7, Canada. Wayne State Univ, Sch Med, Detroit, MI USA. Univ Kentucky, Med Ctr, Lexington, KY USA. NASA, Houston, TX USA. Wyle Life Sci, Houston, TX USA. RP Kirkpatrick, AW (reprint author), Vancouver Hosp & Hlth Sci Ctr, Trauma Serv, 3rd Floor,855 W 10th Ave, Vancouver, BC V5Z 1L7, Canada. NR 94 TC 12 Z9 12 U1 1 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0022-5282 J9 J TRAUMA JI J. Trauma-Injury Infect. Crit. Care PD JAN PY 2001 VL 50 IS 1 BP 162 EP 168 DI 10.1097/00005373-200101000-00036 PG 7 WC Critical Care Medicine; Surgery SC General & Internal Medicine; Surgery GA 392UQ UT WOS:000166431300036 PM 11231691 ER PT J AU Chang, L Zhao, YW Hall, PB Thom, R Moore, C AF Chang, L Zhao, YW Hall, PB Thom, R Moore, C TI On heat generation in rolling contacts under boundary and mixed lubrication SO JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID LOAD ROLLING/SLIDING CONTACTS; ROUGHNESS; SURFACES AB This paper reports on experiments and theoretical analyses of heat generation and scuffing failure in rolling contacts. The experiments were conducted with dry contacts, and the theoretical analyses were carried out using a deterministic thermal contact model. The research reveals that heat generated by asperity plastic deformation in the direction normal to the contact can be significant in high-lend, high-speed contacts under boundary and mixed lubrication conditions. Under near rolling conditions, heat generated by the plastic deformation largely dominates that by the friction and is the main source leading to contact scuffing. This heat generation is shown to be significant compared to frictional heating even at relatively large slide-to-roll ratios. Parametric studies show that the ratio of asperity-plastic-deformation healing to frictional heating is sensitive to slide-to-roll ratio, hardness and surface finish but insensitive to contact load, rolling velocity and fluid/asperity load sharing. C1 Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. NASA, George C Marshall Space Flight Ctr, Nondestruct Evaluat & Tribol Branch, Huntsville, AL 35812 USA. RP Chang, L (reprint author), Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4787 J9 J TRIBOL-T ASME JI J. Tribol.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 61 EP 66 DI 10.1115/1.1330733 PG 6 WC Engineering, Mechanical SC Engineering GA 395UR UT WOS:000166600100009 ER PT J AU Suder, KL Hathaway, MD Thorp, SA Strazisar, AJ Bright, MB AF Suder, KL Hathaway, MD Thorp, SA Strazisar, AJ Bright, MB TI Compressor stability enhancement using discrete tip injection SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 45th International Gas Turbine and Aeroengine Congress and Exhibition CY MAY 08-11, 2000 CL MUNICH, GERMANY ID SPEED AXIAL COMPRESSOR; ROTATING STALL CONTROL; INLET DISTORTION; ACTIVE STABILIZATION; STAGE; CLEARANCE; SURGE; ROTOR; FLOW; FAN AB Mass injection upstream of the tip of a high-speed axial compressor rotor is a stability enhancement approach known to be effective in suppressing stall in tip-critical rotors. This process is examined in a transonic axial compressor rotor through experiments and time-averaged Navier-Stokes CFD simulations. Measurements and simulations for discrete injection are presented for. a range of injection rates nr and distributions of injectors around the annulus. The simulations indicate that tip injection increases stability by unloading the rotor tr;a and that increasing injection velocity improves the effectiveness of tip injection. For the rested rotor, experimental results demonstrate that at 70 percent speed the stalling flow coefficient can be reduced by 30 percent using an injected massflow; equivalent to I percent of the annulus flow. At design speed, the stalling flow coefficient was reduced by 6 percent rising an injected massflow equivalent to 2 percent of the annulus pow. The experiments show that stability enhancement is related to the mass-averaged axial velocity at the tip. For a given injected massflow, the mass-averaged axial velocity at the tip is increased by injecting flow over-discrete portions of the circumference as opposed to full-annular injection. The implications of these results on the design of recirculating casing treatments and other methods to enhance stability will be discussed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. USA, Vehicle Technol Directorate, Cleveland, OH 44135 USA. RP Suder, KL (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 31 TC 85 Z9 96 U1 3 U2 20 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 14 EP 23 DI 10.1115/1.1330272 PG 10 WC Engineering, Mechanical SC Engineering GA 403PF UT WOS:000167051100003 ER PT J AU Thurman, D Poinsatte, P AF Thurman, D Poinsatte, P TI Experimental heat transfer and bulk air temperature measurements for a multipass internal cooling model with ribs and bleed SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 45th International Gas Turbine and Aeroengine Congress and Exhibition CY MAY 08-11, 2000 CL MUNICH, GERMANY ID PASSAGES; FRICTION; CHANNEL AB An experimental study was made to obtain heat transfer and air temperature data for a simple three-leg serpentine lest section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady-state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found ro be greater for ribs near bleed holes compared to ribs between holes, and both configuration rations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discrete locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model. C1 USA, Res Lab, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Thurman, D (reprint author), USA, Res Lab, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 15 TC 18 Z9 19 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 90 EP 96 DI 10.1115/1.1333090 PG 7 WC Engineering, Mechanical SC Engineering GA 403PF UT WOS:000167051100016 ER PT J AU Van Fossen, GJ Bunker, RS AF Van Fossen, GJ Bunker, RS TI Augmentation of stagnation region heat transfer due to turbulence from a DLN can combustor SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 45th International Gas Turbine and Aeroengine Congress and Exhibition CY MAY 08-11, 2000 CL MUNICH, GERMANY AB Heat transfer measurements have been made in the stagnation. region of a flat plate with a circular leading edge. Electrically heated aluminum strips placed symmetrically about the lending edge stagnation region were used to measure spanwise-averaged heat transfer coefficients. The maximum Reynolds number obtained based on leading edge diameter, was about 100,000. The model was immersed ill the flow field downstream of nit approximately half-scale model of a can-type combustor from a low NOx, ground-based power-generating turbine. The tests were conducted with room temperature air no fuel was added. Room air flowed into the combustor through sir vane-type fuel/air swirlers. The combustor can contained no dilution holes. The fuel/air swirlers all swirled the incoming airflow in a counterclockwise direction (facing downstream). A five-hole probe flow field survey in the plane of the model stagnation point showed the flow was one big vortex with flow angles up to 36 deg at the enter edges of the rectangular test section. Hot-wire measurements showed rest section flow had very high levels of turbulence, around 28.5 percent, and had a relatively large axial-length scale-to-leading edge diameter ratio of 0.5. X-wire measurements showed the turbulence to be nearly isotropic. Stagnation heat transfer augmentation:over laminar levels was around 77 percent and was about 14 percent higher than predicted by a previously developed correlation for isotropic grid-generated turbulence. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Gen Elect, Moscow 123098, Russia. RP Van Fossen, GJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 16 TC 12 Z9 12 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 140 EP 146 DI 10.1115/1.1330270 PG 7 WC Engineering, Mechanical SC Engineering GA 403PF UT WOS:000167051100022 ER PT J AU Boyle, RJ Spuckler, CM Lucci, BL Camperchioli, WP AF Boyle, RJ Spuckler, CM Lucci, BL Camperchioli, WP TI Infrared low-temperature turbine vane rough surface heat transfer measurements SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 45th International Gas Turbine and Aeroengine Congress and Exhibition CY MAY 08-11, 2000 CL MUNICH, GERMANY ID PREDICTION; FLOWS AB Turbine vane heat transfer distributions obtained using an infrared camera technique are described. Infrared thermography was used because noncontact surface temperature measurements were desired. Surface temperatures were 80 degreesC or less. Tests were conducted in a three-vane linear cascade, with inlet pressures between 0.14 and 1.02 atm, and exit Mach numbers of 0.3, 0.7, and 0.9, for turbulence intensities of approximately 1 and 10 percent Measurements were taken on, the vane suction. side, and on the pressure side leading edge region. The designs for both the vane and test facility are discussed. The approach used to account for: conduction within the vane is described. Midspan heat transfer distributions are given for the range of test conditions. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Boyle, RJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 24 TC 9 Z9 12 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 168 EP 177 DI 10.1115/1.1333693 PG 10 WC Engineering, Mechanical SC Engineering GA 403PF UT WOS:000167051100026 ER PT J AU Halicioglu, T AF Halicioglu, T TI Calculated energetics for adsorption and desorption steps during etching of Si(110) surface by Cl SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID SILICON; CHLORINE; DYNAMICS; SI; SI(100)-(2X1); SPECTROSCOPY AB Energetics and the configurational aspects related to the adsorption of Cl on the (110) index plane of Si and the subsequent desorption of SiClchi species from the surface (leading to etching) were investigated. Calculations were conducted for varying surface Cl concentrations. First and second chlorination steps for surface Si atoms were analyzed and the role played by surface vacancies was investigated. On the Si(110) surface, steric effects coming from repulsive forces among the adsorbed Cl atoms, were found to be quite significant. Results indicate that the second chlorination step which leads to the formation of attached SiCl2 species, is very important in the overall eching process. (C) 2001 American Vacuum Society. C1 NASA, Ames Res Ctr, Thermosci Inst, Moffett Field, CA 94035 USA. RP Halicioglu, T (reprint author), Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA. NR 22 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JAN-FEB PY 2001 VL 19 IS 1 BP 372 EP 375 DI 10.1116/1.1322650 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 394BY UT WOS:000166505200057 ER PT J AU Leamy, MJ Gottlieb, O AF Leamy, MJ Gottlieb, O TI Nonlinear dynamics of a taut string with material nonlinearities SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article ID FORCED VIBRATION; RESONANT MOTION; NONPLANAR AB A spatial string model incorporating a nonlinear (and nonconservative) material law is proposed using finite deformation continuum mechanics. The resulting model is shown to reduce to the classical nonlinear string when a linens material law is used. The influence of material nonlinearities on the string's dynamic response to excitation near a transverse natural frequency is shown to be small due to their appearance at high orders only. Material nonlinearities appear at low Order in the equations for excitation near a longitudinal natural frequency. and a solution for this case is developed by applying a second order multiple scales method directly to the partial differential equations. The material nonlinearities are found to influence both the degree of nonlinearity in the response and its softening Or hardening nature. C1 Technion Israel Inst Technol, Fac Mech Engn, IL-32000 Haifa, Israel. RP Leamy, MJ (reprint author), NASA, Langley Res Ctr, Mail Stop 201,11 W Taylor St,Bldg 1146,Room 116, Hampton, VA 23665 USA. NR 19 TC 1 Z9 1 U1 1 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1048-9002 J9 J VIB ACOUST JI J. Vib. Acoust.-Trans. ASME PD JAN PY 2001 VL 123 IS 1 BP 53 EP 60 DI 10.1115/1.1325411 PG 8 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 398ZZ UT WOS:000166787500008 ER PT J AU Watson, AB AF Watson, Andrew B. TI Welcome to the Journal of Vision SO JOURNAL OF VISION LA English DT Editorial Material C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Watson, AB (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 1534-7362 J9 J VISION JI J. Vision PY 2001 VL 1 IS 1 BP I EP III AR i DI 10.1167/1.1.i PG 3 WC Ophthalmology SC Ophthalmology GA V02EU UT WOS:000206907300001 ER PT J AU Schofield, D Mjolsnes, E Buckley, J Wold, B Triche, TJ AF Schofield, D Mjolsnes, E Buckley, J Wold, B Triche, TJ TI Gene expression patterns in pediatric rhabdomyosarcoma. SO LABORATORY INVESTIGATION LA English DT Meeting Abstract C1 Univ So Calif, Keck Sch Med, Los Angeles, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 0023-6837 EI 1530-0307 J9 LAB INVEST JI Lab. Invest. PD JAN PY 2001 VL 81 IS 1 MA 34 BP 6P EP 6P PG 1 WC Medicine, Research & Experimental; Pathology SC Research & Experimental Medicine; Pathology GA 396KE UT WOS:000166634901455 ER PT J AU Schofield, D Mjolsness, E Buckley, J Wold, B Triche, TJ AF Schofield, D Mjolsness, E Buckley, J Wold, B Triche, TJ TI Gene expression patterns in pediatric sarcomas as a predictor of clinical outcome SO LABORATORY INVESTIGATION LA English DT Meeting Abstract C1 Univ So Calif, Keck Sch Med, Los Angeles, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 0023-6837 EI 1530-0307 J9 LAB INVEST JI Lab. Invest. PD JAN PY 2001 VL 81 IS 1 MA 87 BP 18A EP 18A PG 1 WC Medicine, Research & Experimental; Pathology SC Research & Experimental Medicine; Pathology GA 396KE UT WOS:000166634900100 ER PT S AU Maleki, L Young, B AF Maleki, L Young, B BE Hall, JL Ye, J TI Clocks and oscillators in space SO LASER FREQUENCY STABILIZATION, STANDARDS, MEASUREMENT AND APPLICATIONS SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Laser Frequency Stabilization, Standards, Measurement, and Applications CY JAN 24-26, 2001 CL SAN JOSE, CA SP SPIE ID LASER AB Clocks and oscillators have traditionally played an important role in space navigation and communication, as well as in space science and in tests of fundamental physical laws. Microwave clocks currently in use in space will be replaced by laser cooled clocks capable of significantly improved performance. Beyond this, lasers will play an important role as oscillators used for their spectral purity in interferometry based experiments, and will likely be used as the local oscillators for future optical clocks. In this paper a short review of the role of clocks and oscillators in space is presented, together with some future projections for laser based systems. C1 CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, Pasadena, CA 91109 USA. RP Maleki, L (reprint author), CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3947-9 J9 PROC SPIE PY 2001 VL 4269 BP 178 EP 183 DI 10.1117/12.424467 PG 6 WC Optics; Physics, Applied SC Optics; Physics GA BS41H UT WOS:000169777100020 ER PT S AU Ilchenko, VS Maleki, L AF Ilchenko, VS Maleki, L BE Kudryashov, AV Paxton, AH TI Novel whispering-gallery resonators for lasers, modulators, and sensors SO LASER RESONATORS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Resonators IV CY JAN 23-25, 2001 CL SAN JOSE, CA SP SPIE DE microsphere; microcavity; photonics; electrooptic modulator; microsensor ID OPTICAL MICROSPHERE RESONATORS; CAVITY; MODES AB This report describes novel whispering-gallery resonators with added physical properties, including a micro-toroidal cavity with large free spectral range similar to 400GHz and finesse > 10(4), a lithium niobate spherical cavity in a high-efficiency X-band electro-optic modulator, and an immersed silica microsphere as high-resolution chemical sensor. C1 CALTECH, Jet Prop Lab, MS 298100, Pasadena, CA 91109 USA. RP Ilchenko, VS (reprint author), CALTECH, Jet Prop Lab, MS 298100, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 47 Z9 47 U1 1 U2 8 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3948-7 J9 P SOC PHOTO-OPT INS PY 2001 VL 4270 BP 120 EP 130 DI 10.1117/12.424663 PG 11 WC Optics; Physics, Applied SC Optics; Physics GA BS33Z UT WOS:000169530300015 ER PT S AU Maleki, L Huang, SH Iltchenko, V Le, T AF Maleki, L Huang, SH Iltchenko, V Le, T GP IEEE IEEE TI Photonic synthesis of RF frequency SO LEOS 2001: 14TH ANNUAL MEETING OF THE IEEE LASERS & ELECTRO-OPTICS SOCIETY, VOLS 1 AND 2, PROCEEDINGS SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 14th Annual Meeting of the IEEE Lasers-and-Electro-Optics-Society CY NOV 11-15, 2001 CL SAN DIEGO, CA SP IEEE, IEE Lasers and Electro Opt Soc ID OPTOELECTRONIC MICROWAVE-OSCILLATOR C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Lute.Maleki@jpl.nasa.gov NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1092-8081 BN 0-7803-7105-4 J9 IEEE LEOS ANN MTG PY 2001 BP 119 EP 120 PG 2 WC Engineering, Electrical & Electronic; Optics; Physics, Condensed Matter SC Engineering; Optics; Physics GA BU32T UT WOS:000175700800060 ER PT S AU Qiu, Y Gogna, P Forouhar, S Stintz, A Lester, L AF Qiu, Y Gogna, P Forouhar, S Stintz, A Lester, L GP IEEE IEEE TI High temperature continuous wave operation of InAs quantum dot lasers near 1-3 mu m SO LEOS 2001: 14TH ANNUAL MEETING OF THE IEEE LASERS & ELECTRO-OPTICS SOCIETY, VOLS 1 AND 2, PROCEEDINGS SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 14th Annual Meeting of the IEEE Lasers-and-Electro-Optics-Society CY NOV 11-15, 2001 CL SAN DIEGO, CA SP IEEE, IEE Lasers and Electro Opt Soc ID LOW-THRESHOLD; LAYER C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Qiu, Y (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1092-8081 BN 0-7803-7105-4 J9 IEEE LEOS ANN MTG PY 2001 BP 267 EP 268 PG 2 WC Engineering, Electrical & Electronic; Optics; Physics, Condensed Matter SC Engineering; Optics; Physics GA BU32T UT WOS:000175700800134 ER PT S AU Hartley, JB AF Hartley, JB BE Singh, UN Itabe, T Sugimoto, N TI NASA's future active remote sensing missions for earth science SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE NASA; remote sensing; mission; active optical; laser; lidar; active microwave; radar AB Since the beginning of space remote sensing of the earth, there has been a natural progression widening the range of electromagnetic radiation used to sense the earth, and slowly, steadily increasing the spatial, spectral, and radiometric resolution of the measurements. There has also been a somewhat slower trend toward active measurements across the electromagnetic spectrum, motivated in part by increased resolution, but also by the ability to make new measurements. Active microwave instruments have been used to measure ocean topography, to study the land surface, and to study rainfall from space. Future NASA active microwave missions may add detail to the topographical studies, sense soil moisture, and better characterize the cryosphere. Only recently have active optical instruments been flown in space by NASA; however, there are currently several missions in development which will sense the earth with lasers and many more conceptual active optical missions which address the priorities of NASA's earth science program. Missions are under development to investigate the structure of the terrestrial vegetation canopy, to characterize the earth's ice caps, and to study clouds and aerosols. Future NASA missions may measure tropospheric vector winds and make vastly improved measurements of the chemical components of the earth's atmosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hartley, JB (reprint author), NASA, Goddard Space Flight Ctr, Code 710, Greenbelt, MD 20771 USA. NR 9 TC 2 Z9 2 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 5 EP 12 DI 10.1117/12.417027 PG 8 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600002 ER PT S AU Yu, J Singh, UN Barnes, JC Barnes, NP Petros, M AF Yu, J Singh, UN Barnes, JC Barnes, NP Petros, M BE Singh, UN Itabe, T Sugimoto, N TI A high energy 2-mu m laser for multiple lidar applications SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE 2-mu m laser; diode pumped laser; laser amplifier; lidar; DIAL ID YLF LASER; HO AB Solid-state 2-mum laser has been receiving considerable interest because of its eye-safe property and efficient diode pump operation. It has potential for multiple lidar applications to detect water vapor, carbon dioxide and winds. In this paper, we describe a 2-mum double pulsed Ho:Tm:YLF laser and end-pumped amplifier system. A comprehensive theoretical model has been developed to aid the design and optimization of the laser performance. hi a single Q-switched pulse operation, the residual energy stored in the Tm atoms will be wasted However, in a double pulses operation mode, the residual energy stored in the Tm atoms will repopulate the Ho atoms that were depleted by the extraction of the first Q-switched pulse. Thus, the Tm sensitized Ho:YLF laser provides a unique advantage in applications that require double pulse operation, such as Differential Absorption Lidar (DIAL). A total output energy of 146 mJ per pulse pair under Q-switch operation is achieved with as high as 4.8 % optical to optical efficiency. Compared to a single pulse laser, 70% higher laser efficiency is realized. To obtain high energy while maintaining the high beam quality, a master-oscillator-power-amplifier 2-mum system is designed. We developed an end-pumped Ho:Tm:YLF disk amplifier. This amplifier uses two diode arrays as pump source. A non-imaging lens duct is used to couple the radiation from the laser diode arrays to the laser disk. Preliminary result shows that the efficiency of this laser can be as high as 3 %, a factor of three increases over side-pump configuration. This high energy, highly efficient and high beam quality laser is a promising candidate for use in an efficient, multiple lidar applications. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Yu, J (reprint author), NASA, Langley Res Ctr, MS 474, Hampton, VA 23681 USA. NR 9 TC 0 Z9 0 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 70 EP 77 DI 10.1117/12.417025 PG 8 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600010 ER PT S AU Mo, SY Cutler, AD Choi, SH Lee, MH Singh, UN AF Mo, SY Cutler, AD Choi, SH Lee, MH Singh, UN BE Singh, UN Itabe, T Sugimoto, N TI New submount requirement of conductively cooled laser diodes for lidar applications SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE high power diode laser; thermal dissipation; thermal runaway; LIDAR AB New submount technology is essential for the development of conductively cooled high power diode laser. The simulation and experimental results indicate that thermal conductivity of submount for high power laser-diode must be at least 600 W/m/k or higher for stable operation. We have simulated several theoretical thermal. model based on new submount designs and characterized high power diode lasers to determine temperature effects on the performances of laser diodes. The characterization system measures the beam power, output beam profile, temperature distribution, and spectroscopic property of high power diode laser. The characterization system is composed of four main parts: an infrared imaging camera, a CCD camera, a monochromator, and a power meter. Thermal characteristics of two commercial-grade CW 20-W diode laser bars with open heat-sink type were determined with respect to the line shift of emission spectra and beam power stability. The center wavelength of laser emission has a tendency to shift toward longer wavelength as the driving current and heat sink temperature are increased. The increase of heat sink temperature decreases the output power of the laser bar too. Such results lay the guidelines for the design of new submount for high power laser-diodes. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Mo, SY (reprint author), NASA, Langley Res Ctr, MS 188B, Hampton, VA 23681 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 104 EP 113 DI 10.1117/12.417034 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600014 ER PT S AU Grant, WB Browell, EV AF Grant, WB Browell, EV BE Singh, UN Itabe, T Sugimoto, N TI Airborne UV DIAL measurements of ozone and aerosols SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE aerosols; airborne measurements; Differential Absorption Lidar (DIAL); lidar; NASA; ozone; pollution; troposphere; stratosphere; volcano ID AIR-MASS CHARACTERISTICS; CONTINENTAL OUTFLOW; BURNING SEASON; PACIFIC; POLLUTION; DISTRIBUTIONS; TROPOSPHERE; TRANSPORT; BASIN; ASIA AB The NASA Langley Research Center's airborne UV Differential Absorption Lidar (DIAL) system measures vertical profiles of ozone and aerosols above and below the aircraft along its night track. This system has been used in over 20 airborne field missions designed to study the troposphere and stratosphere since 1980. Four of these missions involved tropospheric measurement programs in the Pacific Ocean with two in the western North Pacific and two in the South Pacific. The UV DIAL system has been used in these missions to study such things as pollution outflow, long-range transport, and stratospheric intrusions; categorize the air masses encountered; and to guide the aircraft to altitudes where interesting features can be studied using the in situ instruments. This paper will highlight the findings with the UV DIAL system in the Pacific Ocean field programs and introduce the mission planned for the western North Pacific for February-April 2001. This will be an excellent opportunity for collaboration between the NASA airborne mission and those with ground-based lidar systems in Asia Pacific Rim countries to make a more complete determination of the transport of air from Asia to the western Pacific. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Grant, WB (reprint author), NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. OI Grant, William/0000-0002-1439-3285 NR 28 TC 1 Z9 1 U1 0 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 290 EP 295 DI 10.1117/12.417058 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600036 ER PT S AU Bruce, BM Chen, HL Li, SX AF Bruce, BM Chen, HL Li, SX BE Singh, UN Itabe, T Sugimoto, N TI GLOW - The Goddard Lidar Observatory for Winds SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE Doppler lidar; tropospheric wind; Fabry-Perot etalon ID DOPPLER LIDAR; EDGE TECHNIQUE; VALIDATION AB GLOW (Goddard Lidar Observatory for Winds) is a mobile Doppler lidar system which uses direct detection Doppler lidar techniques to measure wind profiles from the surface into the lower stratosphere. The system is contained in a modified van to allow deployment in field operations. The lidar system uses a Nd:YAG laser transmitter to measure winds using either aerosol backscatter at 1064 nm or molecular backscatter at 355 nm. The receiver telescope is a 45 cm Dall-Kirkham which is fiber coupled to separate Doppler receivers, one optimized for the aerosol backscatter wind measurement and another optimized for the molecular backscatter wind measurement. The receivers are implementations of the 'double edge' technique and use high spectral resolution Fabry-Perot etalons to measure the Doppler shift. A 45 cm aperture azimuth-overelevation scanner is mounted on the roof of the van to allow full sky access and a variety of scanning options. GLOW is intended to be used as a deployable field system for studying atmospheric dynamics and transport and can also serve as a testbed to evaluate candidate technologies developed for use in future spaceborne systems. In addition, it can be used for calibration/validation activities following launch of spaceborne wind lidar systems. A description of the mobile system is presented along with the examples of lidar wind profiles obtained with the system. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Bruce, BM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 314 EP 320 DI 10.1117/12.417062 PG 7 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600039 ER PT S AU Edwards, WC Chen, S Petway, LB Marsh, WD Storm, ME Barnes, JC AF Edwards, WC Chen, S Petway, LB Marsh, WD Storm, ME Barnes, JC BE Singh, UN Itabe, T Sugimoto, N TI A novel high efficient laser transmitter design for a space-borne ozone Differential Absorption Lidar (DIAL) SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE ozone DIAL; ultra-violet laser technology; solid-state UV laser transmitter ID GENERATION AB Development of a UV laser transmitter capable of operating from a space platform is a critical step in enabling global earth observations of aerosols and ozone at resolutions greater than current passive instrument capabilities. Tropospheric chemistry is well recognized as the next frontier for global atmospheric measurement. NASA Langley Research Center (LaRC) and the Canadian Space Agency (CSA) have jointly studied the requirements for a satellite based, global ozone monitoring instrument. The study, called Ozone Research using Advanced Cooperative Lidar Experiment (ORACLE) has defined the Differential Absorption Lidar (DIAL) instrument performance, weight and power, and configuration requirements for a space based measurement. In order to achieve the measurement resolution and acceptable signal-to-noise from lidar returns, 500mJ/pulse (5 Watts average power) is required at both 305-308nm and 315-320nm wavelengths. These are consecutive pulses, in a 10 Hz, double-pulsed format. The two wavelengths are used as the on- and off-lines for the ozone DIAL measurement. NASA Langley is currently developing technology for a UV laser transmitter capable of meeting the ORACLE requirements. Experimental efforts to date have shown that the UV generation scheme is viable, and that energies greater than 100mJ/pulse are possible, in this paper, we will briefly discuss the down select process for the proposed laser design, the study effort to date and the laser system design, including both primary and alternate approaches. We will describe UV laser technology that minimizes the total number of optical components (for enhanced reliability) as well as the number of UV coated optics required to transmit the light from the laser (for enhanced optical damage resistance). While the goal is to develop a laser that will produce 500 mJ of energy, we will describe an optional design that will produce output energies between 100-200mJ/unit and techniques for combining multiple laser modules in order to transmit a minimum of 500mJ of UV energy in each pulse of the on- and off-line pulse pairs. This modular laser approach provides redundancy and significantly reduces development time, risk and cost when compared to the development of a single, 500mJ double-pulsed Laser subsystem. Finally, we will summarize the laser development effort to date, including results that include the highest known UV energy (130 mJ @ 320nm) ever produced by a solid-state laser operating in this wavelength region. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Edwards, WC (reprint author), NASA, Langley Res Ctr, MS 474, Hampton, VA 23681 USA. NR 10 TC 0 Z9 0 U1 1 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 350 EP 358 DI 10.1117/12.417067 PG 9 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600043 ER PT S AU Kavaya, MJ Spiers, GD Frehlich, RG AF Kavaya, MJ Spiers, GD Frehlich, RG BE Singh, UN Itabe, T Sugimoto, N TI Potential pitfalls related to space-based lidar remote sensing of the Earth with an emphasis on wind measurement SO LIDAR REMOTE SENSING FOR INDUSTRY AND ENVIRONMENT MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Remote Sensing for Industry and Environment Monitoring CY OCT 09-12, 2000 CL SENDAI, JAPAN SP SPIE, Natl Space Dev Agcy Japan, Tohoku Inst Technol, NASA Langley Res Ctr, NPOESS, TRW DE lidar; wind; coherent; laser; earth remote sensing ID COHERENT LIDAR; PERFORMANCE; 2-MU-M; ORBIT AB A collection of issues is discussed that are potential pitfalls, if handled incorrectly, for earth-orbiting lidar remote sensing instruments. These issues arise due to the long target ranges, high lidar-to-target relative velocities, low signal levels, use of laser scanners, and other unique aspects of using lasers in earth orbit. Consequences of misunderstanding these topics range from minor inconvenience to improper calibration to total failure. We will focus on wind measurement using coherent detection Doppler lidar, but many of the potential pitfalls apply also to noncoherent lidar wind measurement, and to measurement of parameters other than wind. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Kavaya, MJ (reprint author), NASA, George C Marshall Space Flight Ctr, MS SD60, Huntsville, AL 35812 USA. NR 22 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3806-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4153 BP 385 EP 393 DI 10.1117/12.417072 PG 9 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics, Applied SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Optics; Physics GA BS25P UT WOS:000169198600047 ER PT S AU Rummel, JD AF Rummel, JD BE Debus, A Rummel, JD Horneck, G Rettberg, P TI Implementing planetary protection requirements for sample return missions SO LIFE SCIENCES: PLANETARY PROTECTION; OZONE AND UVB RADIATION EFFECTS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4/F3 6 Symposium of COSPAR Scientific Commission F held at the 32nd COSPAR Scientific Meeting CY JUL, 1998 CL NAGOYA, JAPAN SP Ctr Natl Etudes Spatiales, Natl Aeronaut & Space Adm, Comm Space Res, World Meteorol Org, Eurpean Comm, Wolrd Climate Res Programme, Stratospher process & Role Climate AB NASA is committed to exploring space while avoiding the biological contamination of other solar system bodies and protecting the Earth against potential harm from materials returned from space. NASA's planetary protection program evaluates missions (with external advice from the US National Research Council and others) and imposes particular constraints on individual missions to achieve these objectives. In 1997 the National Research Council's Space Studies Board published the report, Mars Sample Return: Issues and Recommendations, which reported advice to NASA on Mars sample return missions, complementing their 1992 report, The Biological Contamination of Mars: Issues and Recommendations. Meanwhile, NASA has requested a new Space Studies Board study to address sample returns from bodies other than Mars. This study recognizes the variety of worlds that have been opened up to NASA and its partners by small, relatively inexpensive, missions of the Discovery class, as well as the reshaping of our ideas about life in the solar system that have been occasioned by the Galileo spacecraft's discovery that an ocean under the ice on Jupiter's moon Europa might, indeed, exist. This paper will report on NASA's planned implementation of planetary protection provisions based on these recent National Research Council recommendations, and will suggest measures for incorporation in the planetary protection policy of COSPAR. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA Headquarters, Off Space Sci, Washington, DC USA. RP Rummel, JD (reprint author), NASA Headquarters, Off Space Sci, Washington, DC USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 26 IS 12 BP 1893 EP 1899 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43X UT WOS:000169859200001 ER PT S AU Barengoltz, JB AF Barengoltz, JB BE Debus, A Rummel, JD Horneck, G Rettberg, P TI Planetary protection issues for Mars sample acquisition flight projects SO LIFE SCIENCES: PLANETARY PROTECTION; OZONE AND UVB RADIATION EFFECTS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4/F3 6 Symposium of COSPAR Scientific Commission F held at the 32nd COSPAR Scientific Meeting CY JUL, 1998 CL NAGOYA, JAPAN SP Ctr Natl Etudes Spatiales, Natl Aeronaut & Space Adm, Comm Space Res, World Meteorol Org, Eurpean Comm, Wolrd Climate Res Programme, Stratospher process & Role Climate AB The planned NASA sample acquisition flight missions to Mars pose several interesting planetary protection issues. In addition to the usual forward contamination procedures for the adequate protection of Mars for the sake of future missions, there are reasons to ensure that the sample is not contaminated by terrestrial microbes from the acquisition mission. Recent recommendations by the Space Studies Board (SSB) of the National Research Council (United States), would indicate that the scientific integrity of the sample is a planetary protection concern (SSB, 1997). Also, as a practical matter, a contaminated sample would interfere with the process for its release from quarantine after return for distribution to the interested scientists. These matters are discussed in terms of the first planned acquisition mission. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barengoltz, JB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 26 IS 12 BP 1911 EP 1916 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43X UT WOS:000169859200003 ER PT S AU Lambert, JC Van Roozendael, M Simon, PC Pommereau, JP Goutail, F Gleason, JF Andersen, SB Arlander, DW Van, NAB Claude, H de la Noe, J De Maziere, M Dorokhov, V Eriksen, P Green, A Tornkvist, KK Hoiskar, BAK Kyro, E Leveau, J Merienne, MF Milinevsky, G Roscoe, HK Sarkissian, A Shanklin, JD Stahelin, J Tellefsen, CW Vaughan, G AF Lambert, JC Van Roozendael, M Simon, PC Pommereau, JP Goutail, F Gleason, JF Andersen, SB Arlander, DW Van, NAB Claude, H de la Noe, J De Maziere, M Dorokhov, V Eriksen, P Green, A Tornkvist, KK Hoiskar, BAK Kyro, E Leveau, J Merienne, MF Milinevsky, G Roscoe, HK Sarkissian, A Shanklin, JD Stahelin, J Tellefsen, CW Vaughan, G BE Debus, A Rummel, JD Horneck, G Rettberg, P TI Combined characterisation of GOME and TOMS total ozone measurements from space using ground-based observations from the NDSC SO LIFE SCIENCES: PLANETARY PROTECTION; OZONE AND UVB RADIATION EFFECTS SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3 4/F3 6 Symposium of COSPAR Scientific Commission F held at the 32nd COSPAR Scientific Meeting CY JUL, 1998 CL NAGOYA, JAPAN SP Ctr Natl Etudes Spatiales, Natl Aeronaut & Space Adm, Comm Space Res, World Meteorol Org, Eurpean Comm, Wolrd Climate Res Programme, Stratospher process & Role Climate ID VALIDATION; SENSORS; NO2 AB Several years of total ozone measured from space by the ERS-2 GOME, the Earth Probe TOMS, and the ADEOS TOMS, are compared with high-quality ground-based observations associated with the Network for the Detection of Stratospheric Change (NDSC), over an extended latitude range and a variety of geophysical conditions. The comparisons with each spaceborne sensor are combined altogether for investigating their respective solar zenith angle (SZA) dependence, dispersion, and difference of sensitivity. The space- and ground-based data are found to agree within a few percent on average. However, the analysis highlights for both GOME and TOMS several sources of discrepancies: (i) a SZA dependence with TOMS beyond 80 degrees SZA; (ii) a seasonal SZA dependence with GOME beyond 70 degrees SZA; (iii) a difference of sensitivity with COME at high latitudes; (iv) a difference of sensitivity to low ozone values between satellite and SAOZ sensors around the southern tropics; (v) a north/south difference of TOMS with the ground-based observations; and (vi) internal inconsistencies in COME total ozone. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Inst Aeron Spatiale Belgique, BIRA, B-1180 Brussels, Belgium. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. DMI, DK-2100 Copenhagen, Denmark. Norweigian Inst Air Res, N-2007 Kjeller, Norway. Univ Estadual Sao Paulista, UNESP, BR-17001 Bauru, SP, Brazil. DWD, D-82383 Hohenpeissenberg, Germany. Univ Bordeaux 1, CNRS, INSU, Observ Bordeaux, F-33270 Floirac, France. CAO, Dolgoprudnyi 141700, Moscow, Russia. Univ Coll Wales, Aberystwyth SY23 3BZ, Dyfed, Wales. FMI, Sodankyla Observ, FI-99600 Sodankyla, Finland. Univ La Reunion, LPA, F-97715 St Denis 9, France. Univ Reims, GSMA, Fac Sci, F-51687 Reims 2, France. KTSU, Space Phys Lab, UA-252022 Kiev, Ukraine. British Antarctic Survey, Cambridge CB3 0ET, England. Swiss Fed Inst Technol, Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland. RP Lambert, JC (reprint author), Inst Aeron Spatiale Belgique, BIRA, Ave Circulaire 3, B-1180 Brussels, Belgium. RI Gleason, James/E-1421-2012; andersen, signe/C-4809-2013; Vaughan, Geraint/O-2459-2015 OI andersen, signe/0000-0002-8216-0141; Vaughan, Geraint/0000-0002-0885-0398 NR 15 TC 3 Z9 3 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2001 VL 26 IS 12 BP 1931 EP 1940 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43X UT WOS:000169859200005 ER PT S AU Peeters, P Muller, JF Simon, PC Gillotay, D Celarier, EA Herman, JR AF Peeters, P Muller, JF Simon, PC Gillotay, D Celarier, EA Herman, JR BE Debus, A Rummel, JD Horneck, G Rettberg, P TI Monitoring surface UV-B irradiance from space using GOME; Comparisons with ground-based measurements SO LIFE SCIENCES: PLANETARY PROTECTION; OZONE AND UVB RADIATION EFFECTS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4/F3 6 Symposium of COSPAR Scientific Commission F held at the 32nd COSPAR Scientific Meeting CY JUL, 1998 CL NAGOYA, JAPAN SP Ctr Natl Etudes Spatiales, Natl Aeronaut & Space Adm, Comm Space Res, World Meteorol Org, Eurpean Comm, Wolrd Climate Res Programme, Stratospher process & Role Climate ID SATELLITE ESTIMATION AB Since UV exposure increase may have several harmful effects on human health or ecosystems and given that the ozone depletion has not yet reached its maximum, the necessity for monitoring the surface UV radiation is of great importance. Satellite measurements are the only way to achieve a global view of the radiative fields. We present some preliminary results of global UV fields estimation at the Earth's surface computed using data from the Global Ozone Monitoring Experiment (COME) instrument. A first simple model is used to test the best strategy for implementing the cloud modeling. It relies heavily on the cloud coverage estimation from GOME. We have compared this scheme with a more accurate model derived from the algorithm developed for the Total Ozone Mapping Spectrometer (TOMS) instrument by NASA/GSFC. First comparisons of the daily CIE weighted irradiance showed deviations between satellite estimates and measurements as large as a factor of 2.5. Possible explanations are discussed. A first comparison between the two different satellite models is also presented. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Belgian Inst Space Aeronomy, BIRA, IASB, B-1180 Brussels, Belgium. Software Corp Amer, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Peeters, P (reprint author), Belgian Inst Space Aeronomy, BIRA, IASB, 3 Ave Circulaire, B-1180 Brussels, Belgium. NR 11 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 26 IS 12 BP 1941 EP 1947 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43X UT WOS:000169859200006 ER PT S AU Mancinelli, RL White, MR AF Mancinelli, RL White, MR BE Debus, A Rummel, JD Horneck, G Rettberg, P TI Inhibition of denitrification by ultraviolet radiation SO LIFE SCIENCES: PLANETARY PROTECTION; OZONE AND UVB RADIATION EFFECTS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4/F3 6 Symposium of COSPAR Scientific Commission F held at the 32nd COSPAR Scientific Meeting CY JUL, 1998 CL NAGOYA, JAPAN SP Ctr Natl Etudes Spatiales, Natl Aeronaut & Space Adm, Comm Space Res, World Meteorol Org, Eurpean Comm, Wolrd Climate Res Programme, Stratospher process & Role Climate ID STRATOSPHERIC OZONE DEPLETION; ANTARCTIC MARINE ORGANISMS; TROPICAL SOLAR-RADIATION; B RADIATION; GLIDING CYANOBACTERIA; MOTILITY; EXPOSURE; BACTERIA AB It has been shown that UV-A (lambda =320 - 400 nm) and UV-B (lambda = 280 - 320 nm) inhibit photosynthesis, nitrogen fixation and nitrification. The purpose of this study was to determine the effects, if any, on denitrification in a microbial community inhabiting the intertidal. The community studied is the microbial mat consisting primarily of Lyngbya that inhabits the Pacific marine intertidal, Baja California, Mexico. Rates of denitrification were determined using the acetylene blockage technique. Pseudomonas fluorescens (ATCC # 17400) was used as a control organism, and treated similarly to the mat samples. Samples were incubated either beneath a PAR transparent, UV opaque screen (OP3), or a mylar screen to block UV-B, or a UV transparent screen(UVT) for 2 to 3 hours. Sets of samples were also treated with nitrapyrin to inhibit nitrification, or DCMU to inhibit photosynthesis and treated similarly. Denitrification rates were greater in the UV protected samples than in the UV exposed samples the mat samples as well as for the Ps. fluorescens cultures. Killed controls exhibited no activity. In the DCMU and nitrapyrin treated samples denitrification rates were the same as in the untreated samples. These data indicate that denitrification is directly inhibited by UV radiation. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mancinelli, RL (reprint author), NASA, Ames Res Ctr, Mail Stop 239-12, Moffett Field, CA 94035 USA. RI Mancinelli, Rocco/L-8971-2016 NR 32 TC 1 Z9 1 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 26 IS 12 BP 2041 EP 2046 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BS43X UT WOS:000169859200017 ER PT S AU Nesbitt, JA AF Nesbitt, JA BE Schutze, M Quadakkers, WJ Nicholls, JR TI COSIM - A finite-difference computer model to predict ternary concentration profiles associated with oxidation and interdiffusion of overlay-coated substrates SO LIFETIME MODELLING OF HIGH TEMPERATURE CORROSION PROCESSES SE EUROPEAN FEDERATION OF CORROSION PUBLICATIONS LA English DT Proceedings Paper CT EFC Workshop on Lifetime Modelling of High Temperature Corrosion Processes CY FEB 22-23, 2001 CL DECHEMA, FRANKFURT, GERMANY SP European Federat Corros, Corros Hot Gases & Combust Prod Working Party HO DECHEMA ID CYCLIC OXIDATION; ALLOYS AB A finite-difference computer program (COSIM) has been written which models the one-dimensional, diffusional transport associated with high-temperature oxidation and interdiffusion of overlay-coated substrates. The program predicts concentration profiles for up to three elements in the coating and substrate after various oxidation exposures. Surface recession due to solute loss is also predicted. Ternary cross terms and concentration-dependent diffusion coefficients are taken into account. The program also incorporates a previously developed oxide growth and spalling model to simulate either isothermal or cyclic oxidation exposures. In addition to predicting concentration profiles after various oxidation exposures, the program can also be used to predict coating life based on a concentration dependent failure criterion (e.g. surface solute content drops to 2%). The computer code is written in FORTRAN and employs numerous subroutines to make the program flexible and easily modifiable to other coating oxidation problems. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Nesbitt, JA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 15 TC 8 Z9 8 U1 0 U2 0 PU MANEY PUBLISHING PI LEEDS PA STE 1C, JOSEPHS WELL, HANOVER WALK, LEEDS LS3 1AB, W YORKS, ENGLAND SN 1354-5116 BN 1-902653-47-5 J9 EUR FED CORR PUBL PY 2001 IS 34 BP 359 EP 378 PG 20 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA BW12J UT WOS:000180939800025 ER PT J AU DellaCorte, C AF DellaCorte, C TI Making room for more ... SO LUBRICATION ENGINEERING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Washington, DC 20546 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD JAN PY 2001 VL 57 IS 1 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 391XL UT WOS:000166381500001 ER PT B AU Magee, KP Head, JW AF Magee, KP Head, JW BE Ernst, RE Buchan, KL TI Large flow fields on Venus: Implications for plumes, rift associations, and resurfacing SO MANTLE PLUMES: THEIR IDENTIFICATION THROUGH TIME SE GEOLOGICAL SOCIETY OF AMERICA SPECIAL PAPERS LA English DT Proceedings Paper CT Symposium on Locating Old Mantle Plumes held at the Annual Meeting of the Geological-Society-of-America CY OCT, 1998 CL TORONTO, CANADA SP Geol Soc Amer, Geophys Div, Geol Soc Amer, Int Div, Geol Assoc Canada, Geophys Div ID IMPACT CRATER DENSITIES; WESTERN EISTLA REGIO; GLOBAL DISTRIBUTION; THERMAL EVOLUTION; LAVA FLOWS; BETA-REGIO; HOT-SPOT; MAGELLAN OBSERVATIONS; TOPOGRAPHIC RISES; CORONAE AB A global analysis reveals 208 large flow fields on Venus; they average similar to220 000 km(2) and together constitute similar to11% of the plains area. Coronae, large volcanic shields, and fissures and fractures within rifts and fracture belts are the most common source vents for large flow fields. The majority (up to 74%) of all large flow fields are located within zones of extension (major rifts and fracture belts). The emplacement of these flow fields largely postdates the onset of extensional deformation although many have been deformed by subsequent fracturing along their associated rift. Large flow fields on Venus have been compared to terrestrial flood basalts owing to their similarity in scale. One aspect of the controversy regarding the formation of flood basalts on Earth centers on the relative importance of (1) large-scale mantle upwellings (or plume heads) and (2) lithospheric extension to enhance decompression melting. On Venus, the close association of large flow fields with rifts and fracture belts strongly suggests that conditions of lithospheric extension and thinning are necessary for the formation of the majority of flood-scale lavas. Stratigraphic relationships indicate that large flow fields are mostly younger than the surrounding regional plains. Lack of significant erosion on Venus permits the analysis of the nature of, and associations and temporal relationships between, these important magmatic events over several hundreds of millions of years, information that is useful for developing criteria for the recognition of plumes and related features in the less well-preserved record on Earth. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Magee, KP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 106 TC 8 Z9 8 U1 0 U2 4 PU GEOLOGICAL SOC AMER INC PI BOULDER PA 3300 PENROSE PL, PO BOX 9140, BOULDER, CO 80301 USA BN 0-8137-2352-3 J9 GEOL S AM S PY 2001 IS 352 BP 81 EP 101 PG 21 WC Geology SC Geology GA BT62J UT WOS:000173543800007 ER PT J AU Castro, KM Cobb, JS Wahle, RA Catena, J AF Castro, KM Cobb, JS Wahle, RA Catena, J TI Habitat addition and stock enhancement for American lobsters, Homarus americanus SO MARINE AND FRESHWATER RESEARCH LA English DT Article; Proceedings Paper CT 6th International Conference and Workshop on Lobster Biology and Management CY SEP 10-15, 2000 CL KEY WEST, FLORIDA SP Darden Environm Trust, Fl Sea Grant Program, Nat Conservancy, Fl Keys Natl Marine Sanctuary, Natl Marine Fisheries Serv, Florida Fish & Wildlife Conservat Commiss, VA Inst Marine Sci, Old Dominion Univ, Florida State Univ DE artificial reef; production; attraction ID RECRUITMENT PROCESSES; JUVENILE LOBSTER; POPULATIONS; POSTLARVAL; CRUSTACEA; BEHAVIOR; REEFS; LIFE AB Six experimental artificial reefs for lobsters were established in Narragansett Bay, Rhode Island, in February 1997. These have been monitored according to a before-after-control-impact design since placement by means of visual surveys, traps, tag-recapture, photoquadrats, and airlift sampling. Juvenile and adult lobster density at the reef increased from near zero to >1 lobster m(-2), significantly higher than the two control areas. Settlement of young-of-year lobsters has significantly increased. We used microwire tags to mark hatchery-reared lobsters and released over 2000 marked 5th-6th-stage lobsters in each of two years. The density of young-of-year lobsters on enhanced reefs was not different from that on the control reefs. Despite intensive sampling, we have recovered only one of the hatchery-reared animals. Field observations indicate possible behaviour differences in the hatchery-reared lobsters that might make them more susceptible to predation. C1 Univ Rhode Isl, Kingston, RI 02881 USA. Bigelow Lab Ocean Sci, Boothbay Harbor, ME 04575 USA. Natl Marine Fisheries Serv, Restorat Ctr, Gloucester, MA 01930 USA. RP Castro, KM (reprint author), Univ Rhode Isl, Kingston, RI 02881 USA. NR 38 TC 28 Z9 28 U1 0 U2 7 PU C S I R O PUBLISHING PI COLLINGWOOD PA 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA SN 1323-1650 J9 MAR FRESHWATER RES JI Mar. Freshw. Res. PY 2001 VL 52 IS 8 BP 1253 EP 1261 DI 10.1071/MF01095 PG 9 WC Fisheries; Limnology; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 516RT UT WOS:000173571100023 ER PT J AU Moisan, TA Mitchell, BG AF Moisan, TA Mitchell, BG TI UV absorption by mycosporine-like amino acids in Phaeocystis antarctica Karsten induced by photosynthetically available radiation SO MARINE BIOLOGY LA English DT Article ID ULTRAVIOLET-B RADIATION; FLUORESCENCE EXCITATION-SPECTRA; ABSORBING COMPOUNDS; OZONE DEPLETION; MARINE-PHYTOPLANKTON; LIGHT-ABSORPTION; CARBON FIXATION; SOUTHERN-OCEAN; PHOTOSYSTEM-II; BARENTS SEA AB Mycosporine-like amino acids (MAAs), which occur in diverse taxonomic groups, exhibit in vivo absorption maxima between 310 nm and 360 nm and may play a photoprotective role against ultraviolet (UV) exposure. Using cultures of colonial Phaeocystis antarctica, we examined the relationship between MAA concentration, in vivo UV absorption, photoprotective (carotenoid) and photosynthetic pigments, and photosynthetically available radiation (PAR, 350 700 nm). UV absorption was high; chlorophyll-specific absorption, a*(ph), at 330 nm ranged from 0.06 to 0.41 m(2)/mg chlolophyll a. Values of a*(ph) (330) were 4-13 times greater than a*(ph) (676). Mycosporine-glycine, shinorine, and mycosporine-glycine valine al-e responsible for the strong in vivo UV absorption. The sum of all MAAs increased with irradiance when normalized to chlorophyll rr or carbon concentrations, whereas individual MAAs varied independently from each other. Mycosporine-glycine concentrations showed no statistically significant change over the range of light intensities, whereas mycosporine-glycine and shinorine concentrations increased at higher il radiances. The relative fluorescence yield for chlorophyll Lr was low in the UV region compared to the visible region, implying that absorbed UV radiation (<375 nm) is transferred inefficiently to chlorophyll ii in the reaction center. Quantitative estimates of UV screening by MAAs are attributed to elevated MAA concentrations and increased diameter at high light. C1 Univ Calif San Diego, Scripps Inst Oceanog, Div Marine Res, La Jolla, CA 92093 USA. RP Moisan, TA (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. NR 66 TC 51 Z9 55 U1 0 U2 10 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD JAN PY 2001 VL 138 IS 1 BP 217 EP 227 DI 10.1007/s002270000424 PG 11 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 398CT UT WOS:000166738900022 ER PT J AU Rooker, JR Secor, DH Zdanowicz, VS Itoh, T AF Rooker, JR Secor, DH Zdanowicz, VS Itoh, T TI Discrimination of northern bluefin tuna from nursery areas in the Pacific Ocean using otolith chemistry SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE otolith chemistry; Pacific bluefin tuna; North Pacific Ocean ID EAST-CHINA-SEA; SHAD ALOSA-SAPIDISSIMA; FISH OTOLITHS; STRONTIUM; MICROCHEMISTRY; TEMPERATURE; SEDIMENTS; ELEMENTS; CALCIUM; STOCKS AB Otolith chemistry of juvenile Pacific bluefin tuna Thunnus orientalis was measured to assess differences in composition among 3 nursery areas in the North Pacific Ocean: East China Sea, Sea of Japan and the Pacific Ocean off Shikoku. Six elements (Li, Mg, Ca, Mn, Sr and Ba) were measured in whole otoliths using solution-based inductively coupled plasma mass spectrometry, Univariate contrasts of T. orientalis otoliths collected in 1994 and 1995 indicated that concentrations of 5 elements (Li, Mg, Ca, Mn, Sr) differed among nurseries. Concentrations of Ca and Sr were significantly higher in the Pacific Ocean than in either marginal sea (East China Sea or Sea of Japan) nursery, while concentrations of Li, Mg and Mn were higher in fishes inhabiting marginal seas. Discriminant analysis showed clear separation of elemental fingerprints between Pacific Ocean and marginal sea nurseries, and to a lesser degree separation between the 2 marginal sea groups, Temporal stability of the elemental fingerprint was examined over a 3 yr period (1995 to 1997) in the East China Sea, Significant interannual trends were observed for 3 elements (Mg, Mn and Ba); however, elemental fingerprints of T orientalis from the Pacific Ocean nursery were markedly different from all year classes in the East China Sea. C1 Texas A&M Univ, Dept Marine Biol, Galveston, TX 77551 USA. Univ Maryland, Chesapeake Biol Lab, Ctr Environm Sci, Solomons, MD 20688 USA. Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. Natl Res Inst Far Seas Fisheries, Shimizu, Shizuoka 424, Japan. RP Rooker, JR (reprint author), Texas A&M Univ, Dept Marine Biol, 5007 Ave U, Galveston, TX 77551 USA. EM rookerj@tamug.tamu.edu RI Secor, D/D-4367-2012; Rooker, Jay/M-3197-2013 OI Secor, D/0000-0001-6007-4827; Rooker, Jay/0000-0002-5934-7688 NR 41 TC 74 Z9 78 U1 1 U2 11 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 EI 1616-1599 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 218 BP 275 EP 282 DI 10.3354/meps218275 PG 8 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 474XN UT WOS:000171132300023 ER PT J AU Benoit-Bird, KJ Au, WWL Brainard, RE Lammers, MO AF Benoit-Bird, KJ Au, WWL Brainard, RE Lammers, MO TI Diel horizontal migration of the Hawaiian mesopelagic boundary community observed acoustically SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE mesopelagic boundary community; diel horizontal migration; diel vertical migration; acoustic sampling; Hawaiian Islands AB The mesopelagic boundary community off the leeward coasts of 2 Hawaiian Islands, Oahu and Hawaii, was investigated with an echosounder modified to read directly into a laptop computer, Acoustic sampling was conducted over a total distance of 12.6 km off the Waianae coast of Oahu and 46.3 km off the Kona coast of Hawaii. The density of organisms was determined using echo energy integration, and relative abundance was determined in a way analogous to catch-per-unit-effort, The vertical range of mesopelagic organisms expanded as the mesopelagic layer rose and then compressed as it descended. The vertical range of the layer off the Kona coast was larger than that off the Waianae coast, possibly because of the greater bottom depth off Kona. Near midnight, the boundary community 3 km from the shoreline was split into 2 distinct layers, one beginning approximately 25 m from the surface and one beginning approximately 90 m from the surface. The density and the relative abundance of mesopelagic organisms were consistently higher off the Waianae coast than the Kona coast. However, the density of organisms observed in both locations was high, reaching a maximum of 1800 organisms m(-3) off Waianae and 700 organisms m(-3) off Kona. The maximum relative abundance off Waianae neared 100%, while off Kona it never exceeded 70%. In both locations, organisms were found within 1 km of shore, in waters much shallower than their assumed daytime habitat. The temporal patterns of relative abundance and density of organisms in waters closest to the shores of each island resembled a bell curve, with a peak in relative abundance and density around midnight. In waters further from shore, the temporal patterns in relative abundance and density had a bimodal distribution, with peaks around both 21:00 and 03:00 h. These patterns in relative abundance and density are significantly affected by the distance of the sampling location from the shoreline, but not by the depth of the sampling site. The data suggest that the organisms of the mesopelagic boundary community undergo a diel horizontal migration that is reciprocal, 1.8 km in 2 h toward shore and then the same distance in approximately the same amount of time away from shore, in addition to their well-established vertical migration. The temporal patterns of the horizontal component of the migration are predictable and are conserved between days, phases of the moon, seasons, and islands. C1 Univ Hawaii, Hawaii Inst Marine Biol, Kailua, HI 96734 USA. Univ Hawaii, Dept Zool, Kailua, HI 96734 USA. Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Benoit-Bird, KJ (reprint author), Univ Hawaii, Hawaii Inst Marine Biol, POB 1106, Kailua, HI 96734 USA. EM benoit@hawaii.edu NR 44 TC 43 Z9 44 U1 1 U2 15 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 217 BP 1 EP 14 DI 10.3354/meps217001 PG 14 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 469AL UT WOS:000170790300001 ER PT J AU Sogard, SM Olla, BL AF Sogard, SM Olla, BL TI Growth and behavioral responses to elevated temperatures by juvenile sablefish Anoplopoma fimbria and the interactive role of food availability SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE growth efficiency; temperature selection; ration; activity ID VERTICAL-DISTRIBUTION; SALVELINUS-ALPINUS; THERMAL-GRADIENT; BODY-COMPOSITION; RAINBOW-TROUT; LIFE-HISTORY; ARCTIC CHARR; RATION SIZE; MARINE FISH; ENERGY AB Larval and age-0 sablefish Anoplopoma fimbria reside in neustonic waters of the North Pacific during spring and summer. We estimated the potential impacts of elevated surface temperatures on ecological processes of growth, conversion efficiency, and behavior in early juvenile sablefish. Growth experiments tested a wide range of temperatures from 6 to 24(degrees)C, with fish receiving ad libitum or low (3 % body weight d(-1)) rations. With unlimited food, growth increased rapidly as temperature increased to 14(degrees)C, then displayed a more gradual rise to 22 degreesC. Growth rates at the warmer temperatures were among the highest recorded for teleosts, attaining a maximum of 3.3 nun d(-1) in length and a specific growth in weight of 11.8 %. A similar response to temperature was observed at low rations, although at lower overall growth rates. At 24 degreesC, there was a severe decline in growth for both ration levels, and few fish survived the 3 wk experiments. Gross growth efficiency, measured at temperatures of 6 to 22 degreesC, displayed an interactive effect of temperature with ration level consistent with bioenergetic relationship, Conversion peaked at 16 to 20 degreesC for fish receiving ad libitum rations, and at 10 degreesC for fish on restricted rations. Conversion rates of sablefish were comparable to those calculated for a diverse array of fish species, suggesting that the rapid growth rates are driven by high consumption rather than unusually efficient energy transfer. Experiments analyzing sablefish behavior in thermally stratified water columns demonstrated increasing movement into colder water as ration level decreased, in agreement with an energy conserving strategy. Average monthly temperatures within the major nursery areas of neustonic juveniles (north of 40 degreesN) did not exceed 19 degreesC during the last 19 yr. These results suggest that juvenile sablefish are capable of tolerating and thriving at increased temperatures, with the critical caveat that sufficient food resources must be available. Thus, impacts on early life stages exerted by El Nino conditions, oceanographic regime shifts, or climate changes induced by current global warming scenarios are likely to be a consequence of indirect effects on circulation and productivity patterns rather than direct effects of warmer temperatures. However, because the upper thermal limit for growth nearly coincides with the upper limit for survival, exhibiting a sharp demarcation between favorable growth conditions and intolerable temperatures, juvenile sablefish at the southern Limit of their distribution may suffer the direct effects of elevated temperature; recruitment of juveniles to southern populations may become more sporadic if the frequency of warming events increases with climate change. C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Sogard, SM (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. EM susan.sogard@noaa.gov NR 53 TC 26 Z9 26 U1 4 U2 20 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 217 BP 121 EP 134 DI 10.3354/meps217121 PG 14 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 469AL UT WOS:000170790300011 ER PT J AU Stone, RP O'Clair, CE AF Stone, RP O'Clair, CE TI Seasonal movements and distribution of Dungeness crabs Cancer magister in a glacial southeastern Alaska estuary SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE dungeness crab; biotelemetry; essential habitat; migration ID TEMPERATURE; BRACHYURA; CANCRIDAE; DECAPODA; RANGE AB The movements of 10 female and 8 male adult Dungeness crabs, Cancer magister (Dana, 1852), were monitored biweekly to monthly with ultrasonic biotelemetry for periods ranging from 73 to 555 d. Female and male crabs had different seasonal patterns of habitat use, depth distribution, and activity. The general pattern for female crabs was: (1) a relatively inactive period between November and mid-April at depths below 20 m; ovigerous crabs were typically buried during this period in a dense aggregation; (2) abrupt movement into shallow water (<8 m) in late April and residence there until early June; this movement was coincident with the spring phytoplankton bloom and initiation of larval hatching; (3) increased activity beginning in July with movement back to deeper water, presumably to forage. Females that molted prior to oviposition did so in June and July. Male crabs occupied deep water (> 40 m) from November to April, then concentrated in shallow water (< 25 m), segregated from females, until late July. Males were most active in late summer and moved into deeper water (> 30 m) near the mouth of the cove in fall. The range of depths were -0.5 to -61.3 m for females and +0.1 to -89.0 m for males. Female crabs showed fidelity to the head of the cove and typically ranged only 1.5 km from there. Male crabs, however, moved. up to 7.2 km from the head of the cove, but did not move close to the nearest established population of Dungeness crabs 9.6 km distant. The discrete population of adult Dungeness crabs in Fritz Cove may be representative of most Dungeness crab populations inhabiting shallow embayments of the coastal fjord system of southeastern Alaska. C1 NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. RP Stone, RP (reprint author), NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, 11305 Glacier Highway, Juneau, AK 99801 USA. EM bob.stone@noaa.gov NR 29 TC 23 Z9 23 U1 4 U2 8 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 214 BP 167 EP 176 DI 10.3354/meps214167 PG 10 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 437DG UT WOS:000168974500016 ER PT J AU Stoner, AW Manderson, JP Pessutti, JP AF Stoner, AW Manderson, JP Pessutti, JP TI Spatially explicit analysis of estuarine habitat for juvenile winter flounder: combining generalized additive models and geographic information systems SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE habitat; nursery; spatial analysis; generalized additive model; estuary; flounder ID PLAICE PLEURONECTES-PLATESSA; DUTCH WADDEN SEA; PSEUDOPLEURONECTES-AMERICANUS; NURSERY AREAS; ENVIRONMENTAL-FACTORS; SEDIMENT PREFERENCE; SALINITY GRADIENTS; FIELD OBSERVATIONS; ABIOTIC FACTORS; 0-GROUP PLAICE AB Quasisynoptic seasonal beam trawl surveys for age-0 winter flounder Pseudopleuronectes americanus were conducted in the Navesink River/Sandy Hook Bay estuarine system (NSHES), New Jersey, from 1996 to 1998, to develop spatially explicit models of habitat association. Relationships between environmental parameters and fish distribution were distinctly nonlinear and multivariate. Logistic generalized additive models (GAMs) revealed that the distribution of newly settled flounder (< 25 mm total length) in spring collections was associated with low temperature and high sediment organic content, placing them in deep, depositional environments. Fish 25 to 55 mm total length were associated with high sediment organics, shallow depth (<3 m), and salinity near 20 ppt. The largest age-0 fish (56 to 138 mm) were associated with shallow depths (< 2 m), temperature near 22 degreesC, and presence of macroalgae. Abundance of prey organisms contributed significantly to the GAM for fish 25 to 55 mm total length, but not for fish > 55 mm. Independent test collections and environmental measurements made at 12 new sites in NSHES during 1999 showed that the GAMs had good predictive capability for juvenile flounder, and new GAMs developed for the test set demonstrated the robustness of the original models. Maps for the probability of capturing fish of particular sizes were produced by integrating GAMs with maps of environmental data in a geographic information system (GIS). These plots revealed 2 important centers of settlement in the system, probably related to hydrographic conditions, and the fact that nursery locations shift rapidly with fish size during the first year of life. It was also apparent that nursery habitats are dynamic-expanding, contracting, and shifting position with changes in key environmental variables. C1 NE Fisheries Sci Ctr, Behav Ecol Branch, Natl Marine Fisheries Serv, Highlands, NJ 07732 USA. RP Stoner, AW (reprint author), NOAA, NMFS, Fisheries Behav Ecol Program, Alaska Fieheries Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM al.stoner@noaa.gov NR 81 TC 114 Z9 118 U1 1 U2 20 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 213 BP 253 EP 271 DI 10.3354/meps213253 PG 19 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 432PP UT WOS:000168704100020 ER PT J AU Wilson, PR Ainley, DG Nur, N Jacobs, SS Barton, KJ Ballard, G Comiso, JC AF Wilson, PR Ainley, DG Nur, N Jacobs, SS Barton, KJ Ballard, G Comiso, JC TI Adelie penguin population change in the pacific sector of Antarctica: relation to sea-ice extent and the Antarctic Circumpolar Current SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE Adelie penguin; population regulation; sea-ice extent; Southern Oscillation; Antarctic Circumpolar Current; climate change; Ross Sea; Pygoscelis adeliae ID ROSS SEA; BELLINGSHAUSEN SEAS; VARIABILITY; TEMPERATURE; OCEAN; KRILL; RECRUITMENT; SEABIRDS; AMUNDSEN; DYNAMICS AB One of the longest continuing data sets involving a marine organism in the Antarctic is that of annual estimates of breeding population size of Adelie penguins Pygoscelis adeliae at colonies on Ross Island, Ross Sea, 1959 to 1997. The sizes of these colonies have displayed significant interannual variability during the 29-yr period. We hypothesized that changes are related to natural environmental factors; and used path analysis to analyze annual variation in population growth in relation to physical environmental factors during that part of the record with comparable sea-ice satellite imagery from 1973 to 1997. The Ross Sea sector of the Southern Ocean lying north of Ross Island, from 150 degreesE to 1300 W, comprised our study area. Annual population growth measured during summer was explained best, and inversely, by the extent of sea-ice in the study area 5 winters earlier, and in some way related to the Southern Oscillation. Analysis of a subset of the sea-ice data from 1979 to 1997 indicated strong correlations to ice conditions in the eastern portion of the study area (174 to 130 degreesW), and virtually no correlations to the western half (150 degreesE to 175 degreesW). This result supported other indirect evidence that the Ross Island penguins winter in the eastern Ross Sea/western Amundsen Sea. A demographic model indicated that variation in survival of juveniles and subadults might account for the observed population variation, and would also explain the 5-yr lag as 5 yr is the average age of recruitment to the summer breeding population. Extensive sea-ice during winter appears to reduce subadult survival, expressed subsequently when these cohorts reach maturation. We hypothesize that extensive (more northerly) sea-ice Limits access of penguins to productive waters known to occur south of the southern boundary of the Antarctic Circumpolar Current, with starvation or increased predation disproportionately affecting less-experienced birds. The observed patterns of penguin population change, including those preceding the satellite era, imply that sea-ice extent has changed significantly over recent decades. C1 Landcare Res, Nelson, New Zealand. HT Harvey & Associates, San Jose, CA 95118 USA. Point Reyes Bird Observ, Stinson Beach, CA 94970 USA. Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NASA, Goddard Space Flight Ctr, Lab Proc Hydrospher Proc, Greenbelt, MD 20771 USA. RP Wilson, PR (reprint author), Landcare Res, Private Bag 6, Nelson, New Zealand. EM wilsonpr@landcare.cri.nz NR 51 TC 101 Z9 106 U1 7 U2 52 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 213 BP 301 EP 309 DI 10.3354/meps213301 PG 9 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 432PP UT WOS:000168704100023 ER PT J AU Secor, DH Rooker, JR Zlokovitz, E Zdanowicz, VS AF Secor, DH Rooker, JR Zlokovitz, E Zdanowicz, VS TI Identification of riverine, estuarine, and coastal contingents of Hudson River striped bass based upon otolith elemental fingerprints SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE Hudson River; striped bass; anadromy; migration; otolith microchemistry; strontium; elemental fingerprint ID LASER-ABLATION ICPMS; COD GADUS-MORHUA; CHESAPEAKE BAY; FISH OTOLITHS; STOCK IDENTIFICATION; ATLANTIC CROAKER; MORONE-SAXATILIS; MICROCHEMISTRY; MIGRATIONS; WATERS AB Elemental fingerprints of otoliths from Hudson River striped bass Morone saxatilis were used to define resident, estuarine, and ocean migratory contingents, which had previously been determined by otolith microprobe analysis of Sr:Ca. Using solution-based inductively coupled plasma mass-spectrometry, 7 metals were quantified in whole otoliths. Discriminant analysis of elements showed a high degree of separation among the 3 migratory contingents. Barium was significantly higher in otoliths from the freshwater resident group, while Sr and Na were significantly lower in comparison to mesohaline and ocean contingents. Identification of contingents by the bulk chemistry method indicated that divergent migratory patterns persist over lifetimes for Hudson River striped bass. C1 Univ Maryland, Ctr Environm Sci, Chesapeake Biol Lab, Solomons, MD 20688 USA. Texas A&M Univ, Dept Marine Biol, Galveston, TX 77553 USA. Maryland Dept Nat Resources, Stevensville, MD 21666 USA. NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Secor, DH (reprint author), Univ Maryland, Ctr Environm Sci, Chesapeake Biol Lab, POB 38, Solomons, MD 20688 USA. EM secor@cbl.umces.edu RI Secor, D/D-4367-2012; Rooker, Jay/M-3197-2013; Mason, Robert/A-6829-2011 OI Secor, D/0000-0001-6007-4827; Rooker, Jay/0000-0002-5934-7688; NR 44 TC 107 Z9 116 U1 0 U2 14 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 2001 VL 211 BP 245 EP 253 DI 10.3354/meps211245 PG 9 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA 412NM UT WOS:000167561300021 ER PT J AU Holland, DS Ginter, JJC AF Holland, DS Ginter, JJC TI Common property institutions in the Alaskan groundfish fisheries SO MARINE POLICY LA English DT Article DE common property; fisheries; cooperatives; institutions ID MANAGEMENT; RESOURCES AB This paper describes the process by which the groundfish resources off Alaska are being transformed from essentially open access to more manageable common property resources. Selected common property institutions that were created or developed in these fisheries are described in terms of the problems they were designed to solve, their success or lack of success in doing so, and the factors that influenced both emergence and success of these institutions. The institutions discussed include the North Pacific Fishery Management Council, the Community Development Quota system, the Pollock Conservation Cooperative, and the cooperative bycatch control system known as Sea State used by the factory trawler fleets. Conclusions applicable to other fisheries and other common property resources are then drawn from the analysis of these common property institutions in the Alaskan groundfish fisheries. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Univ Massachusetts, Sch Marine Sci & Technol, New Bedford, MA 02744 USA. Natl Marine Fisheries Serv, Alaska Reg, Juneau, AK 99802 USA. RP Holland, DS (reprint author), Univ Massachusetts, Sch Marine Sci & Technol, 706 S Rodney French Blvd, New Bedford, MA 02744 USA. OI Holland, Daniel/0000-0002-4493-859X NR 21 TC 24 Z9 24 U1 1 U2 6 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0308-597X J9 MAR POLICY JI Mar. Pol. PD JAN PY 2001 VL 25 IS 1 BP 33 EP 42 DI 10.1016/S0308-597X(00)00033-6 PG 10 WC Environmental Studies; International Relations SC Environmental Sciences & Ecology; International Relations GA 406EN UT WOS:000167202100004 ER PT B AU Gabb, TP Gayda, J Kantzos, PT Biles, T Konkel, WA AF Gabb, TP Gayda, J Kantzos, PT Biles, T Konkel, WA BE Zhao, JC Fahrmann, M Pollock, TM TI The tensile properties of disk superalloys during supersolvus quenching heat treatments SO MATERIALS DESIGN APPROACHES AND EXPERIENCES LA English DT Proceedings Paper CT Symposium on Materials Design Approaches and Experiences held at the 2001 TMS Fall Meeting CY NOV 04-08, 2001 CL INDIANAPOLIS, IN SP Minerals, Met & Mat Soc AB There is a need to increase the temperature capabilities of superalloy turbine disks. This would allow full utilization of higher temperature combustor and airfoil concepts under development. One approach to meet this goal is to modify the processing and chemistry of advanced alloys, while preserving the ability to use rapid cooling supersolvus heat treatments to achieve coarse grain, fine gamma prime microstructures. An important step in this effort is to understand the key high temperature tensile properties of advanced alloys as they exist during supersolvus heat treatments. This could help in projecting cracking tendencies of disks during quenches from supersolvus heat treatments. The objective of this study was to study the tensile properties of two advanced disk superalloys during simulated quenching heat treatments. Specimens were cooled from the solution heat treatment temperatures at controlled rates, interrupted, and immediately tensile tested at various temperatures. The responses and failure modes were compared and related to the quench cracking tendencies of disk forgings. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Gabb, TP (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd,MS 49-3, Cleveland, OH 44135 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-503-4 PY 2001 BP 267 EP 279 PG 13 WC Engineering, Manufacturing; Materials Science, Coatings & Films SC Engineering; Materials Science GA BT53L UT WOS:000173272500021 ER PT S AU Bandara, SV Gunapala, SD Liu, JK Rafol, SB Ting, DZ Mumolo, JM Reininger, FM Fastenau, JM Liu, AK AF Bandara, SV Gunapala, SD Liu, JK Rafol, SB Ting, DZ Mumolo, JM Reininger, FM Fastenau, JM Liu, AK BE Longshore, RE TI Large format, broadband and multi-color GaAs/AlGaAs quantum well infrared photodetector (QWIP) focal plane arrays SO MATERIALS FOR INFRARED DETECTORS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Materials for Infrared Detectors CY JUL 30-AUG 01, 2001 CL SAN DIEGO, CA SP SPIE DE broadband; multi-band; intersubband transitions; infrared (IR); long-wavelength infrared (LWIR); very long-wavelength (VLWIR); gallium arsenide (GaAs); Quantum Well Infrared Photodetector (QWIP); focal plane arrays; infrared imaging ID CAMERA AB The GaAs/AlGaAs based Quantum Well Infrared Photodetectors (QWIPs) afford greater flexibility than the usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored over any wavelength between 6-20 mum. The spectral band width of these detectors can be tuned from narrow (Deltalambda/lambda similar to 10 %) to wide (Deltalambda/lambda similar to 50 %) allowing various applications. Also, QWIP offers multi-color infrared cameras which is capable of simultaneously acquiring images in different infrared bands. Each pixel of such array consists of vertically stacked, independently readable, QWIP detectors sensitive in different narrow (Deltalambda similar to 1 mum) infrared bands. In this article, we discuss the results of a 10-16 mum large format broadband QWIP focal plane array (FPA). The size of the FPA is 640x512 and its pixel pitch is 25 microns. The highest operating temperature of the FPA is 45K, and it was determined by the charge storage capacity and the other features of the particular readout multiplexer used in this demonstration. Excellent imagery, with a noise equivalent differential temperature (NEDeltaT) of 55 mK has been achieved. In addition, we will discuss the developments and results of the 640x512 dual-band QWIP FPA. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bandara, SV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 8 Z9 9 U1 1 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4168-6 J9 P SOC PHOTO-OPT INS PY 2001 VL 4454 BP 30 EP 39 DI 10.1117/12.448187 PG 10 WC Instruments & Instrumentation; Materials Science, Multidisciplinary; Optics SC Instruments & Instrumentation; Materials Science; Optics GA BT74U UT WOS:000173939500004 ER PT S AU Newton, RL Davidson, JL AF Newton, RL Davidson, JL BE Muhlstein, CL Brown, SB TI The effects of radiation on the mechanical properties of polysilicon and polydiamond thin films SO MECHANICAL PROPERTIES OF STRUCTURAL FILMS SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Mechanical Properties of Structural Films CY NOV 15-16, 2000 CL ORLANDO, FL SP Amer Soc Testing & Mat DE CVD diamond; polycrystalline silicon; radiation effects; nanoindention; Raman spectroscopy; MEMS; hardness; Young's modulus; cross-sectional ID DIAMOND; MEMS AB Due to its many excellent properties, diamond is being explored as a material for MicroElectroMechanical Systems (MEMS). However, as is true in the case of silicon, a large amount of basic material characterization issues still warrant investigation. This paper presents preliminary results from charged particle irradiation or Chemical Vapor Deposited (CVD) polycrystalline diamond films. The films were simultaneously dosed to a level of 9.4 x 10(13) particles/cm(2) using 700 keV protons and 1 MeV electrons. fie samples were then subject to cross-sectional nanoindention analysis and Raman spectroscopy. Polycrystalline silicon was also investigated for comparison purposes. The diamond was unaffected by the irradiation. However, the silicon did indicate a slight decrease in Young's modulus. C1 NASA, George C Marshall Space Flight Ctr, ED 36A, Huntsville, AL 35812 USA. RP Newton, RL (reprint author), NASA, George C Marshall Space Flight Ctr, ED 36A, Huntsville, AL 35812 USA. NR 14 TC 0 Z9 0 U1 2 U2 2 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2889-4 J9 AM SOC TEST MATER PY 2001 VL 1413 BP 318 EP 327 DI 10.1520/STP10998S PG 10 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BT32J UT WOS:000172648600023 ER PT J AU Nicholson, LM Whitley, KS Gates, TS AF Nicholson, LM Whitley, KS Gates, TS TI The combined influence of molecular weight and temperature on the physical aging and creep compliance of a glassy thermoplastic polyimide SO MECHANICS OF TIME-DEPENDENT MATERIALS LA English DT Article DE creep compliance; glassy; molecular weight; physical aging; polyimide; temperature; thermoplastic ID VISCOELASTIC PROPERTIES; AMORPHOUS POLYMERS; FREE-VOLUME; TERM CREEP; COMPOSITES; SUPERPOSITION; REJUVENATION; PERFORMANCE; DEFORMATION; DEPENDENCE AB The effect of molecular weight on the viscoelastic performance of an advanced polymer (LaRC(TM)-SI) was investigated through the use of creep compliance tests. Testing consisted of short-term isothermal creep and recovery with the creep segments performed under constant load. The tests were conducted at three temperatures below the glass transition temperature of five materials of different molecular weight. Through the use of time-aging-time superposition procedures, the material constants, material master curves and aging-related parameters were evaluated at each temperature for a given molecular weight. The time-temperature superposition technique helped to describe the effect of temperature on the timescale of the viscoelastic response of each molecular weight. It was shown that the low molecular weight materials have higher creep compliance and creep rate, and are more sensitive to temperature than the high molecular weight materials. Furthermore, a critical molecular weight transition was observed to occur at a weight-average molecular weight of (M) over bar (w) similar to 25,000 g/mol below which, the temperature sensitivity of the time-temperature superposition shift factor increases significantly. The short-term creep compliance data were used in association with Struik's effective time theory to predict the long-term creep compliance behavior for the different molecular weights. At long timescales, physical aging serves to significantly decrease the creep compliance and creep rate of all the materials tested. Long-term test data verified the predictive creep behavior. Materials with higher temperature and lower molecular weights had greater creep compliance and higher creep rates. C1 NASA, ICASE Struct & Mat Div, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Mech & Durabil Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP NASA, ICASE Struct & Mat Div, Langley Res Ctr, MS 188E,2 West Reid St, Hampton, VA 23681 USA. EM t.s.gates@larc.nasa.gov NR 47 TC 5 Z9 5 U1 2 U2 7 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1385-2000 EI 1573-2738 J9 MECH TIME-DEPEND MAT JI Mech. Time-Depend. Mater. PY 2001 VL 5 IS 3 BP 199 EP 227 DI 10.1023/A:1017911509777 PG 29 WC Mechanics; Materials Science, Characterization & Testing SC Mechanics; Materials Science GA 471VN UT WOS:000170949500001 ER PT J AU Moore, AD Lee, SMC Charles, JB Greenisen, MC Schneider, SM AF Moore, AD Lee, SMC Charles, JB Greenisen, MC Schneider, SM TI Maximal exercise as a countermeasure to orthostatic intolerance after spaceflight SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE microgravity; intense exercise; stand test ID INTENSE EXERCISE; SPACE-SHUTTLE; RESPONSES; FLIGHT; TILT AB Previous investigators have suggested that maximal exercise performed 24 h before the end of bed rest, a spaceflight analog, restores prebed rest plasma volume, baroreflex responses, and orthostatic tolerance. Purpose: In this case report, we examined the effect of a similar exercise protocol 24 h before a Shuttle landing on the orthostatic responses of four crewmembers (EX) after spaceflights of 8-14 d. Four additional crewmembers (CON) served as controls and did not perform exercise during the final day of the flight. Methods: Each crewmember performed a 10-min stand test approximately 10 d before launch (L-10) and within 1-2 h of landing (R+0). Cardiac stroke volume was measured (Doppler ultrasound) supine and during each min of standing for three EX and three CON subjects. Results: Preflight, all crewmembers completed the stand test and each group had similar heart rate and blood pressure responses. Postflight, all subjects also completed the 10-min stand test. Each group had similarly elevated supine and standing heart rates, elevated diastolic and mean arterial blood pressures, and reduced pulse pressures compared to L-10. However, postflight cardiac output, mean +/- SEM, (EX: 4.5 +/- 0.6 L.min(-1); CON: 3.1 +/- 0.3 L.min(-1)) and stroke volume (EX: 43 +/- 7 mL.beat; CON: 30 +/- 6 mL.beat) were higher after 10 min standing in the EX subjects compared to CON subjects. Conclusions: For these four crewmembers, maximal exercise performed 24 h before landing may have helped maintain stroke Volume but did not maintain heart rate and blood pressure responses during standing compared to preflight. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Wyle Labs, Life Sci Syst & Serv Div, Houston, TX 77058 USA. RP Schneider, SM (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 25 TC 22 Z9 22 U1 1 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD JAN PY 2001 VL 33 IS 1 BP 75 EP 80 PG 6 WC Sport Sciences SC Sport Sciences GA 390RW UT WOS:000166311100014 PM 11194115 ER PT S AU Basdogan, C AF Basdogan, C BE Westwood, JD Hoffman, HM Mogel, GT Stredney, D Robb, RA TI Real-time simulation of dynamically deformable finite element models using modal analysis and spectral Lanczos Decomposition methods SO MEDICINE MEETS VIRTUAL REALITY 2001: OUTER SPACE, INNER SPACE, VIRTUAL SPACE SE STUDIES IN HEALTH TECHNOLOGY AND INFORMATICS LA English DT Proceedings Paper CT Conference on Medicine Meets Virtual Reality 2001 CY JAN 24-27, 2001 CL NEWPORT BEACH, CA ID EQUATIONS AB Real-time simulation of deformable objects using finite element models is a challenge in medical simulation. We present two efficient methods for simulating real-time behavior of a dynamically deformable 3D object modeled by finite element equations. The first method is based on modal analysis, which utilizes the most significant vibration modes of the object to compute the deformation field in real-time for applied forces. The second method uses the spectral Lanczos decomposition to obtain the explicit solutions of the finite element equations that govern the dynamics of deformations. Both methods rely on modeling approximations, but generate solutions that are computationally faster than the ones obtained through direct numerical integration techniques. In both methods, the errors introduced through approximations were insignificant compare to the computational advantage gained for achieving real-time update rates. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Basdogan, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Basdogan, Cagatay /H-5192-2011 OI Basdogan, Cagatay /0000-0002-6382-7334 NR 14 TC 11 Z9 11 U1 0 U2 0 PU I O S PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0926-9630 BN 1-58603-143-0 J9 ST HEAL T PY 2001 VL 81 BP 46 EP 52 PG 7 WC Computer Science, Information Systems; Medical Informatics SC Computer Science; Medical Informatics GA BS21P UT WOS:000169103300010 PM 11317791 ER PT S AU Dawson, DL Billica, RD McDonald, PV AF Dawson, DL Billica, RD McDonald, PV BE Westwood, JD Hoffman, HM Mogel, GT Stredney, D Robb, RA TI Modeling and simulation for space medicine operations: Preliminary requirements considered SO MEDICINE MEETS VIRTUAL REALITY 2001: OUTER SPACE, INNER SPACE, VIRTUAL SPACE SE STUDIES IN HEALTH TECHNOLOGY AND INFORMATICS LA English DT Proceedings Paper CT Conference on Medicine Meets Virtual Reality 2001 CY JAN 24-27, 2001 CL NEWPORT BEACH, CA ID TEXAS MEDICINE; FEBRUARY 1998; SUPPORT AB The NASA Space Medicine program is now developing plans for more extensive use of high-fidelity medical simulation systems. The use of simulation is seen as means to more effectively use the limited time available for astronaut medical training. Training systems should be adaptable for use in a variety of training environments, including classrooms or laboratories, space vehicle mockups, analog environments, and in microgravity. Modeling and simulation can also provide the space medicine development program a mechanism for evaluation of other medical technologies under operationally realistic conditions. Systems and procedures need preflight verification with ground-based testing. Traditionally, component testing has been accomplished, but practical means for "human in the loop" verification of patient care systems have been lacking. Medical modeling and simulation technology offer potential means to accomplish such validation work. Initial considerations in the development of functional requirements and design standards for simulation systems for space medicine are discussed. C1 NASA, Lyndon B Johnson Space Ctr, Space Med & Hlth Care Syst Off, Houston, TX 77058 USA. RP Dawson, DL (reprint author), NASA, Lyndon B Johnson Space Ctr, Space Med & Hlth Care Syst Off, Houston, TX 77058 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU I O S PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0926-9630 BN 1-58603-143-0 J9 ST HEAL T PY 2001 VL 81 BP 106 EP 112 PG 7 WC Computer Science, Information Systems; Medical Informatics SC Computer Science; Medical Informatics GA BS21P UT WOS:000169103300022 PM 11317721 ER PT S AU Li, MJ Aslam, IS Ewin, A Fettig, RK Franz, D Kotecki, C Kutyrev, AS Moseley, SH Monroy, C Mott, DB Zheng, Y AF Li, MJ Aslam, IS Ewin, A Fettig, RK Franz, D Kotecki, C Kutyrev, AS Moseley, SH Monroy, C Mott, DB Zheng, Y BE Behringer, UFW Uttamchandani, DG TI Fabrication of microshutter arrays for space application SO MEMS DESIGN, FABRICATION, CHARACTERIZATION, AND PACKAGING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on MEMS Design, Fabrication, Characterization, and Packaging CY MAY 30-JUN 01, 2001 CL EDINBURGH, SCOTLAND SP SPIE, Scottish Enterprise, European Opt Soc, IEE DE microshutter; MEMS; DRIE; micro-optics; near-infrared AB Two-dimensional microshutter arrays are being developed at NASA Goddard Space Flight Center for the Next Generation Space Telescope (NGST) for use in the near-infrared region. Functioning as object selection devices, the microshutter arrays are designed for the transmission of light with high efficiency and high contrast. The NGST environment requires cryogenic operation at 45K. Arrays are close-packed silicon nitride membranes with a pixel size of 100x100 mum. Individual shutters are patterned with a torsion flexure permitting shutters to open 90 degrees with a minimized mechanical stress concentration. The mechanical shutter arrays are fabricated with MEMS technologies. The processing includes a RIE front-etch to form shutters out of the nitride membrane, an anisotropic back-etch for wafer thinning, and a deep RIE (DRIE) back-etch down to the nitride shutter membrane to form frames and to relieve shutters from the silicon substrate. Two approaches for shutter actuation have been developed. Shutters are actuated using either a combined mechanical and electrostatic force or a combined magnetic and electrostatic force. A CMOS circuit embedded in the frame between shutters allows programmable shutter selection for the first approach. A control of row and column electrodes fulfills shutter selection for the second approach. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Li, MJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Moseley, Harvey/D-5069-2012 NR 7 TC 5 Z9 5 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4108-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4407 BP 295 EP 303 DI 10.1117/12.425314 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BT02D UT WOS:000171644100034 ER PT J AU Horz, F AF Horz, F TI ZERIN: A new resource for impact cratering studies in Nordlingen, Germany SO METEORITICS & PLANETARY SCIENCE LA English DT Editorial Material C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Horz, F (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SN2, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 2001 VL 36 IS 1 BP 3 EP 5 PG 3 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 414EH UT WOS:000167652600001 ER PT J AU Noble, SK Pieters, CM Taylor, LA Morris, RV Allen, CC McKay, DS Keller, LP AF Noble, SK Pieters, CM Taylor, LA Morris, RV Allen, CC McKay, DS Keller, LP TI The optical properties of the finest fraction of lunar soil: implications for space weathering SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID EVOLUTION AB The fine fraction of lunar soils (<45 m) dominates the optical properties of the bulk soil. Definite trends can be seen in optical properties of size separates with decreasing particle size: diminished spectral contrast and a steeper continuum slope. These trends are related to space weathering processes and their affects on different size fractions. The finest fraction (defined here as the <10 m fraction) appears to be enriched in weathering products relative to the larger size fractions, as would be expected for surface correlated processes. This <10 m fraction tends to exhibit very little spectral contrast, often with no distinguishable ferrous iron absorption bands. Additionally, the finest fractions of highland soils are observed to have very different spectral properties than the equivalent fraction of mare soils when compared with larger size fractions. The spectra of the finest fraction of feldspathic soils flatten at longer wavelengths, whereas those of the finest fraction of basaltic soils continue to increase in a steep, almost linear fashion. This compositional distinction is due to differences in the total amount of nanophase iron that accumulates in space weathering products. Such ground-truth information derived from the <10 m fraction of lunar soils provides valuable insight into optical properties to be expected in other space weathering environments such as the asteroids and Mercury. C1 Brown Univ, Providence, RI 02912 USA. Univ Tennessee, Knoxville, TN 37996 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lockheed Martin, Houston, TX 77058 USA. MVA Inc, Norcross, GA 30093 USA. RP Noble, SK (reprint author), Brown Univ, Providence, RI 02912 USA. RI Noble, Sarah/D-7614-2012 NR 34 TC 102 Z9 108 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 2001 VL 36 IS 1 BP 31 EP 42 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 414EH UT WOS:000167652600005 ER PT J AU Kress, ME Tielens, AGGM AF Kress, ME Tielens, AGGM TI The role of Fischer-Tropsch catalysis in solar nebula chemistry SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID INTERPLANETARY DUST PARTICLES; POLYCRYSTALLINE IRON; KINETIC INHIBITION; SUPPORTED METALS; H2-CO MIXTURES; GROUP-8 METALS; N-2 REDUCTION; HYDROCARBONS; CO; CARBON AB Fischer-Tropsch catalysis, the iron/nickel catalyzed conversion of CO and H(2) to hydrocarbons, would have been the only thermally-driven pathway available in the solar nebula to convert CO into other forms of carbon. A major issue in meteoritics is to determine the origin of meteoritic organics: are they mainly formed from CO in the solar nebula via a process such as Fischer-Tropsch, or are they derived from interstellar organics? In order to determine the role that Fischer-Tropsch catalysis may have played in the organic chemical evolution of the solar nebula, we have developed a kinetic model for this process. Our model results agree well with experimental data from several existing laboratory studies. In contrast, empirical rate equations, which have been derived from experimental rate data for a limited temperature (T) and pressure (P) range, are inconsistent with experimental rate data for higher T and lower P. We have applied our model to pressure and temperature profiles for the solar nebula, during the epoch in which meteorite parent bodies condensed and agglomerated. We find that, under nebular conditions, the conversion rate of CO to CH(4) does not simply increase with temperature as the empirically-derived equations suggest. Instead, our model results show that this process would have been most efficient in a fairly narrow region that coincides with the present position of the asteroid belt. Our results support the hypothesis that Fischer-Tropsch catalysis may have played a role in solar nebula chemistry by converting CO into less volatile materials that can be much more readily processed in the nebula and in parent bodies. C1 Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kress, ME (reprint author), Univ Washington, Dept Astron, Seattle, WA 98195 USA. EM kress@astro.washington.edu NR 53 TC 53 Z9 54 U1 1 U2 8 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 2001 VL 36 IS 1 BP 75 EP 91 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 414EH UT WOS:000167652600008 ER PT J AU Bogardi, DD Garrison, DH Masarik, J AF Bogardi, DD Garrison, DH Masarik, J TI The Monahans chondrite and halite: Argon-39/argon-40 age, solar gases, cosmic-ray exposure ages, and parent body regolith neutron flux and thickness SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID COSMOGENIC NUCLIDES; COLLISIONAL HISTORY; NOBLE-GASES; METEORITES; WIND; IRRADIATION; ABUNDANCES; METEOROIDS; PETROLOGY; EVOLUTION AB The Monahans H-chondrite is a regolith breccia containing light and dark phases and the first reported presence of small grains of halite. We made detailed noble gas analyses of each of these phases. The Ar-39-Ar-40 age of Monahans light is 4.533 +/- 0.006 Ma. Monahans dark and halite samples show greater amounts of diffusive loss of Ar-40 and the maximum ages are 4.50 and 4.33 Ga, respectively. Monahans dark phase contains significant concentrations of He, Ne and Ar implanted by the solar wind when this material was extant in a parent body regolith. Monahans light contains no solar gases. From the cosmogenic He-3, Ne-21, and Ar-38 in Monahans light we calculate a probable cosmic-ray, space exposure age of 6.0 +/- 0.5 Ma. Monahans dark contains twice as much cosmogenic 21Ne and Ar-38 as does the light and indicates early near-surface exposure of 13-18 Ma in a H-chondrite regolith. The existence of fragile halite grains in H-chondrites suggests that this regolith irradiation occurred very early. Large concentrations of Ar-36 in the halite were produced during regolith exposure by neutron capture on Cl-35, followed by decay to Ar-36. The thermal neutron fluence seen by the halite was (2-4) x 10(14) n/cm(2) The thermal neutron flux during regolith exposure was similar to0.4-0.7 n/cm(2)/s. The Monahans neutron fluence is more than an order of magnitude less than that acquired during space exposure of several large meteorites and of lunar soils, but the neutron flux is lower by a factor of less than or equal to5. Comparison of the Ar-36(n)/Ne-21(cos) ratio in Monahans halite and silicate with the theoretically calculated ratio as a function of shielding depth in an H-chondrite regolith suggests that irradiation of Monahans dark occurred under low shielding in a regolith that may have been relatively shallow. Late addition of halite to the regolith can be ruled out. However, irradiation of halite and silicate or different times at different depths in an extensive regolith cannot be excluded. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lockheed Martin Corp, Houston, TX 77058 USA. Comenius Univ, Dept Nucl Phys, Bratislava, Slovakia. RP Bogardi, DD (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SN2, Houston, TX 77058 USA. NR 38 TC 20 Z9 20 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 2001 VL 36 IS 1 BP 107 EP 122 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 414EH UT WOS:000167652600010 ER EF