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  • Other Sources  (459)
  • EARTH RESOURCES AND REMOTE SENSING  (295)
  • ENERGY PRODUCTION AND CONVERSION
  • 2010-2014
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  • 1990-1994  (459)
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  • 1
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    Improvement in detection of small wildfires (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Detecting and imaging small wildfires with an Airborne Scanner is done against generally high background levels. The Airborne Scanner System used is a two-channel thermal IR scanner, with one channel selected for imaging the terrain and the other channel sensitive to hotter targets. If a relationship can be determined between the two channels that quantifies the background signal for hotter targets, then an algorithm can be determined that removes the background signal in that channel leaving only the fire signal. The relationship can be determined anywhere between various points in the signal processing of the radiometric data from the radiometric input to the quantized output of the system. As long as only linear operations are performed on the signal, the relationship will only depend on the system gain and offsets within the range of interest. The algorithm can be implemented either by using a look-up table or performing the calculation in the system computer. The current presentation will describe the algorithm, its derivation, and its implementation in the Firefly Wildfire Detection System by means of an off-the-shelf commercial scanner. Improvement over the previous algorithm used and the margin gained for improving the imaging of the terrain will be demonstrated.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: Infrared technology XVII; Proceedings of the Meeting, San Diego, CA, July 22-26, 1991 (A93-38376 15-35); p. 207-212.
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  • 2
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    Exploratory geological analysis of AVIRIS data (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The size and complexity of AVIRIS data sets makes analysis difficult. We present a technique that allows the researcher to rapidly scan the full data set in image form in order to empirically find significant spatial patterns anywhere across the spectrum. Our approach takes advantage of the speed and power of computer graphics workstations to allow real-time, interactive data manipulation and display. Empirical data selection avoids the bias inherent in theoretical selection criteria, and allows discovery of unexpected relationships within the data set. Link Winds, a prototype data analysis system under development, provides the visualization tools used in this study. We are applying this approach to geological studies in the eastern Mojave Desert.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: Thematic Conference on Geologic Remote Sensing, 8th, Denver, CO, Apr. 29-May 2, 1991, Proceedings. Vol. 1 (A93-28978 10-43); p. 423-426.
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  • 3
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    Comparison of three atmospheric correction models for a vegetated airborne visible/infrared imaging spectrometer (AVIRIS) scene (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Current atmospheric correction models applied to imaging spectroscopy data include such methods as residual or scene average, flat field correction, regression method or empirical line algorithm, the continuum interpolated band ratio (CIBR) derivation and the LOWTRAN 7 method. Due to the limitations of using residual and flat field corrections on vegetated scenes, three methods will be compared: regression, CIBR derivation and LOWTRAN 7. Field-measured bright and dark targets taken at the time of the 13 April, 1989 AVIRIS overflight of Jasper Ridge, California were used to formulate the regression method atmospheric correction. Using this corrected scene as 'ground truth', the CIBR derivation and the LOWTRAN 7 method with both input models are compared on the vegetated Jasper Ridge scene. Although representing a qualitative approach, this is a first approximation and shows the need for more quantitative analysis.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: Thematic Conference on Geologic Remote Sensing, 8th, Denver, CO, Apr. 29-May 2, 1991, Proceedings. Vol. 1 (A93-28978 10-43); p. 413-421.
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  • 4
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    Regional exploration in desert terrains - A guide to the use of Landsat Thematic Mapper imagery (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: This paper provides a guide for the acquisition, processing, and interpretation of Landsat Thematic Mapper (TM) imagery of desert terrains for use in regional exploration. Sun angle considerations, data quality cautions, noise suppression routines, band selections, data calibration, spectral enhancements, perceptual considerations of displays, and general interpretation guidelines are all discussed as components of an image-information extraction procedure.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: Thematic Conference on Geologic Remote Sensing, 8th, Denver, CO, Apr. 29-May 2, 1991, Proceedings. Vol. 1 (A93-28978 10-43); p. 277-285.
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  • 5
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    I-BIEM calculations of the frequency dispersion and ac current distribution at disk and ring-disk electrodes (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The Iterative Boundary Integral Equation Method (I-BIEM) has been applied to the problem of frequency dispersion at a disk electrode in a finite geometry. The I-BIEM permits the direct evaluation of the AC potential (a complex variable) using complex boundary conditions. The point spacing was made highly nonuniform, to give extremely high resolution in those regions where the variables change most rapidly, i.e., in the vicinity of the edge of the disk. Results are analyzed with respect to IR correction, equipotential surfaces, and reference electrode placement. The current distribution is also examined for a ring-disk configuration, with the ring and the disk at the same AC potential. It is shown that the apparent impedance of the disk is inductive at higher frequencies. The results are compared to analytic calculations from the literature, and usually agree to better than 0.001 percent.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: In: Modeling of batteries and fuel cells; Proceedings of the Symposium, Phoenix, AZ, Oct. 13-19, 1991 (A93-34244 13-25); p. 324-350.
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  • 6
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    Remote spectral identification of surface aggregates by thermal imaging techniques - Progress report (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The NASA Thermal Infrared Multispectral Scanner (TIMS) has been successfully used for the remote identification of a variety of soil and aggregate deposits in vegetated areas of two states. Over three million cubic meters of gravel deposits were identified from the imagery during a two year period. Verification was accomplished by ground reconnaissance using drilling machinery and by ground instrumentation. The method has been used to differentiate between fine and coarse grained soils, and gravel deposits. The deposits were found to have been naturally sorted according to grain size by depositional processes, providing each deposit with distinct spectral qualities. It was found that the masking effects of relatively dense vegetation were largely overcome by using imagery acquired at higher altitudes above terrain than 9000 meters, due to loss of resolution of the finer detail. The mechanics of image resolution are discussed, a method of data analysis used is described, and sample spectral signatures are illustrated.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: Earth and atmospheric remote sensing; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991 (A93-24176 08-42); p. 358-369.
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  • 7
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    Using image pyramids for the visualization of large terrain data sets (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Viewing terrain data from various remote sensors in three dimensions has proven to be a valuable tool for scientists in understanding a variety of problems. A technique is presented for using image pyramids in such visualization of large terrain data sets, providing up to two orders of magnitude performance enhancement over simpler techniques, while at the same time eliminating false high-frequency information, which causes animations to sparkle.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Imaging Systems and Technology (ISSN 0899-9457); p. 157-166.
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  • 8
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    An evaluation of short-wave-infrared (SWIR) data from the AVIRIS and GEOSCAN instruments for mineralogical mapping at Cuprite, Nevada (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: An evaluation was performed on SWIR (2000-2400 nm) data from two airborne remote sensing systems for discriminating and identifying alteration minerals at Cuprite, Nevada. The data were acquired by the NASA Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) and the GEOSCAN Mk II multispectral scanner. The evaluation involved comparison of processed imagery and image-derived spectra with existing alteration maps and laboratory spectra of rock samples from Cuprite. Results indicate that both the AVIRIS and GEOSCAN data permit the discrimination of areas of alunite, buddingtonite, kaolinite, and silicification using color composite images formed from three SWIR bands processed with either the decorrelation stretch or a log residual algorithm. The laboratory spectral features alunite, kaolinite and buddingtonite could be seen clearly only in the log residual processed AVIRIS data. However, this does not preclude their identification with the GEOSCAN data.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geophysics (ISSN 0016-8033); 56; 9; p. 1432-1440.
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  • 9
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    Improved Li-TiS2 cell cycling in ether-based electrolytes with synergistic additives (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Results of the application of 2-MeF and KOH additives to improve the lithium stability in THF, dioxolane, and THF/2-MeTHF solvent-based electrolytes are presented. The stability of these electrolytes with and without additives is evaluated by microcalorimetry and AC impedance spectroscopy. A novel method, cathode turnover number, is proposed to represent the electrolyte performance in a given system. The lithium cycling efficiency and cathode turnover number of the electrolytes are calculated from the cycle life data in experimental Li-TiS2 cells. Overall, THF/2-MeTHF electrolyte containing 2-MeF and/or KOH exhibited higher stability, lithium cycling efficiency, and cathode turnover number compared to THF and dioxolane electrolytes with and without additives.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: In: Primary and secondary lithium batteries (A93-37355 14-25); p. 280-292.
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  • 10
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    Evaluation of lithium alloy anode materials for Li-TiS2 cells (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: A study was performed to select candidate lithium alloy anode materials and establish selection criteria. Some of the selected alloy materials were evaluated for their electrochemical properties and performance. This paper describes the criteria for the selection of alloys and the findings of the studies. Li-Si and Li-Cd alloys have been found to be unstable in the EC+2-MeTHF-based electrolyte. The Li-Al alloy system was found to be promising among the alloy systems studied in view of its stability and reversibility. Unfortunately, the large volume changes of LiAl alloys during charge/discharge cycling cause considerable 'exfoliation' of its active mass. This paper also describes ways how to address this problem. The rate of disintegration of this anode would probably be surpressed by the presence of an inert solid solution or a uniform distribution of precipitates within the grains of the active mass. It was discovered that the addition of a small quantity of Mn may improve the mechanical properties of LiAl. In an attempt to reduce the Li-Al alloy vs. Li voltage, it was observed that LiAlPb(0.1)Cd(0.3) material can be cycled at 1.5 mA/sq cm without exfoliation of the active mass.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: In: Primary and secondary lithium batteries (A93-37355 14-25); p. 395-406.
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  • 11
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    Finite linear diffusion model for design of overcharge protection for rechargeable lithium batteries (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The overcharge condition in secondary lithium batteries employing redox additives for overcharge protection has been theoretically analyzed in terms of a finite linear diffusion model. The analysis leads to expressions relating the steady-state overcharge current density and cell voltage to the concentration, diffusion coefficient, standard reduction potential of the redox couple, and interelectrode distance. The model permits the estimation of the maximum permissible overcharge rate for any chosen set of system conditions. The model has been experimentally verified using 1,1-prime-dimethylferrocene as a redox additive. The theoretical results may be exploited in the design and optimization of overcharge protection by the redox additive approach.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: In: Primary and secondary lithium batteries (A93-37355 14-25); p. 109-117.
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  • 12
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    Design of mission operations systems for scientific remote sensing (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The present work describes the mission operations system (MOS) design process for remote-sensing missions. A MOS is defined as the system required to perform, monitor, and control an operation, encompassing personnel, hardware, software and/or documentation. Attention is given to telecommunications and remote-sensing instrumentation, MOS definition program phases and reviews, and MOS organization, management, and staffing. Also treated are the uplink and downlink processes, anomalies and contingency plans, the illustrative case of the MOS for the Magellan radar sensing mission, and a projection of future MOSs incorporating AI.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 13
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    Biomass burning - Combustion emissions, satellite imagery, and biogenic emissions (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: After detailing a technique for the estimation of the instantaneous emission of trace gases produced by biomass burning, using satellite imagery, attention is given to the recent discovery that burning results in significant enhancement of biogenic emissions of N2O, NO, and CH4. Biomass burning accordingly has an immediate and long-term impact on the production of atmospheric trace gases. It is presently demonstrated that satellite imagery of fires may be used to estimate combustion emissions, and could be used to estimate long-term postburn biogenic emission of trace gases to the atmosphere.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 14
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    The great Chinese fire of 1987 - A view from space (1991)
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    Publication Date: 2011-08-24
    Description: One of the largest forest fires ever recorded burned in the People's Republic of China (PRC) and the Soviet Union in May 1987. The fire covered over 1.0 million hectares in the PRC and almost 4 million hectares in the Soviet Union. The progress and areal extent of the fire were measured using satellite images analyzed in the imaging facilities at NASA-Langley and Forestry Canada. The analyses show the utility and value of satellite measurements to assess the areal extent and geographical distribution of fires, and have important implications for future measurements to be obtained from space platforms, such as the Earth Observing System.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 15
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    What does remote sensing do for ecology? (1991)
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    Publication Date: 2011-08-24
    Description: The application of remote sensing to ecological investigations is briefly discussed. Emphasis is given to the recruitment problem in marine population dynamics, the regional analysis of terrestrial ecosystems, and the monitoring of ecological changes. Impediments to the use of remote sensing data in ecology are addressed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Ecology (ISSN 0012-9658); 72; 6, De
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  • 16
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    Earth observations during Space Shuttle flight STS-35 - Columbia's Mission to Planet Earth, December 2-10, 1990 (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Some of the most significant earth-viewing imagery obtained during Space Shuttle Columbia's flight STS-35, December 2-10, 1990, is reviewed with emphasis on observations of the Southern Hemisphere. In particular, attention is given to environmental observations in areas of Madagascar, Brazil, and Persian Gulf; observation of land resources (Namibia, offshore Australia); and observations of ocean islands (Phillipines, Indonesia, and Reunion). Some of the photographs are included.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geocarto International (ISSN 1010-6049); 6; 4, De
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  • 17
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    Space batteries for mobile battlefield power applications (1991)
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    Publication Date: 2011-08-24
    Description: A review of space power systems was undertaken to identify advanced space batteries for mobile applications. State-of-the-art systems are described. The technology issues that need to be addressed in order to bring these systems along and meet the needs of the user are discussed. Future research directions are examined.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Aerospace and Electronic Systems Magazine (ISSN 0885-8985); 6; 45-48
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  • 18
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    Continuous cost movement models (1991)
    In:  CASI
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    Publication Date: 2005-08-04
    Description: Use of current space imaging systems and airborne platforms has direct use in survey design and site location when used in concert with a comprehensive GIS environment. Local conditions and site physical and chemical properties are key factors in successful applications. Conjoining of environmental constraints and site properties are present for the later prehistoric occupations in the Arkansas and Mississippi River areas. Direct linkages between comprehensive site databases and satellite images can be used to evaluate site distributions for research and management.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Stennis Space Center, Applications of Space-Age Technology in Anthropology; p 237-250
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  • 19
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    Protecting rain forests and forager's rights using LANDSAT imagery (1991)
    In:  CASI
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    Publication Date: 2005-08-04
    Description: Creating rain forest reserves is vital given the global decline in biodiversity. Yet, the plants and animals that will be protected from untrammeled commercial exploitation within such reserves constitute essential resources for indigenous foragers and farmers. Balancing the needs of local subsistence level populations with the goals of national and international conservation agencies requires a thorough understanding of the mutual impacts that arise from the interaction of park and people. In the Ituri forest of Zaire, LANDSAT TM image analysis and GPS ground truth data were used to locate human settlements so that boundaries of the proposed Okapi Reserve could be chosen to minimize its impact on the subsistence practices of the local foragers and farmers. Using satellite imagery in conjunction with cultural information should help to ensure traditional resource exploitation rights of indigenous peoples whilst simultaneously protecting the largest contiguous area of undisturbed forest.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Stennis Space Center, Applications of Space-Age Technology in Anthropology; p 181-193
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  • 20
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    Very-to-barely remote sensing of prehistoric features under tephra in Central America (1991)
    In:  CASI
    Details
    Publication Date: 2005-08-04
    Description: A wide variety of remote sensing instruments have been utilized to attempt to detect archaeological features under volcanic ash in Central America. Some techniques have not been successful, such as seismic refraction, for reasons that are not difficult to understand. Others have been very successful and provide optimism for archaeologists witnessing the destruction of unburied sites throughout Central America. The sudden burial of buildings, gardens, and footpaths by volcanic ash can preserve them extremely well providing a rich data base for understanding human life and culture at certain points in time.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Stennis Space Center, Applications of Space-Age Technology in Anthropology; p 167-179
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  • 21
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    Applications of ecological concepts and remote sensing technologies in archaeological site reconnaissance (1991)
    In:  CASI
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    Publication Date: 2005-08-04
    Description: The concept of integrating ecological perspectives on early man's settlement patterns with advanced remote sensing technologies shows promise for predictive site modeling. Early work with aerial imagery and ecosystem analysis is discussed with respect to the development of a major project in Maya archaeology supported by NASA and the National Geographic Society with technical support from the Mississippi State Remote Sensing Center. A preliminary site reconnaissance model will be developed for testing during the 1991 field season.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Applications of Space-Age Technology in Anthropology; p 121-136
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  • 22
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    GIS modeling of archaeological site locations: A low-tech approach (1991)
    In:  CASI
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    Publication Date: 2005-08-04
    Description: A Geographic Information System (GIS)-type analysis of archaeological site locations using a dBase III plus program and a desk top computer is presented. A previously developed model of site locations in the Sequatchie Valley of northeastern Alabama is tested against known site locations in another large survey area there. The model fails to account for site locations in the test area. A model is developed for the test area and indicates the site locations are indeed different. Whether this is due to differences in site locations on a sub-regional level, or to sample error in the original model is unknown.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Stennis Space Center, Applications of Space-Age Technology in Anthropology; p 95-110
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  • 23
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    Settlement patterns, GIS, remote sensing, and the late prehistory of the Black Prairie in east central Mississippi (1991)
    In:  CASI
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    Publication Date: 2005-08-04
    Description: Data recovered as the result of a recent field project designed to test a model of the distribution of protohistoric settlement in an unusual physiographic zone in eastern Mississippi are examined using GIS based techniques to manipulate soil and stream distance information. Significant patterning is derived. The generally thin soils and uniform substratum of the Black Prairie in combination with a distinctive settlement pattern offer a promising opportunity for the search for site specific characteristics within airborne imagery. Landsat TM data provide information on modern ground cover which is used as a mask to select areas in which a multivariate search for archaeological site signatures within a TIMS image is most likely to prove fruitful.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Stennis Space Center, Applications of Space-Age Technology in Anthropology; p 111-120
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  • 24
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    Satellite spectral data and archaeological reconnaissance in western Greece (1991)
    In:  CASI
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    Publication Date: 2005-08-04
    Description: A Macro-geographical reconnaissance of the Western Peloponnesos adopts spectral signatures taken by Landsat-5 Thematic Mapper as a new instrument of archaeological survey in Greece. Ancient records indicate that indigenous resources contributed to the prosperity of the region. Natural resources and Ancient, Medieval, and Pre-modern Folklife in the Western Peloponnesos describes the principal lines of research. For a supervised classification of attested ancient resources, a variety of biophysical surface features were pinpointed: stone quarries, coal mines, forests of oak and silver fir, terracotta-producing clay beds, crops, and various wild but exploited shrubs such as flax.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Stennis Space Center, Applications of Space-Age Technology in Anthropology; p 63-79
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  • 25
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    Terrestrial reference systems related to the TOPEX/Poseidon project (1991)
    In:  CASI
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    Publication Date: 2006-06-13
    Description: In the TOPEX/POSEIDON project, several satellite positioning systems, such as Laser, Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), and Global Positioning Satellite (GPS) (on an experimental basis), will be used to track the satellite and to provide accurate orbits. Unfortunately, these systems will provide their dedicated tracking-station coordinates and the satellite orbits in different reference frames. Each technique will use, de facto, a different reference frame. In fact, even for the same technique, each group, depending on the hypothesis used in its computation, will use a different reference frame. This problem is not new for geodesists and can be overcome, in large part, but could create trouble for other scientists when they compare or combine different coordinate data sets. The main purpose of this investigation is to determine a consistent terrestrial system for TOPEX/POSEIDON in which all the tracking-station coordinates, all the orbit ephemerides, and all the other station coordinates of specific interest (such as tide gauges) could be expressed. Another issue of this investigation is the provision of reliable information concerning the relationships between all the possible reference frames of interest for th TOPEX/POSEIDON project. To be more explicit, we plan to provide the possible transformation formula between the TOPEX/POSEIDON terrestrial reference frame and the Laser, DORIS, GPS, and other internationally recognized frames such as the International Terrestrial Reference Frame (ITRF).
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: JPL, TOPEX(Poseidon Science Investigations Plan; p 27-28
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  • 26
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    Application of precise altimetry to the study of precise leveling of the sea surface, the Earth's gravity field, and the rotation of the Earth (1991)
    In:  CASI
    Details
    Publication Date: 2006-06-13
    Description: Our program includes five research items: (1) determination of a precision geoid and gravity anomaly field; (2) precise leveling and detection of tidal changes of the sea surface and study of the role of the tide in the global energy exchange; (3) oceanic effect on the Earth's rotation and polar motion; (4) geological and geophysical interpretation of the altimetry gravity field; and (5) evaluation of the effectiveness of local tracking of TOPEX/POSEIDON by use of a laser tracker.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: JPL, TOPEX(Poseidon Science Investigations Plan; p 126-130
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  • 27
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    Free-piston Stirling Engine system considerations for various space power applications (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (ac, dc, high or low voltage, and fixed or variable load). This paper reviews potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. This paper briefly outlines the program and recent progress.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: In: Space nuclear power systems; Proceedings of the 8th Symposium, Albuquerque, NM, Jan. 6-10, 1991. Pt. 2 (A93-13751 03-20); p. 598a-604a.
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  • 28
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    Wheat yield estimation at the farm level using TM Landsat and agrometeorological data (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: A model for estimating wheat yields on the farm level was developed, that integrates the Landsat TM data and agrometeorological information. Results obtained for a test site in southern Brasil for years of 1986 and 1987 show that the vegetation index derived from Landsat TM could account for the 60 to 40 percent wheat-yield variability observed between the two crop years. Compared to results using either the Landsat TM vegetation index or the agrometeorological data alone, the joint use of both types of data in a single model yielded a significant improvement.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 2477-248
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    Passive microwave remote and in situ measurements of Arctic and subarctic snow covers in Alaska (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Airborne and satellite passive microwave measurements acquired simultaneously with ground measurements of depth, density, and stratigraphy of the snow in central and northern Alaska between March 11 and 19, 1988, are reported. A good correspondence in brightness temperature (TB) trends between the aircraft and satellite data was found. An expected inverse correlation between depth hoar thickness and TB was not found to be strong. A persistent TB minimum in both the aircraft and the satellite data was detected along the northern foothills of the Brooks Range. In an area located at about 68 deg 60 min N, 149 deg 20 min W, the TB as recorded from the aircraft microwave sensor dropped by 55 K. Satellite microwave measurements showed a TB decrease of up to 45 K at approximately the same location. An examination of microwave satellite data from 1978 to 1987 revealed that similar low late-winter values were found in approximately the same locations as those observed in March 1988.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 38; 161-172
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    Modeling multi-frequency diurnal backscatter from a walnut orchard (1991)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The Michigan Microwave Canopy Scattering Model (MIMICS) is used to model scatterometer data that were obtained during the August 1987 EOS (Earth Observing System) synergism study. During this experiment, truck-based scatterometers were used to measure radar backscatter from a walnut orchard in Fresno County, California. Multipolarized L- and X-band data were recorded for orchard plots for which dielectric and evapotranspiration characteristics were monitored. MIMICS is used to model a multiangle data set in which a single orchard plot was observed at varying impedance angles and a series of diurnal measurements in which backscatter from this same plot was measured continuously over several 24-h periods. MIMICS accounts for variations in canopy backscatter driven by changes in canopy state that occur diurnally as well as on longer time scales. L-band backscatter is dependent not only on properties of the vegetation but also on properties of the underlying soil surface. The behavior of the X-band backscatter is dominated by properties of the tree crowns.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 29; 852-863
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    An evaluation of techniques for the extraction of mineral absorption features from high spectral resolution remote sensing data (1991)
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    Publication Date: 2011-08-24
    Description: Airborne Visible/Infrared Imaging Spectrometer data covering the wavelength range between 2000 and 2400 nm are examined for their ability to display the diagnostic mineral absorption features of certain alteration minerals, employing various data processing techniques. The techniques may be separated into two broad categories: scene based techniques that use parameters derived from the data themselves, and correction techniques utilizing external information such as solar/atmospheric models. Results indicate that the data corrected utilizing the LOWTRAN 7 atmospheric transfer code constrained with local weather station data are the most effective at showing the diagnostic absorption features of the regions of known mineralogy and introduce the least number of artifacts into the data.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Photogrammetric Engineering and Remote Sensing (ISSN 0099-1112); 57; 1303-130
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    Polarimetric radar measurements of a forested area near Mt. Shasta (1991)
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    Publication Date: 2011-08-19
    Description: The authors present the results of an experiment using the NASA/JPL DC-8 AIRSAR (aircraft synthetic-aperture radar) over a coniferous forest near Mt. Shasta (California) in 1989. Calibration devices were deployed in clearings and under the forest canopy and passes at 20, 40, and 55 deg incidence angles were made with the AIRSAR. A total of eight images at differing incidence angles have been processed and calibrated. The multipolarization, multifrequency data were examined, and it was found that the C-band cross section averaged over like and cross polarizations is the best parameter for distinguishing between two stands with differing forest biomass. The average cross section at P- and L-bands is useful only for smaller incidence angles. Parameters describing the polarization behavior of the scattering were primarily useful in identifying the dominant scattering mechanisms for forest backscatter. It was found that both branch scattering and ground/tree interactions are important at P-band. At L-band and C-bands, the return is primarily from the canopy. Comparison with model calculations verified this conclusion.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 29; 444-450
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    Multiple vs single scattering - Assessment of magnitudes (1991)
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    Publication Date: 2011-08-19
    Description: All orders of scattering are analyzed for two artifical canopies. The SHL canopy consists of Small Horizontal Leaves that are much smaller than the leaf-to-leaf spacing. The IHL canopy consists of Infinite Horizontal Layers, where each leaf is of infinite extent (a horizontal plane). Hemispheric leaf reflectances and transmittances independent of the direction of illumination lead to exact solutions for these models. Sunlight that penetrates to a given leaf area index level is much stronger in an SHL canopy than that in IHL; but the difference becomes muted when leaf transmittance is large. Multiple scattering enhances the hemispheric canopy reflectance more strongly in SHL than it does in IHL. The enhancement depends linearly on leaf transmittance in SHL and on the transmittance squared in IHL. Comparison with measured reflectances indicates that IHL model grossly underestimates multiple scattering in soybean canopies.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Applied Optics (ISSN 0003-6935); 30; 1562-156
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    Cloud-screening for Africa using a geographically and seasonally variable infrared threshold (1991)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A spatially variable monthly, infrared cloud-threshold data base has been used to screen cloud-contaminated observations from radiances measured by the NOAA-9 AVHRR over Africa. Cloud-screening through a monthly average infrared threshold based on measured surface air temperature, which is geographically dependent, shows an improvement over using a seasonally and geographically independent thermal cloud threshold of 287 K. It is found that differences in cloud-screening for these two thresholds occur for cases of lower altitude clouds or subpixel clouds where the radiative temperature is higher than the 287 K infrared threshold, yet colder than the variable threshold developed by Stowe et al. (1988) for the Nimbus-7 global cloud climatology. The variable IR threshold is shown to be effective over persistently cloud-covered regions, such as the coastal region of the Gulf of Guinea, but may introduce some erroneous cloud identifications over mountains.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 1205-122
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    Temporal and spatial variability of aerosol optical depth in the Sahel region in relation to vegetation remote sensing (1991)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In order to monitor the aerosol characteristics needed for atmospheric correction of remotely sensed data, a network of sun photometers was established in the Sahel region of Senegal, Mali, and Niger. Data analysis suggests that there is a high spatial variability of the aerosol optical thickness tau(a) in the western Sahel region. At a 67 percent confidence level the instantaneous values of tau(a) can be extrapolated approximately 270-400 km with an error tolerance of 50 percent. Spatial variability in the dry season is found to be of a similar magnitude. The ranges of variations in the NDVI in the Sahel region are shown to be approximately 0.02 and 0.01, respectively, due to commonly observed fluctuations in the aerosol optical thickness and aerosol size distribution.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 1147-116
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    Mean and inter-year variation of growing-season normalized difference vegetation index for the Sahel 1981-1989 (1991)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Images are presented that show the mean and coefficient of variation of nine years (1981-1989) of NOAA AVHRR normalized difference vegetation index (NDVI) data for the growing season (July-October) in Africa, north of the equator. The variation in the growing season NDVI is represented by the coefficient of variation image that shows the large variation in the Sahelian growing season between years. It is concluded that these images illustrate some aspects of the perspective being brought to regional and continental scale processes by coarse resolution satellite sensors and the potential of these sensors to provide consistent, long-term datasets.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 1133-113
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    A new technique for enlargement and reconstruction of digital sensor imagery (1991)
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    Publication Date: 2011-08-19
    Description: A new image enlargement and reconstruction routine, the digital image enlarging balanced reconstruction algorithm (DIEBRA), is described. Using a highly modified form of 'balanced' two-dimensional polynomial interpolation, this program enlarges digital imagery, creating synthetic high spatial resolution images. Statistical analysis shows the DIEBRA-generated imagery to be significantly closer to true high spatial resolution imagery at all frequencies than imagery generated by a cubic convolutional reconstruction filter.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 627-634
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    Spectral and spatial characterization of rice field mosquito habitat (1991)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Irrigated rice provides an ideal breeding habitat for Anopheles free-borni, the western malaria mosquito, throughout California. In a 1985 study, it was determined that early-season rice canopy development, as monitored using remotely sensed data, could be used to distinguish between high and low mosquito producing rice fields. This distinction could be made over two months prior to peak mosquito production. It was found that high-producing fields were located in an area characterized by a diversity of land use, including livestock pastures, whereas the low-producing fields were in an area devoted almost exclusively to the cultivation of rice. The ability to distinguish between high and low mosquito producing fields prior to peak mosquito production is important in terms of mosquito habitat surveillance and control.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 621-626
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    Polarimetric signatures of a layer of random nonspherical discrete scatterers overlying a homogeneous half-space based on first- and second-order vector radiative transfer theory (1991)
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    Publication Date: 2011-08-19
    Description: Complete polarimetric signatures of a layer of random, nonspherical discrete scatterers overlying a homogeneous half space are studied with the first- and second-order solutions of the vector radiative transfer theory. Some of the salient features of the numerical results are as follows: (1) the inclusion of the nondiagonal extinction matrix in the vector radiative transfer theory accounts for an appreciable phase difference between vv and hh polarizations, particularly for aligned scatterers; (2) the ensemble-averaged scattered Stokes vector is generally partially polarized, with the degree of polarization less than unity; (3) there generally exists a pedestal in the copolarization return when plotted as a function of ellipticity and orientation angles, which may be due to heterogeneity of scattering objects and/or multiple scattering effects; and (4) multiple scattering effects generally enhance the pedestal in copolarization return, decrease the degree of polarization, affect phase difference, and also enhance the depolarization return.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 29; 242-253
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    A comparison of Stokes parameters for sky and a soybean canopy (1991)
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    Publication Date: 2011-08-19
    Description: An evaluation of the polarization signatures obtained from the four Stokes parameters is reported for the atmosphere and a soybean canopy. The polarimeter design and operation are set forth, and the Stokes parameters' relationships are discussed. The canopy polarization was different from the sky at azimuths of 90 and 270 degrees, demonstrating a response that reflecting the sky polarization signatures across a plane parallel to the polarization axis and passing through a phase angle of about 90 degrees would produce. Classical behavior in terms of electromagnetic theory was found in the fourth Stokes parameter of the canopy which was obtained in the principal plane. Only the third Stokes parameter is demonstrated to be unambiguously affected in a comparison of sky polarization signatures and aerosol optical densities. The similarity between the sky at azimuth 180 degrees and the soybean canopy data at the principal plane is interesting considering the disparity of the subjects.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 1087-109
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    Measurements of radar backscatter from an artificial tree - An indication of azimuthal variations and polarization sensitivity of trees (1991)
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    Publication Date: 2011-08-19
    Description: Measurements of radar backscatter from an artificial tree were made in the laboratory at 6 and 10 GHz at horizontal incidence. The system had a resolution cylinder 18 cm in diameter and 11 cm long, so about half of the tree (30.5 cm high) was within the beam. The mean returned power from the target with leaves was always higher than that from the target without leaves, as expected. The signal faded with an exponential distribution when the artificial tree was rotated about its trunk, with no angular trend apparent. When the leaves were present, tilted polarizations gave results favoring an angle corresponding with that of the branches. When leaves were absent, the trunk of the tree dominated the radar backscatter at all polarizations.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 401-417
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    Low temperature electrolytes for lithium/silver vanadium oxide cells (1991)
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    Publication Date: 2011-08-19
    Description: Combinations of methyl formate (MF) and propylene carbonate (PC) using salt concentrations of 0.6 to 2.4 M, with lithium hexafluoroarsenate and lithium tetrafluoroborate in a five to one molar ratio, were investigated as electrolytes in lithium/silver vanadium oxide batteries. The composition of the electrolyte affected cell performance at low temperature, self-discharge and abuse resistance as characterized by short circuit and crush testing. The electrolyte that provided the best combination of good low temperature performance, low cell self-discharge and abuse resistance was 0.6 M salt in 10:90 PC/MF.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Power Sources (ISSN 0378-7753); 34; 51-64
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    Data volume reduction for single-look polarimetric imaging radar data (1991)
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    Publication Date: 2011-08-19
    Description: An 8-b quantization scheme to reduce the data volume for single-look complex scattering matrix data measured by polarimetric imaging radar systems is described. The scattering matrices are not symmetrized before compression, thereby retaining information about background noise and system effects. The data volume is reduced by a factor of 3.2. It is shown, with measured data, that the signal to quantization noise ratio for the compression scheme is more than 35 dB for the cross-polarized channels, and more than 45 dB for the copolarized channels.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 29; 784-786
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    Global change and terrestrial hydrology - A review (1991)
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    Publication Date: 2011-08-19
    Description: This paper reviews the role of terrestrial hydrology in determining the coupling between the surface and atmosphere. Present experience with interactive numerical simulation is discussed and approaches to the inclusion of land hydrology in global climate models ae considered. At present, a wide range of answers as to expected changes in surface hydrology is given by nominally similar models. Studies of the effects of tropical deforestation and global warming illustrate this point.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Tellus, Series A-B: Special Issue (ISSN 0280-6495); 43A-B; 176-181
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    Analyzing remote sensing geobotanical trends in Quetico Provincial Park, Ontario, Canada, using digital elevation data (1991)
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    Publication Date: 2011-08-19
    Description: A 10 x 13-km area in Quetico Provincial Park, Canada has been studied using a digital elevation model to separate different drainage classes and to examine the influence of site factors and lithology on vegetation. Landsat Thematic Mapper data have been classified into six forest classes of varying deciduous-coniferous cover through nPDF, a procedure based on probability density functions. It is shown that forests growing on mafic lithologies are enriched in deciduous species, compared to those growing on granites. Of the forest classes found on mafics, the highest coniferous component was on north facing slopes, and the highest deciduous component on south facing slopes. Granites showed no substantial variation between site classes. The digital elevation derived site data is considered to be an important tool in geobotanical investigations.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Photogrammetric Engineering and Remote Sensing (ISSN 0099-1112); 57; 1179-118
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    Remote sensing and landslide hazard assessment (1991)
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    Publication Date: 2011-08-19
    Description: Remotely acquired multispectral data are used to improve landslide hazard assessments at all scales of investigation. A vegetation map produced from automated interpretation of TM data is used in a GIS context to explore the effect of vegetation type on debris flow occurrence in preparation for inclusion in debris flow hazard modeling. Spectral vegetation indices map spatial patterns of grass senescence which are found to be correlated with soil thickness variations on hillslopes. Grassland senescence is delayed over deeper, wetter soils that are likely debris flow source areas. Prediction of actual soil depths using vegetation indices may be possible up to some limiting depth greater than the grass rooting zone. On forested earthflows, the slow slide movement disrupts the overhead timber canopy, exposes understory vegetation and soils, and alters site spectral characteristics. Both spectral and textural measures from broad band multispectral data are successful at detecting an earthflow within an undisturbed old-growth forest.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Photogrammetric Engineering and Remote Sensing (ISSN 0099-1112); 57; 1185-119
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    Expansion and contraction of the Sahara Desert from 1980 to 1990 (1991)
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    Publication Date: 2011-08-19
    Description: Data from polar-orbiting meteorological satellites have been used to determine the extent of the Sahara Desert and to document its interannual variation from 1980 to 1990. The Sahara Desert ranged from 8,633,000 square kilometers in 1980 to 9,982,000 square kilometers in 1984. The greatest annual north-south latitudinal movement of the southern Saharan boundary was 110 kilometers from 1984 to 1985 and resulted in a decrease in desert area of 724,000 square kilometers.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Science (ISSN 0036-8075); 253; 299-301
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    Measurement of surface microtopography (1991)
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    Publication Date: 2011-08-19
    Description: Acquisition of ground truth data for use in microwave interaction modeling requires measurement of surface roughness sampled at intervals comparable to a fraction of the microwave wavelength and extensive enough to adequately represent the statistics of a surface unit. Sub-centimetric measurement accuracy is thus required over large areas, and existing techniques are usually inadequate. A technique is discussed for acquiring the necessary photogrammetric data using twin film cameras mounted on a helicopter. In an attempt to eliminate tedious data reduction, an automated technique was applied to the helicopter photographs, and results were compared to those produced by conventional stereogrammetry. Derived root-mean-square (RMS) roughness for the same stereo-pair was 7.5 cm for the automated technique versus 6.5 cm for the manual method. The principal source of error is probably due to vegetation in the scene, which affects the automated technique but is ignored by a human operator.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Photogrammetric Engineering and Remote Sensing (ISSN 0099-1112); 57; 1075-107
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    Analysis of redox additive-based overcharge protection for rechargeable lithium batteries (1991)
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    Publication Date: 2011-08-19
    Description: The overcharge condition in secondary lithium batteries employing redox additives for overcharge protection, has been theoretically analyzed in terms of a finite linear diffusion model. The analysis leads to expressions relating the steady-state overcharge current density and cell voltage to the concentration, diffusion coefficient, standard reduction potential of the redox couple, and interelectrode distance. The model permits the estimation of the maximum permissible overcharge rate for any chosen set of system conditions. Digital simulation of the overcharge experiment leads to numerical representation of the potential transients, and estimate of the influence of diffusion coefficient and interelectrode distance on the transient attainment of the steady state during overcharge. The model has been experimentally verified using 1,1-prime-dimethyl ferrocene as a redox additive. The analysis of the experimental results in terms of the theory allows the calculation of the diffusion coefficient and the formal potential of the redox couple. The model and the theoretical results may be exploited in the design and optimization of overcharge protection by the redox additive approach.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Electrochemical Society, Journal (ISSN 0013-4651); 138; 2224-222
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    Earth observations during Space Shuttle flight STS-41 - Discovery's mission to planet earth (1991)
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    Publication Date: 2011-08-19
    Description: An overview of space flight STS-41 is presented, including personal observations and comments by the mission astronauts. The crew deployed the Ulysses spacecraft to study the polar regions of the sun and the interplanetary space above the poles. Environmental observations, including those of Lake Turkana, Lake Chad, biomass burning in Madagascar and Argentina, and circular features in Yucatan are described. Observations that include landforms and geology, continental sedimentation, desert landscapes, and river morphology are discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Geocarto International (ISSN 1010-6049); 6; 69-80
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    Investigation of soil influences in AVHRR red and near-infrared vegetation index imagery (1991)
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    Publication Date: 2011-08-19
    Description: The effects of soil optical properties on vegetation index imagery are analyzed with ground-based spectral measurements and both simulated and actual AVHRR data from the NOAA satellites. Soil effects on vegetation indices were divided into primary variations associated with the brightness of bare soils, secondary variations attributed to 'color' differences among bare soils, and soil-vegetation spectral mixing. Primary variations were attributed to shifts in the soil line owing to atmosphere or soil composition. Secondary soil variance was responsible for the Saharan desert 'artefact' areas of increased vegetation index response in AVHRR imagery.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 1223-124
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    Atmospheric effects on NOAA AVHRR data over Sahelian regions (1991)
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    Publication Date: 2011-08-19
    Description: Variable atmospheric conditions have a significant impact on satellite monitoring of vegetation in the Sahelian zone of Africa. The effects of atmospheric O3, H2O, and aerosols on spectral, directional reflectances and derived measures, such as the normalized difference vegetation index are discussed using a sensitivity study. An atmospheric correction scheme is presented based on measurements of optical thicknesses from the ground and is applied to NOAA AVHRR data. The use of the reflectance of the ocean surface close to the terrestrial target to estimate atmospheric effects on terrestrial reflectance is also discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 12; 1189-120
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    Diurnal change in trees as observed by optical and microwave sensors - The EOS Synergism Study (1991)
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    Publication Date: 2011-08-24
    Description: The EOS (Earth Observing System) Synergism Study examined the temporal variability of the optical and microwave backscatter due to diurnal change in canopy properties of interest to ecosystem modelers. The experiment was designed to address diurnal changes in canopy water status that relate to transpiration. Multispectral optical and multifrequency, multipolarization microwave measurements were acquired using boom-truck-based systems over a two-week period. Sensor and canopy properties were collected around the clock. The canopy studied was a walnut orchard in the San Joaquin Valley of California. The results demonstrate a large diurnal variation in the dielectric properties of the tree that in turn produces significant diurnal changes in the microwave backscatter. The results suggest that permanently orbiting spaceborne sensors such as those on EOS should be placed in orbits that are optimized for the individual sensor and need not be tied together by a tight simultaneity requirement on the order of minutes to hours for the purpose of monitoring ecosystem properties.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); 29; 807-821
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    Satellite estimation of incident photosynthetically active radiation using ultraviolet reflectance (1991)
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    Publication Date: 2011-08-24
    Description: A new satellite remote sensing method for estimating the amount of photosynthetically active radiation (PAR, 400-700 nm) incident at the earth's surface is described and tested. Potential incident PAR for clear sky conditions is computed from an existing spectral model. A major advantage of the UV approach over existing visible band approaches to estimating insolation is the improved ability to discriminate clouds from high-albedo background surfaces. UV spectral reflectance data from the Total Ozone Mapping Spectrometer (TOMS) were used to test the approach for three climatically distinct, midlatitude locations. Estimates of monthly total incident PAR from the satellite technique differed from values computed from ground-based pyranometer measurements by less than 6 percent. This UV remote sensing method can be applied to estimate PAR insolation over ocean and land surfaces which are free of ice and snow.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 38; 135-146
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    Project Copernicus: An Earth observing system (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Hunsaker Aerospace Corporation is presenting this proposal for Project Copernicus to fulfill the need for space-based remote sensing of Earth. Concentration is on data acquisition. Copernicus is designed to be a flexible system of spacecraft in a low near-polar orbit. The goal is to acquire data so that the scientists may begin to understand many Earth processes and interactions. The mission objective of Copernicus is to provide a space-based, remote-sensing measurement data acquisition and transfer system for 15 years. A description of the design project is presented.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Universities Space Research Association, Houston, Proceedings of the Seventh Annual Summer Conference. NASA(USRA: University Advanced Design Program; p 191-196
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  • 56
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    Review of thin film solar cell technology and applications for ultra-light spacecraft solar arrays (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Developments in thin-film amorphous and polycrystalline photovoltaic cells are reviewed and discussed with a view to potential applications in space. Two important figures of merit are discussed: efficiency (i.e., what fraction of the incident solar energy is converted to electricity), and specific power (power to weight ratio).
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 180-203
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    An approach for configuring space photovoltaic tandem arrays based on cell layer performance (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Meeting solar array performance goals of 300 W/Kg requires use of solar cells with orbital efficiencies greater than 20 percent. Only multijunction cells and cell layers operating in tandem produce this required efficiency. An approach for defining solar array design concepts that use tandem cell layers involve the following: transforming cell layer performance at standard test conditions to on-orbit performance; optimizing circuit configuration with tandem cell layers; evaluating circuit sensitivity to cell current mismatch; developing array electrical design around selected circuit; and predicting array orbital performance including seasonal variations.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 167-179
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  • 58
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    Indium phosphide solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The direction for InP solar cell research; reduction of cell cost; increase of cell efficiency; measurements needed to better understand cell performance; n/p versus p/n; radiation effects; major problems in cell contacting; and whether the present level of InP solar cell research in the USA should be maintained, decreased, or increased were considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 484-486
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  • 59
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    Mini-dome Fresnel lens photovoltaic concentrator development (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Since 1986 work on a new high-performance, light-weight space photovoltaic concentration array has been conducted. An update on the mini-dome lens concentrator array development program is provided. Recent prototype cell and lens test results indicate that near-term array performance goals of 300 w/sq m and 100 w/kg are feasible, and that a longer-term goal of 200 w/kg is reasonable.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 443-459
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  • 60
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    Integral bypass diodes in an amorphous silicon alloy photovoltaic module (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Thin-film, tandem-junction, amorphous silicon (a-Si) photovoltaic modules were constructed in which a part of the a-Si alloy cell material is used to form bypass protection diodes. This integral design circumvents the need for incorporating external, conventional diodes, thus simplifying the manufacturing process and reducing module weight.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 433-442
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  • 61
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    The Advanced Photovoltaic Solar Array (APSA) technology status and performance (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In 1985, the Jet Propulsion Laboratory initiated the Advanced Photovoltaic Solar Array (APSA) program. The program objective is to demonstrate a producible array system by the early 1990s with a specific performance of at least 130 W/kG (beginning-of-life) as an intermediate milestone towards the long range goal of 300 W/kG. The APSA performance represents an approximately four-fold improvement over existing rigid array technology and a doubling of the performance of the first generation NASA/OAST SAFE flexible blanket array of the early 1980s.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 421-432
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  • 62
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    Optimization and performance of Space Station Freedom solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: High efficiency, large area and low cost solar cells are the drivers for Space Station solar array designs. The manufacturing throughput, process complexity, yield of the cells, and array manufacturing technique determine the economics of the solar array design. The cell efficiency optimization of large area (8 x 8 m), dielectric wrapthrough contact solar cells are described. The results of the optimization are reported and the solar cell performance of limited production runs is reported.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 400-409
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  • 63
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    Spaceflight performance of several types of silicon solar cells on the LIPS 3 satellite (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Results from exposure of several types of Solarex silicon cells to a space environment for nearly two years on the LIPS 3 satellite are presented. Experiments include standard thickness (10 mil) cells with and without back surface fields, and ultrathin (2 mil) cells also with and without back surface fields. A comparison between a widely used coverslide adhesive, DC 93-500 and a potential alternate is also presented. The major findings from the data are that the 2 mil cells without a back surface field show the smallest normalized short circuit current degradation and that the 10 mil back surface field cells show the greatest absolute power output for the radiation exposures and temperatures encountered. The new encapsulant (McGhan Nusil CV-2500) exhibits a degradation comparable to DC 93-500. A comparison is made with each of the cell types in this experiment with expectations based on JPL Radiation Handbook data.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 385-388
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  • 64
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    Annealing characteristics of irradiated hydrogenated amorphous silicon solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: It was shown that 1 MeV proton irradiation with fluences of 1.25E14 and 1.25E15/sq cm reduces the normalized I(sub SC) of a-Si:H solar cell. Solar cells recently fabricated showed superior radiation tolerance compared with cells fabricated four years ago; the improvement is probably due to the fact that the new cells are thinner and fabricated from improved materials. Room temperature annealing was observed for the first time in both new and old cells. New cells anneal at a faster rate than old cells for the same fluence. From the annealing work it is apparent that there are at least two types of defects and/or annealing mechanisms. One cell had improved I-V characteristics following irradiation as compared to the virgin cell. The work shows that the photothermal deflection spectroscopy (PDS) and annealing measurements may be used to predict the qualitative behavior of a-Si:H solar cells. It was anticipated that the modeling work will quantitatively link thin film measurements with solar cell properties. Quantitative predictions of the operation of a-Si:H solar cells in a space environment will require a knowledge of the defect creation mechanisms, defect structures, role of defects on degradation, and defect passivation and annealing mechanisms. The engineering data and knowledge base for justifying space flight testing of a-Si:H alloy based solar cells is being developed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 389-399
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    Radioisotope thermal photovoltaic application of the GaSb solar cell (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An examination of a RTVP (radioisotopic thermophotovoltaic) conceptual design has shown a high potential for power densities well above those achievable with radioisotopic thermoelectric generator (RTG) systems. An efficiency of 14.4 percent and system specific power of 9.25 watts/kg were predicted for a system with sixteen GPHS (general purpose heat source) sources operating at 1100 C. The models also showed a 500 watt system power by the strontium-90 isotope at 1200 C at an efficiency of 17.0 percent and a system specific power of 11.8 watts/kg. The key to this level of performance is a high-quality photovoltaic cell with narrow bandgap and a reflective rear contact. Recent work at Boeing on GaSb cells and transparent back GaAs cells indicate that such a cell is well within reach.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 349-358
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  • 66
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    GaP betavoltaic cells as a power source (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Maximum power output for the GaP cells of this study was found to be on the order of 1 microW. This resulted from exposure to 200 and 40 KeV electrons at a flux of 2 x 10(exp 9) electrons/sq cm/s, equivalent to a 54 mCurie source. The efficiencies of the cells ranged from 5 to 9 percent for 200 and 40 KeV electrons respectively. The lower efficiency at higher energy is due to a substantial fraction of energy deposition in the substrate, further than a diffusion length from the depletion region of the cell. Radiation damage was clearly observed in GaP after exposure to 200 KeV electrons at a fluence of 2 x 10(exp 12) electrons/sq cm. No discernable damage was observed after exposure to 40 KeV electrons at the same fluence. Analysis indicates that a GaP betavoltaic system would not be practical if limited to low energy beta sources. The power available would be too low even in the ideal case. By utilizing high activity beta sources, such as Sr-90/Y-90, it may be possible to achieve performance that could be suitable for some space power applications. However, to utilize such a source the problem of radiation damage in the beta cell material must be overcome.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Lewis Research Center, Space Photovoltaic Research and Technology, 1989; p 359-370
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    Investigation of anodic and chemical oxides grown on p-type InP with applications to surface passivation for n(+)-p solar cell fabrication (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Most of the previously reported InP anodic oxides were grown on a n-type InP with applications to fabrication of MISFET structures and were described as a mixture of In2O3 and P2O5 stoichiometric compounds or nonstoichiometric phases which have properties similar to crystalline compounds In(OH)3, InPO4, and In(PO3)3. Details of the compositional change of the anodic oxides grown under different anodization conditions were previously reported. The use of P-rich oxides grown either by anodic or chemical oxidation are investigated for surface passivation of p-type InP and as a protective cap during junction formation by closed-ampoule sulfur diffusion. The investigation is based on but not limited to correlations between PL intensity and X-ray photoelectron spectroscopy (XPS) chemical composition data.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 316-331
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  • 68
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    Determination of series resistance of indium phosphide solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The series resistance of a solar cell is an important parameter, which must be minimized to achieve high cell efficiencies. The cell series resistance is affected by the starting material, its design, and processing. The theoretical approach proposed by Jia, et. al., is used to calculate the series resistance of indium phosphide solar cells. It is observed that the theoretical approach does not predict the series resistance correctly in all cases. The analysis was modified to include the use of effective junction ideality factor. The calculated results were compared with the available experimental results on indium phosphide solar cells processed by different techniques. It is found that the use of process dependent junction ideality factor leads to better estimation of series resistance. An accurate comprehensive series resistance model is warranted to give proper feedback for modifying the cell processing from the design state.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 311-315
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  • 69
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    Key factors limiting the open circuit voltage of n(+)pp(+) indium phosphide solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Solar cells made from gallium arsenide (GaAs), with a room temperature bandgap of E(sub g) = 1.43 eV have exhibited the best measured open circuit voltage (V sub OC) of 1.05 V at 1 AMO, 25 C. The material InP is in many ways similar to GaAs. A simple calculation comparing InP to GaAs then shows that solar cells made from InP, with E(sub g) = 1.35 at 300 K, should exhibit the best measured (V sub OC) of approximately 950 mV at 1 AMO, 300 K. However, to date, the best measured V(sub OC) for InP solar cells made by any fabrication method is 899 mV at AM1.5, 25 C which would translate to 912 mV at 1 AMO, 25 C. The V(sub OC) of an n(+)pp(+) InP solar cell is governed by several factors. Of these, some factors, such as the thickness and doping of the emitter and base regions, are easily controlled and can be adjusted to desired values dictated by a good performance optimizing model. Such factors were not considered. There are other factors which also govern V(sub OC), and their values are not so easily controlled. The primary ones among these are (1) the indirect or Hall-Shockley-Read lifetimes in the various regions of the cell, (2) the low-doping intrinsic carrier concentration n(sub i) of the InP material, (3) the heavy doping factors in the emitter and BSF regions, and (4) the front surface recombination velocity S(sub F). The influence of these latter factors on the V(sub OC) of the n(+)pp(+) InP solar cell and the results were used to produce a near-optimum design of the n(+)pp(+) InP solar cell.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 298-310
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  • 70
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    A comparative study of performance parameters of n(+)-p InP solar cells made by closed-ampoule sulfur diffusion into Cd- and Zn-doped p-type InP substrates (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Preliminary results indicate that Cd-doped substrates are better candidates for achieving high efficiency solar cells fabricated by closed-ampoule sulfur (S) diffusion than Zn-doped substrates. The differences in performance parameters (i.e., 14.3 percent efficiency for Cd-doped vs. 11.83 percent in the case of Zn-doped substrates of comparable doping and etch pit densities) were explained in terms of a large increase in dislocation density as a result of S diffusion in the case of Zn-doped as compared to Cd-doped substrates. The In(x)S(y) and probably Zn(S) precipitates in the case of Zn-doped substrates, produce a dead layer which extends deep below the surface and strongly affects the performance parameters. It should be noted that the cells had an unoptimized single layer antireflective coating of SiO, a grid shadowing of 6.25 percent, and somewhat poor contacts, all contributing to a reduction in efficiency. It is believed that by reducing the external losses and further improvement in cell design, efficiencies approaching 17 percent at 1 AMO, 25 degrees should be possible for cells fabricated on these relatively high defect density Cd-doped substrates. Even higher efficiencies, 18 to 19 percent should be possible by using long-lifetime substrates and further improving front surface passivation. If solar cells fabricated on Cd-doped substrates turn out to have comparable radiation tolerance as those reported in the case of cells fabricated on Zn-doped substrates, then for certain space missions 18 to 19 percent efficient cells made by this method of fabrication would be viable.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 332-346
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    Effects of proton irradiation on the performance of InP/GaAs solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: InP solar cells are known to be more radiation resistant than either GaAs or Si. In addition, AMO total area efficiencies approaching 19 percent were attained for InP. However, the present high substrate cost presents a barrier to the eventual widespread use of InP cells in space. In addition, if cell thinning becomes desirable, their relative fragility presents a problem. For these reasons, the NASA Lewis Research Center has initiated a program, aimed at producing thin InP cells, by heteroepitaxial deposition of InP on cheaper, more durable substrates. To date, a short term feasibility study as Spire has resulted in cells processed from InP heteroepitaxially deposited on Si substrates with an intervening thin GaAs layer (InP/GaAs/Si) and cells produced from InP deposited on GaAs (InP/GaAs). As a result of this short study efficiencies of over 7 and 9 percent were achieved for InP/GaAs/Si and InP/GaAs respectively. Although these efficiencies are low, they represent a modest and encouraging starting point for a more intensive program. Obviously, when considering economy and mechanical strength, cells processed on silicon substrates are preferred. However, although the InP/GaAs cells are not the final desirable products of this program, their properties serve to highlight several roadblocks to be overcome in producing cells with the more desirable cost and strength properties. Hence, in the present case, the properties of the InP/GaAs cells before and after irradiation by 10 MeV protons are examined. A similar study of InP/GaAs/Si cells will be reported on at a later date.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology, 1989; p 289-297
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    Manufacturing with the Sun (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Concentrated solar radiation is now a viable alternative source for many advanced manufacturing processes. Researchers at the National Renewable Energy Laboratory (NREL) have demonstrated the feasibility of processes such as solar induced surface transformation of materials (SISTM), solar based manufacturing, and solar pumped lasers. Researchers are also using sunlight to decontaminate water and soils polluted with organic compounds; these techniques could provide manufacturers with innovative alternatives to traditional methods of waste management. The solar technology that is now being integrated into today's manufacturing processes offer greater potential for tomorrow, especially as applied to the radiation abundant environment available in space and on the lunar surface.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Washington, Technology 2001: The Second National Technology Transfer Conference and Exposition, Volume 1; p 217-224
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  • 73
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    The Geologic Remote Sensing Field Experiment (GRSFE) (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Field measurements for the Geologic Remote Sensing Field Experiment (GRSFE) were concentrated in the Lunar Lake area of Nevada. The GRSFE data are meant to be used in a variety of investigations, including tests of multispectral radiative transfer models for scattering and emission from planetary surfaces in support of the Earth Observing System (EOS), Mars Observer, and Magellan Missions. Studies will also be pursued to establish the neotectonic and paleoclimatic history of the arid southwestern United States. The data will also be used to support Mars Rover Sample Return (MRSR) simulation studies.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1990; p 306-307
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  • 74
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    Two-terminal monolithic InP-based tandem solar cells with tunneling intercell ohmic connections (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A monolithic two-terminal InP/InGaAsP tandem solar cell was successfully fabricated. This tandem solar cell consists of a p/n InP homojunction top subcell and a 0.95 eV p/n InGaAsP homojunction bottom subcell. A patterned 0.95 eV n(+)/p(+) InGaAsP tunnel diode was employed as an intercell ohmic connection. The solar cell structure was prepared by two-step liquid phase epitaxial growth. Under one sun, AM1.5 global illumination, the best tandem cell delivered a conversion efficiency of 14.8 pct.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 8 p
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  • 75
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    Photoreflectance and DLTS evaluation of plasma-induced damage in GaAs and InP prior to solar cell fabrication (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The effect is considered of plasma etching on both GaAs and InP followed by damage removal using rapid thermal annealing (RTA). Effects of these processes were studied by photoreflectance spectroscopy (PR) and deep level transient spectroscopy (DLTS). These techniques are useful in evaluation of wafers prior to and effects of plasma processing during solar cell fabrication.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 9 p
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  • 76
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    Recent advances in GaAs/Ge solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: By growing the GaAs cell on a Ge substrate, the advantages of GaAs cells can be retained and the higher mechanical strength of the Ge makes larger, thinner GaAs cells possible. To conform to immediate user requirements, GaAs growth conditions were modified to eliminate the additional PV output at GaAs/Ge interface. To demonstrate acceptable cell manufacturing technology, the major areas in cell manufacture were analyzed and developed, and efficiency combined. Also the cells were successfully assembled on current lightweight arrays. The main areas of effort are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 10 p
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  • 77
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    Improvements in contact resistivity and thermal stability of Au-contacted InP solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Specific contact resistivities for as-fabricated Au contacts on n-p InP solar cells are typically in the 10(exp -3) ohm/sq cm range, but contact resistivities in the 10(exp -6) ohm/sq cm range can be obtained if the cells are heat treated at 400 C for a few minutes. This heat treatment, however, results in a dramatic drop in the open circuit voltage of the cell due to excessive dissolution of the emitter into the metallization. It was found that low values of contact resistivity can be secured without the accompanying drop in the open circuit voltage by adding Ga and In in the Au metallization. It is shown that Au contacts containing as little as 1 percent atomic Ga can suppress the reaction that takes place at the metal-InP interface during heat treatment, while exhibiting contact resistivity values in the low 10(exp -5) ohm/sq cm. Detailed explanations for the observed superior thermal stability of these contacts are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology Conference; 7 p
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  • 78
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    A pointable, helicopter-based remote sensing data acquisition system for collecting bidirectional reflectance data (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Discussed here is a new configuration of a helicopter-borne remote sensing system to support field measurements programs such as studies of forest decline damage associated with atmospheric deposition and the Forest Ecosystems Dynamics project. In this new configuration, the sensor payload is mounted externally on a hinged pallet located on the starboard side of the Bell Iroquois UH-1B (HUEY) helicopter. The sensor payload includes a set of bore-sighted instruments consisting of a Barnes Modular Multiband Radiometer (MMR), a Spectron Engineering (SE) 590 spectroradiometer, an Everest infrared temperature sensor, and a Sony CCD video camera with a 10x zoom lens. The system was tested and excellent data was acquired in 1990.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 297-298
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  • 79
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    The 1990 forest ecosystem dynamics multisensor aircraft campaign (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The overall objective of the Forest Ecosystem Dynamics (FED) research activity is to develop a better understanding of the dynamics of forest ecosystem evolution over a variety of temporal and spatial scales. Primary emphasis is being placed on assessing the ecosystem dynamics associated with the transition zone between northern hardwood forests in eastern North America and the predominantly coniferous forests of the more northerly boreal biome. The approach is to combine ground-based, airborne, and satellite observations with an integrated forest pattern and process model which is being developed to link together existing models of forest growth and development, soil processes, and radiative transfer.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 295-296
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  • 80
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    Visible and near infrared observation on the Global Aerosol Backscatter Experiment (GLOBE) (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Global Aerosol Backscatter Experiment (GLOBE) was intended to provide data on prevailing values of atmospheric backscatter cross-section. The primary intent was predicting the performance of spaceborne lidar systems, most notably the Laser Atmospheric Wind Sounder (LAWS) for the Earth Observing System (EOS). The second and related goal was to understand the source and characteristics of atmospheric aerosol particles. From the GLOBE flights, extensive data was obtained on the structure of clouds and the marine planetary boundary layer. A notable result for all observations is the consistency of the large increases in the aerosol scattering ratio for the marine boundary layer. Other results are noted.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 261-262
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  • 81
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    Remote sensing of the seasonal variation of coniferous forest structure and function (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: One of the objectives of the Oregon Transect Ecosystem Research (OTTER) project is the remotely sensed determination of the seasonal variation of leaf area index (LAI) and absorbed photosynthetically active radiation (APAR). These measurements are required for input into a forest ecosystem model which predicts net primary production evapotranspiration, and photosynthesis of coniferous forests. Details of the study are given.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 257-259
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    Ames Research Center C-130 (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The C130 Earth Resources Aircraft provides a platform for a variety of sensors that collect data in support of terrestrial and atmospheric projects sponsored by NASA in coordination with Federal, state, university, and industry investigators. This data is applied to research in the areas of forestry, agriculture, land use and land cover analysis, hydrology, geology, photogrammetry, oceanography, meteorology, and other earth science disciplines. The C130 is a platform aircraft flying up to 25,000 feet above sea level at speeds between 150 and 330 knots True Air Speed. The aircraft is capable of precise flight line navigation by means of an optical borescope from which line guidance is provided to the pilots.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 189-191
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  • 83
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    A PC-based multispectral scanner data evaluation workstation: Application to Daedalus scanners (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In late 1989, a personal computer (PC)-based data evaluation workstation was developed to support post flight processing of Multispectral Atmospheric Mapping Sensor (MAMS) data. The MAMS Quick View System (QVS) is an image analysis and display system designed to provide the capability to evaluate Daedalus scanner data immediately after an aircraft flight. Even in its original form, the QVS offered the portability of a personal computer with the advanced analysis and display features of a mainframe image analysis system. It was recognized, however, that the original QVS had its limitations, both in speed and processing of MAMS data. Recent efforts are presented that focus on overcoming earlier limitations and adapting the system to a new data tape structure. In doing so, the enhanced Quick View System (QVS2) will accommodate data from any of the four spectrometers used with the Daedalus scanner on the NASA ER2 platform. The QVS2 is designed around the AST 486/33 MHz CPU personal computer and comes with 10 EISA expansion slots, keyboard, and 4.0 mbytes of memory. Specialized PC-McIDAS software provides the main image analysis and display capability for the system. Image analysis and display of the digital scanner data is accomplished with PC-McIDAS software.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 183-184
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  • 84
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    Airborne water vapor DIAL system and measurements of water and aerosol profiles (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Lidar Applications Group at NASA Langley Research Center has developed a differential absorption lidar (DIAL) system for the remote measurement of atmospheric water vapor (H2O) and aerosols from an aircraft. The airborne H2O DIAL system is designed for extended flights to perform mesoscale investigations of H2O and aerosol distributions. This DIAL system utilizes a Nd:YAG-laser-pumped dye laser as the off-line transmitter and a narrowband, tunable Alexandrite laser as the on-line transmitter. The dye laser has an oscillator/amplifier configuration which incorporates a grating and prism in the oscillator cavity to narrow the output linewidth to approximately 15 pm. This linewidth can be maintained over the wavelength range of 725 to 730 nm, and it is sufficiently narrow to satisfy the off-line spectral requirements. In the Alexandrite laser, three intracavity tuning elements combine to produce an output linewidth of 1.1 pm. These spectral devices include a five-plate birefringent tuner, a 1-mm thick solid etalon and a 1-cm air-spaced etalon. A wavelength stability of +/- 0.35 pm is achieved by active feedback control of the two Fabry-Perot etalons using a frequency stabilized He-Ne laser as a wavelength reference. The three tuning elements can be synchronously scanned over a 150 pm range with microprocessor-based scanning electronics. Other aspects of the DIAL system are discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 167-168
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  • 85
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    Goodard Space Flight Center/Wallops Flight Facility airborne geoscience support capability (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Goddard Space Flight Center's Wallops Facility (GSFC/WFF), operates six aircraft which are used as airborne geoscience platforms. The aircraft complement consists of two UH-1B helicopters, one twin engine Skyvan, one twin jet T-39, and two four engine turboprop aircraft (P-3 and Electra) offering the research community a wide range of payload, altitude, speed, and range capabilities. WFF's support to a principal investigator include mission planning of all supporting elements, installation of equipment on the aircraft, fabrication of brackets, and adapters as required to adapt payloads to the aircraft, and planning of mission profiles to meet science objectives. The flight regime includes local, regional, and global missions. The WFF aircraft serve scientists at GSFC, other NASA centers, other government agencies, and universities. The WFF mode of operation features the walk on method of conducting research projects. The principal investigator requests aircraft support by letter to WFF and after approval is granted, works with the assigned mission manager to plan all phases of project support. The instrumentation is installed in WFF electronics racks, mounted on the aircraft, the missions are flown, and the equipment is removed when the scientific objectives are met. The principal investigator reimburses WFF for each flight hours, any overtime and travel expenses generated by the project, and for other mission-related expenses such as aircraft support services required at deployment bases.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 81-83
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  • 86
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    FIESTA ROC: A new finite element analysis program for solar cell simulation (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Finite Element Semiconductor Three-dimensional Analyzer by Ralph O. Clark (FIESTA ROC) is a computational tool for investigating in detail the performance of arbitrary solar cell structures. As its name indicates, it uses the finite element technique to solve the fundamental semiconductor equations in the cell. It may be used for predicting the performance (thereby dictating the design parameters) of a proposed cell or for investigating the limiting factors in an established design.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 6 p
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  • 87
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    Grooved surfaces on InP (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Formation of a textured or grooved front surface on a solar cell can increase the efficiency in several ways, including enhanced absorption and light trapping. In III-IV materials the (111) plane is chemically different form the (1'1'1') plane, and both etching and epitaxial deposition behave differently on these surfaces. The current state of profile etching in InP is summarized. Data are presented on novel geometries attainable as a function of etchant temperature and composition, substrate orientation and carrier concentration, and the oxide thickness between the substrate and the photoresist. Depending on dopant concentration, the same etchant can produce either anisotropic or isotropic grooves. V-grooved solar cells were manufactured on InP, and the improved optical absorption was demonstrated. Preferred parameters for various applications are listed and discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology Conference; 6 p
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  • 88
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    A comparative study of p(+)n and n(+)p InP solar cells made by a closed ampoule diffusion (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The purpose was to demonstrate the possibility of fabricating thermally diffused p(+)n InP solar cells having high open-circuit voltage without sacrificing the short circuit current. The p(+)n junctions were formed by closed-ampoule diffusion of Cd through a 3 to 5 nm thick anodic or chemical phosphorus-rich oxide cap layer grown on n-InP:S Czochralski LEC grown substrates. For solar cells made by thermal diffusion the p(+)n configuration is expected to have a higher efficiency than the n(+)p configuration. It is predicted that the AM0, BOL efficiencies approaching 19 percent should be readily achieved providing that good ohmic front contacts could be realized on the p(+) emitters of thickness lower than 1 micron.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Research and Technology Conference; 12 p
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  • 89
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    Airborne Ground Penetrating Radar (GPR) for peat analyses in the Canadian Northern wetlands study (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The study was conducted as part of the NASA Biospherics Research on Emissions from Wetlands (BREW) program. An important aspect of the program is to investigate the terrestrial production and atmospheric distribution of methane and other gases contributing to global warming. Multi-kilometer transects of airborne (helicopter) Ground Penetrating Radar (GPR) data were collected periodically along the 100 km distance from the coast inland so as to obtain a regional trend in peat depth and related parameters. Global Positioning System (GPS) data were simultaneously collected from the helicopter to properly georeference the GPR data. Additional 50 m ground-based transects of GPR data were also collected as a source of ground truthing, as a calibration aid for the airborne data sets, and as a source of higher resolution data for characterizing the strata within the peat. In situ peat depth probing and soil characterizations from excavated soil pits were used to verify GPR findings. Results from the ground-based data are presented.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 225-226
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  • 90
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    End-to-end remote sensing at the Science and Technology Laboratory of John C. Stennis Space Center (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Science and Technology Laboratory (STL) of Stennis Space Center (SSC) was developing an expertise in remote sensing for more than a decade. Capabilities at SSC/STL include all major areas of the field. STL includes the Sensor Development Laboratory (SDL), Image Processing Center, a Learjet 23 flight platform, and on-staff scientific investigators.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 187-188
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  • 91
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    Advanced Solid-State Array Spectrometer (ASAS) data sets from the 1990 field season: A unique look at two forested ecosystems (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Advanced Solid-state Array Spectrometer (ASAS) is a pointable imaging spectrometer which uses a solid-state array to acquire imagery of terrestrial targets in 29 spectral bands from .4 to .8 microns. Performance and calibration of the instrument are described. The ASAS data sets obtained in 1990 provide a unique look at forest canopies from two different forest regions of the North America continent under varying temporal, spectral, and bidirectional conditions. These data sets will be used to study such parameters as the albedo of forest canopies, the dynamics of scene radiation due to factors such as canopy architecture, moisture stress, leaf chemistry, topography, and understory composition.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 287-288
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  • 92
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    C-130 Automated Digital Data System (CADDS) (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Real time airborne data acquisition, archiving and distribution on the NASA/Ames Research Center (ARC) C-130 has been improved over the past three years due to the implementation of the C-130 Automated Digital Data System (CADDS). CADDS is a real time, multitasking, multiprocessing ROM-based system. CADDS acquires data from both avionics and environmental sensors inflight for all C-130 data lines. The system also displays the data on video monitors throughout the aircraft.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 243-244
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  • 93
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    The Pilot Land Data System (PLDS) at the Ames Research Center manages aircraft data in collaboration with an ecosystem research project (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Pilot Land Data System (PLDS) is a data and information system serving NASA-supported investigators in the land science community. The three nodes of the PLDS, one each at the Ames Research Center (ARC), the Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL), cooperate in providing consistent information describing the various data holding in the hardware and software (accessible via network and modem) that provide information about and access to PLDS-held data, which is available for distribution. A major new activity of the PLDS node at the Ames Research Center involves the interaction of the PLDS with an active NASA ecosystem science project, the Oregon Transect Ecosystems Research involves the management of, access to, and distribution of the large volume of widely-varying aircraft data collected by OTTER. The OTTER project, is managed by researchers at the Ames Research Center and Oregon State University. Its principal objective is to estimate major fluxes of carbon, nitrogen, and water of forest ecosystems using an ecosystem process model driven by remote sensing data. Ten researchers at NASA centers and universities are analyzing data for six sites along a temperature-moisture gradient across the western half of central Oregon (called the Oregon Transect). Sensors mounted on six different aircraft have acquired data over the Oregon Transect in support of the OTTER project.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, 4th Airborne Geoscience Workshop; p 93-95
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  • 94
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    Potential commercial uses of EOS remote sensing products (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The instrument complement of the Earth Observing System (EOS) satellite system will generate data sets with potential interest to a variety of users who are now just beginning to develop geographic information systems tailored to their special applications and/or jurisdictions. Other users may be looking for a unique product that enhances competitive position. The generally distributed products from EOS will require additional value added processing to derive the unique products desired by specific users. Entrepreneurs have an opportunity to create these proprietary level 4 products from the EOS data sets. Specific instruments or collections of instruments could provide information for crop futures trading, mineral exploration, television and printed medium news products, regional and local government land management and planning, digital map directories, products for third world users, ocean fishing fleet probability of harvest forecasts, and other areas not even imagined at this time. The projected level 3 product are examined that will be available at launch from EOS instruments and commercial uses of the data after value added processing is estimated.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, Technology 2000, Volume 2; p 122-129
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  • 95
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    The Land Analysis System (LAS) (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Land Analysis System (LAS) is an interactive software system, available in the public domain, for the analysis, display, and management of multispectral and other digital image data. The system was developed to support earth sciences research and development activities. LAS provides over 240 applications functions and utilities, a flexible user interface, complete on-line and hardcopy documentation, extensive image data file management, reformatting, and conversion utilities, and high level device independent access to image display hardware. The capabilities are summarized of the latest release of the system (version 5). Emphasis is given to the system portability and the isolation of hardware and software dependencies in this release.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, Technology 2000, Volume 2; p 115-121
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  • 96
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    Center for Mapping, Ohio State University (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: There are many future opportunities for Centers for the Commercial Development of Space (CCDS) activities that are directly linked to industry strategic objectives. In the fields of mapping, remote sensing, and geographic information systems (GIS), the near term opportunities may exceed all that have occurred in the past 10 years. It is strongly believed that a national spatial data infrastructure must be established in this country, if we are to remain a leader in the information age.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA, Washington, Proceedings of the Second Annual Symposium on Industrial Involvement and Successes in Commercial Space; 17 p
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  • 97
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    Commercial applications of new photovoltaic technologies (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The National Renewable Energy Laboratory (NREL) has directed and managed photovoltaic (PV) research and development (R&D) activities for the Department of Energy for more than 13 years. The NREL budget for these activities is almost $33 million for FY 1991. With the world's increasing concern for the environment and the United States' renewed apprehension over secure and adequate energy supplies, the use of semiconducting materials for the direct conversion of sunlight to electricity - photovoltaics - is an excellent example of government-supported high technology ready for further development by U.S. companies. Some new PV technologies and their research progress, some commercial applications of PV, and NREL's technology transfer activities for helping U.S. industry in its efforts to bring new products or services to the marketplace are described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA, Washington, Technology 2001: The Second National Technology Transfer Conference and Exposition, Volume 2; p 265-273
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  • 98
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    Annealing characteristics of amorphous silicon alloy solar cells irradiated with 1.00 MeV protons (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Amorphous Si:H and amorphous Si sub x, Ge sub (1-x):H solar cells were irradiated with 1.00 MeV proton fluences in the range of 1.00E14 to 1.25E15 cm (exp -2). Annealing of the short circuit current density was studied at 0, 22, 50, 100, and 150 C. Annealing times ranged from an hour to several days. The measurements confirmed that annealing occurs at 0 C and the initial characteristics of the cells are restored by annealing at 200 C. The rate of annealing does not appear to follow a simple nth order reaction rate model. Calculations of the short-circuit current density using quantum efficiency measurements and the standard AM1.5 global spectrum compare favorably with measured values. It is proposed that the degradation in J sub sc with irradiation is due to carrier recombination through the fraction of D (o) states bounded by the quasi-Fermi energies. The time dependence of the rate of annealing of J sub sc does appear to be consistent with the interpretation that there is a thermally activated dispersive transport mechanism which leads to the passivation of the irradiation induced defects.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 9 p
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  • 99
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    Temperature coefficients and radiation induced DLTS spectra of MOCVD grown n(+)p InP solar cells (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The effects of temperature and radiation on n(+)p InP solar cells and mesa diodes grown by metallorganic chemical vapor deposition (MOCVD) were studied. It was shown that MOCVD is capable of consistently producing good quality InP solar cells with Eff greater than 19 percent which display excellent radiation resistance due to minority carrier injection and thermal annealing. It was also shown that universal predictions of InP device performance based on measurements of a small group of test samples can be expected to be quite accurate, and that the degradation of an InP device due to any incident particle spectrum should be predictable from a measurement following a single low energy proton irradiation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 9 p
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  • 100
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    Production status of GaAs/Ge solar cells and panels (1991)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: GaAs/Ge solar cells with lot average efficiencies in excess of 18 percent were produced by MOCVD growth techniques. A description of the cell, its performance and the production facility are discussed. Production GaAs/Ge cells of this type were recently assembled into circuits and bonded to aluminum honeycomb panels to be used as the solar array for the British UOSAT-F program.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center, Space Photovoltaic Research and Technology Conference; 7 p
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