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  • Other Sources  (1,745)
  • EARTH RESOURCES AND REMOTE SENSING  (560)
  • METEOROLOGY AND CLIMATOLOGY  (496)
  • ENERGY PRODUCTION AND CONVERSION  (385)
  • SOLAR PHYSICS  (304)
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  • 1
    Publication Date: 2006-04-06
    Description: Isolated knobs that are erosional remnants of central volcanoes or of folded rocks occur in several areas of the Altiplano are visible on both optical and images. The optically visible streaks occur in the immediate lee of the knobs, whereas the radar visible streaks occur in the zone downwind between the knobs. Aerial reconnaissance and field studies showed that the optically visible streaks consist of a series of small ( 100 m wide) barchan and barchanoid dunes, intradune sand sheets, and sand hummocks (large shrub coppice dunes) up to 15 m across and 5 m high. On LANDSAT images these features are poorly resolved but combine to form a bright streak. On the radar image, this area also appears brighter than the zone of the radar dark streak; evidently, the dunes and hummocks serve as radar reflectors. The radar dark streak consists of a relatively flat, smooth sand sheet which lacks organized aerolian bedforms, other than occasional ripples. Wind velocity profiles show a greater U value in the optically bright streak zone than in the radar dark streak.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Washington Rept. of Planetary Geology Program, 1983; p 271-272
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  • 2
    Publication Date: 2006-04-06
    Description: The diversity of proposed origins for large Martian outflow channels results from the differing interpretations given to the landforms associated with the outflow channels. In an attempt to help limit the possible mechanisms of channel erosion, detailed studies of three of the channel features were done; the streamlined islands, longitudinal grooves and scour marks. This examination involved a comparison of the martian streamlined islands with various streamlined landforms on Earth including those found in the Channel Scabland in large rivers, glacial drumlins, and desert yardangs. The comparisons included statistical analyses of the landform lengths versus widths and positions of maximum width, and an examination of the degree of shape agreement with the geometric lemniscate which was in turn demonstrated to correspond closely with true airfoil shapes. The analyses showed that the shapes of the martian islands correspond closely to the streamlined islands in rivers and the Channel Scabland land. Drumlins show a much smaller correlation. Erosional rock islands formed by glaciers are very much different in shape.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Washington Rept. of Planetary Geol. Programs; p 200-202
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  • 3
    Publication Date: 2006-02-14
    Description: The design and operations of a low cost, high rate thermal cycling facility designed for LEO conditions is described. Thermal cycling facilities were constructed with various design criteria. Some were designed to duplicate as closely as possible the conditions a cell or module would encounter while in orbit about the Earth. A typical facility to perform this type of cycling was a large vacuum system with liquid nitrogen cooled walls. The cells were heated by an AMO spectrum solar simulator, then a shutter was closed allowing the cells to give up their heat to the cold walls. This system was good at duplicating the orbital conditions but was slow and very costly to operate. Other systems used a gas atmosphere and heated the cells with radiant heat and cooled the cells by moving them into close proximity to a cold plate. The systems greatly increased the cycle times. Other systems moved the heating and cooling atmosphere into and out of the test areas and achieved reasonable cycle rates. All these systems, however, are expensive to operate.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1983; p 223-227
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  • 4
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    In:  CASI
    Publication Date: 2006-02-14
    Description: The development of the GaAs solar cells for space applications is described. The activities in the fabrication of GaAs solar panels are outlined. Panels were fabricated while introducing improved quality control, soldering laydown and testing procedures. These panels include LIPS II, San Marco Satellite, and a low concentration panel for Rockwells' evaluation. The panels and their present status are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 205-209
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  • 5
    Publication Date: 2006-02-14
    Description: The solar array for the San Marco D/L spacecraft is described and the performance of 4 GaAs solar cell panels are examined. In comparison to the typical Si solar cell panel for San Marco D/L, it is shown that each GaAs solar cell panel provides at least 23 percent more specific power at maximum output and 28 deg C. Also described here, are several measurements that will be made to evaluate the relative performance of Si and GaAs solar cell panels during the San Marco D/L flight.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 176-181
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  • 6
    Publication Date: 2006-02-14
    Description: The results of heteroepitaxial growth of GaAs and GaAlAs directly on Si are presented, and applications to new cell structures are suggested. The novel feature is the elimination of a Ge lattice transition region. This feature not only reduces the cost of substrate preparation, but also makes possible the fabrication of high efficiency monolithic cascade structures. All films to be discussed were grown by organometallic chemical vapor deposition at atmospheric pressure. This process yielded reproducible, large-area films of GaAs, grown directly on Si, that are tightly adherent and smooth, and are characterized by a defect density of 5 x 10(6) power/sq cm. Preliminary studies indicate that GaAlAs can also be grown in this way. A number of promising applications are suggested. Certainly these substrates are ideal for low-weight GaAs space solar ells. For very high efficiency, the absence of Ge makes the technology attractive for GaAlAs/Si monolithic cascades, in which the Si substrates would first be provided with a suitable p/n junction. An evaluation of a three bandgap cascade consisting of appropriately designed GaAlAs/GaAs/Si layers is also presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 128-139
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  • 7
    Publication Date: 2006-02-14
    Description: Deep level transient spectroscopy reveals that the main electron traps for one-MeV electron irradiated GaAs cells are E9c)-0.31, E(c)-0.90 eV, and the main hole trap is due to the level. Electron trap density was found to vary from 3/tens-trillion ccm for 2/one quadrillion cm 3/3.7 quadrillion cm for 21 sextillion cm electron fluence for electron fluence; a similar result was also obtained for the hole trap density. As for the grown-in defects in the Al(x)Ga(1-x)As p-n junciton cells, only two electron traps with energies of E(c)-0.20 and E(c)-0.34 eV were observed in samples with x = 0.17, and none was found for x 0.05. Auger analysis on the Al(x)Ga(1-x) As window layer of the GaAs solar cell showed a large amount of oxygen and carbon contaminants near the surface of the AlGaAs epilayer. Thermal annealing experiment performed at 250 C for up to 100 min. showed a reduction in the density of both electron traps.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 91-101
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  • 8
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    In:  CASI
    Publication Date: 2006-02-14
    Description: A short circuit current (I sub sc) degradation model for gallium arsenide (GaAs) solar cells irradiated by protons from low energy to 100 MeV was developed. This model was found to be satisfactory in predicting the I sub sc degradation of GaAs cells, but not that of silicon (Si) cells. A modification to the aforementioned model that preserves the optical wavelength dependency in the photogeneration of minority carrier pairs was described herein. Spectral Si and GaAs response and I sub sc for the Si and GaAs solar cells were discussed, and also were presented in graph form. The overall predictability of the modified model was deemed to be satisfactory.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 56-62
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  • 9
    Publication Date: 2006-02-14
    Description: Manufacturing technology for mass producing high efficiency GaAs solar cells is discussed. A progress using a high throughput MO-CVD reactor to produce high efficiency GaAs solar cells is discussed. Thickness and doping concentration uniformity of metal oxide chemical vapor deposition (MO-CVD) GaAs and AlGaAs layer growth are discussed. In addition, new tooling designs are given which increase the throughput of solar cell processing. To date, 2cm x 2cm AlGaAs/GaAs solar cells with efficiency up to 16.5% were produced. In order to meet throughput goals for mass producing GaAs solar cells, a large MO-CVD system (Cambridge Instrument Model MR-200) with a susceptor which was initially capable of processing 20 wafers (up to 75 mm diameter) during a single growth run was installed. In the MR-200, the sequencing of the gases and the heating power are controlled by a microprocessor-based programmable control console. Hence, operator errors can be reduced, leading to a more reproducible production sequence.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 18-24
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  • 10
    Publication Date: 2006-02-14
    Description: Various coatings developed in the FRG (i.e., second-surface mirrors with interference filters with and without conductive layers, conductive layers on solar-cell covers, and selective absorber coatings) have been qualified by accelerated tests under simulated space environment conditions. Experiments with coatings and solar cells have shown, however, that the thermo-optical behavior can differ considerably when performed on the ground and in space because of the great difficulty in simulating the space environment realistically. The objective of this experiment is to qualify these coatings under realistic space environment conditions. In addition, the experiment will provide design criteria, techniques, and test methods to insure control of the combined space and spacecraft environment effects, such as contamination, electrical conductance, and optical degradation, on the coatings. Data to be measured include the temperature of the samples, the electrical resistance of the conductive layers of the samples, the short circuit current of the solar-cell modules, and the deposition of contaminants on the samples (using quartz crystal microbalances (QCM's)).
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 91-93
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  • 11
    Publication Date: 2006-02-14
    Description: The objective of this experiment is to evaluate the synergistic effects of the space environment on various solar-array materials, including solar cells, cover slips with various antireflectance coatings, adhesive, encapsulants, reflector materials, substrate strength materials, mast and harness materials, structural composites, and thermal control treatments. The experiment is passive and consists of an arrangement of material specimens mounted in a 3-in.-deep peripheral tray. The effects of the space environment on the specimens will be determined by comparison of preflight and postflight measurements of mechanical, electrical, and optical properties.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 86-87
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  • 12
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    In:  CASI
    Publication Date: 2006-02-14
    Description: As a user of devices and procedures for lightning protection, the author is asking the lightning research community for cookbook recipes to help him solve his problems. He is lamenting that realistic devices are scarce and that his mission does not allow him the time nor the wherewithal to bridge the gap between research and applications. A few case histories are presented. In return for their help he is offering researchers a key to lightning technology--the use of the Eastern Test Range and its extensive resources as a proving ground for their experiment in the lightning capital of the United States. A current example is given--a joint lightning characterization project to take place there. Typical resources are listed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Langley Research Center Intern. Aerospace and Ground Conf. on Lightning and Static Elec.; 6 p
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  • 13
    Publication Date: 2006-04-06
    Description: In order to understand better the polygenetic evolution of landforms on the martian surface, field studies were conducted in and around the Kharga Depression, Egypt. The Kharga region, on the eastern edge of Egypt's Western Desert, was subject to erosion under mostly hyperarid climatic conditions, punctuated by brief pluvial episodes of lesser aridity, since early Pleistocene time. The region contains numerous landforms analogous to features on the martian surface: yardangs carved in layered surficial deposits and in bedrock, invasive dune trains, wind-modified channels and interfluves, and depressions bounded by steep scarps. Like many of the topographic depresions on Mars, the Kharga Depression was invaded by crescentic dunes. In Egypt, stratigraphic relations between dunes, yardangs, mass-wasting debris, and wind-eroded flash-flood deposits record shifts in the relative effectiveness of wind, water, and mass-wasting processes as a function of climate change.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Washington Rept. of Planetary Geology Program, 1983; p 225-227
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  • 14
    Publication Date: 2006-04-03
    Description: The design and structural properties of a low concentration ratio solar array are discussed. The assembled module consists of six interconnected containers which are compactly stowed in a volume of 3.24 m(3) for delivery to orbit by the shuttle. The containers deploy in accordian fashion into a rectangular area of 19.4 x 68 meters and can be attached to the user spacecraft along the longitudinal centerline of the end container housing. Five rotary incremental actuators requiring about 8 watts each will execute the 180-degree rotation at each joint. Deployable masts (three per side) are used to extend endcaps from the housing in both directions. Each direction is extended by three masts requiring about 780 watts for about 27 minutes. Concentrator elements are extended by the endcaps and are supported by cable systems that are connected between the housings and endcaps. These power generating elements contain reflector panels which concentrate light onto the solar panels consisting of an aluminum radiator with solar cells positioned within the element base formed by the reflectors. A flat wire harness collects the power output of individual elements for transfer to the module container housing harnesses.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center STEP Expt. Requirements; p 185-198
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  • 15
    Publication Date: 2006-04-06
    Description: Sand bars and islands within braided rivers have characteristic rhomboid or diamond shapes, often becoming very complex in form as the density of islands increases. Similar forms are observed in the martian outflow channels where the islands occur in groups. This contrasts with the more isolated martian islands which have airfoil shapes, as do isolated streamlined islands in rivers and in the Channeled Scabland. These observations indicate that the bar and island forms are controlled by the density of the islands, with increasing island interaction and flow modification as the density increases. As a continuation of previous flume experiments on the shapes of isolated islands, a new series of experiments investigate the modifications produced by a progressive increase in island density, finally leading to a true braided system.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA. Washington Rept. of Planetary Geol. Programs; p 198-199
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  • 16
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Participants expressed more interest in GaAs cells than in Si cells. For silicon cells, the beginning of life efficiency is not a major problem but more research is needed in the end of life efficiency. The beginning of life efficiency of GaAs cells must be brought up to 20% at AMO. More proton damage tests must be conducted. Liquid phase epitaxy technology is current but chemical vapor deposition technology is more flexible. There are no obvious problems in limiting process yields. Technology transfer should occur when market demands are generated.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 251-252
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  • 17
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Principles and design considerations of IR transparent solar arrays are discussed. Optimization of performance of flexible solar arrays was studied. Measured solar absorptance as low as alpha s = 0.59 was achieved which leads to a predicted BOL power density of 182.7 = W/square meters. Advanced array concepts, system level cascaded panels, and transparent rigid panels are proposed and expected benefits discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 210-219
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  • 18
    Publication Date: 2006-02-14
    Description: A number of structurally efficient configurations for wing-type solar arrays are developed by a combination of deepening the planform of the blanket and structure and by partitioning the blanket with battens and frequent attachments to the support structure. This technique reduces the tension required to avoid a low natural frequency for the blanket, and the load reduction results in a lighter structure. The use of three different structures are investigated: the Astromast, the Extendible Support Structure (ESS), and a new beam called the STACBEAM (Stacking Triangular Articulated Compact Beam) and their relative performances are compared. The investigation of the STACBEAM is emphasized because its sequential deployment is more reliable for very long systems, and its linear deployment facilitates local attachments to the blanket and the development of a low mass deployer.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 193-204
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  • 19
    Publication Date: 2006-02-14
    Description: Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 182-192
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  • 20
    Publication Date: 2006-02-14
    Description: A miniaturized Cassegrainian concentrator (MCC) solar array system is examined to assess the practicality of assembling the basic MCC element into a total array system capable of producing multi-hundred kilowatts of power for Space Platform/Space Station or other low Earth orbit long lifetime missions. Preliminary mechanical and electrical subsystems are developed in order to determine first order performance characteristics. Results of the study support the feasibility of a 100-kilowatt MCC array system with beginning-of-life (BOL) performance of 160 watts per square meter and 28 W/kg. The performance numbers are based on 20 percent efficient (at operating temperature) solar cells and 0.25-millimeter thick electroformed nickel optics. These performance numbers can be improved upon significantly with the development of higher efficiency solar cells and/or lighter weight optics.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 157-162
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  • 21
    Publication Date: 2006-02-14
    Description: High-efficiency, monolithic, two-color, three-terminal solar cells were fabricated by a novel growth technique, vacuum metal-organic chemical vapor deposition. The technique uses the expensive metal alkyls efficiently and toxic gases sparingly. The fact that the outer chamber is constructed of nonbreakable stainless steel is an attractive safety feature associated with this deposition system.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 148-154
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  • 22
    Publication Date: 2006-02-14
    Description: Computer analysis was used to determine the AMO conversion efficiency of single-junction crystalline cells, two-cell and three-cell crystalline tandem structures operating under 100 suns and at 80 C. For optimally designed devices, the calculated efficiencies are 24% for single-junction cells, 33 to 35% for two-cell tandem structures, and 37 to 39% for three-cell tandem structures. Practical efficiencies are expected to be about 15 relative percentage points lower in each case.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 120-127
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  • 23
    Publication Date: 2006-02-14
    Description: The short-circuit current reduction in GaAs shallow junction heteroface solar cells was calculated according to a simplified solar cell damage model in which the nonuniformity of the damage as a function of penetration depth is treated explicitly. Although the equivalent electron fluence was not uniquely defined for low-energy monoenergetic proton exposure, an equivalent electron fluence is found for proton spectra characteristic of the space environment. The equivalent electron fluence ratio was calculated for a typical large solar flare event for which the proton spectrum is PHI(sub p)(E) = A/E(p/sq. cm) where E is in MeV. The equivalent fluence ratio is a function of the cover glass shield thickness or the corresponding cutoff energy E(sub c). In terms of the cutoff energy, the equivalent 1 MeV electron fluence ratio is r(sub p)(E sub c) = 10(9)/E(sub c)(1.8) where E(sub c) is in units of KeV.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 112-117
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  • 24
    Publication Date: 2006-02-14
    Description: Some n(+)/p cells in which lithium is introduced as a counterdopant, by ion-implantation, into the cell's boron-doped p-region were studied. To determine if the cells radiation resistance could be significantly improved by lithium counterdoping. Defect behavior was related to cell performance using deep level transient spectroscopy. Results indicate a significantly increased radiation resistance for the lithium counterdoped cells when compared to the boron doped 1 ohm-cm control cell. The increased radiation resistance of the lithium counterdoped cells is due to the complexing of lithium with divacancies and boron. It is speculated that complexing with oxygen and single vacancies also contributes to the increased radiation resistance. Counterdoping silicon with lithium results in a different set of defects.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1983; p 102-110
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  • 25
    Publication Date: 2006-02-14
    Description: Telemetry from the Living Plume Shield's gallium arsenide solar panel experiment was evaluated to determine degradation. The data were culled to preclude spurious results from possible shadowing or inaccurate measurements on a cold array. Two independent methods were then used to obtain the maximum power points and the various characteristics of the solar array. Fill factor, open circuit voltage, short circuit current, and series and shunt resistances were examined. The data analysis concluded that, to date, nearly all of the solar array degradation is due to the reduction in the short circuit current.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 81-89
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  • 26
    Publication Date: 2006-02-14
    Description: The radiation tolerance of the following three low resistivity, high voltage silicon solar cells was investigated: (1) the COMSAT MSD (multi-step diffused) cell, (2) the MinMIS cell, and (3) the MIND cell. A description of these solar cells is given along with drawings of their configurations. The diffusion length damage coefficients for the cells were calculated and presented. Solar cell spectral response was also discussed. Cells of the MinMIS type were judged to be unsuitable for use in the space radiation environment.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1983; p 74-80
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  • 27
    Publication Date: 2006-02-14
    Description: Gallium Arsenide (GaAs) solar cells are viewed as a potential primary power source on certain future Earth orbiting satellites. However, the relative merits of gallium arsenide over silicon in a space radiation environment are largely unknown because a general degradation model for gallium arsenide does not exist. The results of a test simulating the proton radiation environment existing in a polar orbit and the concomitant effects on GaAs and thin silicon (Si) solar cells are presented. The objectives and methodology of the simulation test were discussed. The electrical characteristics of GaAs and Si solar cells are given in graph form. It was concluded that GaAs cells are viable for use on satellites in low Earth orbit.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 63-73
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  • 28
    Publication Date: 2006-02-14
    Description: Significant discrepancies have been observed between predicted and actual in-orbit silicon solar array degradation in orbits other than LEO (low Earth orbits) and GEO (geosynchronous orbit). These discrepancies have been diagnosed to arise probably from a combination of a lack of appropriate solar cell test data and from inadequacies in the models that relate the unidirectional and mono-energetic proton test data to the omnidirectional flux-energy spectra actually found in orbit. Relative damage coefficients and solar cell power outputs were discussed, and also were presented in graph form. Silicon and gallium arsenide solar cells were considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 49-55
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  • 29
    Publication Date: 2006-02-14
    Description: The radiation damage of solar cells has become a prime concern to the U.S. Air Force due to longer satellite lifetime requirements. Flight experiments were undertaken on the Navy Living Plume Shield (LPS) satellite and the NASA/Air Force Combined Release and Radiation Effects Satellite (CRRES) to complement existing radiation testing. Each experiment, the rationale behind it, and its approach and status are presented. The effect of space radiation on gallium arsenide (GaAs) solar cells was the central parameter investigated. Specifications of the GaAs solar cells are given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 41-48
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  • 30
    Publication Date: 2006-02-14
    Description: A computer program, SCAP2D (Solar Cell Analysis Program in 2-Dimensions), is used to evaluate the Etched Multiple Vertical Junction (EMVJ) and grating solar cells. The aim is to demonstrate how SCAP2D can be used to evaluate cell designs. The cell designs studied are by no means optimal designs. The SCAP2D program solves the three coupled, nonlinear partial differential equations, Poisson's Equation and the hole and electron continuity equations, simultaneously in two-dimensions using finite differences to discretize the equations and Newton's Method to linearize them. The variables solved for are the electrostatic potential and the hole and electron concentrations. Each linear system of equations is solved directly by Gaussian Elimination. Convergence of the Newton Iteration is assumed when the largest correction to the electrostatic potential or hole or electron quasi-potential is less than some predetermined error. A typical problem involves 2000 nodes with a Jacobi matrix of order 6000 and a bandwidth of 243.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 34-40
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  • 31
    Publication Date: 2006-02-14
    Description: Several modifications were made to an infinite solution liquid phase epitaxy system that help fabricate both GaAs-based cells and thin cells that effectively reduce power-to-weight ratio for space applications. The most important development is the multiwell crucible for multilayer growth. Using a split crucible in one system, as many as five layers were grown in succession with varying Al levels and dopants. The structures grown were used to produce thin GaAs cells only 10 to 20 microns thick and also to grow cascade cell components. Results of these studies are presented and their applications to the future development of GaAs-based cells are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 12-17
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  • 32
    Publication Date: 2006-02-14
    Description: A fabrication process for structurally stable thin solar cell wafers that produce good power output after irradiation is described. The fabrication process is as follows. A 6 mil, circular wafer is oxidized on both sides. One side is then patterned with a rectangular array of holes in the oxide that are nominally 75 mils square and separated by 2 mil spacings. Wells are then etched into the silicon with KOH to a depth of 4 mils, leaving a 2 mil, unetched thickness. Two areas on the surface are left unetched to provide pads for bonding or testing. All oxide is then removed and the rest of the processing is normal; the unetched face is used as the illuminated face. When all other processing is complete, a 2 X 2 cm cell is sawed from the starting wafer leaving a border that is approximately 10 mils wide. The effective thickness, determined by weighing an unmetallized sample, of such a cell is about 2.4 mil.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 8-11
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  • 33
    Publication Date: 2006-02-14
    Description: In-flight calibration for the solr and Earth flux channels was examined. Earth Radiation on Budget (ERB) channel components were exposed to the space environment and then retrieved and resubmitted to radiometric calibration after exposure. It is suggested that corrections may be applied to ERB results and information will be obtained to aid in the selection of components for future operational solar and Earth radiation budget experiments. To assure that these high accuracy devices are measuring real variations and are not responding to changes induced by the space environment, it is desirable to test such devices radiometrically after exposure to the best approximation of the orbital environment.
    Keywords: SOLAR PHYSICS
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 167-169
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  • 34
    Publication Date: 2006-02-14
    Description: The advanced photovoltaics-related experiments for investigating a portion of the solar spectrum and the effect of the space environment on photovoltaics. The information will be used to provide correlation between space and ground testing and also to provide for more accurate performance measurement in the laboratory. Specific objectives of these experiments are to provide information on the performance and endurance of advanced and conventional solar cells, to improve reference standards for photovoltaic measurements, and to measure the energy distribution in the extraterrestrial solar spectrum. Data to be obtained will include temperatures and short-circuit current of the samples. Six-point current-voltage (I-V) characteristics will be obtained for selected samples. These data will be recorded once a day during the flight. Orbit data will be correlated with preflight and postflight measurement of the samples.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 88-90
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  • 35
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    Publication Date: 2011-08-19
    Description: Sample images obtained with the Shuttle Imaging Radar A (SIR-A) are presented, along with design and performance features of the SIR-A, Seasat and Landsat images of the same scenes for comparison purposes. The SIR-A functions at the L-band 25 cm at a frequency of 1278 GHz with a spectral bandwidth of 6 MHz. The images were taken at an angle of 47 deg and furnished a resolution of 40 m from an altitude of 259 km. The images covered a ground swath 50 km wide. The images are provided to assist in the development of effective techniques for interpreting radar imagery. The SIR-A instrument is a precursor of another imaging device which will be flown around Venus. The images provided include sections of France, Sardinia and Algeria.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Photo Interpretation (ISSN 0031-8523); 23; 4-17
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  • 36
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    Publication Date: 2011-08-19
    Description: The present conference on electrochemical power sources encompasses systems of such types as the thermoelectric, advanced rechargeable, lithium reserve, rechargeable, and nonrechargeable, nickel-cadmium and nickel-hydrogen rechargeable, lead-acid, nickel-zinc and nickel-iron rechargeable, nickel-cadmium and nickel-hydrogen rechargeable, and fuel cells. Attention is given to Si-Ge alloy multicouple technology, sodium-sulfur battery development status, the safety aspects of a rechargeable lithium C cell, fiber-structure electrodes for nickel-cadmium batteries, energy density improvements in Li/carbon monofluoride cells, zinc-air button cell technology, catalyzed cathodes for Li/SOCl2 cells, the effect of polymer structure on the rate capability of the lithium-iodine cell, and a methanol fuel cell powerplant.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 37
    Publication Date: 2011-08-19
    Description: The collective character of carbon exchanges between the atmosphere and other pools is partially revealed by comparing the record of CO2 concentration beginning in 1958 with estimates of the releases from fossil fuels during this period. In analyzing the secular increase in CO2 concentration induced by fossil fuel use, the atmosphere is generally treated as a single well-mixed reservoir; however, to study finer structure in the CO2 records, the influence of atmospheric circulation must be more carefully considered. The rate of carbon uptake by the oceans, the primary sink for fossil fuel CO2, is assessed more reliably than influences on the atmosphere due to interactions with other pools. Models of the global carbon cycle are being substantially refined while data that reflect the response of the cycle to fossil fuel use and other perturbations are being extended.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: JPL The interaction of Global Biochemical Cycles; p 55-84
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  • 38
    Publication Date: 2011-08-18
    Description: A statistical correlation technique is applied to the retrieval of vertical moisture profiles under clear-sky conditions from down-looking radiometric measurements of atmospheric radiation at microwave wavelengths. For a given set of channels, the method selects the optimum radiometric channels for estimating water vapor at specific pressure levels between the surface and 300 mb. The water vapor mixing ratio at these pressure levels is then calculated from a linear combination of the selected channel brightness temperatures. To test its validity the algorithm was applied, in a numerical experiment, to fifty independent tropical radiosondes. The rms absolute deviation of the estimated moisture profiles from the actual profiles was comparable to that obtained using an iterative retrieval method reported earlier. The statistical method, however, requires several orders of magnitude less computer time than the iterative method; it is suitable for high speed processing of large amounts of data.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 23; 1110-111
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  • 39
    Publication Date: 2011-08-18
    Description: A computer-implemented classification has been derived from Landsat-4 Thematic Mapper data acquired over Baldwin County, Alabama on January 15, 1983. One set of spectral signatures was developed from the data by utilizing a 3x3 pixel sliding window approach. An analysis of the classification produced from this technique identified forested areas. Additional information regarding only the forested areas. Additional information regarding only the forested areas was extracted by employing a pixel-by-pixel signature development program which derived spectral statistics only for pixels within the forested land covers. The spectral statistics from both approaches were integrated and the data classified. This classification was evaluated by comparing the spectral classes produced from the data against corresponding ground verification polygons. This iterative data analysis technique resulted in an overall classification accuracy of 88.4 percent correct for slash pine, young pine, loblolly pine, natural pine, and mixed hardwood-pine. An accuracy assessment matrix has been produced for the classification.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 40
    Publication Date: 2011-08-18
    Description: Among the topics discussed are NASA's land remote sensing plans for the 1980s, the evolution of Landsat 4 and the performance of its sensors, the Landsat 4 thematic mapper image processing system radiometric and geometric characteristics, data quality, image data radiometric analysis and spectral/stratigraphic analysis, and thematic mapper agricultural, forest resource and geological applications. Also covered are geologic applications of side-looking airborne radar, digital image processing, the large format camera, the RADARSAT program, the SPOT 1 system's program status, distribution plans, and simulation program, Space Shuttle multispectral linear array studies of the optical and biological properties of terrestrial land cover, orbital surveys of solar-stimulated luminescence, the Space Shuttle imaging radar research facility, and Space Shuttle-based polar ice sounding altimetry.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
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  • 41
    Publication Date: 2011-08-18
    Description: The extent and thermal stratification of the region of convective overshoot underneath the convection zone of the sun are investigated. The phenomenon of convective overshoot in general is discussed, and some of the modal and model approaches to studying it are briefly reviewed. A detailed theoretical description of the motion of plumes in a stably stratified medium is given, leading to a 'derivation' of the plume equations from the hydrodynamic equations. Entrainment is discussed, and it is shown how the plume equations can be used to compute convective overshoot in the sun. The limitations of the plume model are addressed, arguing that a thin boundary layer must exist which separates convective and radiative regions. The results of numerical integrations of the plume equations, as applied to the region of convective overshoot underneath the solar convective zone, are discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 282; 316-329
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  • 42
    Publication Date: 2011-08-18
    Description: The Andre et al. (1976, 1978) third-order closure model, in which the time rate of change terms, the relaxation and rapid effects for pressure-related terms, and the clipping approximation are used along with the quasi-normal closure, is invoked in the study of turbulence in a cloudy layer that is radiatively cooled from above. A spurious oscillation whose greatest amplitude lies near the inversion is shown by analysis to arise from the mean gradient and buoyancy terms of the triple-moment equations. An attempt is made to damp the oscillation through the introduction of diffusion terms into the triple-moment equations. The results obtained are noted to be sensitive to the ad hoc eddy coefficient applied in the third-moment equations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 41; 1588-160
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  • 43
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    Publication Date: 2011-08-18
    Description: Oil and gas deposits in the Alaskan Arctic are estimated to contain up to 40 percent of the remaining undiscovered crude oil and oil-equivalent natural gas within U.S. jurisdiction. Most (65 to 70 percent) of these estimated reserves are believed to occuur offshore beneath the shallow, ice-covered seas of the Alaskan continental shelf. Offshore recovery operations for such areas are far from routine, with the primary problems associated with the presence of ice. Some problems that must be resolved if efficient, cost-effective, environmentally safe, year-round offshore production is to be achieved include the accurate estimation of ice forces on offshore structures, the proper placement of pipelines beneath ice-produced gouges in the sea floor, and the cleanup of oil spills in pack ice areas.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Science (ISSN 0036-8075); 225; 371-378
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  • 44
    Publication Date: 2011-08-18
    Description: A feasibility study has been conducted for a NASA Kennedy Space Center liquid hydrogen/liquid oxygen production facility using solar cell arrays as the power source for electrolysis. The 100 MW output of the facility would be split into 67.6 and 32 MW portions for electrolysis and liquefaction, respectively. The solar cell array would cover 1.65 sq miles, and would be made up of 249 modular 400-kW arrays. Hydrogen and oxygen are generated at either dispersed or centralized water electrolyzers. The yearly hydrogen output is projected to be 5.76 million lbs, with 8 times that much oxygen; these fuel volumes can support approximately 18 Space Shuttle launches/year.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 45
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    Publication Date: 2011-08-18
    Description: It is demonstrated that the common assumption made in solar flare beam transport theory that the beam-accompanied return current is purely electrostatically driven is incorrect, and that the return current is both electrostatically and inductively driven, in accordance with Lenz's law, with the inductive effects dominating for times greater than a few plasma periods. In addition, it is shown that a beam can only exist in a solar plasma for a finite time which is much smaller than the inductive return current dissipation time. The importance of accounting for the role of the acceleration mechanism in forming the beam is discussed. In addition, the role of return current driven anomalous resistivity and its subsequent anomalous Joule heating during the flare process is elucidated.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 280; 448-456
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  • 46
    Publication Date: 2011-08-18
    Description: The way in which the initial development of solar filament radiative cooling and the magnetic reconnection of a solar flare can occur in the center of a field-shear layer is demonstrated. Since the present treatment unites these two mechanisms, it indicates the common as well as the disparate features they possess. Unstable radiation serves to increase the Coulomb resistivity at the X-point, so that the reconnection is not self-quenching. The surprising dominance of the magnetic component of the perturbation in the midwavelength range indicates the need to examine the nonlinear saturation of the energy transport of the radiative mode, taking the accompanying magnetic reconnection and potential-energy release into account, for comparison with observations of filaments as well as for clues to the character of the preflare state.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 280; 391-398
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  • 47
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    Publication Date: 2011-08-18
    Description: Using NASA's Tracking and Data Relay Satellite as a communications link, astronomers are able to receive scans from the Solar Maximum Mission (SMM) satellite immediately and regularly at the Goddard Space Flight Center. This major operational improvement permits the examination of SMM imagery and spectra as they arrive, as well as the formulation of future observational sequences on the basis of the solar activity in progress. Attention is given to aspects of the sun that change in the course of the 11-year sunspot cycle's movement from maximum to minimum. Proof has been obtained by means of SMM for the near-simultaneity of X-ray and UV bursts at flare onset.
    Keywords: SOLAR PHYSICS
    Type: Sky and Telescope (ISSN 0037-6604); 67; 498-500
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  • 48
    Publication Date: 2011-08-18
    Description: An investigation has been conducted in order to compile quantitative data on the reflective properties of metallic indium. The fabricated samples were of sufficiently high quality that differences from similar second-surface silvered mirrors were not apparent to the human eye. Three second-surface mirror samples were prepared by means of vacuum deposition techniques, yielding indium thicknesses of approximately 1000 A. Both hemispherical and specular measurements were made. It is concluded that metallic indium possesses a sufficiently high specular reflectance to be potentially useful in many solar energy applications.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy (ISSN 0038-092X); 32; 2, 19; 311
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  • 49
    Publication Date: 2011-08-18
    Description: Lithium-counterdoped n(+)p silicon solar cells are found to exhibit significantly increased radiation resistance to 1-MeV electron irradiation when compared to boron-doped n(+)p silicon solar cells. In addition to improved radiation resistance, considerable damage recovery by annealing is observed in the counterdoped cells at T less than or equal to 100 C. Deep level transient spectroscopy measurements are used to identify the defect whose removal results in the low-temperature aneal. It is suggested that the increased radiation resistance of the counterdoped cells is primarily due to interaction of the lithium with interstitial oxygen.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Applied Physics Letters (ISSN 0003-6951); 44; 1071-107
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  • 50
    Publication Date: 2011-08-18
    Description: Space-time mapping of VHF sources from four severe storms on June 19, 1980 reveals that lightning processes for cloud-to-ground (CG) and large intracloud (IC) flashes are confined to an altitude below about 10 km and closely associated with the central regions of high reflectivity. Another class of IC flashes produces a splattering of sources within the storms' main electrically active volumes and also within the large divergent wind canopy aloft. There is no apparent temporal association between the small high altitude IC flashes that occur almost continuously and the large IC and CG flashes that occur sporadically in the lower portions of storms.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Geophysical Research Letters (ISSN 0094-8276); 11; 545-548
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  • 51
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    Publication Date: 2011-08-18
    Description: A variational principle for time dependent diffusion problems is presented and is demonstrated by applying it to simple seasonal climate models. Two cases are treated. The first, a North-Coakley-type model with constant properties, is used as a tutorial example for the application of the technique. For the second case, heat capacity and thermal conductivity are considered to be latitude dependent in order to treat the effects of land/ocean distribution on the seasonal temperature distribution over the earth. The variational equations are derived and approximate analytical solutions are developed which delineate the influences of the physical asymmetries of the hemispheres in producing an asymmetric annual cycle.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 89; 2601-260
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  • 52
    Publication Date: 2011-08-18
    Description: The present investigation has the objective to develop a simple 'user's' model for simulating the measured radar backscattering coefficients from vegetation-covered fields in conjunction with the data obtained by Jackson et al. (1980, 1982). The theoretical work reported by Fung and Eom (1981) provides the basis for the model. Certain modifications are related to a consideration of the effect of a vegetation canopy. The first part of the model is concerned with a description of scatter from rough bare soil, while the second part takes into account the effect of a vegetation cover. It is shown that the measured angular distribution of the backscattering coefficient of vegetation-covered fields can be satisfactory reproduced by using the developed model.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 15; 119-133
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  • 53
    Publication Date: 2011-08-18
    Description: The atmospheric effect on the upward radiance of sunlight scattered from the earth-atmosphere system is strongly influenced by the contrasts between fields and their sizes. In this paper, the radiances above finite fields are computed to simulate radiances measured by a satellite. A simulation case including 11 agricultural fields and four natural fields (water, soil, savanah, and forest) is used to test the effect of field size, background reflectance, and optical thickness of the atmosphere on the classification accuracy. For a given atmospheric turbidity, the atmospheric effect on classification of surface features may be much stronger for nonuniform surfaces than for uniform surfaces. Therefore, the classification accuracy of agricultural fields and urban areas is dependent not only on the optical characteristics of the atmosphere, but also on the size of the surface elements to be classified and their contrasts. It is concluded that new atmospheric correction methods, which take into account the finite size of the fields, are needed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 15; 95-118
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  • 54
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    Publication Date: 2011-08-18
    Description: Lorenz (1969) has considered the possibility that an atmospheric circulation pattern might recur, taking into account the definition of a pair of analogous flows or 'analogs'. The present investigation is concerned with a search of time series of Northern Hemisphere wintertime geopotential heights for possible analogs. Attention is given to data and analysis procedure, analog quality, and error growth rates. The obtained results imply that the found analogs are not a useful tool for forecasting the evolution of the midlatitude flow on time scales of several days. It is pointed out, however, that the negative results should not be extended to other applications of analog forecasting.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 41; 177-189
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  • 55
    Publication Date: 2011-08-18
    Description: Recent investigations using measurements at 1 AU have discovered three types of long term variation in the interplanetary magnetic field: solar minimum decreases, solar maximum enhancements, and small decreases around solar reversal. In this study the 1972-1982 Helios 1, 2, ISEE-3, and Pioneer 10, 11 observations between 0.3 and 12 AU are examined to further investigate these changes. It was found that all three IMF solar cycle effects are also present in the Helios and Pioneer measurements, confirming that these variations occur throughout the low latitude heliosphere. In addition, the comparison of measurements by identical magnetometers on ISEE-3, Pioneer 10 and Pioneer 11 has revealed a more rapid decrease in IMF intensity than predicted by classical Parker theory. Causes and ramifications of both the long term variations and steeper-than-expected radial gradients in the interplanetary magnetic field are discussed.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters (ISSN 0094-8276); 11; 279-282
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  • 56
    Publication Date: 2011-08-18
    Description: The presence of positive serial correlation (autocorrelation) in remotely sensed data results in an underestimate of the variance-covariance matrix when calculated using contiguous pixels. This underestimate produces an inflation in F statistics. For a set of Thematic Mapper Simulator data (TMS), used to test the ability to discriminate a known geobotanical anomaly from its background, the inflation in F statistics related to serial correlation is between 7 and 70 times. This means that significance tests of means of the spectal bands initially appear to suggest that the anomalous site is very different in spectral reflectance and emittance from its background sites. However, this difference often disappears and is always dramatically reduced when compared to frequency distributions of test statistics produced by the comparison of simulated training sets possessing equal means, but which are composed of autocorrelated observations.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 5; 315-332
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  • 57
    Publication Date: 2011-08-18
    Description: The validity of using data from the Advanced Very High Resolution Radiometer (AVHRR) of the satellites NOAA-6 and NOAA-7 for land cover mapping is assessed by making comparisons with much higher resolution LANDSAT multi-spectral scanner (MSS) data. Near synchronous data for both systems are analysed for test sites in the Imperial Valley, California, the Nile Delta, and southern Italy. The results strongly indicate that despite the very coarse resolution of the AVHRR data compared with conventional MSS data they are sufficiently strongly correlated to suggest that the former have significant potential for land cover mapping, especially at small scales and for large areas. Hence the outstanding benefits of AVHRR data, namely their high temporal frequency, relative cheapness and low data volumes for image processing, may readily be taken advantage of for such tasks.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 5; 497-504
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  • 58
    Publication Date: 2011-08-18
    Description: A numerical investigation is conducted into the way in which a solar wind model initially satisfying both steady state and energy balance conditions is disturbed and deformed, under the assumption of heating that correspoonds to the energy release of solar flares of an importance value of approximately 1 which occur in radial open field regions. Flare-associated solar wind transient behavior is modeled for 1-8 solar radii. The coronal temperature around the heat source region rises, and a large thermal conductive flux flows inward to the chromosphere and outward to interplanetary space along field lines. The speed of the front of expanding chromospheric material generated by the impingement of the conduction front on the upper chromosphere exceeds the local sound velocity in a few minutes and eventually exceeds 100 million cm/sec.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 277; 379-391
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  • 59
    Publication Date: 2011-08-18
    Description: The radiometric measurements over bare field and fields covered with grass, soybean, corn, and alfalfa were made with 1.4- and 5-GHz microwave radiometers during August-October 1978. The measured results are compared with radiative transfer theory treating the vegetated fields as a two-layer random medium. It is found that the presence of a vegetation cover generally gives a higher brightness temperature T sub B than that expected from a bare soil. The amount of this T sub B excess increases with increase in the vegetation biomass and in the frequency of the observed radiation. The results of radiative transfer calculations, which include a parameter characterizing ground surface roughness, generally match well with the experimental data.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-22; 143-150
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  • 60
    Publication Date: 2011-08-18
    Description: The technique for inverting a vegetation canopy reflectance model described earlier (Goel and Strebel, 1983) is investigated further. The novel concept of an 'angle transform' is introduced. This concept allows the formation of functions of reflectances at different view zenith and azimuth angles, which are either sensitive or insensitive to a certain agronomic parameter. A proper combination of these functions can allow determination of all the important agronomic and spectral parameters from measured canopy reflectance data. The technique is demonstrated using Suits' (1972) model for homogeneous canopies. It is shown that leaf area index, leaf reflectance and transmittance, and average leaf angle all can be determined from the canopy reflectance at a set of selected view zenith and azimuth angles. A sensitivity analysis of the calculated values to the errors in the data is also carried out. Guidelines are formulated for the number and types of observations required to obtain the values of a particular canopy variable to within a given degree of accuracy for a given level of error in the measurement of canopy reflectance.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Remote Sensing of Environment (ISSN 0034-4257); 14; 77-111
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  • 61
    Publication Date: 2011-08-18
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Radio Science (ISSN 0048-6604); 19; 238-242
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  • 62
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    Publication Date: 2011-08-19
    Description: The numbers and spectra of the accelerated protons and nuclei that produce the neutrons and gamma-rays observed in solar flares are derived, and the results are compared with interplanetary observations of flare protons. The two most widely studied flare acceleration mechanisms, stochastic and diffusive shock acceleration, are discussed, and the arguments favoring the thick-target interaction model for neutron and gamma-ray production at the sun are briefly reviewed. The pertinent results of the theory of neutron and gamma-ray production are presented. The number and spectrum of the accelerated particles are derived from observations of nuclear deexcitation lines and the 2.223 MeV line from several flares. The June 21, 1980 and June 3, 1982 flares, from which a wealth of neutron, gamma-ray and energetic-particle data has recently become available, are discussed.
    Keywords: SOLAR PHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 4; 7, 19
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  • 63
    Publication Date: 2011-08-19
    Description: Time sequences of recurrent mass ejections have been observed during a coordinated SMY program (Sept. 1, 1980 - Sept. 23, 1980 - Oct. 2, 1980). Comparison of the temporal evolution of H-alpha and CIV brightnesses shows a weak phase lag between H-alpha and CIV maxima, in the case of homologous flares, with CIV brightness maxima preceding H-alpha maxima. The analysis of the variation of the ejection velocities is expected to lead to the determination of an energy balance. Such recurrent ejections could be due to periodic energy storage and periodic reorganization of magnetic field as envisaged to occur for flares, but at lower energy levels.
    Keywords: SOLAR PHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 4; 7, 19
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  • 64
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    Publication Date: 2011-08-19
    Description: Glacial landforms in the drumlin drift belt of Ireland and the Alaska Range can be identified and mapped from Seasat synthetic-aperture radar (SAR) images. Drumlins cover 60 percent of the Ireland scene. The width/length ratio of individual drumlins can be measured on the SAR images, allowing regional differences in drumlin shape to be mapped. This cannot be done with corresponding Landsat multispectral scanner (MSS) images because of lower spatial resolution and because of shadowing effects that vary seasonally. The Alaska scene shows the extent and nature of morphological features such as medial and lateral moraines, stagnant ice, and fluted ground moraine in glaciated valleys. Perception of these features on corresponding Landsat MSS images is limited by seasonal diffrences in solar illumination. Because SAR is not affected by such differences or by cloud cover, it is particularly well suited for monitoring glacial movement. The disadvantage of distorted high-relief features on Seasat SAR images can be reduced in future SAR systems by modifying the radar illumination geometry.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Quaternary Research (ISSN 0033-5894); 22; 314-327
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  • 65
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    Publication Date: 2011-08-19
    Description: Simple climate models which invoke diffusive heat transport and ice cap albedo feedback have equilibrium solutions with no stable ice cap smaller than a radius of about 20 deg on a great circle. Attention is presently given to a solution of this phenomenon which is physically appealing. The ice-free solution has a thermal minimum, and if the minimum temperature is just above the critical value for ice formation, then the artificial addition of a patch of ice leads to a widespread depression of the temperature below the critical freezing temperature. A second stable solution will then exist whose spatial extent is determined by the range of the influence function of a point sink of heat, due to the albedo shift in the patch.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 41; 3390-339
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  • 66
    Publication Date: 2011-08-19
    Description: A comment is presented on a recent paper by Pagnotti and Bosart (1984) which contrasted different forcing mechanisms for weak and strong cyclones along the east coast of the U.S., and Bosart replies. The comment argues that the paper did not give a clear definition of 'weak' upper-level forcing and did not provide sufficient evidence to support its claim that the return branch of transverse circulations may be coupled to the middle as opposed to the lower troposphere.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 112; 2540
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  • 67
    Publication Date: 2011-08-19
    Description: In NOAA Active Region 2372 (April 1980), 4 x 10 to the 20th maxwells of magnetic flux concentrated in an area 30 arcsec across disappeared overnight. Vector magnetograms show that all components of the magnetic field weakened together. If the field had weakened through diffusion or fluid flow, 90 percent of the original flux would still have been detected by the magnetograph within a suitably enlarged area. In fact there was a threefold decrease in detected flux. Evidently, magnetic field was removed from the photosphere. Since the disappearing flux was located in a region of low magnetic shear and low activity in H-alpha and Ly-alpha, it is unlikely that the field dissipated through reconnection. It is argued that the most likely possibility is that flux submerged. The observations suggest that even during the growth phase of active regions, submergence is a strong process comparable in magnitude to emergence.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 287; 404-411
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  • 68
    Publication Date: 2011-08-19
    Description: Coronal bullets are small ejecta of cool, dense plasma observed to accelerate through the solar atmosphere from 20 to 450 km/s. The NRL Dynamic Flux Tube Model has been used to simulate the evolving physical properties of these dynamic events. The present calculations utilize an adaptive-gridding technique to resolve the fine structure within and around the bullets. In this work, an identification was made of a component of shocked plasma which piles up ahead of the bullet and eventually dominates both the dynamics and heating of the original bullet mass. The observational consequences of this shocked component are discussed in terms of the available HRTS EUV data, and suggestions are made for optimizing future observations of this phenomenon. An investigation has also been conducted of the structure of the bullet material visible in EUV spectral lines and the observable characteristics of the EUV-emitting plasma. Finally, the most likely mechanisms for accelerating the bullets, as well as favorable sites of origin are evaluated.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 287; 396-403
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  • 69
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    Publication Date: 2011-08-19
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy (ISSN 0038-092X); 33; 1, 19
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  • 70
    Publication Date: 2011-08-19
    Description: A fully nonlinear numerical model of the point jet barotropic instability is used to test and confirm the hypothesis that the magnitude of the wave vorticity does not exceed the magnitude of the initial shear. This result arises directly from the local conservation of vorticity following a parcel and the fact that unstable waves are principally confined to the region where the zonal mean vorticity can be smoothed by the wave so as to eliminate the instability. Comparisons are made between fully nonlinear and quasi-linear models of the point jet instability and their tracer transport properties. Differences become particularly evident after wave saturation. The most important effect neglected by the wave-mean flow model appears to be the advection of wave vorticity by the most unstable mode. However, as equilibration of the instability proceeds, the globally averaged properties of both models are found to be similar.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 41; 2869-288
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  • 71
    Publication Date: 2011-08-19
    Description: Low-noise (S/N greater than 100), high spectral resolution observations of two pure rotation transitions of OH from the solar photosphere are used to make inferences concerning the thermal structure and inhomogeneity of the upper photosphere. It is found that the v = O R22(24.5)e line strengthens at the solar limb, in contradiction to the predictions of current one-dimensional photospheric models. The results for this line support a two-dimensional model in which horizontal thermal fluctuations in the upper photosphere are of the order plus or minus 800 K. This thermal bifurcation may be maintained by the presence of magnetic flux tubes and may be related to the solar limb extensions observed in the 30-200-micron region.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 94; 57-74
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  • 72
    Publication Date: 2011-08-19
    Description: An evaluation of Thematic Mapper Simulator (TMS) data for the geobotanical discrimination of rock types based on vegetative cover characteristics is addressed in this research. A methodology for accomplishing this evaluation utilizing univariate and multivariate techniques is presented. TMS data acquired with a Daedalus DEI-1260 multispectral scanner were integrated with vegetation and geologic information for subsequent statistical analyses, which included a chi-square test, an analysis of variance, stepwise discriminant analysis, and Duncan's multiple range test. Results indicate that ultramafic rock types are spectrally separable from nonultramafics based on vegetative cover through the use of statistical analyses.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-22; 525-530
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  • 73
    Publication Date: 2011-08-19
    Description: An assessment is made of the information content of Thematic Mapper Simulator (TMS) data for the case of a forested region, in order to determine the sensitivity of such data to forest crown closure and tree size class. Principal components analysis and Monte Carlo simulation indicated that channels 4, 7, 5 and 3 were optimal for four-channel forest structure analysis. As the number of channels supplied to the Monte Carlo feature selection routine increased, classification accuracy increased. The greatest sensitivity to the forest structural parameters, which included succession within clearcuts as well as crown closure and size class, was obtained from the 7-channel TMS data.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-22; 482-489
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  • 74
    Publication Date: 2011-08-19
    Description: An historical account is given of the development of technology for the processing of satellite-acquired multispectral data aimed at the identification of the type, condition, and ontogenic stages of agricultural areas. During 1972 and 1973, research established the feasibility of automating digital classification for the processing of large volumes of Landsat MSS data. This capability was successfully demonstrated during the Large Area Crop Inventory Experiment, which estimated wheat crop production on a global basis. This achievement in turn led to the Agriculture and Resources Inventory Surveys Through Aerospace Remote Sensing, which investigated other portions of the electromagnetic spectrum and expanded the study of key commercial crops in important agricultural areas.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-22; 473-482
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  • 75
    Publication Date: 2011-08-19
    Description: We calculate the seasonal changes that are largely associated with the half-yearly wave, autocorrelation functions, and the mean planetary waves in the monthly mean sea level pressure from two data sources. One covers the period from 1951 to 1958 (from the South African Weather Bureau) and the other the period from 1972 to 1980 (from the Australian Bureau of Meteorology). Thirty years of data from stations over the southern hemisphere are used to assess the reliability of the differences between the two periods that the grid-point data show. These differences are especially large over the Atlantic Ocean and the Pacific Ocean. The station data confirm the changes between the two periods and thus the observed differences in the mean waves, which are especially large for wave number 3.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Geophysical Research (ISSN 0148-0227); 89; 9541-954
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  • 76
    Publication Date: 2011-08-19
    Description: The present model for the temporal behavior of agricultural greenness is applied to the extraction of Landsat-derived profile features, distinguishing small from large grain crops. An additional feature derivable from the temporal behavior of the ratio of greenness to brightness is noted which aids in the separation of crops from other vegetation. A limited training set of 20 pure pixels/class, obtained from ground data, is subjected to the Ho-Kashyap (1965) linear classifier. The initial correct classification value for pure pixels of about 85 percent drops to 75 percent for all Landsat pixels.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 5; 783-797
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  • 77
    Publication Date: 2011-08-19
    Description: The utility of Landsat MSS classification methods in the case of small, highly urbanized hydrological basins containing complex land-use patterns is limited, and is plagued by misclassifications due to the spectral response similarity of many dissimilar surfaces. Landsat MSS data for the Conley Creek basin near Atlanta, Georgia, have been compared to thematic mapper simulator (TMS) data obtained on the same day by aircraft. The TMS data were able to alleviate many of the recurring patterns associated with MSS data, through bandwidth optimization, an increase of the number of spectral bands to seven, and an improvement of ground resolution to 30 m. The TMS is thereby able to detect small water bodies, powerline rights-of-way, and even individual buildings.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 5; 761-770
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  • 78
    Publication Date: 2011-08-19
    Description: An attempt has been made to relate hand-held radiometer measurements, and airborne multispectral scanner readings, with both different wheat stand densities and grain yield. Aircraft overflights were conducted during the tillering, stem extension and heading period stages of growth, while hand-held radiometer readings were taken throughout the growing season. The near-IR/red ratio was used in the analysis, which indicated that both the aircraft and the ground measurements made possible a differentiation and evaluation of wheat stand densities at an early enough growth stage to serve as the basis of management decisions. The aircraft data also corroborated the hand-held radiometer measurements with respect to yield prediction. Winterkill was readily evaluated.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 5; 771-781
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  • 79
    Publication Date: 2011-08-19
    Description: The cloud observation archive from the NASA Global Atmospheric Sampling Program (GASP) is analyzed in order to derive the probability of cloud encounter at altitudes normally flown by commercial airliners, for application to a determination of the feasability of Laminar Flow Control (LFC) on long-range routes. The probability of cloud encounter is found to vary significantly with season. Several meteorological circulation features are apparent in the latitudinal distribution of cloud cover. The cloud encounter data are shown to be consistent with the classical midlatitude cyclone model with more clouds encountered in highs than in lows. Aircraft measurements of route-averaged time-in-clouds fit a gamma probability distribution model which is applied to estimate the probability of extended cloud encounter, and the associated loss of LFC effectiveness along seven high-density routes. The probability is demonstrated to be low.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Aircraft (ISSN 0021-8669); 21; 851-857
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  • 80
    Publication Date: 2011-08-19
    Description: Ratios of intensities of near-infrared spectral bands, measured in reflectance, quantitatively predict the iron content of granitic rocks. Such data from the 1.60- and 1.05-micron bands of the Shuttle multispectral infrared radiometer have been used to study granitic rocks along orbits crossing Baja California, Mexico, and the Eastern Desert of Egypt. Both regions are arid and relatively to essentially free of vegetation, and there is no indication in the spectra that surface chemical alteration masks the true composition of the unweathered rock. Predicted values of iron are consistent with known compositional types of most of the rocks along the orbital paths. Results demonstrate that the near-infrared method used is a powerful technique to average the variability of these rocks on the scales of meters to kilometers.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Journal of Geophysical Research (ISSN 0148-0227); 89; 9439-944
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  • 81
    Publication Date: 2011-08-19
    Description: Solar irradiance measurements from the ACRIM experiment show a clear response to the rotation periods of g-mode oscillations (l = 1, 2, and 3) and their first harmonics. Peaks in the ACRIM spectrum at 16.6, 18.3, 20.7, 36.5, and about 71 days all lie within about 1 percent of periods arising from g-mode rotation. This means that the g-modes are a fundamental cause of irradiance fluctuations. On time scales of months and less they modulate the irradiance by means of transient flows of global scale which they stimulate in the sun's convective envelope. Dimensional arguments indicate that the flows carry up heat at an average rate of about 0.001 solar luminosities, which is not in conflict with observed changes in the irradiance. Five additional tests for g-modes and large-scale convection are given. An instability is described which undermines diffusion models of sunspot energy storage.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 93; 1-13
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  • 82
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    Publication Date: 2011-08-19
    Description: Attention is given to physical principles that affect the determination of atmospheric temperature profiles from observations of outgoing IR and microwave radiation. Simultaneous analysis of IR and microwave observations enhances observations in each spectral region. While IR soundings have higher sensitivity to lower tropospheric temperatures, ground temperatures, and sea surface temperatures, microwave observations are not only more suited to stratospheric sounding but are sensitive to snow and ice cover. They significantly aid correction of IR observations for cloud effects. Because effective cloud parameters and snow and ice cover can be inferred from the observations, 'temperature sounders' also yield data for a number of important climatic parameters.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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  • 83
    Publication Date: 2011-08-18
    Description: The result of a study on the application of an improved statistical prediction method for estimating the intermediate-term (months) and long-term (years) behavior of solar flux is discussed. The study indicates that better predictions, in a chi square sense, are possible by selecting sets of the solar flux data such that each set (cycle) starts and ends at the maxima (or minima) for the data base and initialization point of the procedure. Then one applies a Lagrangian least-squares statistical technique. Evidence is also presented to support the existence of an aperiodic variation in the periods as well as the amplitudes.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 89; 11-16
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  • 84
    Publication Date: 2011-08-18
    Description: A statistical correlation technique is applied to the retrieval of vertical moisture profiles from downlooking radiometric measurements of atmospheric radiation at microwave wavelengths. Only an optimum subset of available radiometer channels is selected for estimating water vapor at specific pressure levels. To test its validity the algorithm was applied, in a numerical experiment, to 50 independent tropical radiosondes over a sea surface. It was also used to retrieve continuous sequences of atmospheric moisture profiles from a set of data obtained with a 4-channel microwave radiometer carried aboard an aircraft over a land surface.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: ESA IGARSS 84. Remote Sensing: From Res. towards Operational Use, Vol. 1; p 449-451
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  • 85
    Publication Date: 2011-08-18
    Description: The SEASAT altimeter (ALT), scatterometer (SASS), and scanning microwave multichannel radiometer (SMMR) measured sea surface wind speed. During the satellite lifetime from June to October 1978, the Austral winter, the highest wind speeds were recorded in the Southern Ocean. Three-month, monthly, and three-day surface wind speed fields deduced from the three Seasat wind speed sensors are compared. The monthly and three-day fields show a pronounced mesoscale (1000 km) variability in wind speed. At all space and time scales analyzed, differences of 40% are found in the magnitude of the wind speed features, with the ALT consistently yielding the lowest wind speed and the SMMR the highest.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: ESA IGARSS 84. Remote Sensing: From Res. towards Operational Use, Vol. 1; p 403-409
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  • 86
    Publication Date: 2011-08-18
    Description: Passive microwave measurements of the Bering Sea were made with the NASA CV-990 airborne laboratory during February. Microwave data were obtained with imaging and dual-polarized, fixed-beam radiometers in a range of frequencies from 10 to 183 GHz. The high resolution imagery at 92 GHz provides a particularly good description of the marginal ice zone delineating regions of open water, ice compactness, and ice-edge structure. Analysis of the fixed-beam data shows that spectral differences increase with a decrease in ice thickness. Polarization at 18 and 37 GHz distinguishes among new, young, and first-year sea ice types.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: ESA IGARSS 84. Remote Sensing: From Res. towards Operational Use, Vol. 1; p 379-384
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  • 87
    Publication Date: 2011-08-18
    Description: Data acquired with the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7 Satellite for a six-week period in Fram Strait were analyzed with a procedure for calculating sea ice concentration, multiyear fraction, and ice temperature. Calculations were compared with independent observations made on the surface and from aircraft to check the validity of the calculations based on SMMR data. The calculation of multiyear fraction, which was known to be invalid near the melting point of sea ice, is discussed. The indication of multiyear ice is found to disappear a number of times, presumably corresponding to freeze/thaw cycles which occurred in this time period.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: ESA IGARSS 84. Remote Sensing: From Res. towards Operational Use, Vol. 1; p 373-378
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  • 88
    Publication Date: 2011-08-18
    Description: Soil moisture budgets at the Earth's surface were investigated based on soil and atmospheric temperature variations. A number of data sets were plotted and statistically analyzed in order to accentuate the existence and the characteristics of mesoscale soil temperature extrema variations and their relations to other parameters. The correlations between diurnal temperature extrema for air and soil in drought and non-drought periods appear to follow different characteristic patterns, allowing an inference of soil moisture content from temperature data. The recovery of temperature extrema after a precipitation event also follows a characteristic power curve rise between two limiting values which is an indicator of evaporation rates. If these indicators are applied universally to regional temperature data, soil moisture content or drought conditions can be inferred directly from temperature measurements.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Res. Activities of the Geodyn. Branch; 6 p
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  • 89
    Publication Date: 2011-08-18
    Description: The spaceborne gravity gradiometer is a potential sensor for mapping the fine structure of the Earth's gravity field. Error analyses were performed to investigate the accuracy of the determination of the Earth's gravity field from a gravity field satellite mission. The orbital height of the spacecraft is the dominating parameter as far as gravity field resolution and accuracies are concerned.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Res. Activities of the Geodyn. Branch; 6 p
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  • 90
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    Publication Date: 2011-08-18
    Description: The capability of spaceborne altimetry to record the level, or monitor changes in the level, of inland seas was assessed. SEASAT altimetry data from Lake Baikal in Siberia; the Caspian, Black, and Aral Seas in the southern Soviet Union; the Great Salt Lake in the United States; lakes and reservoirs in northwestern and central China; and snow cover in northwestern India and on the Tibetan Plateau were examined.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Res. Activities of the Geodyn. Branch; 6 p
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  • 91
    Publication Date: 2011-08-18
    Description: This work relates to a series of collaborative investigations involving the application of a computational model for the determination of the detailed plasma and magnetic field properties associated with the global interaction of the solar wind with various planetary obstacles throughout the solar system. The theoretical method is based on an established single fluid, steady, dissipationless, magnetohydrodynamic continuum model, and is appropriate for the calculation of supersonic, super-Alfvenic solar wind flow past planetary obstacles. The investigations undertaken relate to studies of various solar wind interaction phenomena with Venus, Earth, Jupiter, and Saturn.
    Keywords: SOLAR PHYSICS
    Type: Appl. of a Global Solar Wind/Planetary Obstacle Interaction Computational Model 11p (SEE N84-26509 16-88)
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  • 92
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    Publication Date: 2011-08-18
    Description: The influence of soil moisture on the persistence of an ongoing drought was investigated. The case study of drought of the summer of 1980 was selected. The difference in the simulation of two identical twin runs: one with the climatological normal soil moisture and the other with anomalous soil moisture for drought conditions, were examined on the mean monthly circulation. It is found that a reduction in soil moisture did produce a corresponding reduction in precipitation. The pattern of the rainfall anomaly however, was not identical to the soil moisture (evapotranspiration) anomaly but had a good resemblance with observations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 335-340
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  • 93
    Publication Date: 2011-08-18
    Description: During the Northern summer, sporadic outbreaks of wind borne Saharan dust are carried out over the Atlantic by the tropical easterlies. Optical depths due to the dust can reach 3 near the African coast, and the dust cloud can be detected as far west as the Caribbean Sea (Carlson, 1979). In order to obtain insight into the possible effects of Saharan dust on the weather and climate of North Africa and the tropical Atlantic Ocean, simulation experiments have been performed with the Climate Model of the Goddard Laboratory for Atmospheric Sciences. The most recent version of the model is described by Randall (1982). The model produces realistic simulations of many aspects of the observed climate and its seasonal variation.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 3323-328
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  • 94
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    Publication Date: 2011-08-18
    Description: A simple interactive biosphere is presented based on an electrical analog of turbulent transport processes that produce heat and moisture fluxes between land and the atmosphere. A network of resistances that effect temperature or vapor pressure fluxes are identified and entered into the quasi steady state equations. A set of solutions that depict a realistic diurnal cycle is included.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Res. Rev., 1983; p 285-291
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  • 95
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    Publication Date: 2011-08-18
    Description: The sensitivity of climate which may have a local maximum as the ice cap passes through a midlatitude region where the atmosphere's transport efficiency varies strongly with latitude is examined. This behavior, found in a two level primitive equations climate model forced with annual mean insolation, was reproduced in an energy balance model (EBM) by making the diffusion coefficient a function of latitude. The two level seasonally varying EBM was applied and the global mean surface temperature vs. solar constant for this model are shown and two regions of enhanced sensitivity appear. The snowcover distributions around the year for three cases are shown.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 227-230
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  • 96
    Publication Date: 2011-08-18
    Description: The role of transient eddies in maintaining the observed local seasonal mean atmospheric circulation was investigated by examining the time-averaged momentum balances and omega equation, using seasonal statistics calculated from daily operational analyses by the European Centre for Medium Range Weather Forecasts. While both the Northern and Southern Hemispheres and several seasons were studied, emphasis was placed upon the Northern Hemisphere during December 1981-February 1982. The results showed that transient eddies played a secondary role in the seasonal mean zonal momentum budget and in the forcing of seasonal mean vertical and a geostrophic motion.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 205-208
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  • 97
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    Publication Date: 2011-08-18
    Description: Contemporaneous correlations between geopotential heights on a given pressure surface at widely separated points on Earth, commonly referred to as teleconnections, are calculated from monthly mean sea level pressure and 500 mb geopotential height analyses for the Southern Hemisphere for five-month winter and summer seasons. During summer (November-March), anomalies over the three continents occur out of phase with anomalies over the subtropical oceans and in a wavenumber 3 pattern over the Southern Ocean near 55 deg S. The subtropical part of the pattern appears largely associated with the interannual variation of the seasonal cycle and annual mean. In winter (May-September) 500 mb geopotential heights over Africa exhibit positive correlations with heights over South America and the central South Pacific near New Zealand and negative correlations with height over the Southern Ocean. A striking wavenumber three pattern is apparent which shows the correlation of 500 mb geopotential height anomalies with 500 mb anomalies at 50 deg S, 95 deg E during winter. The strong positive correlations between 50 deg S, 95 E and 58 deg S, 150 deg W and 38 deg S, 15 deg W contrast with negative correlations over Antarctica and in low latitudes. Time variations in a similar pattern in sea level pressure are in phase with variations in the 500 mb pattern, suggesting an equivalent barotropic structure.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 193-195
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  • 98
    Publication Date: 2011-08-18
    Description: The incorporation of observed zonal topography in a barotropic nonlinear channel model is discussed. The model is then extended to explain the regional features of blocking by employing a two scale method to allow small slow variations of the momentum (zonal) driving.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 190-192
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  • 99
    Publication Date: 2011-08-18
    Description: Stratus and stratocumulus cloud sheets which are among the most common cloud types over the world are discussed. They are characteristic of the undisturbed subtropical marine boundary layer over the eastern oceans, where cool water and large scale sinking motion suppress penetrative cumulus convection. They also occur over the Arctic Ocean, particularly in summer, and behind cold outbreaks over the western oceans in winter. Observational studies were conducted and further observations are planned.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 222-226
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  • 100
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    Publication Date: 2011-08-18
    Description: A numerical simulation study, using the current GLAS climate GCM, was carried out to examine the influence of low bulk aerodynamic drag parameter in the deserts. The results illustrate the importance of yet another feedback effect of a desert on itself, that is produced by the reduction in surface roughness height of land once the vegetation dies and desert forms. Apart from affecting the moisture convergence, low bulk transport coefficients of a desert lead to enhanced longwave cooling and sinking which together reduce precipitation by Charney's (1975) mechanism. Thus, this effect, together with albedo and soil moisture influence, perpetuate a desert condition through its geophysical feedback effect. The study further suggests that man made deserts is a viable hypothesis.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Res. Rev., 1983; p 329-334
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