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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Determination of the Solar Energy Microclimate of the United States Using Satellite Data

The determination of total solar energy reaching the ground over the United States using measurements from meteorological satellites as the basic data set is examined. The methods of satellite data processing are described. Uncertainty analysis and comparison of results with well calibrated surface pyranometers are used to estimate the probable error in the satellite-based determination of ground insolation. It is 10 to 15 percent for daily information, and about 5 percent for monthly values. However, the natural space and time variability of insolation is much greater than the uncertainty in the method. The most important aspect of the satellite-based technique is the ability to determine the solar energy reaching the ground over small areas where no other measurements are available. Thus, it complements the widely spaced solar radiation measurement network of ground stations.

Vonderharr, T. H.↗
NASA NTRS1971

Spectrum sharing criteria for space and terrestrial systems.

The advent of artificial earth orbiting satellites has added a new dimension to electromagnetic compatibility problems. These new EMC problems arise from the necessity of sharing frequency bands between satellite and terrestrial radio systems. The first such sharing arrangement, sharing between communication satellites and line-of-sight radio relay systems in the 4 and 6 GHz bands, has proved the soundness of the sharing concept under a particular set of circumstances and has encouraged frequency management officials to apply the concept to other functional services. This paper discusses a general sharing analysis procedure and illustrates the application of the procedure by presenting an analysis of the sharing feasibility between the Meteorological Satellite and the terrestrial Meteorological Aids services in the 1670-1700 MHz band.

Friel, F. J.↗
NASA NTRS1977

Remote sensing of the atmosphere from environmental satellites

Various applications of satellite remote sensing of the earth are reviewed, including (1) the use of meteorological satellites to obtain photographic and radiometric data for determining weather conditions; (2) determination of the earth radiation budget from measurements of reflected solar radiation and emitted long wave terrestrial radiation; (3) the use of microwave imagery for measuring ice and snow cover; (4) LANDSAT visual and near infrared observation of floods and crop growth; and (5) the use of the Nimbus 4 backscatter ultraviolet instrument to measure total ozone and vertical ozone distribution. Plans for future activities are also discussed.

Allison, L. J.↗
NASA NTRS1976

Earth observations from space

The present state of satellites designed for earth observations is reviewed. Particular attention is given to operational meteorological satellites, experimental atmosphere and ocean satellites, and earth resources satellites. Examples of applications resulting from satellite earth observations are discussed. It is concluded that earth observations from space have greatly advanced man's understanding of atmospheric, oceanic, and geological processes, opening the way to a large number of viable applications.

Nordberg, W.↗
NASA NTRS1977

Moisture convergence from a combined mesoscale moisture analysis and wind field for 24 April 1975

Precipitable water values inferred from the Vertical Temperature Profile Radiometer data of the polar orbiting NOAA-4 satellite are used in conjunction with wind-field analyses obtained from Synchronous Meteorological Satellite visible-channel data to study the moisture convergence in the boundary layer immediately preceding a storm. This combination of data simulates the information that will be available from the Visible and Infrared Spin-Scan Radiometer on board the GOES-D satellite, which is scheduled to begin operation in the 1980s. Serviceable representations of boundary layer flow are developed through analysis of the satellite infrared cumulus velocities, although the flow representations are not exactly located in the vertical.

Negri, A. J.↗
NASA NTRS2009

A Look at Seasonal Snow Cover and Snow Mass in the Southern Hemisphere from 1979-2006 Using SMMR and SSM/I Passive Microwave Data

Seasonal snow cover in extra-tropical areas of South America was examined in this study using passive microwave satellite data from the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7 satellite and from the Special Sensor Microwave Imagers (SSM/I) on board the Defense Meteorological Satellite Program (DMSP) satellites. For the period from 1979-2006, both snow cover extent and snow mass were estimated for the months of May-September. Most of the seasonal snow in South America occurs in the Patagonia region of Argentina. The average snow cover extent for July, the month with the greatest average extent during the 28-year period of record, is 321,674 sq km. The seasonal (May-September) 2 average snow cover extent was greatest in 1984 (464,250 sq km) and least in 1990 (69,875 sq km). In terms of snow mass, 1984 was also the biggest year (1.19 x 10(exp 13) kg) and 1990 was the smallest year (0.12 X 10(exp 13) kg). A strong relationship exists between the snow cover area and snow mass, correlated at 0.95, though no significant trend was found over the 28 year record for either snow cover extent or snow mass. For this long term climatology, snow mass and snow cover extent are shown to vary considerably from month to month and season to season. This analysis presents a consistent approach to mapping and measuring snow in South America utilizing an appropriate and readily available long term snow satellite dataset. This is the optimal dataset available, thus far, for deriving seasonal snow cover and snow mass in this region. Nonetheless, shallow snow, wet snow, snow beneath forests, as well as snow along coastal areas all may confound interpretation using passive microwave approaches. More work needs to be done to reduce the uncertainties in the data and hence, increase the confidence of the interpretation

Foster, James↗
NASA NTRS2010

Satellite Sampling and Retrieval Errors in Regional Monthly Rain Estimates from TMI AMSR-E, SSM/I, AMSU-B and the TRMM PR

Passive and active microwave rain sensors onboard earth-orbiting satellites estimate monthly rainfall from the instantaneous rain statistics collected during satellite overpasses. It is well known that climate-scale rain estimates from meteorological satellites incur sampling errors resulting from the process of discrete temporal sampling and statistical averaging. Sampling and retrieval errors ultimately become entangled in the estimation of the mean monthly rain rate. The sampling component of the error budget effectively introduces statistical noise into climate-scale rain estimates that obscure the error component associated with the instantaneous rain retrieval. Estimating the accuracy of the retrievals on monthly scales therefore necessitates a decomposition of the total error budget into sampling and retrieval error quantities. This paper presents results from a statistical evaluation of the sampling and retrieval errors for five different space-borne rain sensors on board nine orbiting satellites. Using an error decomposition methodology developed by one of the authors, sampling and retrieval errors were estimated at 0.25 resolution within 150 km of ground-based weather radars located at Kwajalein, Marshall Islands and Melbourne, Florida. Error and bias statistics were calculated according to the land, ocean and coast classifications of the surface terrain mask developed for the Goddard Profiling (GPROF) rain algorithm. Variations in the comparative error statistics are attributed to various factors related to differences in the swath geometry of each rain sensor, the orbital and instrument characteristics of the satellite and the regional climatology. The most significant result from this study found that each of the satellites incurred negative longterm oceanic retrieval biases of 10 to 30%.

Fisher, Brad↗
NASA NTRS1977

Satellite-based thunderstorm intensity parameters

Thunderstorm growth rates are investigated through use of infrared data furnished by the Synchronous Meteorological Satellite. Blackbody temperature isotherms provide an accurate method of delineating the areal expansion of cold areas; the blackbody temperature isotherms are valuable analytical tools even in cases when there is very little decrease with time of the minimum cloud top temperature. In an application of the severe storm monitoring technique, the origin of tornadoes is found to be closely linked to a rapid expansion of cold areas in seven out of eight cases.

Adler, R. F.↗
NASA NTRS1986

Pattern recognition of satellite cloud imagery for improved weather prediction

The major accomplishment was the successful development of a method for extracting time derivative information from geostationary meteorological satellite imagery. This research is a proof-of-concept study which demonstrates the feasibility of using pattern recognition techniques and a statistical cloud classification method to estimate time rate of change of large-scale meteorological fields from remote sensing data. The cloud classification methodology is based on typical shape function analysis of parameter sets characterizing the cloud fields. The three specific technical objectives, all of which were successfully achieved, are as follows: develop and test a cloud classification technique based on pattern recognition methods, suitable for the analysis of visible and infrared geostationary satellite VISSR imagery; develop and test a methodology for intercomparing successive images using the cloud classification technique, so as to obtain estimates of the time rate of change of meteorological fields; and implement this technique in a testbed system incorporating an interactive graphics terminal to determine the feasibility of extracting time derivative information suitable for comparison with numerical weather prediction products.

Gautier, Catherine↗
NASA NTRS1995

DMSP satellite detections of gamma-ray bursts

Gamma-ray burst detectors are aboard six U. S. Air Force defense Meteorological Satellite Program (DMSP) spacecraft, two of which are currently in use. Their 800-km altitude orbits give a field of view to 117 degrees from the zenith. A great many bursts have been detected, usually in coincidence with detections by GRO or other satellites such as PVO or ULYSSES. The directions of the sources can be determined with considerable accuracy from such correlated observations, even when GRO/BATSE with its directional capabilities is not involved. Thus these DMSP data, especially in conjunction with other observations, should be helpful in trying to understand the true nature of gamma-ray bursts.

Terrell, J.↗
NASA NTRS1996

Integrated Advanced Microwave Sounding Unit-A (AMSU-A) METOP Stress Analysis Report (Qual Level Random Vibration) A1 Module

Stress analysis of the primary structure of the Meteorological Satellites Project (METSAT) Advanced Microwave Sounding Units-A, A1 Module performed using the Meteorological Operational (METOP) Qualification Level 9.66 grms Random Vibration PSD Spectrum is presented. The random vibration structural margins of safety and natural frequency predictions are summarized.

Mehitretter, R.↗
NASA NTRS2000

Sea Ice Variability in the Sea of Okhotsk from Passive Microwave Satellite Observations

The Sea of Okhotsk, located between 50 and 60 N, is bounded by the Kamchatka Peninsula, Siberia, Sakhalin Island, and the Kuril Island chain and is the largest midlatitude seasonal sea ice zone in the Northern Hemisphere. The winter sea ice cover begins to form in November and expands to cover most of the sea by March. Over the following three months, the ice retreats with only small ice-covered areas remaining by the beginning of June. The sea is ice free or nearly ice free on average for six months of the year, from June through November. The recent compilation of a consistent, long-term record of Northern Hemisphere sea ice extents based on passive microwave satellite observations from the Nimbus 7 Scanning Multichannel Microwave Radiometer and from four Defense Meteorological Satellite Program Special Sensor Microwave Imagers provides the basis for assessing long-term sea ice extent variability in the Sea of Okhotsk. Analysis of this 20-year data record (1979-1998) shows that based on yearly averages the overall extent of the Sea of Okhotsk ice cover is decreasing at the rate of -8.1+/-2.1x10(exp 3) sq km/yr (-17.2%/decade), in contrast to the rate of decrease of -33.3+/-0.7x10(exp 3) sq km/yr (-2.7%/decade) for the Northern Hemisphere as a whole. There is large regional sea ice extent variability of the Arctic ice cover. Two of the nine Arctic regions analyzed, the Bering Sea and the Gulf of St. Lawrence, show increases of 0.8+/-1.4xl0(exp 3) sq km/yr (2.7%/decade) and 1.2+/-0.5xl0(exp 3) sq km/yr (17.1%/decade), respectively. Interestingly, the Sea of Okhotsk and the Gulf of St. Lawrence show about equal percentage changes, but of opposite sign. The Sea of Okhotsk exhibits its greatest percent decrease (-24.3%/decade) during spring (April-June). The year of maximum winter sea ice extent for the Sea of Okhotsk was 1979, whereas the minimum winter sea ice extent occurred in 1984.

Cavalieri, Donald J.↗
NASA NTRS2002

Satellite-Based Surface Heat Budgets and Sea Surface Temperature Tendency in the Tropical Eastern Indian and Western Pacific Oceans for the 1997/98 El Nino and 1998/99 La Nina

The 1997/98 is a strong El Nino warm event, while the 1998/99 is a moderate La Nina cold event. We have investigated surface heat budgets and sea surface temperature (SST) tendency for these two events in the tropical western Pacific and eastern Indian Oceans using satellite-retrieved surface radiative and turbulent fluxes. The radiative fluxes are taken from the Goddard Satellite-retrieved Surface Radiation Budget (GSSRB), derived from radiance measurements of the Japanese Geostationary Meteorological Satellite 5. The GSSRB covers the domain 40 deg S - 4 deg N, 90 deg E-17 deg W and a period from October 1997 to December 2000. The spatial resolution is 0.5 deg x 0.5 deg lat-long and the temporal resolution is 1 day. The turbulent fluxes are taken from Version 2 of the Goddard Satellite-based Surface Turbulent Fluxes (GSSTF-2). The GSSTF-2 has a spatial resolution of 1 deg x 1 deg lat-long over global Oceans and a temporal resolution of 1 day covering the period July 1987-December 2000. Daily turbulent fluxes are derived from the S S M (Special Sensor Microwave/Imager) surface wind and surface air humidity, and the SST and 2-m air temperature of the NCEP/NCAR reanalysis, using a stability-dependent bulk flux algorithm. The changes of surface heat budgets, SST and tendency, cloudiness, wind speed, and zonal wind stress of the 1997/98 El Nino relative to the1998/99 La Nina for the northern winter and spring seasons are analyzed. The relative changes of surface heat budgets and SST tendency of the two events are quite different between the tropical eastern Indian and western Pacific Oceans. For the tropical western Pacific, reduced solar heating (more clouds) is generally associated with decreased evaporative cooling (weaker winds), and vise versa. The changes in evaporative cooling over-compensate that of solar heating and dominate the spatial variability of the changes in net surface heating. Both solar heating and evaporative cooling offset each other to reduce interannual variability of net surface heating. In addition, the area of increased SST tendency is larger than that of increased net surface heating, due to less solar radiation penetration through the bottom of deeper ocean mixed layer (stronger winds). For the tropical eastern Indian Ocean, enhanced solar heating (less clouds) is generally associated with reduced evaporative cooling (weaker winds). Both solar heating and evaporative cooling reinforce each other to increase interannual variability of net surface heating. In addition, the area of increased SST tendency is smaller than that of increased net surface heating in the southern domain. The relative changes in wind and zonal wind stress indicate more solar radiation penetration through the ocean mixed layer and more northward heat transport by Ocean current from the south to the north Indian Ocean for the El Nino than for the La Nina.

Chou, Shu-Hsien↗
NASA NTRSDate not supplied

Advancing NASA SatCORPS Global Data Products with Cloud Computing and Machine Learning

Operational satellite imager radiances are valuable for deriving many different physical parameters that can be used for a variety of weather, aviation, and energy applications. The NASA Satellite ClOud and Radiation Property retrieval System (SatCORPS) applies a suite of algorithms to meteorological satellite data to provide cloud properties, radiative fluxes and other parameters on a global scale. The use of cloud computing has enabled recent enhancements to process a constellation of geostationary satellites at higher spatiotemporal resolutions than previously possible that meet low latency and near real-time needs. Data taken from Meteosat-8 and -11, Himawari, GOES-16, and -17 are processed and combined with operational polar orbiting satellite data and composited on a 3-km grid to provide global coverage. To improve the utility of the data products, machine learning and other innovative methods are applied in various ways to help minimize data product uncertainties under the most challenging conditions and to improve their consistency at all times of day. An update on recent SatCORPS enhancements is presented, highlighting the community benefits achieved with the use of cloud computing and machine learning.

William L Smith↗
NASA NTRS1995

Anticipated uncertainty budgets of PRARETIME and T2L2 techniques as applied to ExTRAS

The Experiment on Timing Ranging and Atmospheric Soundings, ExTRAS, was conceived jointly by the European Space Agency, ESA, and the Russian Space Agency, RSA. It is also designated the 'Hydrogen-maser in Space/Meteor-3M project'. The launch of the satellite is scheduled for early 1997. The package, to be flown on board a Russian meteorological satellite includes ultra-stable frequency and time sources, namely two active and auto-tuned hydrogen masers. Communication between the on-board hydrogen masers and the ground station clocks is effected by means of a microwave link using the modified version for time transfer of the Precise Range And Range-rate Equipment, PRARETIME, technique, and an optical link which uses the Time Transfer by Laser Link, T2L2, method. Both the PRARETIME and T2L2 techniques operate in a two-directional mode, which makes it possible to carry out accurate transmissions without precise knowledge of the satellite and station positions. Due to the exceptional quality of the on-board clocks and to the high performance of the communication techniques with the satellite, satellite clock monitoring and ground clocks synchronization are anticipated to be performed with uncertainties below 0.5 ns (1 sigma). Uncertainty budgets and related comments are presented.

Thomas, Claudine↗
NASA NTRS2002

Calibration Design and Assessment of the Airborne Conical Scanning Millimeterwave Imaging Radiometer (CoSMIR)

The airborne Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) will provide measurements useful for atmospheric studies and satellite calibration and validation (cal/val). Designed to match the tropospheric sounding channels of the Defense Meteorological Satellite Program QMSP) Special Sensor Microwave Imager/Sounder (SSMIS), the CoSMIR consists of four radiometers operating at 50-54 (3 channels - 50.3, 52.8, and 53.6), 91.655 (dual polarization), 150.0, and 193.31 (3 channels 11, 13, and 16.6) GHz. The design of CoSMIR was primarily driven by its intended initial use as an SSMIS cal/val sensor. In particular, three design features were directly affected by this requirement: frequency planning, calibration target design, and the mechanical gimbals. An initial calibration assessment of CoSMIR was performed to determine any needed improvements. We used a combination of laboratory and field measurements to do this. Laboratory measurements included comparisons to a liquid nitrogen standard, IF amplifier and diode linearity tests, LO leakage and reflection testing, and antenna to calibration target coupling tests. Results of these tests will be reported. We also performed a satellite underflight under DM SP F-15 and have compared CoSMIR imagery to SSM/T-2 and SSM/I imagery. Additional information is included in the original extended abstract.

Piepmeier, J. R.↗