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Greaves, J. R.

Publications and source records attributed to Greaves, J. R..

17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

The development of the geosynchronous weather satellite system

A brief history of the U.S. geosynchronous weather satellite program is presented. The introduction of multiparameter observation systems on the Geostationary Synchronous Environmental Satellite (GOES) is discussed, with emphasis given to the visible spin-scan radiometer (VISSR); Data Collection System (DCS); and the Space Environment Monitor (SEM). A synopsis of current measurement capabilities of the GOES satellites is given with respect to temperature and mositure parameters. Several examples of GOES satellite imagery are provided.

Greaves, J. R.↗
NASA NTRS1984

Retrieval of ocean surface parameters from the scanning multifrequency microwave radiometer (SMMR) on the Nimbus-7 satellite

Sea-surface temperature retrievals have been tested on 2 months of Nimbus-7 scanning multichannel microwave radiometer data. Using the prelaunch versions of the instrument calibration and geophysical parameter retrieval algorithms the initial results were poor. Improved algorithms produced substantially better results. It appears that at least for the night-Southern Hemisphere portion of the Nimbus-7 orbit, a rms measurement accuracy of 1.45 C has been achieved. Similar tests with wind speed retrievals yield an accuracy of 2.7 m/s rms with no substantial differences between day and night measurements but limited by availability of surface observations to the Northern Hemisphere. Moreover, it appears that the retrieved wind speed is more nearly related to the square of the wind observed at the surface than to the wind itself.

Wilheit, T. T., Jr.↗
NASA NTRS1983

VISSR Atmospheric Sounder (VAS) Research Review

The VAS, an experimental instrument flown onboard Geostationary Operational Environmental Satellite (GOES), is capable of achieving mutlispectral imagery of atmospheric temperature, water vapor, and cloudiness patterns over short time intervals. In addition, this instrument provides an atmospheric sounding capability from geosynchronous orbit. The VAS demonstration is an effort for evaluating the VAS instrument's performance, and for demonstrating the capabilities of a VAS prototype system to provide useful geosynchronous satellite data for supporting weather forecasts and atmospheric research. The demonstration evaluates the performance of the VAS Instruments on GOES-4-5, and -6, develops research oriented and prototype/operational VAS data processing systems, determines the accuracy of certain basic and derived meteorological parameters that can be obtained from the VAS instrument, and assesses the utility of VAS derived information in analyzing severe weather situations.

Greaves, J. R.↗
NASA NTRS1981

Microwave radiometry and hybrid precipitation measurements

It was necessary to identify the most promising measurement techniques and strategies and to understand those candidate systems in detail. The emphasis was on passive microwave remote-sensing techniques. A brief background in passive microwave and hybrid techniques for measuring precipitation, key problem areas and strategies for dealing with those problems, a precipitation measurement system, and specific recommendations are presented.

Wilheit, T. T.↗
NASA NTRS1979

The data systems tests - The final phase

The U.S.A. has conducted a series of data systems tests (DSTs) as a precursor to its participation in FGGE, the Global Weather Experiment. The paper briefly describes the impact those tests have had on the FGGE observing system and on the data management plans. In particular, the final phase of the DST programs is described, wherein a number of investigators have been selected to work with the DST data sets in research studies directed toward the GARP objectives. Thus, an important first step has been taken in providing feedback to the potential FGGE research community.

Greaves, J. R.↗
NASA NTRS1979

A 'special effort' to provide improved sounding and cloud-motion wind data for FGGE

Enhancement and editing of high-density cloud motion wind assessments and research satellite soundings have been necessary to improve the quality of data used in The Global Weather Experiment. Editing operations are conducted by a man-computer interactive data access system. Editing will focus on such inputs as non-US satellite data, NOAA operational sounding and wind data sets, wind data from the Indian Ocean satellite, dropwindsonde data, and tropical mesoscale wind data. Improved techniques for deriving cloud heights and higher resolution sounding in meteorologically active areas are principal parts of the data enhancement program.

Greaves, J. R.↗
NASA NTRS1977

The data systems test-dress rehearsal for FGGE

A series of Data Systems Tests conducted by NASA as a precursor to the First GARP Global Experiment is described. Included is a description of the global data sets acquired and the influence the tests had on the observing system, the data processing plans and research activities of the Global Experiment itself.

Greaves, J. R.↗
NASA NTRS1973

Marine Resources and Ocean Surveys

A synopsis of significant results achieved within the marine resources and ocean surveys discipline of the overall ERTS program is provided. Summaries are provided of the following subdisciplines: (1) coastal processes; (2) bathymetry; (3) sea ice; (4) oceanic circulation and dynamics; and(5) living marine resources.

Greaves, J. R.↗
NASA NTRS1973

Marine resources and ocean surveys

Application of ERTS-1 remotely sensed multispectral imagery to marine resources and oceanic observations and surveys - Conference

Greaves, J. R.↗
NASA NTRS1973

Development of a global cloud model for simulating earth-viewing space missions.

Existing global cloud models are improved and expanded so that they might be more effectively used in planning and evaluating potential earth-viewing space missions. A relationship is developed between the ground and satellite-derived cloud-amount frequency distributions. This relationship is used to improve internal consistency between the ground-observed unconditional statistics and the satellite-derived conditional statistics as tabulated in previous models. A statistical technique is developed which permits the scaling of the conditional statistics to time and distance separations other than those for which the data base is tabulated. A new technique to increase or decrease the representative area size of the statistical data base is developed. Both the scaling and area adjustment techniques are shown to represent significant improvements over the techniques previously employed.

Greaves, J. R.↗
NASA NTRS1973

Polar mapping with ERTS-1

The applicability of multispectral ERTS-1 imagery to polar ice detection, local current effects, map corrections, relative lake depth measurements, and estimates of ice breakup is discussed.

Greaves, J. R.↗