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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

A satellite technique for quantitatively mapping rainfall rates over the oceans

A theoretical model for calculating microwave radiative transfer in raining atmospheres is developed. These calculations are compared with microwave brightness temperatures at a wavelength of 1.55 cm measured on the Nimbus-5 satellite and rain rates derived from WSR-57 meteorological radar measurements. A specially designed ground based verification experiment was also performed wherein upward viewing microwave brightness temperature measurements at wavelengths of 1.55 cm and 0.81 cm were compared with directly measured rain rates.

Wilheit, T. T.↗
NASA NTRS1977

A satellite technique for quantitatively mapping rainfall rates over the oceans

A theoretical model for calculating microwave radiative transfer in raining atmospheres is developed. These calculations are compared with microwave brightness temperatures at a wavelength of 1.55 cm measured by the Electrically Scanning Microwave Radiometer (ESMR) on the Nimbus-5 satellite and rain rates derived from WSR-57 meteorological radar measurements. A specially designed ground-based verification experiment was also performed, wherein upward-viewing microwave brightness temperature measurements at wavelengths of 1.55 and 0.81 cm were compared with directly measured rain rates. It is shown that, over ocean areas, brightness temperature measurements from ESMR may be interpreted in terms of rain rate with about an accuracy of a factor of 2 over the range 1 to 25 mm/hr rain rate.

Wilheit, T. T.↗
NASA NTRS1977

Analyses of the cloud contents of multispectral imagery from LANDSAT 2: Mesoscale assessments of cloud and rainfall over the British Isles

The author has identified the following significant results. It was demonstrated that satellites with sufficiently high resolution capability in the visible region of the electromagnetic spectrum could be used to check the accuracy of estimates of total cloud amount assessed subjectively from the ground, and to reveal areas of performance in which corrections should be made. It was also demonstrated that, in middle latitude in summer, cloud shadow may obscure at least half as much again of the land surface covered by an individual LANDSAT frame as the cloud itself. That proportion would increase with latitude and/or time of year towards the winter solstice. Analyses of sample multispectral images for six different categories of clouds in summer revealed marked differences between the reflectance characteristics of cloud fields in the visible/near infrared region of the spectrum.

Barrett, E. C.↗
NASA NTRS1980

A first look at the effect of severe rainfall upon an aircraft

An aircraft penetrating heavy rain can be affected aerodynamically in at least four ways: (1) raindrops striking the fuselage and wings of the aircraft impart a downward momentum to the aircraft; (2) increased aircraft drag results from the aircraft striking the raindrops head on; (3) at any instant of time the aircraft will contain a thin layer of water over most of its surfaces which will give additional mass to the aircraft; and (4) the water on the airfoil will result in a roughened airfoil surface that could produce significant aerodynamic penalties. An order of magnitude calculation was made for the penalty associated with the factors one two and three. The roughness factor required detailed modeling and boundary layer calculations and was studied using the 'aerodynamic effects of frost model'. The results achieved on each of the penalty factors are described and the factors most likely to cause significant performance degradation are indicated.

Source record↗
NASA NTRS1980

A Continuation of Base-line Studies for Environmentally Monitoring Space Transportation Systems at John F. Kennedy Space Center: Chemical Studies of Rainfall and Soil Analysis - Volume 2

The results of a study which was designed to monitor, characterize, and evaluate the chemical composition of precipitation (rain) which fell at the Kennedy Space Center, Florida (KSC) during the period July 1977 to March 1979 are reported. Results which were obtained from a soil sampling and associated chemical analysis are discussed. The purpose of these studies was to determine the environmental perturbations which might be caused by NASA space activities.

Madsen, B. C.↗
NASA NTRS1981

The Bristol method of satellite-improved rainfall monitoring

Remote sensing estimates of area average precipitation are useful to agricultural and climatological applications. Estimates obtained by active or passive microwaves, infrared and visible sensors may be augmented and improved using indirect measures of precipitation, such as the change in near surface soil moisture content caused by a particular event. Measurements of soil moisture using infrared radiances do not provide precipitation information in real time since the sky must clear. However, the resultant estimate of precipitation is a time integrated value which provides a significant savings in data handling and can overcome virtually all of the sampling problems associated with the monitoring of precipitation through storms of long duration.

Barrett, E. C.↗