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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Automated cloud tracking using precisely aligned digital ATS pictures.

An interactive man-computer system, termed WINDCO, which was developed to measure cloud motions from pictures obtained by the ATS-I and ATS-III satellites, is described. The system will measure motions to at least three knots at moderate cost in a real-time environment. Accuracy could be improved by a factor of 4 by incorporating high-resolution visible SMS data.

Smith, E. A.↗
NASA NTRS1972

Use of the Hough transformation to detect lines and curves in pictures.

Hough (1962) has proposed an interesting and computationally efficient procedure for detecting lines in pictures. It is pointed out that the use of angle-radius rather than slope-intercept parameters simplifies the computation further. Two alternative interpretations of Hough's method are presented. The transform approach considered can be extended to arbitrary curves. A convenient parameterization for the family of curves of interest has to be selected. It is important to have a small number of parameters since the accumulator implementation requires quantization of the entire parameter space.

Duda, R. O.↗
NASA NTRS1972

Tornado occurrences related to overshooting cloud-top heights as determined from ATS pictures

A sequence of ATS 3 pictures including the development history of large anvil clouds near Salina, Kansas was enlarged by NASA into 8X negatives which were used to obtain the best quality prints by mixing scan lines in 8 steps to minimize checker-board patterns. These images resulted in the best possible resolution, permitting use to compute the heights of overshooting tops above environmental anvil levels based on cloud shadow relationships along with the techniques of lunar topographic mapping. Of 39 heights computed, 6 were within 15 miles of reported positions of 3 tornadoes. It was found that the tornado proximity tops were mostly less than 5000 ft, with one exception of 7000 ft, suggesting that tornadoes are most likely to occur when overshooting height decreases. In order to simulate surface vortices induced by cloud-scale rotation and updraft fields, a laboratory model was constructed. The model experiment has shown that the rotation or updraft field induces a surface vortex but their combination does prevent the formation of the surface vortex. This research leads to a conclusion that the determination of the cloud-top topography and its time variation is of extreme importance in predicting severe local storms for a period of 0 to 6 hours.

Fujita, T. T.↗
NASA NTRS1973

Use of ERTS-1 pictures in coastal oceanography in British Columbia

The ERTS-1 color composite picture of the Vancouver-Victoria region illustrates the value of ERTS data for coastal oceanography. The water of the Fraser River plume which is so clearly visible in the center of the scene has been of interest to oceanographers on the west coast of Canada for a long time as an easily visible tracer of surface water circulation in the strait of Georgia. Maps of the plume at different states of the tide and with different river flow and weather were compiled from oblique aerial photographs in 1950 and used in the siting of sewage and other outfalls in the Vancouver area. More recently high level aerial photomosaics have been used to map the plume area, but the plume can spread over distances of 30 to 40 miles and many photographs, with the uneven illumination inherent in wide angle coverage, are needed for the mosaic. The ERTS satellite gives the first complete view of the plume area. Electronic enhancement of the images shows that the satellite's narrow angle coverage allows very weak surface turbidity features to be made visible to give information on surface currents over a wide area.

Gower, J. F. R.↗
NASA NTRS1974

Venus - Atmospheric motion and structure from Mariner 10 pictures

The Mariner 10 television cameras imaged the planet Venus in the visible and near ultraviolet for a period of 8 days at resolutions ranging from 100 meters to 130 kilometers. The general pattern of the atmospheric circulation in the upper tropospheric/lower stratospheric region is displayed in the pictures. Atmospheric flow is symmetrical between north and south hemispheres. The equatorial motions are zonal (east-west) at approximately 100 meters per second, consistent with the previously inferred 4-day retrograde rotation. Angular velocity increases with latitude. The subsolar region, and the region downwind from it, show evidence of large-scale convection that persists in spite of the main zonal motion. Dynamical interaction between the zonal motion and the relatively stationary region of convection is evidenced by bowlike waves.

Murray, B. C.↗
NASA NTRS1974

Geographical correlation of earth cloud cover pictures obtained from unoriented satellites

Mathematical models have been developed for the determination of the geographic coordinates of cloud photographs taken from earth satellites. The proposed methods were realized on a Minsk-22 computer, and were used to process the earth cloud pictures obtained from the communications satellite Molyniya 1 and the automatic stations Zond 5 and 7. Experience using these methods showed that the accuracy of orientation angular element determination is on the order of 1 deg.

Solovyev, V. I.↗
NASA NTRS1974

Use of TV pictures obtained from weather satellites to study the geological structure of the earth

Results are presented of Soviet investigations into the use of television imagery obtained from meteorological satellites for the interpretation of tectonics, lithology, and structural properties of the earth. The area investigated encompassed the eastern part of Iran, and the western regions of Afghanistan and Pakistan. Interpretation of the features identified during the analysis was accomplished by comparing these features with physical, geographic, geological, and tectonic maps. It was concluded that television pictures of the earth from space can be used for geological and structural analysis.

Bashilova, I. I.↗
NASA NTRS1975

Weather satellite picture receiving stations, APT digital scan converter

The automatic picture transmission digital scan converter is used at ground stations to convert signals received from scanning radiometers to data compatible with ground equipment designed to receive signals from vidicons aboard operational meteorological satellites. Information necessary to understand the circuit theory, functional operation, general construction and calibration of the converter is provided. Brief and detailed descriptions of each of the individual circuits are included, accompanied by a schematic diagram contained at the end of each circuit description. Listings of integral parts and testing equipment required as well as an overall wiring diagram are included. This unit will enable the user to readily accept and process weather photographs from the operational meteorological satellites.

Vermillion, C. H.↗
NASA NTRS1975

Venus - Vertical structure of stratospheric hazes from Mariner 10 pictures

An 'optical barometer' technique for determining the altitudes of haze in the stratosphere of Venus is presented wherein the Rayleigh-scattering component is derived by comparing orange and UV brightness profiles for nearby Mariner 10 television-picture pairs. The derived scale height for CO2 gas is 4.2 km, corresponding to a temperature of 200 K, in good agreement with radio occultation data. The optical barometer yields a pressure of 4 mb for the level at which the slant-path optical depth at the limb is unity. This level corresponds to a distance from the center of Venus equal to 6131 km, which is accurate to within 1 km provided that there is no appreciable contribution to the brightness by Rayleigh-scattering aerosols which mimic CO2 gas. It is possible that the limb haze layering observed between 6130 and 6140 km could be correlated with temperature inversions detected by the Mariner 5 radio-occultation experiment. A model is proposed wherein the concentration of particles increases rapidly with an effective scale height of about 2 km as one descends about 10 km from the limb haze to the main polarization cloud deck.

Oleary, B.↗
NASA NTRS1975

Attitude determination using digital earth pictures

A computer program called PICATT is reported, which stands for picture attitude determination. Described are the particular satellite to which this technique of attitude determination has been applied, the method of solution, and the results that have been attained using the PICATT program.

Gunshol, L. P.↗