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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Atmospheric and surface properties of Mars obtained by infrared spectroscopy on Mariner 9.

During the almost 1-year operational lifetime of Mariner 9 the infrared spectroscopy experiment obtained data over a large portion of Mars. Between June and October 1972, improvements were made in the CO2 transmittances, which are necessary for the interpretation of the thermal emission spectra. Recently obtained spectra indicate that strong seasonal variations in the water vapor distribution occurred over both polar regions. The wettest atmospheric conditions observed so far contain 20 to 30 precipitable microns of water over the north polar cap during northern spring. A low-resolution pressure map is presented that covers that portion of the planet between latitudes -60 and +25 deg. A more detailed study of the Coprates canyon indicates that, at its lowest point, the canyon floor must be at least 5 km below the rim. Applications of tidal theory to temperature fields derived from the spectra indicate diurnal surface pressure fluctuations of as much as 12% during the Great Dust Storm of 1971-1972.

Conrath, B.↗
NASA NTRS1973

Mariner 9 television observations of Phobos and Deimos. II.

Analyses of the Mariner 9 pictures of the Martian satellites have yielded much new information: improved ephemerides, estimates of their principal axes, information about the texture of their surfaces, and estimates of the structural strength of their interiors. Both satellites are found to be in synchronous rotation, as was expected from tidal theory. A close examination of the preorbital satellite pictures has failed to show any unknown satellite. The photometric behavior of Phobos and Deimos indicates that they have intricate surface layers consistent with the presence of a regolith. Morphological features on Phobos and the expected collisional history of both satellites imply that both are made of well-consolidated material.

Pollack, J. B.↗
NASA NTRS1973

Galaxy formation associated with active galaxies and the binding of rich clusters.

A mechanism is proposed for recent formation of dwarf galaxies in the vicinity of active radio galaxies. In the cores of rich clusters these dwarf galaxies are stripped of gas and eventually suffer tidal disruption. This leads us to suggest that the Coma cluster of galaxies may be bound by intergalactic halo-type stars.

Silk, J.↗
NASA NTRS1973

Variations in density and chemical composition at 120 km from chemical and dynamical processes.

Atmospheric parameters show both systematic and random patterns of behavior at 120 km altitude. Variations in density, temperature, pressure, and especially atomic oxygen concentration are important. The variations are particularly significant because constant boundary conditions at this altitude have commonly been assumed in atmospheric model making. It is surprising how well the assumption of constant boundary conditions has served over the past decade. However, their use has probably introduced erroneous concepts into the field of atmospheric structure, or at least held off the recognition and introduction of important new concepts. The variations at 120 km are caused by changes in energy input into the upper atmosphere, including internal gravity waves and tidal energy from below, and changes in the transport processes within the atmosphere.

Johnson, F. S.↗
NASA NTRS1973

The role of rotation in close binary systems of high mass.

A quantitative confrontation of theory and observation of massive close binary systems is presented in order to evaluate the role of axial rotation in the evolution of the individual stellar components as well as of the system as a whole. The detached systems are essentially unevolved, and possess components in approximately uniform rotation. The semidetached systems are definitely evolved, having suffered a heavy mass exchange before the stage of hydrogen exhaustion at the center of the original primary, and often possess mass-gaining components in fast nonuniform rotation. Except in the case of wide systems, tidal friction eventually reinduces synchronism of rotation in both components and both components evolve inhomogeneously. Spin-down times of the envelope and core, total rotational angular momenta, and effects of spin-orbit interaction are calculated.

Stothers, R.↗
NASA NTRS1973

Suspended sediment observations from ERTS-1.

Satellite imagery from four successful ERTS-1 passes over Delaware Bay during different portions of the tidal cycle are interpreted with special emphasis on visibility of suspended sediment and its use as a natural tracer for gross circulation patterns. The MSS red band (band 5) appears to give the best contrast, although the sediment patterns are represented by only a few neighboring shades of grey. Color density slicing improves the differentiation of turbidity levels. However, color additive enhancements are of limited value since most of the information is in a single color band. The ability of ERTS-1 to present a synoptic view of the surface circulation over the entire bay is shown to be a valuable and unique contribution of ERTS-1 to coastal oceanography.

Klemas, V.↗
NASA NTRS1973

Evaluate ERTS imagery for mapping and detection of changes of snowcover on land and on glaciers

The author has identified the following significant results. The standard error of measurement of snow covered areas in major drainage basins in the Cascade Range, Washington, using single measurements of ERTS-1 images, was found to range from 11% to 7% during a typical melt season, but was as high as 32% in midwinter. Many dangerous glacier situations in Alaska, Yukon, and British Columbia were observed on ERTS-1 imagery. Glacier dammed lakes in Alaska are being monitored by ERTS-1. Embayments in tidal glaciers show changes detectable by ERTS-1. Surges of Russell and Tweedsmuir Glaciers, now in progress, are clearly visible. The Tweedsmuir surge is likely to dam the large Alsek River by mid-November, producing major floods down-river next summer. An ERTS-1 image of the Pamir Mountains, Tadjik S.S.R., shows the surging Medvezhii (Bear) Glacier just after its surge of early summer which dammed the Abdukagor Valley creating a huge lake and later a flood in the populous Vanch River Valley. A map was compiled from an ERTS-1 image of the Lowell Glacier after its recent surge, compared with an earlier map compiled from pain-stakingly compiled from a mosaic of many aerial photographs, in a total elapsed time of 1.5 hours. This demonstrates the value of ERTS-1 for rapid mapping of large features.

Meier, M. F.↗
NASA NTRS1972

The reflection effect in Hz Hercules

The magnitude brightness variation due to binary star reflection effect is considered, along with tidal distortion effects. The flat region in the Milne-Sen Law is also reviewed, including the nonfit observations. Several studies are included in this binary star program investigation.

Wilson, R. E.↗
NASA NTRS1974

Use of ERTS-1 data: Summary report of work on ten tasks

The author has identified the following significant results. Depth mapping's for a portion of Lake Michigan and at the Little Bahama Bank test site have been verified by use of navigation charts and on-site visits. A thirteen category recognition map of Yellowstone Park has been prepared. Model calculation of atmospheric effects for various altitudes have been prepared. Radar, SLAR, and ERTS-1 data for flooded areas of Monroe County, Michigan are being studied. Water bodies can be reliably recognized and mapped using maximum likelihood processing of ERTS-1 digital data. Wetland mapping has been accomplished by slicing of single band and/or ratio processing of two bands for a single observation date. Both analog and digital processing have been used to map the Lake Ontario basin using ERTS-1 data. Operating characteristic curves were developed for the proportion estimation algorithm to determine its performance in the measurement of surface water area. The signal in band MSS-5 was related to sediment content of waters by modelling approach and by relating surface measurements of water to processed ERTS data. Radiance anomalies in ERTS-1 data could be associated with the presence of oil on water in San Francisco Bay, but the anomalies were of the same order as those caused by variations in sediment concentration and tidal flushing.

Thomson, F. J.↗
NASA NTRS1973

Lunar Surface Gravimeter Experiment

The lunar surface gravimeter which was emplaced on the moon by the Apollo 17 flight is described and a schematic diagram of the sensor is provided. The objective of the lunar surface gravimeter is to use the moon as an instrumented antenna to detect gravitational waves. Another objective is to measure tidal deformation of the moon. Samples of signals received during lunar sunrise activity and during quiet periods are presented in graph form based on power spectrum analysis

Giganti, J. J.↗
NASA NTRS1974

Periodic variations in stratospheric meridional wind from 20-65 km, at 80 deg N to 8 deg S

The variability of stratospheric meridional winds is examined in both space and time. Height-latitude sections for January along 70 deg E and 90 deg W show a divergence zone above 50 km near 60 deg N and an intense convergence zone 40 km near 50 deg N over North America. This latter structure, with southward winds in the Arctic and northward winds at mid-latitudes over North America, persists from October through April. Tidal winds dominate all other circulation features in summer at all latitudes, and throughout the year at low latitudes. To help understand the observed patterns of variability, long-term periodic features are analyzed. The quasi-biennial oscillation, annual wave, and four-month wave have amplitudes of about 10, 20, and 10 m/sec respectively in the Arctic near 45 km. The phase of the annual wave changes by nearly 180 deg in a narrow zone near 45 deg N. The semiannual wave has an amplitude of 10 m/sec. 50 deg N above 50 km equinoctial phase dates in the region of maximum amplitude. This polar semiannual wave corresponds closely to that previously found in the zonal wind.

Nastrom, G. D.↗
NASA NTRS1973

Remote-sensing studies of hydrologic environments in the lower Raritan River System, New Jersey

A series of remote sensing experiments were conducted in January and November 1968. The airborne multisensor missions included photographic and thermal-infrared sensors operated over a single site at a time when streamflow and water temperature observations were being made on the ground. Remote sensing data show: (1) effect of thermal waste water discharges on stream temperatures, (2) cross-channel variations in thermal characteristics due to waste water discharge, channel characteristics, and tidal currents, (3) influence of flow rates on dispersion, (4) patterns and distribution of ice cover, and (5) movement of sediment loads.

Anderson, P. W.↗
NASA NTRS1973

Remote sensing as an aid for marsh management

NASA aerial photography, primarily color infrared and color positive transparencies, is used in a study of marsh management practices and in comparing managed and unmanaged marsh areas. Weir locations for tidal control are recommended.

Ragan, J. G.↗
NASA NTRS1974

The ROAD program

The philosophy, history, operation, calibration of and some analyses with the ROAD (Rapid Orbit Analysis and Determination) program are described. This semi-numeric trajectory program integrates and analyses mean element variations for earth orbits with great efficiency. Through it's use, extensive zonal, resonant harmonic and earth tidal determinations have been made at Goddard Space Flight Center since 1969.

Wagner, C. A.↗
NASA NTRS1974

Applications of ERTS data to coastal wetland ecology with special reference to plant community mapping and typing and impact of man

Complete seasonal ERTS-1 coverage of Atlantic coastal wetlands from Delaware Bay to Georgia provides a basis for assessment of temporal data for wetland mapping, evaluation, and monitoring. Both MSS imagery and digital data have proved useful for gross wetland species delineation and determination of the upper wetland boundary. Tidal effects and (band to band or seasonal) spectral reflectance differences make it possible to type vegetatively coastal wetlands in salinity related categories. Management areas, spoil disposal sites, drainage ditches, lagoon-type developments and highway construction can be detected indicating a monitoring potential for the future. A northern test site (Maryland-Virginia) and a southern test site (Georgia-South Carolina), representing a range of coastal marshes from saline to fresh, were chosen for intensive study. Wetland maps were produced at various scales using both ERTS imagery (bands 5 and 7) and digital data (bands 4, 5 and 7).

Anderson, R. R.↗
NASA NTRS1974

Tracking air-dropped drogues and dyes from aircraft in support of ERTS-1 circulation studies

The author has identified the following significant results. For two years ERTS-1 has been employed to investigate current circulation patterns in Delaware Bay under different tidal, flow, and wind conditions. Since sufficient numbers of current meters and boats are not available, air-droppable drogues and dye packs have been developed and tested. The drogues consist of a styrofoam float and a line to which is attached a stainless steel biplane. The length of the line determines at what depth currents will be monitored. The floats are color coded to distinguish their movement and mark the depth of the biplanes. Simultaneously floating and anchored dye packs of fluorescein dye have been deployed from aircraft. The movement of the dye and drogues is tracked by sequential aerial photography, using fixed markers on shore or on buoys as reference points to calibrate the scale and direction of drogue movement. The current data obtained by this technique is then used to annotate current circulation maps derived from ERTS-1 imagery.

Klemas, V.↗
NASA NTRS1973

Test for planetary influences on solar activity

A method due to Schuster is used to test the hypothesis that solar activity is influenced by tides raised in the sun's atmosphere by planets. We calculate the distribution in longitude of over 1000 flares occurring in a 6 1/2 yr segment of solar cycle 19, referring the longitude system in turn to the orbital positions of Jupiter and Venus. The resulting distributions show no evidence for a tidal effect.

Dingle, L. A.↗