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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

The use of ERTS-1 to more fully utilize and apply marine station data to the study and productivity along the eastern shelf waters of the United States

The author has identified the following significant results. Sea truth data were obtained during two ERTS overpasses in waters near the entrance of the Chesapeake Bay. Correlations were made between total phytoplankton and chlorophyll values in these waters to radiance detected by ERTS in an effort to map areas of similar productivity levels. Band 4 radiance had the highest correlation to all parameters with bands 5 and 6 showing decreasing correlations in each case. The radiance values were apparently influenced by one or more factors, most likely including the sediment content of the water. Data have shown that ERTS MSS is not suitable for monitoring chlorophyll in near-shore waters where sediment loads are high. It is suggested that in more seaward or pelagic locations, that ERTS MSS would be more efficient in monitoring surface chlorophyll values and establishing direct relationships to phytoplankton concentrations.

Marshall, H. G.↗
NASA NTRS1975

Water color and circulation southern Chesapeake Bay, part 1

Satellite imagery from two EREP passes over the Rappahannock Estuary of the Chesapeake region is analyzed to chart colored water types, to delineate color boundaries and define circulatory patterns. Surface observations from boats and helicopters concurrent with Skylab overpass define the distributions of suspended sediment, transparency, temperature, salinity, phytoplankton, color of suspended material and optical ratio. Important features recorded by the imagery are a large-scale turbidity maximum and massive red tide blooms. Water movement is revealed by small-scale mixing patterns and tidal plumes of apparent sediment-laden water. The color patterns broadly reflect the bottom topography and the seaward gradient of suspended material between the river and the bay. Analyses of red, green and natural color photos by microdensitometry demonstrate the utility of charting water color types of potential use for managing estuarine water quality. The Skylab imagery is superior to aerial photography and surface observations for charting water color.

Nichols, M. M.↗
NASA NTRS1976

Mobile Bay turbidity plume study

Laboratory and field transmissometer studies on the effect of suspended particulate material upon the appearance of water are reported. Quantitative correlations were developed between remotely sensed image density, optical sea truth data, and actual sediment load. Evaluation of satellite image sea truth data for an offshore plume projects contours of transmissivity for two different tidal phases. Data clearly demonstrate the speed of change and movement of the optical plume for water patterns associated with the mouth of Mobile bay in which relatively clear Gulf of Mexico water enters the bay on the eastern side. Data show that wind stress in excess of 15 knots has a marked impact in producing suspended sediment loads.

Crozier, G. F.↗
NASA NTRS1975

The utility of Skylab photo-interpreted earth resources data in studies of marine geology and coastal processes in Puerto Rico and the Virgin Islands

The author has identified the following significant results. Three Skylab earth resources passes over Puerto Rico and St. Croix on 6 June and 30 November 1973 and 18 January 1974 resulted in color photography and multispectral photography and scanner imagery. Bathymetric and turbid water features are differentiable by use of the multispectral data. Photography allows mapping of coral reefs, offshore sand deposits, areas of coastal erosion, and patterns of sediment transport. Bottom sediment types could not be differentiated. Patterns of bottom dwelling biologic communities are well portrayed but are difficult to differentiate from bathymetric detail. Effluent discharges and oil slicks are readily detected and are differentiated from other phenomena by the persistence of their images into the longer wavelength multispectral bands.

Trumbull, J. V. A.↗
NASA NTRS1976

The interaction of unidirectional winds with an isolated barchan sand dune

Velocity profile measurements are determined on and around a barchan dune model inserted in the roughness layer on the tunnel floor. A theoretical investigation is made into the factors influencing the rate of sand flow around the dune. Flow visualization techniques are employed in the mapping of streamlines of flow on the dune's surface. Maps of erosion and deposition of sand are constructed for the barchan model, utilizing both flow visualization techniques and friction velocities calculated from the measured velocity profiles. The sediment budget found experimentally for the model is compared to predicted and observed results reported. The comparison shows fairly good agreement between the experimentally determined and predicted sediment budgets.

Gad-El-hak, M.↗
NASA NTRS1976

Correlation of chlorophyll, suspended matter, and related parameters of waters in the lower Chesapeake Bay area to LANDSAT-1 imagery

The author has identified the following significant results. An effort to relate water parameters of the lower Chesapeake Bay area to multispectral scanner images of LANDSAT 1 has shown that some spectral bands can be correlated to water parameters, and has demonstrated the feasibility of synoptic mapping of estuaries by satellite. Bands 5 and 6 were shown to be useful for monitoring total particles. Band 5 showed high correlation with suspended sediment concentration. Attenuation coefficients monitored continuously by ship along three baselines were cross correlated with radiance values on three days. Improved correlations resulted when tidal conditions were taken into consideration. A contouring program was developed to display sediment variation in the lower Chesapeake Bay from the MSS bands.

Fleischer, P.↗
NASA NTRS1976

Evaluation of water samples collected during LANDSAT-1 overpasses of the lower Chesapeake Bay area

Water samples were collected on 18 days when the LANDSAT-1 satellite was passing over the lower Chesapeake Bay area. A correlation between the various water parameters has been performed for the more than 300 surface samples. Six days were sufficiently cloudless that MSS digital tapes were useful for analysis. Correlation of radiance values with the water parameters revealed a low correlation for chlorophyll and good correlations with particles and sediment. The relation of total particles to sediment was linear, but varied from day to day.

Bowker, D. E.↗
NASA NTRS1975

Evaluation of ERTS MSS digital data for monitoring water in the lower Chesapeake Bay area

Water samples collected during the ERTS overpasses of the lower Chesapeake Bay area have been analyzed for chlorophyll, particles, and sediment. Five ERTS images were sufficiently cloud free that a correlation analysis of radiance values from the MSS bands with the water parameters could be performed. A low correlation was established for chlorophyll, except during algal blooms, when band 6 was responsive. There was a fair to good correlation with particles for combinations of band 5, particularly bands (5 minus 6). Sediment correlations were excellent for band 5 or combinations of band 5 with bands 4 and 6. It was evident that such factors as the atmosphere, tide, and different water masses were tending to confuse the data.

Bowker, D. E.↗
NASA NTRS1975

Skylab analysis of San Francisco Bay

The distribution and volume of sediment present in suspension during the Skylab 4 overpass for San Pablo Bay and the Carquinez Strait is studied along with the movement and eventual distribution of both natural and dredged sediment in San Francisco Bay. The most useful Skylab sensor film is found to be the S-190B color photography. Changes in temperature, dissolved oxygen, pH, salinity, and pollutants information simultaneously collected are correlated with the spectral differences observed in the various Skylab data. The techniques outlined should be applicable for coastal and estuarine process studies in other areas. A suspensate concentration of about 2 mg/liter is quite sufficient to tag a surface current system, and the surface structure of currents with over 250 mg/liter can be imaged by using progressively longer wavelength filters.

Steller, D. D.↗
NASA NTRS1977

Influence of zero-G on single-cell systems and zero-G fermenter design concepts

An analysis was made to identify potential gravity-sensitive mechanisms that may be present in the single-cell growth system. Natural convection (density gradients, induced sedimentation, and buoyancy) is important in microbial systems. The absence of natural convection in the space-flight environment could provide an opportunity for new approaches for developments in industrial fermentation and agriculture. Some of the potential influences of gravity (i.e., convection, sedimentation, etc.) on the cell were discussed to provide insight into what experimental areas may be pursued in future space-flight research programs.

Mayeux, J. V.↗
NASA NTRS1977

California coastal processes study, LANDSAT 2

The authors have identified the following significant results. By using suspended sediments as tracers, objectives were met by qualitative definition of the nearshore circulation along the entire coast of California with special study sites at Humboldt Bay, the mouth of the Russian River, San Francisco Bay, Monterey Bay, and the Santa Barbara Channel. Although LANDSAT primarily imaged fines and silts in the surface waters, the distribution of sediments allowed an examination of upwelling, convergences and coastal erosion and deposition. In Monterey Bay and Humboldt Bay, these coastal phenomena were used to trace seasonal trends in surface currents.

Pirie, D. M.↗
NASA NTRS1978

Large-scale erosional and depositional features of the Channeled Scabland

The channeled scabland is a great anastomosing complex of highly overfit stand channels eroded into the basalt bedrock and overlying sediments of the Columbia Plateau. Both the erosional and depositional bed forms in these channels are described according to a simple hierarchical classification. The catastrophic flood flows produced macroforms (scale controlled by channel width) through the erosion of rock and sediment and by deposition (bars). Mesoforms (scale controlled by channel depth) are also erosional and depositional.

Baker, V. R.↗
NASA NTRS1977

The geology of the Viking Lander 1 site

Stereo pictures show that Viking Lander 1 landed on volcanic terrain of undulating topography in the plains of Chryse. The bedrock is exposed along several ridge crests, and blocks are more numerous than can be attributed to impact ejecta. The presence of a variety of rock types suggests in situ weathering of extrusive and near-surface basaltic igneous rocks along a linear volcanic vent. Fine-grained sediment is present in drift complexes and isolated drifts. A small patch of fine-grained sediment slumped down one of the drift faces during the course of the Viking mission. Otherwise, no other morphological changes unrelated to spacecraft activity have been observed.

Binder, A. B.↗
NASA NTRS1977

The geology of the Viking Lander 2 site

Models are discussed of several competitive geologic histories that can be hypothesized for the Viking Lander 2 site, none of which is uniquely persuasive. The craft landed on a flat plain of fine-grained sediment overlain by dispersed evenly distributed boulders. The fine-grain material appears to be part of a high-latitude mantle comprising material swept south of the pole regions. The boulders, which are covered by distinctive deep pits, or vesicles, may be the residue of an ejecta deposit from the crater Mie. Alternatively, they may be the remnants of lava flows which formerly covered the region. Polygonal sediment-filled cracks may have been formed by ice wedging, similar to the process that occurs in terrestrial permafrost regions. The possibility that they are desiccation polygons may not be excluded.

Mutch, T. A.↗
NASA NTRS1977

The use of Landsat for monitoring water parameters in the coastal zone

Landsats 1 and 2 have been successful in detecting and quantifying suspended sediment and several other important parameters in the coastal zone, including chlorophyll, particles, alpha (light transmission), tidal conditions, acid and sewage dumps, and in some instances oil spills. When chlorophyll a is present in detectable quantities, however, it is shown to interfere with the measurement of sediment. The Landsat banding problem impairs the instrument resolution and places a requirement on the sampling program to collect surface data from a sufficiently large area. A sampling method which satisfies this condition is demonstrated.

Bowker, D. E.↗
NASA NTRS1978

Source indicators of humic substances and proto-kerogen - Stable isotope ratios, elemental compositions and electron spin resonance spectra

Stable isotope ratios of C, N and H, elemental compositions, and electron spin resonance (ESR) data of humic acids and proto-kerogens from twelve widely varying sampling locations are presented. Humic acids and proto-kerogens from algal sources are more aliphatic and higher in N than those from higher plant sources. Oxygen content appears to represent a measure of maturation, even in Recent sediments, and S content may reflect redox conditions in the environment of deposition. The ESR data indicate that the transformation of humic substances to proto-kerogens in Recent sediments is accompanied by an increase in aromatic character. A combination of stable carbon isotope ratio and H/C ratio may be a simple but reliable source indicator which allows differentiation of marine-derived from terrestrially-derived organic matter. The stable nitrogen isotope ratios are useful indicators of nitrogen nutrient source. Deuterium/hydrogen isotope ratios appear to reflect variations in meteoric waters and are not reliable source indicators.

Stuermer, D. H.↗
NASA NTRS1979

A nested numerical tidal model of the southern New England bight

Efforts were focused on the development and application of a three-dimensional numerical model for predicting pollutant and sediment transport in estuarine and coastal environments. To successfully apply the pollutant and sediment transport model to Rhode Island coastal waters, it was determined that the flow field in this region had to be better described through the use of existing numerical circulation models. A nested, barotropic numerical tidal model was applied to the southern New England Bight (Long Island, Block Island, Rhode Island Sounds, Buzzards Bay, and the shelf south of Block Island). Forward time and centered spatial differences were employed with the bottom friction term evaluated at both time levels. Using existing tide records on the New England shelf, adequate information was available to specify the tide height boundary condition further out on the shelf. Preliminary results are within the accuracy of the National Ocean Survey tide table data.

Gordon, R. B.↗
NASA NTRS1978

Penetration depth at green wavelengths in turbid waters

A laboratory and field measurement program was conducted to determine apparent remote sensing penetration depths at a wavelength of 520 nm. Tests were made for various types of sediments under controlled conditions in a laboratory. Field tests were conducted in several different water bodies over a wide range of solar elevation angles. Laboratory results indicate that apparent penetration depth is significantly influenced by mineral content and/or size of suspended sediments. Field measurements show wide variation in apparent penetration depth, even when suspended solids concentration is nearly constant. Apparent penetration depth does not appear to be a strong function of solar elevation angle so long as the water mixture remains constant.

Whitlock, C. H.↗