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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

The influence of coastal fronts on the movement and dispersion of oil slicks

The author has identified the following significant results. LANDSAT, aircraft, and boats were used successfully to study estuarine and coastal fronts or boundaries. Horizontal salinity gradients of 4% in one meter and convergence velocities of the order of 0.1 m/sec were observed. Visibility improved from one meter to two meters as certain boundaries were crossed. Fronts near the mouth of the bay are associated with the tidal exchange with shelf water. By capturing and holding oil slicks, these frontal systems also significantly influence the movement and dispersion of oil slicks in Delaware Bay. Recent oil slick tracking experiments conducted to verify a predictive oil dispersion and movement model have shown that during certain parts of the tidal cycle the oil slicks tend to line up along boundaries.

Klemas, V.↗
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

Analysis of six broadband optical filters for measuring chlorophyll alpha and suspended solids in the Patuxent River

Kodak Wratten broadband optical filters numbered 47B (400 to 500 nm), 57 (500 to 600 nm), 58 (500 to 600 nm), 12 (500 to 700 nm), 25 (600 to 700 nm), and 89B (690 to 900 nm) were tested on October 17, 1972, to see whether each spectral band by itself could be used to quantify chlorophyll a and suspended sediment in the Patuxent River. Band 690 to 900 nm showed promise in being able to detect gross changes in chlorophyll a above 28 micrograms/l. None of the broad spectral bands seem capable of measuring chlorophyll a concentrations less than 28 micrograms/l in turbid estuarine water. Except for the 47B spectral band, the bands do show promise for measuring suspended solids.

Ohlhorst, C. W.↗
NASA NTRS1975

Remote sensing by ERTS satellite of vegetational resources believed to be under possible threat of environmental stress

The distribution of natural vegetation on North Merritt Island, Florida, was studied by computer analysis of ERTS satellite multispectral-scanner data. The boundaries of six distinct plant associations were located in photos produced on the image analyzer with an insignificant mean error of -24.38 meters. The six plant associations are described as: aquatic estuarine association, mangrove, spartina swamp, wooded swamp, sabal hammock, and oak-palmetto. The difference in average reflectance 'grey level' between the lowest of the four spectral scanning bands and the highest spectral scanning band for each of the six vegetation types is described. The decreasing trend of the differences is strongly negatively correlated with height of land, the coefficient of correlation being -0.9696.

Pooni, P.↗
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 NTRS1976

Assessment of the impact of increased solar ultraviolet radiation upon marine ecosystems

Data was provided to assess the potential impact upon marine ecosystems if space shuttle operations contribute to a reduction of the stratospheric ozone layer. The potential for irreversible damage to the productivity, structure and/or functioning of a model estuarine ecosystem by increased UV-B radiation was established. The sensitivity of key community components (the primary producers) to increased UV-B radiation was delineated.

Vandyke, H.↗
NASA NTRS1977

Implantable acoustic-beacon automatic fish-tracking system

A portable automatic fish tracking system was developed for monitoring the two dimensional movements of small fish within fixed areas of estuarine waters and lakes. By using the miniature pinger previously developed for this application, prototype tests of the system were conducted in the York River near the Virginia Institute of Marine Science with two underwater listening stations. Results from these tests showed that the tracking system could position the miniature pinger signals to within + or - 2.5 deg and + or - 135 m at ranges up to 2.5 km. The pingers were implanted in small fish and were successfully tracked at comparable ranges. No changes in either fish behavior or pinger performance were observed as a result of the implantation. Based on results from these prototype tests, it is concluded that the now commercially available system provides an effective approach to underwater tracking of small fish within a fixed area of interest.

Mayhue, R. J.↗
NASA NTRS1976

Analytical notes - Electrochemical method for early detection and monitoring of coliforms

An electrochemical method for detecting bacteria, based on a linear relationship between inoculum size and the time of hydrogen evolution, was tested for the early detection and monitoring of coliforms in naturally contaminated estuarine and fresh water samples. Standard methods for coliform analysis were performed on each sample, and membrane filtration counts were used to construct dose-response curves; relationships and results are discussed herein.

Wilkins, J. R.↗
NASA NTRS1977

Satellite, aircraft, and drogue studies of coastal currents and pollutants

The mounting interest in extracting oil and other resources from the continental shelf and continuing use of shelf and estuarine waters for waste disposal is creating a need for synoptic means of determining currents and monitoring pollutants in this area. A satellite-aircraft-drogue approach is described which employs remotely tracked expendable drogues together with satellite and aircraft observations of waste plumes and current tracers such as dyes or suspended sediment. Tests conducted on the continental shelf and in Delaware Bay indicate that the approach provides a cost-effective means of studying current circulation, oil-slick movement, and ocean waste dispersion under a wide range of environmental conditions.

Klemas, V.↗
NASA NTRS1977

Applications of space observations to the management and utilization of coastal fishery resources

Information needs of those concerned with the harvest and management of coastal fishery resources can be satisfied in part through applications of satellite remote sensing. Recently completed and ongoing investigations have demonstrated potentials for defining fish distribution patterns from multispectral data, monitoring fishing distribution and effort with synthetic aperture radar systems, forecasting recruitment of certain estuarine-dependent species, and tracking marine mammals. These investigations, which are reviewed in this paper, have relied on Landsat 1 and 2, Skylab-3, and Nimbus-6 supported sensors and sensors carried by aircraft and mounted on surface platforms to simulate applications from Seasat-A and other future spacecraft systems. None of the systems are operational as all were designed to identify and demonstrate applications and to aid in the specification of requirements for future spaceborne systems.

Kemmerer, A. J.↗
NASA NTRS1977

Evaluation of change detection techniques for monitoring coastal zone environments

Development of satisfactory techniques for detecting change in coastal zone environments is required before operational monitoring procedures can be established. In an effort to meet this need a study was directed toward developing and evaluating different types of change detection techniques, based upon computer aided analysis of LANDSAT multispectral scanner (MSS) data, to monitor these environments. The Matagorda Bay estuarine system along the Texas coast was selected as the study area. Four change detection techniques were designed and implemented for evaluation: (1) post classification comparison change detection, (2) delta data change detection, (3) spectral/temporal change classification, and (4) layered spectral/temporal change classification. Each of the four techniques was used to analyze a LANDSAT MSS temporal data set to detect areas of change of the Matagorda Bay region.

Weismiller, R. A.↗
NASA NTRS1976

Frequency band justifications for passive sensors, 1 to 10 GHz

Remote sensor systems operating in the microwave region of the frequency spectrum provide information unobtainable with basic imaging techniques such as photography, television, or multispectral imaging. The frequency allocation requirements for passive microwave sensors used in the earth exploration satellite and space research services are presented for: (1) agriculture, forestry, and range resources; (2) land use survey and mapping: (3) water resources; (4) weather and climate; (5) environmental quality; and (6) marine resources, estuarine and oceans. Because measurements are required simultaneously in multiple frequency bands to adequately determine values of some phenomena, the relationships between frequency bands are discussed. The various measurement accuracies, dynamic range, resolutions and frequency needs are examined. A band-by-band summary of requirements, unique aspects, and sharing analyses of the required frequency bands is included.

Source record↗
NASA NTRS1977

Assessment of the impact of increased solar ultraviolet radiation upon marine ecosystems

Specifically, the study has addressed the following: (1) potential for irreversible damage to the productivity, structure and/or functioning of a model estuarine ecosystem by increased UV-B radiation or ecosystems highly stable or amenable to adaptive change, and (2) the sensitivity of key community components (the primary producers, consumers, and decomposers) to increased UV-B radiation. Three areas of study were examined during the past year: (1) a continuation of the study utilizing the two seminatural ecosystem chambers, (2) a pilot study utilizing three flow-through ecosystem tanks enclosed in a small, outdoor greenhouse, and (3) sensitivity studies of representative primary producers and consumers.

Vandyke, H.↗
NASA NTRS1978

Hydraulic model of the Chesapeake Bay

Preliminary planning for the formulation of the first year of hydraulic studies on the Chesapeake Bay model was recently completed. The primary purpose of this initial effort was to develop a study program that is both responsive to problems of immediate importance and at the same time ensure that from the very beginning of operation maximum economical use is made of the model. The formulation of this preliminary study plan involved an extensive analysis of the environmental, economic, and social aspects of a series of current problems in order to establish a priority listing of their importance. The study program that evolved is oriented towards the analysis of the effects of some of the works of man on the Chesapeake Bay estuarine environment.

Robinson, A. E., Jr.↗
NASA NTRS1978

Regional energetic coupling of man and his environment: Data requirements

An energy analysis methodology was developed to serve as a rational basis for evaluating alternative regional management/use schemes. Human and natural systems are coupled and can be interpreted, using a common base of energy-flow analysis to evaluate past, present, and future states of regional integrated systems in the coastal zone and to provide the capability for rational selection of alternative patterns of resource use. Energy flows (or flows of dollars or materials converted to energy equivalents) are believed to be the basic factor in the organizations of all types of systems. An analysis example is provided of an estuarine subsystem of the Chesapeake Bay, and tabular listings of regional data needs are given. Current remote sensing capabilities were used to provide some of the necessary information.

Mihursky, J. A.↗
NASA NTRS1977

Change detection in coastal zone environments

A study was conducted with the objective to develop and evaluate various change detection techniques based upon computer-aided analysis of Landsat multispectral scanner (MSS) data to monitor coastal zone environments. The study site selected includes a portion of the Matagorda Bay estuarine system located along the Texas Coast. The principal data sources for the study were MSS data collected on November, 27, 1972 and February 25, 1975. The MSS data were processed and a multidata eight-channel data set at a scale of 1:24,000 was obtained. A description is presented of four change detection techniques which were designed and implented for evaluation, taking into account postclassification comparison change detection, delta data change detection, spectral/temporal change classification, and layered spectral/temporal approach. The results of the investigation are discussed.

Weismiller, R. A.↗
NASA NTRS1978

Outfall siting with dye-buoy remote sensing of coastal circulation

A dye-buoy remote sensing technique has been applied to estuarine siting problems that involve fine-scale circulation. Small hard cakes of sodium fluorescein and polyvinyl alcohol, in anchored buoys and low-windage current followers, dissolve to produce dye marks resolvable in 1:60,000 scale color and color infrared imagery. Lagrangian current vectors are determined from sequential photo coverage. Careful buoy placement reveals surface currents and submergence near fronts and convergence zones. The technique has been used in siting two sewage outfalls in Hampton Roads, Virginia: In case one, the outfall region during flood tide gathered floating materials in a convergence zone, which then acted as a secondary source during ebb; for better dispersion during ebb, the proposed outfall site was moved further offshore. In case two, flow during late flood was found to divide, with one half passing over shellfish beds; the proposed outfall site was consequently moved to keep effluent in the other half.

Munday, J. C., Jr.↗