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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Use of ERTS-1 to utlitize and apply marine station data to study productivity along eastern shelf expanded waters of the United States

The author has identified the following significant results. Water samples taken in offshore waters between Cap Cod, Massachusetts, and Charleston, South Carolina have been used with other sea truth information as a basis to correlate productivity values with ERTS-1 sensory data. Positive correlations were established on January 26, 1973 regarding chlorophyll concentrations and optical density values.

Marshall, H. G.↗
NASA NTRS1973

Oceanic turbidity and chlorophyll as inferred from ERTS-1 observations

Spectral signatures of phytoplankton and other obscuring effects are considered in order to determine how to best use satellite data. The results of this study were then used to analyze the spectral data obtained from the ERTS-1 multispectral scanner (MSS). The analyzed satellite data were finally compared with surface ship measurements of chlorophyll concentration. It was found that the effects of water turbidity on the multispectral imagery can be discriminated by rationing the two shortest wavelength channels so that the effect of phytoplankton is enhanced.

Curran, R. J.↗
NASA NTRS1973

Detection of ocean color changes from high altitudes

The detection of ocean color changes, thought to be due to chlorophyll concentrations and gelbstoffe variations, is attempted from high altitude (11.3km) and low altitude (0.3km). The atmospheric back scattering is shown to reduce contrast, but not sufficiently to obscure color change detection at high altitudes.

Hovis, W. A.↗
NASA NTRS1973

Remote measurement of water color in coastal waters

An investigation was conducted to develop procedure to obtain quantitative values for chlorophyll and turbidity in coastal waters by observing the changes in spectral radiance of the backscattered spectrum. The technique under consideration consists of Examining Exotech model 20-D spectral radiometer data and determining which radiance ratios best correlated with chlorophyll and turbidity measurements as obtained from analyses of water samples and sechi visibility readings. Preliminary results indicate that there is a correlation between backscattered light and chlorophyll concentration and secchi visibility. The tests were conducted with the spectrometer mounted in a light aircraft over the Mississippi Sound at altitudes of 2.5K, 2.8K and 10K feet.

Weldon, J. W.↗
NASA NTRS1973

Investigation using data from ERTS-1 to develop and implement utilization of living marine resources

The author has identified the following significant results. This 15-month ERTS-1 investigation produced correlations between satellite, aircraft, menhaden fisheries, and environmental sea truth data from the Mississippi Sound. Selected oceanographic, meteorological, and biological parameters were used as indirect indicators of the menhaden resource. Synoptic and near real time sea truth, fishery, satellite imagery, aircraft acquired multispectral, photo and thermal IR information were acquired as data inputs. Computer programs were developed to manipulate these data according to user requirements. Preliminary results indicate a correlation between backscattered light with chlorophyll concentration and water transparency in turbid waters. Eight empirical menhaden distribution models were constructed from combinations of four fisheries-significant oceanographic parameters: water depth, transparency, color, and surface salinity. The models demonstrated their potential for management utilization in areas of resource assessment, prediction, and monitoring.

Stevenson, W. H.↗
NASA NTRS1975

Requirements for airborne laser systems used in coastal studies

Requirements for airborne laser systems are considered for the following applications: (1) photo-optical determination of shallow water wave spectra; (2) bathymetry in highly turbid waters; (3) chlorophyll concentration monitoring; and (4) oil dispersion mapping.

Klemas, V.↗
NASA NTRS1975

Skylab investigation of the upwelling off the Northwest coast of Africa

The upwelling off the NW coast of Africa in the vicinity of Cape Blanc was studied in February - March 1974 from aircraft and in September 1973 from Skylab. The aircraft study was designed to determine the effectiveness of a differential radiometer in quantifying surface chlorophyll concentrations. Photographic images of the S190A Multispectral Camera and the S190B Earth Terrain Camera from Skylab were used to study distributional patterns of suspended material and to locate ocean color boundaries. The thermal channel of the S192 Multispectral Scanner was used to map sea-surface temperature distributions offshore of Cape Blanc. Correlating ocean color changes with temperature gradients is an effective method of qualitatively estimating biological productivity in the upwelling region off Africa.

Szekielda, K. H.↗
NASA NTRS1975

Dynamics of plankton populations in upwelling areas

The author has identified the following significant results. Spectral properties of the upwelled waters off the NW coast of Africa were studied with observations derived from aircraft and Skylab. Results indicate that the two-channel, ratio approach is ineffective in determining surface chlorophyll concentrations. Ocean color boundaries and temperature gradients were found to be directly correlated with each other and also with fishing effort in the upwelling region. Photographic and scanner data derived from Skylab were effective in locating ocean boundaries and mapping temperature distributions.

Szekielda, K. H.↗
NASA NTRS1976

Soil, water, and vegetation conditions in south Texas

The author has identified the following significant results. Field spectral measurements and laboratory densitometric measurements showed that tree canopy reflectance differences among the Marrs, Redblush, and Valencia varieties in the visible spectral region were due to their different leaf chlorophyll concentrations. Field measurements of visible light reflectance were directly related to the tonal responses on infrared color photos of the varietal tree canopies. Consequently, densitometric measurements of the foliage on the infrared color transparency with red-filtered light successfully discriminated among the three varieties. Reflectance measurements with a field spectroradiometer on nine dates the growing season of two wheat varieties, Milam and Penjamo, documented their spectra over the 0.45 to 2.50 micron wavelength interval associated with plant cover and physiological development. An image analyzer system was used to optically planimeter the percentage of soil background, vegetation and shadow in the vertical photographs taken within the FOV of the spectroradiometer on each measurement date.

Wiegand, C. L.↗
NASA NTRS1978

An evaluation of the first four LANDSAT-D thematic mapper reflective sensors for monitoring vegetation: A comparison with other satellite sensor systems

The first four LANDSAT-D thematic mapper sensors were evaluated and compared to: the return beam vidicon (RBV) and multispectral scanners (MSS) sensors from LANDSATS 1, 2, and 3; Colvocoresses' proposed 'operational LANDSAT' three band system; and the French SPOT three band system using simulation/intergration techniques and in situ collected spectral reflectance data. Sensors were evaluated by their ability to discriminate vegetation biomass, chlorophyll concentration, and leaf water content. The thematic mapper and SPOT bands were found to be superior in a spectral resolution context to the other three sensor systems for vegetational applications. Significant improvements are expected for most vegetational analyses from LANDSAT-D thematic mapper and SPOT imagery over MSS and RBV imagery.

Tucker, C. J.↗
NASA NTRS1978

The Coastal Zone Color Scanner (CZCS) experiment

The CZCS is used to map chlorophyll concentration, sediment distribution, gelbstroffe concentration, and temperature of coastal waters and the open ocean. The data processing techniques used to enhance contrasts over the ocean and to remove the effect of the backscattered atmosphere are presented. The multi-channel scanning radiometer of CZCS is described. The content of water is determined primarily by the CZCS measurement.

Hovis, W.↗
NASA NTRS1979

A comparison of measured and calculated upwelling radiance over water as a function of sensor altitude

A comparison is made between remote sensing data measured over water at altitudes ranging from 30 m to 15.2 km and data calculated for corresponding altitudes using surface measurements and an atmospheric radiative transfer model. Data were acquired on June 22, 1978 in Lake Erie, a cloudless, calm, near haze free day. Suspended solids and chlorophyll concentrations were 0.59 + or - 0.02 mg/1 and 2.42 + or - 0.03 micrograms/1 respectively throughout the duration of the experiment. Remote sensor data were acquired by two multispectral scanners each having 10 bands between 410 nm and 1040 nm. Calculated and measured nadir radiances for altitudes of 152 m and 12.5 km agree to within 16% and 14% respectively. The variation in measured radiance with look angle was poorly simulated by the model. It was concluded that an accurate assessment of the source of error will require the inclusion in the analysis of the contributions made by the sea state and specular sky reflectance.

Coney, T. A.↗
NASA NTRS1978

A comparison of satellite sensor bands for vegetation monitoring

The first four Landsat-D thematic mapper sensor bands were evaluated and compared to the RBV and MSS sensors from Landsats-1, -2, and -3; Colvocoresses' proposed 'operational Landsat' three-band system; and the French SPOT three-band system by using simulation/integration techniques and in situ collected spectral reflectance data. Sensors were evaluated with regard to their ability to discriminate vegetation biomass, chlorophyll concentration, and leaf water content. The thematic mapper and SPOT bands were found to be superior in a spectral resolution context to the other three sensor systems for vegetational applications. Significant improvements are expected for most vegetational analyses from Landsat-D thematic mapper and SPOT imagery over MSS and RBV imagery.

Tucker, C. J.↗
NASA NTRS1979

A comparison of measured and calculated upwelling radiance over water as a function of sensor altitude

The present paper compares remote sensing data measured over water at altitudes ranging from 30 m to 15.2 km to data calculated for corresponding altitudes using surface measurements and an atmospheric radiative transfer model. The data were acquired on June 22, 1978 in Lake Erie and it was found that suspended solids and chlorophyll concentrations were 0.59 + or - 0.02 mg/liter and 2.42 + or - 0.03 micro gram/liter respectively throughout the duration of the experiment. Calculated and measured nadir radiances for altitudes of 152 m and 12.5 km agree to within 16% and 14% respectively. It is noted that the model offered a poor simulation of the variation in measured radiance with look angle. Finally, it is concluded that an accurate assessment of the source of error will require the inclusion in the analysis of the contributions made by the sea state and specular sky reflectance

Coney, T. A.↗
NASA NTRS1979

Remote sensing analysis of water quality and the entrapment zone in the San Francisco Bay and delta

The author has identified the following significant results. Data from an ocean color scanner flown on a U-2 aircraft at 65,000 ft and from LANDSAT MSS were enhanced to identify biologically active areas of San Francisco Bay, and to determine the salinity, turbidity, chlorophylls, and suspended solids. The best fit regression models for mapping water quality parameters were based on bands 3, 5, 7, and 10. Comparision of the results indicate that chlorophyll concentrations can best be estimated by the OCS or MSS data. Salinity can best be estimated by OCS data; turbidity can best be estimated by LANDSAT data. Neither OCS nor MSS data provide reliable basis for estimating suspended solids. Aerial photography of the highest quality taken with either conventional color or infrared-sensitive color films was unable to locate the biologically active areas.

Colwell, R. N.↗
NASA NTRS1978

A comparison between the first four thematic mapper reflective bands and other satellite sensor systems for vegetational monitoring

The first four Landsat-D thematic mapper sensors were evaluated and compared to the RBV and MSS sensors from Landsats-1, 2, and 3, Colvocoresses' proposed 'operational Landsat' three band system, and the French SPOT three band system using simulation/integration techniques and in situ collected spectral reflectance data. Sensors were evaluated by their ability to discriminate vegetation biomass, chlorophyll concentration, and leaf water content. The thematic mapper and SPOT bands were superior in a spectral resolution context to the other three sensor systems for vegetational applications. Significant improvements are expected for vegetational analyses from Landsat-D thematic mapper and SPOT imagery over MSS and RBV imagery.

Tucker, C. J.↗
NASA NTRS1981

Laser induced fluoroescence from algae: Results of a ship-borne field test

A basis is provided for the feasibility of air-borne laser fluorosensing not only of chlorophyll but also of pollutants such as oils and chemicals. There was a satisfactory correlation between the laser data and those obtained manually. The absolute determination of the chlorophyll concentration is discussed.

Hartmann, B.↗
NASA NTRS1981

Temporal relationships between spectral response and agronomic variables of a corn canopy

Attention is given to an experiment in which spectral radiance data collected in three spectral regions are related to corn canopy variables. The study extends the work of Tucker et al. (1979) in that more detailed measurements of corn canopy variables were made using quantitative techniques. Wet and dry green leaf biomass is considered along with the green leaf area index, chlorotic leaf biomass, chlorotic leaf area, and leaf water content. In addition, spectral data were collected with a hand-held radiometer having Landsat-D Thematic Mapper (TM) bands TM3 (0.63-0.69 micrometers), TM4 (0.76-0.90 micrometers), and TM5 (1.55-1.75 micrometers). TM3, TM4, and TM5 seem to be well situated spectrally for making remotely sensed measurements related to chlorophyll concentration, leaf density, and leaf water content.

Kimes, D. S.↗