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Deschamps, P. Y.

Publications and source records attributed to Deschamps, P. Y..

11 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Atmospheric effects on NOAA AVHRR data over Sahelian regions

Variable atmospheric conditions have a significant impact on satellite monitoring of vegetation in the Sahelian zone of Africa. The effects of atmospheric O3, H2O, and aerosols on spectral, directional reflectances and derived measures, such as the normalized difference vegetation index are discussed using a sensitivity study. An atmospheric correction scheme is presented based on measurements of optical thicknesses from the ground and is applied to NOAA AVHRR data. The use of the reflectance of the ocean surface close to the terrestrial target to estimate atmospheric effects on terrestrial reflectance is also discussed.

Soufflet, V.↗
NASA NTRS1990

Comparison of Surface Radiation Budget Satellite algorithms for downwelled shortwave irradiance with Wisconsin Fire/SRB surface-truth data

Surface radiation instruments were operated at various locations during the Wisconsin First ISSCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) and Surface Radiation Budget (SRB) experiment in October 1986. Satellite data were distributed to scientists who had previously developed satellite algorithms to estimate downwelled shortwave irradiance. Results of intercomparison of ground-truth values with the satellite-derived estimates are described.

Whitlock, C. H.↗
NASA NTRS1984

Calibration of TM data from ground-based measurements

Methods of calibrating Thematic Mapper (TM) data by the use of ground based measurements are presented. Applications of the TM remote sensing data are discussed in addition to the ground truth measurement equipment and techniques.

Rasool, S. I.↗
NASA NTRS1982

A simple method to compute the change in earth-atmosphere radiative balance due to a stratospheric aerosol layer

A computer code was developed in terms of a three-layer model for the earth-atmosphere system, using a two-stream approximation for the troposphere and stratosphere. The analysis was limited to variable atmosphere loading by solar radiation over an unperturbed section of the atmosphere. The scattering atmosphere above a Lambertian ground layer was considered in order to derive the planar albedo and the spherical albedo. Attention was given to the influence of the aerosol optical thickness in the stratosphere, the single scattering albedo and asymmetry factor, and the sublayer albedo. Calculations were performed of the zonal albedo and the planetary radiation balance, taking into account a stratospheric aerosol layer containing H2SO4 droplets and volcanic ash. The resulting ground temperature disturbance was computed using a Budyko (1969) climate model. Local decreases in the albedo in the summer were observed in high latitudes, implying a heating effect of the aerosol. An accompanying energy loss of 23-27 W/sq m was projected, which translates to surface temperature decreases of either 1.1 and 0.45 C, respectively, for background and volcanic aerosols.

Lenoble, J.↗
NASA NTRS1982

Sea surface temperature of the coastal zones of France

Thermal gradients in French coastal zones for the period of one year were mapped in order to enable a coherent study of certain oceanic features detectable by the variations in the sea surface temperature field and their evolution in time. The phenomena examined were mesoscale thermal features in the English Channel, the Bay of Biscay, and the northwestern Mediterranean; thermal gradients generated by French estuary systems; and diurnal heating in the sea surface layer. The investigation was based on Heat Capacity Mapping Mission imagery.

Deschamps, P. Y.↗
NASA NTRS1982

Climatic influence of background and volcanic stratosphere aerosol models

A simple modelization of the earth atmosphere system including tropospheric and stratospheric aerosols has been derived and tested. Analytical expressions are obtained for the albedo variation due to a thin stratospheric aerosol layer. Also outlined are the physical procedures and the respective influence of the main parameters: aerosol optical thickness, single scattering albedo and asymmetry factor, and sublayer albedo. The method is applied to compute the variation of the zonal and planetary albedos due to a stratospheric layer of background H2SO4 particles and of volcanic ash.

Deschamps, P. Y.↗
NASA NTRS1980

Sea surface temperature of the coastal zones of France

The results of an investigation to map the various thermal gradients in the coastal zones of France are presented. Paricular emphasis is given to the natural phenomena and man made thermal effluents. It is shown that a close correlation exist between wind speed direction and the offshore width of the effluent.

Deschamps, P. Y.↗
NASA NTRS1980

Sea surface temperature of the coastal zones of France

The various thermal gradients in the coastal zones of France were mapped with regard to natural phenomena and man made thermal effluents. The mesoscale thermal features of the English Channel, the Bay of Biscay, and the northwestern Mediterranean Sea were also studied. The evolution of the thermal gradients generated by the main estuaries of the French coastal zones was investigated along with the modeling of diurnal heating of the sea surface and its influence on the oceanic surface layers.

Deschamps, P. Y.↗
NASA NTRS1979

Sea surface temperature of the coastal zones of France. Heat Capacity Mapping Mission (HCMM)

The author has identified the following significant results. HCMM data analysis shows some mesoscale features which were previously expected to occur: summer coastal upwellings in the Gulf of Lions, tidal fronts bordering the English Channel, and cooler surface waters at the continental shelf break. The analysis of the spectral variance density spectra show that the interpretation of the data usually is limited by the HCMM radiometric performance (noise levels) at wavenumbers below 5 km in the oceanic areas; from this analysis it may also be concluded that a decrease of the radiometric noise level down to 0.1 k against an increase of the ground resolution up to 2 km would give a better optimum of the radiometric performances in the oceanic areas. HCMM data appear to be useful for analysis of the sea surface temperature field, particularly in the very coastal area by profiting from the ground resolution of 500 m.

Deschamps, P. Y.↗
NASA NTRS1977

Remote sensing of ocean color and detection of chlorophyll content

The chlorophyll enrichment of the water in an equatorial upwelling was surveyed and described with the aid of a radiometer specially designed for the airborne measurement of ocean color. A relation is proposed between airborne measurement of difference of albedos at two wavelengths in the blue and green, and the concentration of chlorophyll in the ocean.

Deschamps, P. Y.↗