Accession Number : ADA113142

Title :   A Ground Truth Analysis of DMSP Water Vapor Radiances.

Descriptive Note : Final rept.,

Corporate Author : AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Personal Author(s) : Valovcin,Francis R

PDF Url : ADA113142

Report Date : 03 Nov 1981

Pagination or Media Count : 46

Abstract : SSH H2O data from the Defense Meteorological Satellite Program (DMSP) were received for analysis and evaluation. Approximately 70 measurements of upwelling radiation in the 8-sounder channels of the 18 to 30 micron rotational water vapor band have been compared with calculations for both clear and cloud contaminated conditions. The calculated radiances generally exceed the measured radiances in the clear column comparison. In the mean, the radiance comparison indicates a discrepancy less than 5 percent in the water vapor continuum band. This systematic discrepancy, by approximately a 4:1 ratio, is found in all the DMSP SSH H2O channels. These results are in agreement with McClatchey's 1976 results in his analysis of the DMSP 15 micron CO2 sounder channels. The data sets comparison were divided into three latitude belts, that is, Tropical, Mid-latitude and Arctic. In turn, the discrepancies between calculated and measured radiances appear to be latitudinally dependent. Smaller discrepancies are found in the Tropics and the larger discrepancies are found in the Arctic latitude belt. Also, it appears that the DMSP SSH H2O channels cannot discriminate between low cloud contamination and clear column conditions.

Descriptors :   *SURFACE TRUTH, *METEOROLOGICAL SATELLITES, *REMOTE DETECTORS, *WATER VAPOR, RADIANCE, BAND SPECTRA, MEASUREMENT, COMPUTATIONS, COMPARISON, LATITUDE, ARCTIC REGIONS, TEMPERATE REGIONS, CLOUDS, CLEAR WEATHER, DISCRIMINATION

Subject Categories : Atmospheric Physics
      Meteorology
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE