Accession Number : AD0689033

Title :   AN ON-BOARD TECHNIQUE FOR ESTIMATING THE EFFECT OF WATER VAPOR IN RADIO OCCULTATION MEASUREMENTS OF ATMOSPHERIC DENSITY,

Corporate Author : BOEING SCIENTIFIC RESEARCH LABS SEATTLE WASH GEO-ASTRO PHYSICS LAB

Personal Author(s) : Tank,William G.

Report Date : FEB 1969

Pagination or Media Count : 31

Abstract : S-band phase path measured between two earth satellites - one in an occultation orbit relative to the other - determines the integrated radio refractivity of the neutral earth atmosphere. Atmospheric density is recoverable from such determinations provided an independent estimate of the contribution of water vapor to integrated refractivity is obtained. Transmission measurements in the vicinity of the 22.235 GHz resonant water vapor absorption line provide this estimate. The data so acquired, moreover, relate to the atmospheric water vapor content integrated precisely over the paths of the phase path measurements. Performed optimally at the frequency of minimum dependence on line width of the water vapor absorption coefficient, the transmission measurement would provide the water vapor estimate to an accuracy of about fifteen per cent; this would result in nearly a tenfold increase in the accuracy of the density data ultimately recovered from the phase path measurements. Phase path could be measured at the optimum frequency for the transmission measurement. A single-frequency system could thus provide all the information necessary for the enhanced density data from the occultation experiment. The satellite system providing such data over regions of the globe lacking standard meteorological observation facilities would constitute a valuable adjunct to the ESSA series of weather satellites. (Author)

Descriptors :   (*RADIO TRANSMISSION, ATMOSPHERES), (*ATMOSPHERES, DENSITY), WATER VAPOR, S BAND, PHASE MEASUREMENT, REFRACTION, ABSORPTION, METEOROLOGICAL SATELLITES, NETWORKS, MATHEMATICAL ANALYSIS

Subject Categories : Atmospheric Physics
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE