Accession Number : AD0681915

Title :   STUDIES OF ATMOSPHERIC WATER VAPOR BY MEANS OF PASSIVE MICROWAVE TECHNIQUES.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS

Personal Author(s) : Gaut,Norman E.

Report Date : 20 DEC 1968

Pagination or Media Count : 108

Abstract : Expressions describing the absorption by water vapor near its two lowest rotational spectral lines (22.235 GHz and 183.310 GHz) were developed. These expressions are used to investigate the absorption from model and real atmospheres. Absorption measurements taken near the lower frequency line are compared with computed spectra based on data from simultaneous nearby radiosonde ascents. Comparable spectra occur only on days of high static stability. The spectral spike which excessive stratospheric water vapor might produce was searched for, but not found, in the observed absorption data. Under reasonable assumptions about the distribution of water vapor in the stratosphere, this result follows. A method for determining integrated water using zenith opacity at several frequencies has been derived and evaluated. Estimations within plus or minus 5% of the true values are consistently obtainable. Finally, the statistical scheme of C. D. Rodgers (Clarendon Laboratory) for inverting spectral data in order to obtain the vertical distribution of water vapor has been evaluated for 34 radiosondes from Boston and vicinity. The procedure is shown to be stable against a variety of errors in the data and statistical assumptions. (Author)

Descriptors :   (*ATMOSPHERES, WATER VAPOR), (*WATER VAPOR, *RADIOFREQUENCY SPECTROSCOPY), ABSORPTION SPECTRA, MICROWAVES, LINE SPECTRA, RADIOSONDES, STRATOSPHERE, EMISSIVITY, ATTENUATION, SOLAR RADIATION, DISTRIBUTION, WEATHER FORECASTING, MATHEMATICAL ANALYSIS, PREDICTIONS, BRIGHTNESS, THESES

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE