STUDY OF ATMOSPHERIC CONSTITUENTS AND STRUCTURE BY MEASUREMENT OF TRANSMISSION AND ABSORPTION OF MILLIMETER WAVES OF RADIOASTRONOMICAL ORIGIN.

摘要

It has been proposed that the vertical temperature structure of the troposphere may be measured by observing the emission from the wing of the 5mm band of atmospheric oxygen. The present study was initiated in an attempt to discover whether such a procedure is indeed practical. A radiometer which can be tuned over the range 50 - 60MHz has been constructed and tested. The radiometer is at present capable of measuring the zenith sky brightness at between 4and 6wavelengths in one hour with a precision of about 0.3K at each wavelength. A computer program has been developed for predicting the zenith brightness temperature and for ultimately inverting the measurements to obtain the atmospheric temperature profile. Replacing the Fredholm integral equation by an approximate set of algebraic equations is known to be an unstable procedure,and it is found that measurement precision of the order of 0.1K is required for that technique to work at all. It is noted that a technique such as that suggested by Westwater (1965) will probably work with the measurement precision that is available with the present instrument. (Author)