GLOBAL SURVEY OF ATMOSPHERIC TRACE AND POLLUTANT MOLECULES

Abstract

A global survey of pollutants and trace constituents in the atmosphere yields vital information as to their distribution and cyclic history. The type of instrument used for this purpose from a satellite must be basically a survey or nonspecific type in order to detect various molecular species. Also the response time of the instrument must be fast enought so that the smear due to the orbital motion of the satellite will be significantly small. A high speed interferometer operating in the 1--5 micron region with a resolution of $0.15 cm^{-1}$ can best meet these requirements. The outgoing radiance in this spectral region is entirely dominated by solar radiation reflected from the ground or from clouds. Also this region contains the majority of the useful vibrational bands of molecules. These bands are mainly overtone or combination bands and are weaker than the fundamentals which are usually found at wavelengths greater than 5 microns. However, in terms of minimum detectable concentrations, this factor is more than offset by the very much greater spectral power density difference to be detected, which is characteristic of the shorter wavelength reflection region.