The infrared transmission of atmospheric windows

Abstract This paper describes an approach to the practical problem of infrared atmospheric transmission.It compares and relates published data from diverse investigations. The method separates water vapor band absorption, on which there appears to be general agreement, from the less tractable continuous attenuation by fog, haze, and smoke. This separation is effected by a smooth envelope curve drawn tangent to the principal maxima in the observed transmitted spectra.In each window, the monochromatic transmission at the window peak is shown to be representative of the effect of continuous absorption on the total transmission in the window region. A simple empirical relation is developed to represent the dependence of the band absorption on the water path for each window. The dependence of continuous attenuation upon the water path for clear atmosphere is described, and the effects of haze, fog, and smoke are very briefly discussed.