On the water vapour absorption in the 8?13 ?m spectral region for different atmospheric conditions

Abstract

Experimental measurements of the absorption coefficient of atmospheric water vapour, at wavelengths between 8 and 13 μm, are examined on the basis of atmospheric models describing the meteorological conditions of the observed atmospheres to obtain estimates of the foreign-broadening absorption coefficient for homogeneous paths. The results show that the variable contribution given by unresolved lines predominates on the continuum term due to wing effects of remote lines, even for rather high spectral resolutions. Associated with estimates of the self-broadening absorption coefficient, as proposed byRoberts et al. (1976), these data are applied to a wide set of atmospheric models, corresponding to various latitudes and seasons, indicating that the two components of the atmospheric absorption coefficient are closely related to the surface temperature. Because of the variable weights given by foreign- and self-broadening terms, the atmospheric absorption coefficient turns out to increase with the surface temperature with different rates at various wavelengths.