Experimental Transmission Functions for the Pure Rotation Band of Water Vapor*

Abstract

Experimental transmission data are given for mixtures of water vapor and nitrogen for the 20- to 50-μ region of the pure rotation band of water vapor. These data yield a set of transmission functions for 50 cm−1 intervals in agreement with a theoretical curve of Benedict. Average transmission is plotted as a function of the parameter U=WP*, in which W is the vapor optical path in precipitable centimeters and P* an effective pressure. This effective pressure is the sum of the total pressure and the water vapor partial pressure multiplied by a variable self-broadening factor. For meteorological purposes the self-broadening may be omitted. The set of transmission functions in turn yields a generalized absorption coefficient for the region.