A simple formulation of oxygen absorption at centimeter wavelengths

Carefully performed experiments by a number of investigators have supported the Van Vleck line shape theory for oxygen absorption in the lower-frequency wing (0–50 GHz). In view of the frequent need to compute oxygen absorption at centimeter wavelengths and lower a computationally simple fourline absorption model based on the Van Vleck theory is offered. The approximation yields computational accuracy better than 1% over the entire range of atmospheric pressures and temperatures for frequencies less than 30 GHz when it is compared with the Van Vleck 45-line expression. The versatility of the model in adapting to various line-broadening expressions is also shown. Instead of refining the present theories, this communication is mainly intended to propose a more convenient formulation to compute oxygen absorption.