Absorption by the tails of the oxygen microwave resonances at atmospheric pressures

A variety of methods axe available for calculating atmospheric absorption of microwaves and millimeter waves by oxygen resonances. We compare these methods for the absorption by the tails of the 60 GHz band, the line at 118.75 GHz, and the nonresonant oxygen absorption. For practical, atmospheric calculations the tails of the 60 GHz band consist of frequencies less than 48 GHz and greater than 71 GHz. Gordon's method is selected as being the simplest and most reliable for calculating the absorption by the tails of the 60 GHz band. The interference parameter of the 118.75 GHz line can be chosen such that its high-frequency tail approaches zero as frequency increases.