Microwave absorption in the earth's atmosphere

Abstract

In this paper the microwave absorption has been calculated for different layers of the earth's atmosphere around peak resonance frequencies for each constituent gas. The total absorption for the whole atmosphere is then obtained. For such calculations, it is necessary to know the peak absorption at the centre of the absorption line and its half-width. It has been shown that for atmospheric gases the peak absorption is pressure-independent and that it varies as (3 − x) th power of absolute temperature for diatomic (O 2) and linear polyatomic (N 2O) molecules and as ( 7 2 − x) th power of absolute temperature for symmetric (H 2O) and asymmetric top (O 3) molecules. The half-widths of the absorption lines have been calculated after assuming the temperature from ARDC Model Atmosphere and the vertical distribution of atmospheric constituents as given by Miller. Three sets of curves are also presented whereby the amount of absorption at an operating frequency can be calculated for different atmospheric layers.