Comments on the Infrared Absorption Line Formation in Cloudy Planetary Atmospheres

Abstract

It is proposed, for the interpretation of infrared absorption spectra carrying information of a planetary atmosphere and the condensing clouds, that the following three conditions must be considered: 1) the exchange of the cloud constituents with overlying clear gas due to convective mixing; 2) the partition of constituent gases between the gaseous and the condensed phases, and that with respect to the cloud phase change; and 3) the loss of signal-giving molecules in the condensed phase due to dissociation. In the Venus atmosphere, the presently available data suggest that the line formations of HCl and HF occur in the overlying clear layer if the condensate phase is liquid, and in the light-scattering cloud if the condensate is ice.