Dissipation in Atmospheres: The Thermal Structure of the Martian Lower Atmosphere With and Without Viscous Dissipation

Abstract

The energy relationships for an atmosphere are reviewed and it is pointed out that the role of viscous dissipation can be examined from either a mechanical or a thermodynamic point of view. An entropy integral is derived which represents a constraint on the thermal structure of an atmosphere in the case of zero viscous dissipation. The size of dissipation in actual atmospheres is not very well known. Calculations of thermal structure are performed for the Martian atmosphere, with the results depending greatly on whether high or low dissipation is assumed; better information, therefore, is highly desirable. In the case of low dissipation, the Martian tropopause is high and cold; so cold that C02 clouds form.