Numerical Experiment of Radiative-Convective Equilibrium of the Martian Atmosphere

Abstract

Temperature distributions and its diurnal changes in the Martian atmosphere are computed numerically under a radiative-convective equilibrium. Especially, the green house effect of H2O having the amount obtained by the recent observations, and “dry-ice theory” about the polar cap are investigated. The effects of solar radiation, infrared radiation, sensible heat and conductive heat from the ground are included in this computation. It is assumed that carbon dioxide (83m-STP) and a small quantity of water vapour (35 micron precipitable water) are the radiating gases in the model atmosphere that has a surface pressure of 6.1mb. The model atmosphere is divided into 15 layers with height increment of 2km between the surface and 30km altitudes. The main results indicate that
1) the green house effect of H2O cannot be neglected at the nighttime near the ground;
2) at the nighttime the temperature inversion appears near the ground, and isothermal layer below 6 km except 85°N in summer season;
3) the tropopause-like level may reach 16 km at equatorial equinox, and 10km 42°S in winter and 85°N in summer.
Production rate of solid-CO2 is estimated basing upon the results of temperature structure
and change.
The main results imply that
4) at the winter edge of the polar cap, the solid-CO2 may be produced in the early morning, and an opinion that the Martian North Polar Cap in summer may be composed of CO2 is not supported.