Transient variation of martian ground-atmosphere thermal boundary layer structure.

Results of a numerical simulation of the diurnal redistribution of temperature by radiative and molecular-conductive processes in the Martian soil-atmosphere system. An attempt is made to assess the importance of atmospheric molecular conduction near the surface and to estimate the characteristic depth of the diurnal temperature wave. The computational results are found to indicate a dual structure in the diurnal temperature wave propagation pattern, with a diffusive-type wave in the lowest 150 m superimposed on a radiatively induced disturbance with a characteristic scale of 1.8 km. Atmospheric molecular thermal conduction typically accounts for about 15% of the total heating/cooling in the lowest 25 m. Thermal conduction in both the soil and atmosphere appears to be an important factor in the thermal coupling of these subsystems. A free-convection regime in the conduction layer is predicted by the model for about five hours of the Martian day.