3. Results: dust-free case   a. Horizontal mean fields
3.a.ii. Ground and surface temperature Figure 3c shows the time development of horizontal mean vertical profiles of ground temperature, surface temperature, and atmospheric temperature at about 1.5 m height. The diurnal change of ground temperature is localized almost within the diurnal skin depth from the surface. The amplitude of the diurnal change of surface temperature is about 100 K. The value of surface temperature in daytime can be estimated roughly by the balance between absorbed solar radiation and emitted infrared radiation at the surface. The diurnal changes of surface temperature and atmospheric temperature at about 1.5 m height are similar to those observed at the site of Viking Lander 1 ( Hess et al., 1997). Figure 3c: (Left panel) Diurnal change of the vertical profile of horizontal mean ground temperature of the dust-free case. Profiles are for every 4 hours from LT = 8:00 of the sixth day. Number on each line indicates local time. Vertical axis is normalized by the diurnal skin depth. (Right panel) Diurnal change of horizontal mean surface temperature (red line) and atmospheric temperature at about 1.5 m height (blue line) of the dust-free case.
A numerical simulation of thermal convection in the Martian lower atmosphere.