4. Results: dusty case   b. Horizontal mean fields
4.b.iv. Heat budget of atmosphere and surface Figure 12f shows the diurnal changes of horizontal mean heat budgets at the ground surface and the atmosphere of the dusty case. In each panel, the amount of net heating are almost equal to that of cooling. The amount of net solar radiative heating at the ground surface is smaller than that of the dust-free case (Figure 3e) This is caused by the absorption of solar radiation due to atmospheric dust. The amounts of net infrared radiative heating due to CO2 and sensible heating, which are the dominant contributers in driving convetion, are smaller than those of the dust-free case (Figure 3e). Sum of those reaches 20 Wm-2 during the day time. The reason for the decrease of CO2 infrared heating is the decrease of ground surface temperature. The amount of decrease is about the same order of magnitude of the decrease of 15 μm band infrared emission from the ground surface (i.e., several Wm-2). The reason for the decrease of sensible heating is the decrease of wind velocity associated with convection. The dominant component of net solar heating for the atmosphere is absorption of solar radiation due to dust. Its amount is almost equal to the decrease of net solar radiative flux at the ground surface from that of the dust-free case. Figure 12f: Diurnal changes of the horizontal mean heat budgets of the 6th day of the dusty case. Unit of the vertical axis is Wm-2. (Left panel) Heat budget at the ground surface. Blue line shows net solar radiative flux ((1-A)FSR), red line shows net infrared radiative flux (-FIR,net(0)), green line shows sensible heat flux (-H), and orange line shows the total amount of them. Positive sign indicates heating of the ground surface. (Right panel) Heat budget of the atmosphere. Blue line shows net solar (near infrared) radiative heating (FNIR(∞)- FNIR(0)), red line shows net infrared radiative heating (FIR,net(0)- FIR,net(∞)), green line shows sensible heating (H), purple line shows heating due to turbulent dissipation, and orange line shows the sum of net infrared radiative heating and sensible heating. Positive sign indicates heating of the atmosphere.
A numerical simulation of thermal convection in the Martian lower atmosphere.