Simulations of Atmospheric General Circulations of Earth-like Planets by AFES

For the purpose of acquiring insights into the physical processes characterizing dynamical structures of general circulations of the planetary atmospheres, high resolution simulations of the Martian global atmosphere and the aqua-planet atmosphere which is an abstraction of the Earth's atmosphere have been performed by using GCMs (General Circulation Model) based on the AFES (Atmospheric GCM for the Earth Simulator) as a common dynamical core. In addition, we have developed a physical process module for simulating the Venus atmosphere and performed a preliminary calculation. The results of the Mars simulation with the horizontal resolution of T319 demonstrate a clear frontal structure associated with baroclinic waves, and a number of small and medium scale disturbances including medium scale vortices generated in the vicinity of high mountains. As for the aqua-planet simulation, calculations are performed with and without cumulus parameterization. The results of both cases indicate spontaneous appearance of hierarchical structures in the activities of equatorial precipitation. Analysis of these structures implies that Kelvin wave-CISK (Conditional Instability of the Second Kind) would play a role in organizing precipitation activities. A result of preliminary Venus simulation confirms the importance of thermal tides in maintaining the superrotation. This result is consistent with the results of the previous studies obtained by using linear models.