7. The dust-free case: feature of convection 

The calculated thermal convection is a km-size convection. 
The vertical and horizontal scales of convective cells are 10 km and several km.

The value of convective wind velocity often exceeds 20 m/sec.
The magnitude of the wind velocity is well understood by the estimation that the work done by the buoyancy force is converted to the kinetic energy.

Fig.3: Distributions of potential temperature deviation from the horizontal mean (upper left), turbulent diffusion coefficient (lower left), vertical 
and horizontal winds (upper right and lower right) at LT = 14:00 under dust-free condition. The contour intervals are 5 m/sec for wind velocity.