A further experiment on two-dimensional decaying turbulence on a rotating sphere

A series of numerical experiments on the two-dimensional decaying turbulenc e is performed for a non-divergent barotropic fluid on a rotating sphere by using a high-resolution spectral model. Time variations of the energy spec trum and the flow field are highly dependent on the rotation rate. In non-r otational cases, isolated coherent vortices emerge in the course of time de velopment as in the planar two-dimensional turbulence. As the rotation rate increases, however, the evolution of the flow field changes drastically, a nd a westward circumpolar vortex appears in high-latitudes as well as zonal band structures in mid- and low-latitudes. The dependence of these feature s on the initial energy spectrum is investigated and the dynamics of such p attern formations is discussed.