A nondivergent barotropic vorticity equation on the sphere is solved by the spectral method (T42) to examine the differences of the nature of energy dipersion of initial vortices and thermal forcings in various shapes. The results show that the differences vary with the structures of zonal flows. When the zonal flows are zero or westerly,the differeces in the direction,velocity and intensity of propagation of energy are significant for various initial vortices and thermal forcings. However,there is lack of meridional dispersions in a hemispheric domain and the energy mainly propagates eastwords. While easterly zonal flows exist,the differences are just those in intensity and longer wavelenths propagate polewards as well as eastwards,shorter ones propagate southwards as well as eastwards.Above linear results agree well with the Ray Trace Theory. The nonlinear term can increase dispersion intensity on the poleward flank and decrease their intensity or scale on the equator flank of heating anomalies from the calculation of nonlinear model.