Numerical Study on Votex Rossby-Waves Propagation and Typhoon Tangential Velocity Changes

A semi spectral model of a quasi geostrophic barotropic vorticity equation on a f plane with high resolution is designed in order to investigate the effects of nonlinear on typhoon tangential wind changes and the vortex Rossby wavespropagation characteristics in the circulation of typhoon and the mean flow changes under variable initial disturbances.The results show that the nonlinear weakens the acceleration of typhoon tangential velocity and probably thrinks the maximum wind radius.The location of initial disturbance center exerts a significant influences on vortex Rossby waves propagation and basic flow changes.The largest increase in the maximum azimuthal mean tangential velocity occurs when the convective patch is placed at the radius of maximum wind,in contrast the deceleration occurs when initial a symmetry in outside the region.The smaller convective patch corresponds to slight changes of maximum mean wind speed.The convective patch outside the region of typhoon circulation subtracts the influences of the convective patch at or near eyewall on typhoon maximum tangential velocity.