A PRELIMINARY STUDY ON EFFECTS OF THREE KINDS OF PHYSICAL PROCESSES ON TYPHOON INTENSITY CHANGES

The quasigeost rophic barotropical vonticity equation models in the cylindrical and the Cartesion coodinate systems are designed,with the radial or horizdmal space being 2 km respectively.By using them,eightexperiments are performed in order to investigate the effects of three kinds of physical processes including the linear azimuthal advection,the linear radial advection and the nonlinear advection on the vorticity radially propagating to the near coreregion and typhoon intensity changes.Results show that the azimuthal advection can result in the formation of a spiral vorticity zone,that the radial advection can make the vorticity propagation of the mesoscale vort exlocated in the out sideregion initially to the inside core,that in the condition of stationary typhoon circulation the nonlinear advection of the perturbational vorticity can increase the inward propagating vorticity and intensify the typhoon vortex obvioursly,and that in the case of nonstationary typhoon circulation,on the one hand,the nonlinear advection can also increase the inward vorticity,on the other hand,it may distort the initial symmetric structure of the typhoon exhibiting the complex flow pattern which is able to resist the typhoon intensification.Finally we discuss the possible application of these results to typhoon intensity prediction.