Dynamic studies on the role of baroclinic processes in tropical cyclone movement

Using the primitive equations for adiabatic, no-friction,and noenvironment action,the counterbalances of tropical cyclone(TC) are studied. We obtained the parameter, dI/dt,and its equilibrium equation, describing the intensit y changes of TC. Then we discussed the characteristics of TC motion and int ensity change in barotropic and barclinic model. The results show that, the stationary movement of TC is governed by equivalent-geostrophic balance, t he isolines of potential vorticity and E (E = phi + ( u(2) + v(2))/2) coinc ide with streamline. The TC intensity will weaken owing to the ventilation flow in beta (beta) gyres and shear gyres created by positive( negative) wi nd vertical shear in high-(low-) level. The positive (negative) vertical ad vection of the vorticity at high-(low-) level will strengthen the TC intens ity. Generally, the TC center will move toward the polar region and toward the gradient direction of the vertical advection of high-( low-) level vort icity. Moreover, the asymmetry of vertical velocity and vertical wind shear will affect the TC motion. The gamma effect (gamma =partial derivative bet a/partial derivativey) is one of the dynamic mechanism of TC steered by the ventilation flow in beta gyres and wind shear gyres.