FEATURES OF ENERGY BUDGET AND CONVERSION OF DEVELOPED AND UNDEVELOPED TROPICAL CYCLONE
Zhang Xiang and Deng Bing(Meteorotogical Observatory of South China Sea Naval Fleet, Zhanjiang,524001)
With two cases of local tropical disturbances in both developed and undeveloped phases, contributions to the genesis and development by kinetic formation and transfer from divergent and nondivergent winds are studied using energy budget equations. Computations are done of conversion kinetic energy between the two types of winds. The result indicates that the subgrid scale effect is the principal source of kinetic energy for a tropical cyclone to grow into a typhoon; the cumulus convection plays a dominant role, in company of relatively weaker contributions on vdrious phases of the life cycle by convergence of fluxes of divergent and nondivergent winds as well as the formation of kinetic energy by the former wind. It is also suggested that the conversion of kinetic energy between the divergent and nondivergent winds C(Kx, Kψ)is increasing with the development of disturbance mainly due to the contribution by. The disturbance is shown in the distribution of C(Kx,Kψ)to increase in a favorable anticyclonic outflow corresponding to the upper level where the conversion becomes negative in developing and mature phases while the wind velocity increases with enhanced conversion fr0m Kx to Kψ the lower level in association with the growth of the disturbance. In addition,geopotential energy P converts to kinetic energy of the divergent wind in every stage from formation to mature of the disturbance by means of C(P, Kx), the maximum appearing on the middle and upper layers of the troposphere.The intensity of C(P, Kx) is consistently in phase with variation of C(Kx,Kψ).