THE CONVECTIVE INSTABILITY OF THE INERTIAL WAVE AND THE PHYSICAL ANALYSIS OF THE FORMATION OF THE TYPHOON IN EARLY STAGE

The purpose of the present paper is mainly to discuss whether the non-thermal wind adjusts itself towards the thermal wind equilibrium state or not in the low latitudes.If the atmosphere is situated in conditionary unstable state,i.c.γγm,and the watervapour is saturated,the adjusting process of the thermal wind is entirely different from that discussed in 11.Initially,if the thecmal wind vorticity of wind field is larger than that of the temperature field,and the horizontal scale of the disturbance is smaller than L0 (the characteristic scale of the adjusting process),the connective instability of the inertial wave will occur.In this condition,the thermal wind equilibrium state will never be reached and the ascending motion induced by the adjusting process will be accelerated continuously.This instability of inertial wave may rapidly result in a violent vortex,with an anticyclone on 250 mb level,a cyclone on 750 mb level and a warm tenter in temperature field.This structure is the same as the typhoon.Besides,the physical and the dynamical essence of the starting mechanism of the formation of the typhoon is also discussed.It may be approximately considered that the typhoon is formed within the inherent unity of the destruction and the formation of the thermal wind equilibrium.If there exists the mechanism that may produce non-thermal wind,with the thermal wind votticity in wind field larger than that in temperature field,then a rapid development of the large scale vortex through the instability of the inertial wave will be induced.This is a mechanism of the initiation of the typhoons.