Numerical Simulation Experiment of Torrential Rain Event in East of North-West China

Using the two way nested grid mesoscale model (MM5), the torrential rain event east of north west China on the first ten days of July in 1998 is simulated, and a series of sensitive experiments are carried out. It is shown that the MM5 model can successfully simulate the torrential rain and the development of the mesoscale system which related to the torrential rain; the latent heating of large scale and cumulus convection scale is a main factor in the precipitation event, latent heat release will lead to the high level atmosphere divergence and the low level atmosphere convergence, and enhance the vertical motion, and result in the heavy rain; the low level vapor content in different regions at initial time directly affects on the torrential rain, and it is the vapor source of the torrential rain; the vertical transportation of surface vapor and sensible heat supplies the development of the torrential rain with the energy.