西北区东部一次暴雨的数值模拟试验

运用双向嵌套的中尺度数值预报模式MM5，对1998年7月上旬西北区东部一次暴雨过程进行了高分辨率数值模拟和敏感性试验。结果表明，该模式能较好地模拟这次暴雨过程，对这次暴雨过程相关的中尺度系统的发生发展也作出了较成功的模拟；大尺度及积云对流尺度的凝结潜热在降水过程中是一个主要因子，潜热释放将加热中高层大气，促使高层大气辐散，低层辐合，垂直运动加强，导致较大的降水；初始时刻不同地区低层大气水汽含量的多寡直接对本次暴雨产生影响，并为这次暴雨提供了水汽源；地面水汽和感热的垂直输送为暴雨的发生发展补充了能量。

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.