A Diagnosis and Simulation Study of a Strong Heavy Rainfall in South China
一次罕见的华南大暴雨过程的 诊断与数值模拟研究

Heavy rainfalls occurred in South China in the mid June of 1994. In this paper, a diagnostic study and numerical simulations using MM5 developed by PSU/NCAR have been conducted. The results of diagnosis show that there is enough moisture in the southeast and southwest parts of China, but the heavy rainfalls in Guangxi are severer than other areas, so the heavy rainfalls in Guangxi may be caused by terrain or other factors. The strong cloud clusters are the main mesoscale systems that cause heavy rainfalls in Guangxi. The results of simulations indicate the numerical model can successfully simulate the case, the hydrostatic scheme is better than nonhydrostatic scheme in simulating large scale rainband; on the contrary, in reproducing the maximum centers of heavy rainfalls the opposite is true. The simulation experiments on convective parameterization schemes indicated Kuo scheme can simulate the large scale area of rainfalls well and Grell scheme is better than Kuo scheme in simulating the centers of heavy rainfalls. In addition, the results also show that the PBL process could not be neglected in simulating severe strong rainfalls.