GRAPES与MM5模式对重庆特大暴雨的模拟预报对比分析

利用中国气象局的中尺度模式GRAPES和美国国家大气研究中心的MM5模式,对2004年9月初发生在重庆地区的特大暴雨过程进行了模拟预报。结果表明,GRAPES和MM5模式都较成功的预报出了此次降水过程。但是在降水中心的分布以及降水量级上与实况仍有一定程度的差异,GRAPES模式模拟出的总体落区略优于MM5,而MM5对降水量级的预报好于GRAPES。通过对环流形势的分析发现,MM5预报的垂直速度大于GRAPES的预报结果,这可能是导致降水量级差别的原因之一;通过对模式结果的初步诊断分析发现,两个模式对不稳定条件的模拟结果影响了他们对落区的预报结果。

Simulation and Analysis of Heavy Rainfall Case in Chongqing with GRAPES and MM5

GRAPES and MM5 models are used to simulate and predict the heavy rainfall process in Chongqing in September 2004.The result shows that both models can predict the rainfall development successfully,but there are certain differences between observation and simulated center location and magnitude of rainfall.The rainfall spatial distribution simulated by GRAPES is better than that simulated by MM5.However,the maximum values of the precipitation center are much less than the results of MM5.It is noted that the vertical velocity simulated by MM5 is higher than that simulated by GRAPES through analysis of the general circulation,which may cause the difference in the rainfall magnitude.Through the preliminary diagnostic analysis of simulation,it can be found that the simulation for conditional instability has impact on the spatial distribution prediction for both models.