利用MM5V3.6模式对2004年5月29~30日发生在贵州地区的一次暴雨过程进行了模拟, 模拟结果与实况基本一致。在此基础上, 用模拟结果对强降水的流场以及不稳定机制等进行了诊断分析, 以解释强降水发生的物理机制。结果表明, 这次降水是由多种尺度系统相互作用, 高、低层环流配置以及高空急流位置的变化等共同作用产生的; 高层辐散区发展、低层辐合加强, 形成"抽气机"效应, 低层正涡度和高层负涡度加强, 垂直涡度发展, 激发出次级环流; 对不稳定性的分析表明, 降水开始为对流不稳定能量触发, 降水加强后对流不稳定层次降低, 对流不稳定能量减弱; 中层锋区附近θe面陡立, 有倾斜涡度发展, 继而中层锋区条件性对称不稳定能量发展, 降水加强。

A intensive rainstorm in Guizhou Province from 29 to 30 May 2004 is simulated with MM5V3. 6, their results which are almost in agreement with the observed one are used to study the circulation and unsteady energe in this event. The study shows that the event occurs due to interaction between systems at multiple scales, it is linked to meso-systems, the coupling of upper and lower-level circulations, the changing of high jet etc. Analyses of these results show that the low-level convergence combined with high-level divergence produces "pumping effct". Analysis of unsteady energy condition reveals that the mechanism for the precipitation is thanks to CUE triggering, the development of low-level positive and high-level negative vortivicy, the establishment of θ_e around the mid-level frontal zone leads to a secondary circulation where slantwise vorticity is developing, triggers the mid-level front conditional symmetrical instability development, thus enhancing rainfall.