一次梅雨锋暴雨过程的中尺度对比模拟分析

CONTRASTING ANALYSIS SIMULATION OF A MEIYU FRONT STORM RAINFALL PROCESS

使用新一代细网格WRF中尺度数值模式和MM5(V3)模式,对2003年7月4～6日发生在江淮流域的一次梅雨锋暴雨过程进行了数值模拟对比分析.结果表明:WRF和MM5都能较好的模拟这次暴雨过程雨带的分布和走向,而WRF能更好的模拟降水中心的位置和雨量;与暴雨过程相联系的低空急流和涡度场等分布特征的模拟,WRF模式亦优于MM5模式.此外,在云贵高原东麓山地,与WRF模式相比,MM5模式在低层模拟出虚假的低压环流,这可能与两模式所采用的垂直坐标差异有关.对WRF的模拟结果分析发现,700 hPa湿位涡异常区与暴雨发生区对应很好.

Numerical simulation of a Mei-yu front storm rainfall which occurred in Jianghuai area on July 4-6,2003 was given, using the new generation fine grid mesoscale numerical model named WRF and the MM5（V3） numerical model respectively. Results indicate that WRF and MM5 both can imitate distribution and tendency of the rain belt of this storm rainfall course. And WRF can imitate the location and amount of the precipitation center better. Furthermore,WRF＇s simulating result of distributing character of circulation pattern, lowlevel-jet and eddy field are better than MM5＇s. Contrasting with the dynamical frame of the two model, MM5 simulates an illusive circulation at east of Yun-gui tableland which ought to have relation to the difference of the vertical coordinate of the two models. Analyzing WRF＇s simulating result,we find that the area with negative 700 hPa moisture potential vorticity is well corresponding with rainstorm area.