2010年6月江西省特大暴雨数值模拟及湿位涡分析

A Numerical Simulation and Moist Potential Vorticity Analysis on Heavy Rainfall Event in Jiangxi Province During June 2010

为了探讨特大暴雨的形成机制,提高暴雨预报能力,采用常规报文资料作为初始场,运用中尺度暴雨模式,对2010年6月19~20日的江西省一次特大暴雨过程进行了数值模拟和湿位涡（MPV）分析。结果表明,此次特大暴雨是一次典型的梅雨锋暴雨,华北低涡后冷空气与强盛稳定的副高西北侧西南暖湿空气汇合,导致梅雨锋在江南北部稳定少动;中尺度暴雨模式对降水场模拟结果同实况基本接近,模式对暴雨的位置、强度、中心都有较好的模拟;湿位涡的分布对梅雨锋暴雨的发生、落区有较强的指示性作用。

Based on the conventional ground observational data,a numerical simulation and moist potential vorticity（MPV） analysis was carried on heavy rainfall event over Jiangxi province from 19 June to 20 June 2010,with a meso-scale rainstorm model.The results showed that this rare rainstorm was a typical heavy rainfall over Meiyu front.The cold air flow behind north China vortex joined up the southwestern flow located in the northwest part of the strong and stable subtropical high,thus the cold air and warm air converged and maintained over the northern part of Hunan and Jiangxi province.The simulated precipitation of the high resolution model is very similar to the observational rainfall.The model has a good predictive skill for the location,intensity and center of heavy rainfall.By moist potential vorticity analysis,it was found that the distribution characteristic of MPV had an obvious indication for the occurrence of heavy rainfall and for precipitation forecast.