“07．6”广西柳州极端暴雨过程的多尺度特征分析

Multi-scale Characteristics Analysis of Liuzhou Server Heavy Rainfall in June,2007

利用NCEP1°×1°再分析资料、常规观测资料、自动站、雷达及FY-2C卫星资料,分析了2007年6月12—13日广西柳州极端暴雨过程的多尺度特征,并探讨了此次暴雨过程的成因。结果显示:500hPa高原东侧的低槽引导冷空气南下,地面准静止锋南移进入广西境内,在地面形成锋面低槽的形势。暴雨发生在850hPa低涡切变线上,暴雨中心与β中尺度低涡扰动有很好的对应关系。这次过程的主要降水系统是南部的对流云团和锋面附近的中尺度对流复合体(MCC)。柳州极端暴雨由两个雨团造成,其中一个雨团强度大,持续时间长,这与强降水回波的列车效应和地面中尺度辐合线有关,是柳州高强度降水得以长时间维持的主要原因。

Based on multiple meteorological data, including NCEP 1°× 1° reanalysis data, routineobservational data, automatic weather station data, Doppler radar data and FY-2C satellite TBB data, the multi-scale characteristic of the server heavy rain happened in Liuzhou during 12 - 13 June 2007 was analyzed and its mechanism was also discussed. The results show that： because of the guidance function of east plateau low trough on 500hPa, the cold air gone south. The quasistationary front moved from Guizhou to Guangxi and ＂the front-low trough situation＂ formed at ground surface. The heavy rain developed in the 850hPa low trough, the center of heavy rain had a better relation to the meso-β-scale low vortex disturbance. The precipitation systems were the convective cloud clusters from south Guangxi and MCC near the frontal surface. Liuzhou heavy precipitation was created by two rain clusters. Because of the train effect of precipitation echo and ground mesoscale shear line, one of rain clusters had heavy intensity and long persistent time, this was a main reason which Liuzhou server heavy rainfall produced.