对2005年盛夏十堰市一次连续强降水天气过程的分析

Analysis on Continuous Severe Precipitation Process in Midsummer of 2005 in Shiyan

使用2005年8月14～23日各层(850、700、500 hPa等)天气图资料,以及有关物理量场资料、雷达回波资料和卫星云图资料,采取天气诊断分析方法,对2005年盛夏十堰市一次连续强降水天气过程进行了分析。结果表明:此次过程是在西太平洋副热带高压、"珊瑚"台风、东南急流、南支低槽、中低层低涡切变线等系统共同影响下形成的;贝加尔湖低槽持续分裂冷空气与副热带高压边缘暖湿气流对峙是该过程能够维持的基本条件;短带状强回波与新生的强对流窄回波带相叠加并维持较长时间,中-β尺度云团在本地发展为中-α尺度云团且受地形作用维持近5 h,使得灾情更趋严重。

Using the synoptic charts of different layers （850hPa, 700hPa, 500hPa, etc）, the relevant physical field data, the radar echo data and the satellite nephogram data, the continuous severe precipitation process in midsummer of 2005 in Shiyan is analyzed by synoptic diagnostic method. The results show that the event is caused by the combined interaction of several weather systems, such as the West Pacific sub-tropical high, the typhoon Sanvu, the southeast jet stream, the south trough, the mid-low layer vortex and shear lines. The interaction of the continuously-split cold air from Baikal Lake and the warm wet air current from the rim of subtropical high is the basic factor for the maintenance of the process. The severe synoptic situation is further strengthened by the longlasting overlap of the short-belt-shaped strong radar echo and the new-born strong convective narrow radar echo and the mesoscale-β cloud cluster which then develops into the mesoscale-α cloud cluster lasting for 5 hours by the local topography.