陕西一次远距离台风暴雨天气分析

Synthetic Analysis of a Far Distance Typhoon and Rainstorm Process in Shaanxi Province

利用MICAPS实况观测、卫星云图TBB、地面自动观测站资料,对2010年7月22～25日陕西一次远距离台风暴雨天气过程进行诊断分析,结果表明:500 hPa贝加尔湖南部高压和西太平洋副热带高压稳定少动及甘南低涡加深东移是这次暴雨主要环流特征,700 hPa从台风东侧至陕西建立了温湿能通量的能量输送通道,台风东侧的温湿能沿大陆副热带高压外围偏南风向陕西输送,暴雨位于700 hPa温湿能等值线密集处;条件性对称不稳定与对流不稳定是此次暴雨发展与维持的重要机制,高层湿位涡大值区向下伸展,对暴雨起到加强作用。

By using routine observational data,satellite images and surface automatic observational data,a far distance typhoon and rainstorm process occurred in Shaanxi in July of 2010 was analyzed.Results show that the high pressure over the south of Baikal and west Pacific subtropical high at 500 hPa were stable,the vortex in the southern part of Gansu deepened and moved eastward,they were the main circulation characteristic of the rainstorm weather.The transportation channels of water vapor and enthalpy at the level of 700 hPa was established between the east side of typhoon and Shaanxi,which transported the warmer and wetter airflow toward Shaanxi continuously,and rainstorm occurred in the dense area of enthalpy isoline at 700 hPa.Convective instability and conditional symmetric instability were the important mechanism for development and persisting of the rainstorm.When big value area of moist potential vorticity at high level spreaded downward,the rainstorm became stronger.