强对流天气过程的典型案例分析

Analysis on a Typical Case of Intense Convective Weather Process

运用NCEP/NCAR1°×1°逐6 h再分析资料、贵阳机场多普勒天气雷达数据和贵阳探空资料,通过环流背景、散度场、垂直速度场以及水汽通量、K指数和雷达回波(PPI)图,对2010年9月9日至10日在龙洞堡机场的雷暴天气过程进行分析。此次雷暴天气是在500 hPa西太平洋副热带高压减弱东退的背景下,高层引导气流的转变诱使低层四川东部的切变线向东南方向移动,造成贵阳机场的强对流天气。高层辐散、低层辐合的配置为强上升运动的维持和发展提供了有利条件。高的水汽通量为对流发展维持提供了充分的水汽条件。探空资料和K指数也反映出诱发强对流发展的不稳定条件。

Using the NCEP/NCAR 1°×1°final analysis data, Doppler radar data and Guiyang sounding data, the thunderstorm occurred at Guiyang airport during September 9-10, 2010 was analyzed by circulation pattern, divergence field, vertical motion, moisture flux divergence, K-index and radar plane position indicator （PPI） images. It is indicated that the shear line in east of Sichuan moving to the southeast arises thunderstorm, which caused by conversion of upper air steering flow under the weakened and east retired subtropical anticyclone in 500 hPa. The upper air divergence and low-level convergence provide a favorable condition to the vertical motion. The strong moisture flux provides an enough moisture condition to development and maintenance of convection. The sounding data and K-index reflects the instability air condition which evoking the thunderstorm.