2003年陕西持续性暴雨成因分析

Analysis on Causes of the Continuous Heavy Rain in 2003 in Shaanxi

对2003年发生在陕西的持续性暴雨分析认为:乌山阻高与副热带高压的配置及稳定少动为这次持续性暴雨提供了有利的背景条件。贝湖低压底部分裂出小槽引导的冷空气与副高西北侧暖湿气流在高原东侧一带反复交绥是暴雨的主要成因。高低空急流耦合使高层辐散区迭加在低层辐合区的上方而产生强烈的上升运动,为深对流的发展提供了条件,促进了暴雨时中尺度系统的生成和维持。

The analysis of causes the continuous heavy rain in 2003 in Shaanxi shows that the collocation of the blocking high of Ural and subtropical high, and their stabilization provide favorable background to the continuous heavy rain. The main cause of the continuous heavy rain formation is that the cold air, which leading by the small trough splitting from the bottom of Baikal low, and warm-humid airflow from the west (northwest ) side of subtropical high that mixed time after time on east side region of Plateau. The coupling of high-low jet induces high divergence area overlaying on the top of low convergence area, consequently leading intense ascending movement. It provides the condition of deep convection development and promotes the formation and maintenance of mesoscale system when heavy rain occurs.