青藏高原东南侧一次大范围暴雨天气过程的诊断分析

Diagnosis Analysis of a Heavy Torrential Rain in the Southeast of Tibetan Plateau

本文利用常规观测、天气图、数值预报产品、卫星云图等资料,对2007年5月15～16日发生在青藏高原东南侧的川西高原南部一次大范围暴雨天气过程进行了诊断综合分析。分析结果表明:青藏高压与副热带高压之间的切变是此次过程的直接影响系统,高空冷平流入侵是触发机制,副热带高压的稳定是强降雨天气长时间维持的主要因素,孟加拉湾风暴为这次过程的水汽输送起到了关键性作用。对数值预报产品可预报性检验结果表明:T213数值预报产品中的垂直速度、散度、水汽通量以及水汽通量散度对实际预报有较好的指示意义。

By using the datum of general observations,numerical weather prediction products and satellite information in satellite images,it analyzes a heavy torrential rain which occurred in the southeast of Tibetan Plateau on May.15 to 16,2007.The results show that： the direct effective system is the change from Tibetan high and subtropical high,the trigger is cold advection from high attitude,the stability of the subtropical high is the main reason to maintain the precipitation time,and,the storm of bay of Bengal played a key role for the vapor transportation.The result from forecast tests of the numerical products is： vertical velocity,divergence,water-vapor flux and the moisture flux divergence of T213 are significant for the real forecast.