濮阳市2012年8月4日大暴雨天气简析

利用常规探空、加密地面资料、卫星云图和新一代天气雷达产品资料,对2012年8月4～5日"苏拉"台风倒槽形成的大暴雨天气进行诊断分析。结果表明,台风、副热带高压和华北高压对峙造成了这次大暴雨过程,是典型的中低纬系统相互作用过程;倒槽东侧东南低空急流从低纬海上为大暴雨区输送了丰富的热量和水汽,同时,在它的左前方成为强中尺度对流系统发生的源地;海上新生成台风西移逼近,台风外围气流的叠加,暴雨增幅;卫星云图上,团状的、密实的强中β尺度对流系统的形成和维持是造成短时强暴雨的直接原因;高层反气旋的增强,加强了高空的抽气效应,使辐合上升加强,暴雨增幅。

Analysis on A rainstorm in Aug.4, 2012 in Puyang City

By using routine sounding,encryption ground data,satellite cloud map and new generation weather radar products,a diagnosis analysis was conducted on a heavy rainstorm formed by Sula typhoon inverted trough during Aug.4-5,2012.The result suggested that: the typhoon,subtropical high and North China high caused the heavy rainfall process,that is typical of low latitude systems interaction process.The east side of the inverted trough the rainstorm area southeast LLJ from the low-latitude sea transport of heat and moisture,at the same time,become a source of strong mesoscale convective systems in its left front.A marine generate new typhoon westward movement approaching typhoon airflow superposition of heavy rainfall.The rainstorm area locate on back side of strong convergence area below a convergent line of α mesoscale close anticyclone in 200 hPa high level jet right rear side,and left frontage in 700 hPa southeast low level jet.Mighty and steady subtropical high run out south of North China from Yellow Sea and Bohai Sea,which blocks off the west precipitation system and leads that β mesoscale rainstorm cloud clusters move slowly which park,rotate,develop in northeast of Henan for a long time conducing local heave rainfall.