1006号台风“狮子山”引发江淮暴雨的成因分析

2010年9月2日08时至3日08时,安徽江淮地区出现了暴雨、大暴雨。利用常规天气图及安徽加密雨量站等资料对这次暴雨过程进行了仔细分析。结果表明,台风"狮子山"移进福建后,由于大陆高压与西太平洋副热带高压的对峙,致使其西移减缓且长时间停留。在台风低压、副热带高压和西风带低槽的共同作用下,低空、超低空两支东南风急流的生成与维持,为暴雨提供了充沛的水汽和动力条件。暴雨区位于低空、超低空急流的北侧和高空急流及700 hPa切变线的南侧,并与低层辐合、高层辐散及强烈的上升运动区对应。暴雨出现前期,对流参数显示大气层结极不稳定。云图中,台风的螺旋云带十分明显,其北侧有3次MCS的生成与维持。

Cause Analysis on Jianghuai Rainstorm Caused by NO.1006 Typhoon "Lion Rock"

From 08:00 on September 2 to 08:00 on September 3 in 2010,rainstorm and downpour occurred in Anhui Jianghuai areas.By using the conventional weather charts and encrytion rainfall station data in Anhui,the process of this rainstorm was analyzed carefully.The results showed that because the confrontation between western Pacific subtropical high and continental high,the typhoon "Lion Rock" moved in Fujian,westward slowly and stayed a long time.Under the combined action of typhoon depression,subtropical high and westerlies conditioner,the generation and maintenance of low-level and extreme low-altitude southeaster jet stream provided abundant water vapour and dynamic conditions for rainstorm.The rainstorm areas located in the north of low-altitude jet stream and extreme low-altitude jet stream,the south of 700 hPa shear line and corresponding to the low-level convergence and upper-level convergence and strong vertical ascent motion.Before the appearance of the storm,convective parameters revealed that atmospheric stratification was very unstable.The nephogram revealed that the spiral cloud was very obvious,and had three MCS’s creation and maintenance in the north.