“7·30”区域暴雨的中尺度特征分析

Analysis of"7.30"Regional Rainstorm on the Mesoscale Characteristic

针对2007年7月30日发生在山西省南部的区域暴雨局部特大暴雨天气过程,利用多种资料,计算了多种物理量,分析了其演变特征,指出:a)前期500 hPa 阻塞高压和切断低压的形成和长期维持以及副热带高压的稳定加强、维持,是造成山西大范围降水和区域暴雨天气的特殊环流背景。b)特殊背景下形成的MCS 是造成此次南部区域暴雨的直接影响系统,强烈而持续的水汽夹卷作用、对流层高层强抽吸作用使得MCS 维持和加强。c)地形性辐合的存在使得垂直上升运动加强,而高位势不稳定能量的释放与低层迎风坡面上低云的相互作用,使得 MCS 不断发展,使雨强出现了3次强烈增幅。

Using various meteorological data, the characteristics of ＂2007.7.30＂ local heavy rainstorm weather process occurred in the south of Shanxi province is analyzed. The results show as follows： a） The forming and maintaining of blocking high and cut - off low on 500 hPa and subtropical high are the circulation background of the special weather, b） MCS is the direct Influence system which maintaining and enhancing led by water vapor entrainment and pumping in the high troposphere, c） The strong Vertical upward motion of geographical convergence, the interactions between the releasing of high potential instability energy and low cloud over windward slope cause MCS development and three rainfall intensity Jumps.