【摘要】 本文利用Micaps资料、江苏自动气象站数据、常州多普勒雷达观测和NCEP全球分析场,从降水实况、环流背景、雷达回波特征、动力和热力条件等方面,对2009年8月2日和2011年7月13日两次江苏盛夏局地特大暴雨过程进行了分析和比较。结果表明:大尺度鞍型场背景下副热带高压和大陆高压的同时增强使得降水系统更集中、对流发展更旺盛,降水中心在低空切变的南侧、地面辐合的北侧、水汽在大陆东部输送的顶点。而副热带高压相对较弱的情形下,有利于热带低值系统外围偏东风场的持续水汽输送,对流发展较弱,但持续时间更长;配合低层深厚的中尺度触发系统,使得局地降水强度更有爆发力,降水中心靠近水汽在大陆东部的输送起点。更多还原

【Abstract】 In this paper a contrastive analysis on two torrential rains(August 2,2009 and July 13,2011) of mid-summer in Jiangsu is presented with Micaps products,automatic station data,Changzhou Doppler radar observations and NCEP analysis field.Research includes precipitation,circulation background,characteristics of radar observations,dynamic and thermal conditions,etc.Result shows that simultaneous reinforement of subtropical high and continental high in a saddle pattern leads to concentrative precipitation and heavy convective motions,rain center locates in the south of low shear,in the north of surface convergence,and near the peak of water vapor transportation over east China.Weak subtropical high contributes to sustaining water vapor transport for easterly wind of tropical system,to weak convection and longer duration of the convection,with the cooperation of meso-scale trigger system at low levels,it makes local rainfall more powerful and makes precipitation center closer to the starting point of water vapor transportation over east China.更多还原