重庆"9.5"特大暴雨的诊断分析

利用NCAR/NCEP逐日资料（一日4次）和北京大学物理学院大气科学系研制的客观分析诊断系统对2005年重庆“9．5”特大暴雨的成因进行了天气动力学诊断分析。结果表明：向南运动的高层北风急流下沉与低空急流上升支组成的西南低涡是本次特大暴雨的主要影响天气系统,“桑达”台风移动缓慢可能是造成此次特大暴雨的间接原因;特大暴雨出现在中低层辐合、高层辐散的正涡度中心下方和负涡度中心西侧;湿位涡高值带对应着降雨带,高值中心与暴雨中心基本吻合,对暴雨预报有指示意义。

Diagnostic analysis of Chongqing "9.5" thunderstorm

Using the NCEP/NCAR data the weather dynamics causing the Chongqing "9.5" rainstorm are diagnosed based on the objective analysis and the diagnostic system of the Atmosphere Science department,Peking University.The results show that the major influence systems include the descending branch of the upper-level northerly jet and the southwest vortex from the low-level jet ascending branch.The other indirect trigger of this rainstorm is the "Sanda" typhoon.The maximum rainfall is just below the positive vorticity center and at the west of the negative vorticity center.The high moisture potential vorticity region corresponds to the maximum precipitation,which helps the rainstorm prediction.