2013年5月14—16日江西暴雨过程成因及非常规资料特征分析

利用常规观测资料、NCEP/NCAR 1°×1°再分析资料、风廓线雷达、GPS/MET可降水量等非常规资料,对2013年5月14—16日江西区域性暴雨的成因进行了分析。结果表明:1)此次暴雨过程较强的动力条件和水汽条件是在高空低槽、中低层切变线、西南急流、低涡的共同作用下形成的。2)低层暖湿气流与高层干冷空气的配置有利于热力不稳定能量积聚;稳定度(θse500-850)密集区有利于激发中尺度对流云团发生发展;较强的垂直风切变对不稳定能量的释放和对流性暴雨的产生起到了触发的作用。3)风廓线雷达监测的超低空西南急流脉动与下风方地区的强降水相对应;该雷达监测的中低层风场特征对辅助分析天气尺度系统演变有一定的参考;风廓线雷达特征表现的强信噪比、较大的垂直向下运动与本站的强降水对应。4)强降水落区基本与可降水量(PWV)等值线密集带相对应;最大雨强常在可降水量值达到最高点之后1—3 h出现;在降水出现前站点的PWV值增幅越大,上升至高位值后维持时间越长,同时又有动力触发,对应该站点降水量也越大。

Causes and Analysis of the Unconventional Data Characteristics of the Rainstorm Happened in Jiangxi During 14-16 May 2013

With the help of conventional observation data and some unconventioanl observation data, such as NCEP/NCAR loxlo data, wind profile radar data and GPS/MET precipitable water, this paper analyzes the cause of regional rainstorm happened in Jiangxi during 14-16 May 2013. Some conclusions come to be as follows： （1） Favorable dynamic conditions and abundant moisture during this rainstorm process came from the interaction among the upper trough, low level shear line, southwest jet and vortex. （2） The configuration with warm-wet in the lower layer and dry-cold in the higher layer provided strong thermal instable energy. The intensive stability （θse500-850） was conducive to arouse the growth of mesosacle convective cloud. The strong vertical wind shear and southwest jet at mid and lower level triggered instable energy release. （3） Low level jet stream monitored by wind profile radar was corresponding with heavy rainfall occurred at downwind direction, which meant that the features of radar monitored wind field can be referred to analyzing the evolution of synoptic system. The strong signal noise ratio and strong descend motion presented by wind profile radar coincided with heavy rainfall. （4） Heavy precipitation area was coincided with intensive perceptible water vapor （PWV） belt. The maximum rainfall intensity appeared after 1-3 h of the PWV peak value. Before it rained, if the PWV amplified obviously and maintained as a high value for a longer time, with a suitable dynamic triggering, the rainfall will be heavier.