一次典型梅雨锋影响下赣北地区连续性暴雨过程分析

Analysis of Continuous Rainstorm Process in Northern Jiangxi under the Influence of a Typical Meiyu Front

摘要: 本文利用NCEP再分析资料、常规气象观测资料、卫星资料和雷达拼图资料等观测分析资料，对2017年6月23日~25日赣北地区一次连续性暴雨过程进行分析，得到结论如下：1) 此次连续性暴雨过程是一次典型的梅雨锋暴雨过程，主要影响系统是高空低槽和低层低涡切变线，低层700 hPa、850 hPa、925 hPa上西南急流均达到急流标准，高层200 hPa对应高压辐散区，与低层切变辐合区对应，抬升条件良好，有利于暴雨的形成和维持。2) 整个降水过程中，强西南风气流不断地向赣北地区输送水汽，为强降水过程提供了充足的水汽供应，造成持续性的降水。3) 赣北地区处于假相当位温的高值区，能量锋区位于长江一线，赣北地区的对流不稳定能量(CAPE)值达2000 J/kg，良好的能量条件为此次特大暴雨过程的发生提供充足的能量，有利于对流性降水的发生。4) 此次过程是原地生成的对流云团和由赣西北发展东移的对流云团造成的强降水累积造成的结果，对流云团影响时间长，短时降水强度大，短时间内多次短时强降水的发生给上述地区带来了一次严重的洪水灾害。

Abstract: Based on the NCEP reanalysis data and observation data such as the satellite data and radar data the continuous rainstorm process in northern Jiangxi from June 23th to June 25th in 2017 is analyzed. The conclusions are as follows. 1) This continuous rainstorm process is a typical Meiyu front rainstorm process. The main influence systems are the low trough in upper level and vortex shear line in low level. The southwest jets exit in 700 hPa, 850 hPa and 925 hPa levels. The high-pressure divergence area in 200 hPa level corresponds to the low level shear convergence area. The lifting condition is good which is conducive to the formation and maintenance of rainstorm. 2) The strong southwest jet continuously transports water vapor to northern Jiangxi which provides sufficient water vapor supply in the whole process that resulting in the continuous rainstorm. 3) The energy front area is located in the front line of the Yangtze River and northern Jiangxi is located in the high value area of pseudo equivalent potential temperature. The value of CAPE is up to 2000 J/kg. Good energy conditions provide sufficient energy for this process which is conducive to the occurrence of convective precipitation. 4) The convective cluster which causes this rainstorm is formed by the cluster generated in place and moving cluster from northwest Jiangxi. The occurrence of several short-term heavy precipitation which exists long time in place has brought a serious flood disaster to the northern Jiangxi.