2次江淮气旋暴雨过程的对比分析

吴琼 刘婷 张波 张渊 王扬

摘 要：利用NCEP1°×1°的再分析数据对2次发生原理不同、路径不同的江淮气旋暴雨过程进行对比分析。结果表明：降雨量与气旋强度呈正比，若气旋入海再生，雨量增强。正涡度平流和暖平流均有利于气旋发展，中后期冷平流入侵，气旋减弱。低层正高层负的垂直螺旋度分布有利于较强降水的发生，随着气旋发展，垂直螺旋度向气旋偏东一侧偏移，气旋减弱阶段，垂直螺旋度正值中心抬离地面。2次气旋的水汽通道不同，但均存在水汽通量的强辐合中心。海上潜热通量数值大于陆上数值，陆上地面气旋中心基本在2m潜热通量大值区。若气旋入海后存在潜热通量大值中心，更利于氣旋再生。气旋移速与500hPa引导气流的强弱有关，高空辐散场有利于低层减压，促进气旋发展。

关键词：江淮气旋;暴雨;垂直螺旋度;潜热通量;引导气流

中图分类号 P443 文献标识码 A 文章编号 1007-7731（2020）09-0161-11

A Comparative Analysis of the Heavy Rainstorm Rrocesses of Two Jianghuai Cyclones

Wu Qiong et al.

（Yangzhou Meteorology Bureau， Yangzhou 225000， China）

Abstract：Based on the NCEP 1°×1° reanalysis data， two heavy rainstorms of Jianghuai cyclone with different principles and different routes were compared and analyzed. The results showed that the rainfall was positively proportional to the intensity of cyclone， and if the cyclone was regenerated after entering the sea， the rainfall will also increase. The positive vorticity advection and the warm air advection were beneficial to the development of the ground cyclone， but in the middle and late stages， the cyclone was weakened with the invasion of the cold advection over the cyclone. The vertical helicity degree distribution was positive in the low level and negative in the high layer was conducive to the occurrence of strong precipitation. With the development of cyclone， the vertical helicity degree gradually shifted to the east side of the position of the ground cyclone， in the weakening phase of the cyclone， the vertical helicity degree center rose away from the near ground. The water vapor channels of the two cyclones were different， but both of the cyclones had strong convergence centers of water vapor flux in the development stages. In general， the value of latent heat flux at sea was greater than that at land. On the mainland， the ground cyclone center was basically in the high value area of 2m latent heat flux. When there was a high value center of latent heat flux in the sea after the cyclone entered the sea， the phenomenon of regeneration was more obvious. The velocity of cyclone movement was related to the intensity of guide air flow at 500hPa， the upper level divergence field at 200hPa over the ground cyclone was conducive to the decompression of the lower level and promoted the development of the cyclone.

Key words： Jianghuai cyclone; Heavy rainstorm; Vertical helical degree; Latent heat flux; Guide air flow

江淮气旋是活动于我国江淮流域的重要天气系统之一，一年四季均可发生，其中4—8月间活动的江淮气旋容易给江淮一带造成明显的风雨影响，造成暴雨、大风等灾害及次生灾害。

国内诸多学者对江淮气旋进行了研究，结合现代气象观测数据普遍显示，江淮气旋的结构特征常常会随着气旋的发生、发展、入海而产生一系列的变化。尹尽勇等[1-2]运用涡度倾向方程诊断了1次气旋入海快速发展的个例，运用涡度平流、温度平流和斜压作用来分析各因子对气旋入海后的作用。……