赣东北3类致洪暴雨的对比分析

Comparative Analysis on three Types of Flood-Inducing Rainstorm in Northeast Jiangxi

使用3次不同类型的致洪暴雨个例资料,采用统计对比分析方法,总结出赣东北区域台风类暴雨、副高边缘类暴雨、西风带类暴雨的不同特点和阈值。分析表明:1)3类致洪暴雨都发生在高温、高湿区中,一定强度的对流有效位能和中层"干区"的卷入是产生致洪大暴雨的重要条件;2)台风类和副高边缘类致洪暴雨的0~3 km最大风垂直切变阈值为11~15 m/s,而西风带类致洪暴雨最强达20 m/s;3)西风带类和台风类致洪暴雨的云顶亮温阈值在-70℃,副高边缘类为-100℃;4)台风类致洪暴雨回波强度为30~40 d Bz,ET8~9km,VIL5×kg·m^(-2);西风带类致洪暴雨回波强度为40~45 d Bz,ET10 km,VIL10~15×kg·m^(-2);副高边缘类致洪暴雨回波强度为50 d Bz,ET12 km,VIL20×kg·m^(-2);5)台风暴雨的低层涡度最大,水汽通量与水汽通量辐合也最强。

Three different types of flooding rainstorms were used to analyze the different characteristics and thresholds of typhoon rainstorm, Subtropical High edge rainstorm and Westerlies rainstorm in northeastern Jiangxi Province by using statistical contrast analysis method. Analysis shows： 1 ）Three kinds of flooding rainstorms occurred in the high temperature and high humidity areas, the entrainment of the convective energy and the involvement of the mid-level ＂dry zone＂ were the important conditions to produce flooding rainstorm ;2）Typhoon and Subtropical High edge rainstorm 0 - 3 km maximum vertical wind shear threshold is 11 - 15 m/s,while the threshold is 20 m/s in the Westerlies rainstorm; 3 ） Westerly and typhoon rainstorm threshold of TBB is at - 70 ℃ and the edge of the Subtropical High is - 100 ℃;4） The thresholds of echo characteristic, ET, VIL of typhoon, westerlies,and Subtropical High edge type are 30 -40 dBz,8 -9 km,5 g · km^-3/40 -45 dBz,10 km,10 -15 g ^ km^-3/50 dBz,12 kin,20 g ·km^-3 ;5）The low vorticity of the typhoon is the largest,and the convergence of water vapor and water vapor is also the strongest.