2021年6月底赣闽地区一次强降水成因与预报着眼点  

Causes and Forecast Focus of a Heavy Rainfall in Jiangxi and Fujian at the End of June 2021

作　　者：陈翔翔 陈云辉 黄美金[4] 王萱 欧阳鸿翔 Chen Xiangxiang;Chen Yunhui;Huang Meijin;Wang Xuan;Ouyang Hongxiang(Jiangxi Meteorological Observatory,Nanchang 330096,China;Nanchang National Climate Observatory,Nanchang 330043,China;Key Laboratory of Climate Change Risk and Meteorological Disaster Prevention of Jiangxi Province,Nanchang 330096,China;Fujian Meteorological Observatory,Fuzhou 350001,China)

机构地区：[1]江西省气象台,江西南昌330096 [2]南昌国家气候观象台,江西南昌330043 [3]气候变化风险与气象灾害防御江西省重点实验室,江西南昌330096 [4]福建省气象台,福建福州350001

出　　处：《气象与减灾研究》2024年第3期184-193,共10页Meteorology and Disaster Reduction Research

基　　金：2021年江西省气象局指导项目(编号:JDX2021Z02);2020年江西省气象局面上项目(编号:JX2020M15);2021年福建省科技计划项目(编号:2021J01458);福建灾害天气重点实验室重大科技专项(编号:2020BY10);珠江流域(华南区域)气象科研开放基金(编号:ZJLY202311)。

摘　　要：利用地面气象观测站常规观测资料、探空资料、雷达资料及NCEP 0.5°×0.5°再分析资料,对2021年6月28日—7月1日赣闽地区出现的一次强降水过程进行了成因与预报偏差分析,总结了此类暴雨的预报着眼点。得到以下结论:1)此次过程累计降水量大、持续时间长,极端降水出现在赣闽交界的武夷山脉北段,整个降水过程分暖区暴雨、多雨带、暖式切变南侧暴雨3个阶段。2)赣闽两省位于南亚高压脊北侧的高层辐散区,有明显气流分流;中层处于径向度较高的低槽槽后,不断有小槽移入;低层切变线维持在长江沿岸,其南侧多次出现急流脉动,导致了风速辐合区的变动,与赣闽两省主要暴雨区的南北摆动步调一致。武夷山脉北段附近因地形导致的涡旋和气流爬坡,有利于边界层气流辐合抬升,从而影响降水强度。3)此类暴雨的预报着眼点是,中层处于冷槽后部西北气流中、边界层有弱锋区,同时锋区南侧暖脊发展、伴随高温、高湿的结构易触发强对流型暴雨,当数值模式的降水预报倾向于系统性降水时,雨带中心可以向模式(ECMWF)的500 hPa槽底、高空强辐散区、低层急流顶端和锋区南侧暖脊顶端位置订正,同时还需关注中尺度雨团的触发位置及中高层气流对其传播的影响。Based on conventional observation data from ground meteorological observation stations,sounding data,radar data,and NCEP 0.5°×0.5°reanalysis data,forecast deviation and difficulties of the precipitation concentration period in Jiangxi and Fujian from June 28 to July 1,2021 were analyzed.The results showed that,1)This process presented large cumulative rainfall and long duration.Extreme precipitation occurred in the northern section of Wuyi Mountains at the junction of Jiangxi and Fujian.The process can be divided into three stages:rainstorm in warm zone,multiple rain belts,and rainstorm in the south of warm shear.2)Jiangxi and Fujian Provinces were located in the upper level divergence zone on the north side of the South Asian high-pressure ridge,with obvious airflow diversion;The middle level zone was located behind a low trough at 500 hPa and small troughs were active;The low-level shear line was maintained along the Yangtze River.The north-south migration pace of main rainstorm over Jiangxi and Fujian was consistent with the shear line.Jet pulsations occurred many times in the south of the shear line,leading to changes in the wind speed convergence zone.The vortex and airflow ramp caused by the terrain near the northern section of Wuyi Mountains were conducive to the convergence and uplift of the boundary layer airflow and affected the rainfall.3)Finally,the Forecast focus of this kind of rainstorm is proposed.It is easy to trigger a strong convective rainstorm if it is under the northwest air flow of the upper cold vortex,with hot and humid boundary layer.If the precipitation forecast of numerical models is systematic precipitation,the location can be adjusted to the bottom of the 500 hPa trough,the upper strong divergence,the top of the low-level jet stream and the top of the warm ridge in the south of the front area.At the same time,we need to pay attention to the trigger position of the mesoscale rain cluster and the impact of the changes in the upper and middle air flow.

关 键 词：强降水 暖区暴雨 回波特征 风速辐合 

分 类 号：P457.6[天文地球—大气科学及气象学]