2011—2019年影响安徽致暴江淮气旋统计分析

采用安徽国家基本站逐小时降水及欧洲ERA5再分析资料,统计分析了2011—2019年影响安徽致暴江淮气旋气候概况、雨区、路径及环流场特征。结果表明,影响安徽致暴江淮气旋多发生于湖北、湖南等地,约占同期总气旋数的18.9%,年均2.8次;降水大值中心主要位于大别山南麓至皖南山区西南一带,高海拔山区尤其明显。根据斜旋转T模态主成分客观分析法,将影响安徽致暴江淮气旋主要划分为高压脊型(SP1型)、高空槽型(SP2型)、暖式切变型(SP3型);其中,SP1型致暴天气过程最多,占40%,SP2型次之,占36%,SP3型占20%。高压脊型(SP1型)江淮气旋一般偏南东移,安徽以西有一高压脊,高压脊东侧有显著的经向环流,中高层有明显干侵入过程,低层暖湿舌伸向皖南山区,暖湿不稳定层结的配置有利于皖南山区对流性强降水的产生;高空槽型(SP2型)江淮气旋一般向偏东方向移动,安徽中北部中高层为东北—西南向高空槽,低层表现为冷锋南侵,与南方暖湿气流汇合于安徽长江流域,导致雨区分布于安徽长江一线;暖式切变型(SP3型)江淮气旋一般偏北东移,低涡位于安徽以西,西南强盛的暖湿气流经大别山区向东北方输送,整层均为大湿区,低层有较强的辐合抬升,降水效率高,雨区主要分布于大别山区,属于暖区暴雨或强降水类型。

Statistical analysis of the violent Jianghuai cyclones affecting Anhui from 2011 to 2019

By using the hourly precipitation data from the Anhui National Basic Station and the European ERA5 reanalysis data, the climate profile, rain area, path and circulation field characteristics of the violent Jianghuai cyclones that affected Anhui from 2011 to 2019 were statistically analyzed.Resultsshow that most of the violent Jianghuai cyclones that affect Anhui occur in Hubei, Hunan and other places, accounting for about 18.9% of the total number of cyclones in the same period, with an average of 2.8 times per year. May to July is a prone period, with extreme rain intensity and cumulative precipitation being easy. Occurs in July; the center of high rainfall is located from the southern foot of the Dabie Mountains to the southwestern part of the southern Anhui mountainous area, especially in high-altitude mountainous areas. According to the principal component objective analysis method of the oblique rotation T mode, the cyclone that affects Anhui''s Yangtze River and Huaihe River is divided into high pressure ridge type(SP1 type), north trough and south vortex type(SP2 type), and warm shear type(SP3 type); among them, SP1 type weather process is the most, accounting for 40%, SP2 type is the second, accounting for 36%, and SP3 type accounts for 20%. The high pressure ridge type(SP1) Jianghuai cyclone generally moves southward and eastward, there is a high pressure ridge in the west of Anhui, there is a significant meridional circulation in the east of the high pressure ridge, there is an obvious dry intrusion process in the middle and high levels, the warm and wet tongue in the lower level extends to the mountain area of southern Anhui, and the configuration of warm and wet unstable stratification is conducive to the generation of convective heavy precipitation in the mountain area of southern Anhui. The high trough type(SP2 type) Jianghuai cyclone generally moves to the East. The middle and upper layers in the central and northern part of Anhui are northeast southwest high trough, and the lower layer is characterized by the southward invasion of cold front, which converges with the warm and humid air flow in the south in the Yangtze River Basin of Anhui, resulting in the distribution of rain areas in the first line of the Yangtze River in Anhui. The warm shear type(SP3 type) Jianghuai cyclone generally moves northward and eastward, and the low vortex is located in the west of Anhui. The strong warm moisture in the southwest flows through the Dabie Mountains to the northeast. The whole layer is a large wet area. The low layer has strong convergence and uplift, and the precipitation efficiency is high. The rain area is mainly distributed in the Dabie Mountains, belonging to the type of rainstorm or heavy precipitation in the warm area.