抚州“5.5”特大暴雨成因及中尺度特征

Causes and mesoscale characteristics of"5.5"extremely heavy rainstorm in Fuzhou

为了做好特大暴雨的预报预警工作,利用常规气象资料、天气图、NCEP再分析资料和卫星云图等,对2023-05-05-2023-05-06江西省抚州市特大暴雨过程进行分析。结果表明:抚州市200 hPa急流辐散区,500 hPa乌拉尔山阻塞高压,巴尔喀什湖切断低涡内分裂小槽东移为特大暴雨过程提供了有利的环流条件;850 hPa切变线、地面冷锋、静止锋、中尺度辐合中心是此次特大暴雨的直接影响系统;中低层西南低涡稳定少动,东部850和925 hPa有低空和超低空西南风急流稳定维持,是产生此次特大暴雨的关键因素;赣东地区850 hPa比湿达15 g/kg,假相当位温达346 K,平均对流有效位能大值区中心值达1 250 J/kg,为此次特大暴雨提供了有利的水汽和不稳定能量条件;此次特大暴雨过程是由多个对流云团和中尺度对流复合体造成的,武夷山西麓迎风坡地形对暴雨增幅有重要作用。研究结果为江西抚州特大暴雨预报预警提供了分析依据。

In order to do a good job in the prediction and early warning of extremely heavy rainstorm,conventional meteorological data,weather maps,NCEP reanalysis data and satellite cloud images are used to analyze the extremely heavy rainstorm process in Fuzhou City,Jiangxi Province,from May 5th to 6th,2023.The results indicate that:Jet Divergence Zone at 200 hPa in Fuzhou City,the Ural Mountains block the high pressure at 500 hPa,and the splitting trough in the cut off vortex of the Balkhash Lake moves eastward,providing favorable circulation conditions for the extremely heavy rainstorm process;850 shear line,surface cold front,stationary front and mesoscale convergence center are the direct impact systems of this extremely heavy rainstorm;The southwest vortex at the middle and low levels is stable with little movement,and the southwest jet at 850 and 925 hPa in the east is stable and maintained at low and ultra low levels,which is the key factor for this extremely heavy rainstorm.The specific humidity at 850 hPa in the eastern Jiangxi region reaches 15 g/kg,with a false equivalent potential temperature reached 346 K,and the central value of the maximum area of the average convective effective potential energy(CAPE)reached 1250 J/kg,which provided favorable water vapor and unstable energy conditions for the extremely heavy rainstorm.The extremely heavy rainstorm process is caused by multiple convective cloud clusters and mesoscale convective complexes.The topography of the windward slope at the west foot of Mount Wuyi Mountain plays an important role in the increase of rainstorm.The research provides an analytical basis for the prediction and early warning of extremely heavy rainstorm in Fuzhou,Jiangxi Province.