2009—2021年萍乡市极端暴雨过程基本特征分析  

Analysis of the Basic Characteristics of Extreme Rainstorms inPingxiang City from 2009 to 2021

作　　者：李侃 蔡莉 甘维金 Li Kan;Cai Li;Gan Weijin(Pingxiang Meteorological Office of Jiangxi Province,Pingxiang 337002,China;Zixi Meteorological Station of Jiangxi Province,Fuzhou 335300,China;Shangli Meteorological Station of Jiangxi Province,Pingxiang 337009,China)

机构地区：[1]江西省萍乡市气象局,江西萍乡337002 [2]资溪县气象局,江西抚州335300 [3]上栗县气象局,江西萍乡337009

出　　处：《气象与环境科学》2025年第2期54-63,共10页Meteorological and Environmental Sciences

基　　金：江西省气象科技项目(JX2020M08);中国气象局复盘总结专项(FPZJ2024-071)。

摘　　要：基于2009—2021年萍乡市地面观测降水资料和欧洲中期天气预报中心ERA-5再分析资料,采用百分位法识别出14次极端暴雨过程,并按环流形势将极端暴雨分为低槽型、典型两高切变型和非典型两高切变型。分析表明:低槽型极端暴雨受明确天气系统影响,低层西南气流较强,预报准确率较高但发生频率低;两高切变型极端暴雨多位于副高(或副高边缘)暖区,预报难度较大但频次高。进一步对低层西南急流、环境参数标准化异常度、降水效率和持续时间的分析发现:(1)典型两高切变型极端暴雨异常强的上升运动更易形成较高的对流系统,同时强抬升条件将低层异常充沛的水汽持续地输送到0℃层以上,形成了深厚的湿层,有利于形成高降水效率的大雨滴。(2)非典型两高切变型极端暴雨过程中层干冷空气侵入叠加至低层异常高温高湿的空气上,造成了异常明显的对流不稳定,易形成低质心高降水效率的对流系统。两高切变型极端暴雨不仅有高降水效率,而且降水持续时间长。(3)低槽型极端暴雨动力抬升条件的异常程度明显强于普通暴雨的抬升条件,但中层引导气流和垂直风切变均偏大,不利于强降水长时间维持,降水增强时其环境参数值增长幅度偏低,极端降水的范围和强度要弱于两高切变型极端暴雨的降水范围和强度。Based on precipitation data in Pingxiang City from 2009 to 2021 and ERA-5 reanalysis data from the European Centre for Medium-Range Weather Forecasts(ECMWF),14 extreme rainstorm events are identified by the percentile method.These events are classified into three types based on their circulation patterns,i.e.,low-trough type,typical double-high shear-type,and atypical double-high shear-type.The low-trough type extreme rainstorms are characterized by clearer impact systems,stronger southwesterly flows in low levels,and relatively good forecast performance,but they occur less frequently.The double-high shear-type extreme rainstorms occur more frequently in the warm zone of the subtropical high(or its periphery),and are more challenging to forecast.Further analysis of the low-level southwesterly jet,standardized anomalies of environmental parameters,precipitation efficiency,and duration reveals that:(1)The typical double-high shear-type events are more favorable for higher convective systems due to abnormally strong upward motion.Intense lifting conditions continuously transport abundant low-level moisture above the freezing layer,forming a deep moist layer conducive to the generation of high-efficiency precipitation and large raindrops.(2)Atypical double-high shear-type involved the intrusion of mid-level cold,and dry air overlaid on abnormally hot and humid low-level air resulted in significant convective instability,favoring the development of low-center,high-efficiency convective systems.The double-high shear-type extreme rainstorms have not only high precipitation efficiency,but also prolonged rainfall duration.(3)Low-trough type extreme rainstorms show more pronounced dynamic lifting anomalies compared to ordinary rainstorms,but their mid-level steering flow and vertical wind shear are relatively larger,which is unfavorable for prolonged maintenance of heavy rainfall.In addition,the increase in ambient parameter values during rainfall intensification is smaller,resulting in weaker range and intensity of extrem

关 键 词：极端暴雨 低层西南急流 标准化异常度 

分 类 号：P463.213[天文地球—大气科学及气象学]