摘要
2021年7月19—21日,郑州地区出现了罕见的极端暴雨天气,过程累计降水量达到了732 mm,引发了严重的城市内涝,造成了巨大的人员和财产损失。利用国家级自动观测站逐小时降水数据和欧洲中期天气预报中心第五代大气再分析资料(ERA-5)分析了郑州地区“21.7”极端降水过程的降水特征以及其影响系统。结果表明:此次降水过程降水量大,持续时间长,强降水范围集中在郑州及周边地区,强降水时段集中在20日14时以后,其中郑州站20日17时小时降水量达到了201.9 mm·h^(-1),超过了历史极值。降水过程中南亚高压东移,郑州位于200 hPa高空槽前,500 hPa副高加强西伸,与大陆高压对峙,郑州位于低压区形成低空辐合高空辐散的高低空配置。郑州低空850 hPa有东南急流发展,产生东风切变线同时伴随着地面辐合线影响郑州地区,东南急流也将西太平洋上的水汽输送至暴雨区,并在地形阻挡作用下在郑州地区汇集。低空急流与强降水在时间上有明显同步,急流在地形作用下产生的辐合抬升也在暴雨区形成强烈的垂直上升运动,对此次极端暴雨的产生和维持有明显的影响。
A rare extreme rainstorm occurred in Zhengzhou from July 19 to 21,2021.The accumulated precipitation in the rainstorm process reached 732 mm,and this process caused serious urban waterlogging,casualties and property loss.Here we use the national automatic meteorological observation hourly data and the ERA-5 reanalysis data to analyze features and influencing systems of the“21.7”extreme precipitation process in Zhengzhou.Results show that the precipitation process has the features of large accumulated rainfall and a long duration.The extremely heavy rainfall was concentrated in Zhengzhou after 14∶00 BST on July 20,during which the precipitation at Zhengzhou station exceeded the historical record and reached 201.9 mm at 17∶00 BST.During the precipitation process,the eastward extension of the South Asian high leaded Zhengzhou to be located in front of the 200 hPa trough.Meanwhile the Western Pacific subtropical high extended to west and confronted the high pressure system over the continental,leading to a 500 hPa low pressure located above Zhengzhou,and finally formed a configuration of convergence at low altitude and divergence at high altitude.There was a southeastern low-level jet at 850 hPa above Zhengzhou,which produces easterly wind shear line and surface convergence line affecting this area.The water vapor was transported from West Pacific to rainstorm area through the southeastern low-level jet and converged over the area of Zhengzhou due to the terrain obstruction.The time evolution of low-level jet is well consistent with the rainstorm process.The convergence and uplifting caused by topographic forcing formed the strong upward vertical motions over the rainstorm area,which caused a significant impact on the occurrence and maintenance of this extreme rainstorm.
作者
段汀
陈权亮
廖雨静
DUAN Ting;CHEN Quanliang;LIAO Yujing(School of Atmospheric Science,Plateau Atmospheric&Environment Laboratory of Sichuan Province,Chengdu University of Information Technology,Chengdu 610225,China;School of Compute Science&Technology,Chengdu University of Information Technology,Chengdu 610225,China)
出处
《气象科学》
北大核心
2022年第2期152-161,共10页
Journal of the Meteorological Sciences
基金
国家自然科学基金资助项目(U20A2097,41875108)。
关键词
郑州极端暴雨
影响系统
低空急流
地形抬升
extreme rainstorm in Zhengzhou
influencing systems
low-level jet
terrain elevation