摘要
利用常规气象观测资料、ERA-5水平分辨率0.25°×0.25°再分析资料、FY-4A云顶亮温资料和6.2μm卫星水汽图像、洛阳双偏振天气雷达等资料,采用等熵面水汽输送、位涡及对称不稳定等动力诊断分析方法,对郑州“7·20”特大暴雨极端性成因进行了分析。结果表明:(1)暴雨期间,台风“查帕卡”“烟花”建立了良好的水汽输送通道,在308 K等熵面上郑州地区存在由气压高值区向低值区爬升的暖湿输送带,为暴雨产生提供了充沛的水汽条件。(2)在北上的台风“查帕卡”、西进的台风“烟花”、西伸加强的副热带高压及中心位置稳定少动的蒙古高压共同作用下,蒙古高压和副热带高压包围的α中尺度黄淮低涡在向东北方向移动的过程中发生分裂,在高空位涡异常、低层暖锋式切变及大尺度降水产生的凝结潜热作用下,在洛阳附近生成了深厚稳定的β中尺度低涡,是郑州极端暴雨事件的主要影响系统。(3)洛阳β中尺度低涡西南部中高层有较强的干冷空气沿着其南部的偏西气流向郑州附近相对湿度为95%的大湿度区侵入,同时500 hPa干冷西风气流和西南气流汇合区中的Q矢量辐合也进一步增大,有较强的强迫上升运动;中低层850 hPa和700 hPa的东南暖湿急流和偏北急流的暖锋式切变线在郑州形成了对流和对称不稳定;低层有较强的辐合,高层有明显的辐散。在这种极为有利的热力、动力条件下,在洛阳β中尺度低涡东南部触发了郑州附近强对流的发生。(4)郑州2021年7月20日16到17时201.9 mm/h的最大雨强是由TBB大值中心低于-64℃的上冲对流云砧后部(西南部)的对流云团造成的,对应最大雷达回波强度达60 dBZ,并在郑州上空滞留长达1 h。
On the basis of the conventional meteorological observation data,ERA-50.25°×0.25°reanalysis data,FY-4A blackbody brightness temperature data,6.2μm satellite water vapor image and Luoyang dual polarization weather radar data,the causes of the extreme rainstorm that hit Zhengzhou,Henan Province,on 20 July,2021 are analyzed by using the dynamic diagnosis methods such as isentropic water vapor transport,potential vorticity and symmetrical instability.The results show that:(1)During the rainstorm,the two typhoons“Cempaka”and“In-Fa”established good water vapor transport channels.On the 308 K isentropic surface,there was a warm and humid transport belt from the high pressure area to the low pressure area over Zhengzhou,which provided sufficient water vapor conditions for the generation of rainstorm.(2)The meso-α-scale Huang-Huai vortex surrounded by Mongolian high and subtropical high split in the process of moving to the direction of northeast affected by the interactions of the north-moving Typhoon“Cempaka”,the west-moving Typhoon“In-Fa”,the westward extension and strengthening of the subtropical high,and the Mongolian high with stable and less moving center.Under the action of high-level potential vorticity anomaly,low-level warm front shear and condensation latent heat generated by large-scale precipitation,one deep and stable meso-β-scale vortex was generated near Luoyang and this was the major influence system of the extreme rainstorm events in Zhengzhou.(3)In the mid-high level of the southwest of Luoyang meso-β-scale low vortex,strong dry and cold air intruded into the high humidity area(95%)near Zhengzhou along the westerly air flow in the south of Luoy-ang meso-β-scale vortex.At the same time,the convergence of Q vector in the confluence area of dry-cold westerly flow and southwest flow at 500 hPa increased further and there was a strong forced upward movement.The warm front shear lines of the southeast jet and the northeast jet at 850 hPa and 700 hPa in the middle and lower layers formed convective symmetric instability in Zhengzhou.Besides,there was strong convergence at the lower level and obvious divergence at the upper level.Such extremely favorable thermodynamic and dynamic conditions triggered the occurrence,development and maintenance of severe convection near Zhengzhou in the southeast of Luoyang meso-β-scale vortex.(4)The hourly maximum rainfall intensity of 201.9 mm from 16:00 to 17:00 BT 20 July,2021 in Zhengzhou was caused by the convective cloud cluster in the rear(southwest)of the upwelling convective cloud anvil with the TBB large-value center lower than-64℃.The corresponding maximum radar echo intensity reached 60 dBZ,which stayed over Zhengzhou for one hour.
作者
张入财
田金华
陈超辉
李振锋
付伟基
周洪亮
陈红霞
王琨鸿
Zhang Rucai;Tian Jinhua;Chen Chaohui;Li Zhenfeng;Fu Weiji;Zhou Hongliang;Chen Hongxia;Wang Kunhong(No. 78127 of PLA,Chengdu 610031,China;Zhengzhou Meteorological Office,Zhengzhou 450007,China;Institute of Meteorology and Oceanography,National University of Defense Technology,Changsha 410073,China;No. 63898 of PLA,Jiyuan 459000,China;No. 96606 of PLA,Luoyang 471000,China;Luoyang Meteorological Office,Luoyang 471000,China)
出处
《气象与环境科学》
2022年第2期52-64,共13页
Meteorological and Environmental Sciences
基金
中国气象局·河南省农业气象保障与应用技术重点实验室应用技术研究基金项目(KY202028)。
关键词
特大暴雨
中尺度涡旋
等熵面分析
1.5
PV面分析
extreme rainstorm
meso-scale vortex
isentropic surface analysis
1.5PV surface analysis
