2021年“7·20”郑州地区强降水过程诊断分析

Diagnostic Analysis of Heavy Precipitation Process in Zhengzhou on July 20,2021

【目的】对郑州地区此次降水过程的环流形势、热力及不稳定能量等物理量特征进行诊断分析,以期对区域性强降水过程建立更深入、全面的认识。【方法】使用河南国家观测站降水资料、FNL再分析资料对2021年7月19—21日郑州地区暴雨的天气学成因进行了诊断分析。【结果】本次郑州地区的强降水过程是南亚高压、副热带高压、低层切变线和双台风共同作用造成的,具备范围广、突发性强、持续时间较长的特征。【结论】强降水发生时郑州地区水汽充沛、处于高能高湿的环境场中,有不稳定能量的蓄积;同时在河南省北部地区有物质以及能量的密集交换,K指数及假相当位温均较大,表明在郑州地区上空有深厚的不稳定层结,有利于强降水的发生发展。

[Purposes]By diagnosing and analyzing the circulation situation,heat,and unstable energy characteristics of the precipitation process in Zhengzhou,this paper aims to establish a deeper and comprehensive understanding of the regional heavy precipitation process.[Methods]This paper uses the precipitation data of Henan National Observatory and FNL reanalysis data to diagnose and analyze the synoptic cause of the heavy precipitation process in Zhengzhou from July 19 to 21,2021.[Findings]The heavy precipitation process in Zhengzhou region was caused by the combined action of the South Asian High,Subtropical High,low-level shear line,and two typhoons,with characteristics of wide range,strong suddenness,and long duration.[Conclusions]When the heavy rainfall occurs,Zhengzhou area is rich in water vapor and in the environment field of high energy and high humidity,with the the accumulation of unstable energy;At the same time,there is a dense exchange of matter and energy in the northern part of Henan Province.The K index and pseudo-potential temperature are both large,indicating that there is a deep unstable stratification over Zhengzhou,which is conducive to the occurrence and development of heavy precipitation.