河南2021年“21.7”暴雨极端性特征及其与1975年“75.8”暴雨的对比  

Extreme Characteristics of the“21.7”Rainstorm Event in Henan Province in 2021 and Its Comparison with the“75.8”Rainstorm in 1975

作　　者：张芳华 孔期 袁溢 冉令坤[4,5] 申冬冬 ZHANG Fanghua;KONG Qi;YUAN Yi;RAN Lingkun;SHEN Dongdong(National Meteorological Center,Beijing 100081;School of Environmental Studies,China University of Geosciences,Wuhan 430074;China Meteorological Administration Hydro-Meteorology Key Laboratory,Beijing 100081;Institute of Atmosphere Physics,Chinese Academy Sciences,Beijing 100029;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]国家气象中心,北京100081 [2]中国地质大学环境学院,武汉430074 [3]中国气象局水文气象重点开放实验室,北京100081 [4]中国科学院大气物理研究所,北京100029 [5]中国科学院大学,北京100049

出　　处：《大气科学》2024年第6期2405-2423,共19页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2022YFC3003905;国家自然科学基金项目U2233218,42275010,42230612;河北省重点研发计划项目22375404D;中科院战略性先导科技专项XDB0760100。

摘　　要：利用国家站降水资料分析了2021年7月19~21日河南特大暴雨(简称“21.7”暴雨)在强降水影响范围、持续时间、降雨强度和累计降水量等方面的极端性;基于ERA5再分析数据和广义Omega方程,研究此次过程中影响垂直运动的关键物理因子,并讨论与“75.8”暴雨(1975年8月河南特大暴雨)的差异。结果表明,“21.7”暴雨中河南省约10%测站累计降水量超过500 mm,20日全省平均降水量92.8 mm,居1961年以来历史首位;20日16:00~17:00(北京时)郑州的小时降水量(201.9 mm)打破中国大陆小时降水极值。“21.7”与“75.8”暴雨均伴有台风环流输送水汽,“21.7”暴雨水汽主要来自台风“烟花”和副高之间东南急流的水汽输送,并且水汽辐合层深厚,而“75.8”暴雨存在印度洋西南气流和西太平洋东南气流两支水汽通道。这两次暴雨中广义Omega方程的总Q矢量散度异常值区与强垂直运动区都有一定的对应关系,“21.7”暴雨的垂直上升运动、总Q矢量散度的强度略弱于“75.8”暴雨,前者的垂直运动主要由低层动力强迫和热力强迫共同造成,在低层触发和加强垂直运动,而后者的垂直运动主要由中低层的热力强迫和低层动力强迫引起,在中层加强垂直运动。垂直运动空间层次分布的差异可能是导致郑州地区更易于出现低质心、高效率的短时强降水的原因之一。The extreme characteristics of the“21.7”rainstorm that occurred in Henan Province during July 19–21,2021,including the impact range,duration,rainfall intensity,and cumulative precipitation,were studied using national precipitation data.With ERA5 reanalysis data and generalized Omega equation,key physical factors affecting vertical movement were studied,and their differences from the“75.8”rainstorm(torrential rainstrom in Henan Province in August 1975)were discussed.The results show that about 10%of the stations in Henan Province accumulated precipitation exceeding 500 mm during the“21.7”rainstorm,with an average precipitation of 92.8 mm on July 20,2021,ranking first since 1961.On that day,the hourly precipitation during 1600 BJT–1700 BJT(Beijing time)in Zhengzhou broke the extreme hourly record in the Chinese Mainland(201.9 mm).Both rainstorms were accompanied by the transport of water vapor from typhoon flows.The water vapor of the“21.7”rainstorm primarily originated from the vapor transport of the southeastern jet stream between Typhoon Fireworks and the sub-high,while the“75.8”rainstorm had two water vapor channels,namely,the southwest airflow from the Indian Ocean and the southeast airflow from the western Pacific Ocean.In both rainstorms,the total Q-vector divergence anomalies of the generalized Omega equation were related to areas of strong vertical movements.The vertical velocity intensity and total Q-vector divergence intensity of the“21.7”rainstorm were slightly weaker than those of the“75.8”rainstorm.The vertical motion of the“21.7”rainstorm primarily resulted from the combined low-level dynamics and thermal forcing,whereas that of the“75.8”rainstorm mainly resulted from the middle–low-level thermal forcing and low-level dynamic forcing.The different spatial distributions of vertical motion may be one of the reasons that the Zhengzhou area is prone to short-duration intense precipitation with low centroids and high efficiency.

关 键 词：“21.7”暴雨 “75.8”暴雨 水汽输送 垂直运动 Q矢量散度 

分 类 号：P458[天文地球—大气科学及气象学]