On the Key Dynamical Processes Supporting the 21.7 Zhengzhou Record-breaking Hourly Rainfall in China  

作　　者：Peng WEI Xin XU Ming XUE Chenyue ZHANG Yuan WANG Kun ZHAO Ang ZHOU Shushi ZHANG Kefeng ZHU 

机构地区：[1]Key Laboratory of Mesoscale Severe Weather/Ministry of Education and School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China [2]Center for Analysis and Prediction of Storms and School of Meteorology,University of Oklahoma,Norman,Oklahoma 73072,USA [3]Key Laboratory of Transportation Meteorology of China Meteorological Administration,Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210041,China

出　　处：《Advances in Atmospheric Sciences》2023年第3期337-349,共13页大气科学进展（英文版）

基　　金：supported by the National Science Foundation of China(Grant No.42122036);the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0105);the National Key R&D Programs of China(2018YFC1507300);the National Science Foundation of China(Grant No.91837207);the Beijing Climate Center(QHMS2021008).

摘　　要：An extremely heavy rainfall event occurred in Zhengzhou,China,on 20 July 2021 and produced an hourly rainfall rate of 201.9 mm,which broke the station record for China's Mainland.Based on radar observations and a convection-permitting simulation using the WRF-ARW model,this paper investigates the multiscale processes,especially those at the mesoscale,that support the extreme observed hourly rainfall.Results show that the extreme rainfall occurred in an environment characteristic of warm-sector heavy rainfall,with abundant warm moist air transported from the ocean by an abnormally northward-displaced western Pacific subtropical high and Typhoon In-Fa(2021).However,rather than through back building and echo training of convective cells often found in warm-sector heavy rainfall events,this extreme hourly rainfall event was caused by a single,quasi-stationary storm in Zhengzhou.Scale separation analysis reveals that the extreme-rainproducing storm was supported and maintained by the dynamic lifting of low-level converging flows from the north,south,and east of the storm.The low-level northerly flow originated from a mesoscale barrier jet on the eastern slope of the Taihang Mountain due to terrain blocking of large-scale easterly flows,which reached an overall balance with the southerly winds in association with a low-level meso-β-scale vortex located to the west of Zhengzhou.The large-scale easterly inflows that fed the deep convection via transport of thermodynamically unstable air into the storm prevented the eastward propagation of the weak,shallow cold pool.As a result,the convective storm was nearly stationary over Zhengzhou,resulting in record-breaking hourly precipitation.

关 键 词：extreme rainfall multiscale processes OROGRAPHY barrier jet low-level mesoscale vortex 

分 类 号：P458.121.1[天文地球—大气科学及气象学]