On the Influences of Urbanization on the Extreme Rainfall over Zhengzhou on 20 July 2021: A Convection-Permitting Ensemble Modeling Study  

作　　者：Yali LUO Jiahua ZHANG Miao YU Xudong LIANG Rudi XIA Yanyu GAO Xiaoyu GAO Jinfang YIN 

机构地区：[1]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China [2]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China [3]School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,China

出　　处：《Advances in Atmospheric Sciences》2023年第3期393-409,共17页大气科学进展（英文版）

基　　金：The National Natural Science Foundation of China(Grant Nos.42030610 and 42075083);the Innovation and Development Project of China Meteorological Administration(CXFZ2022J014)supported this study.

摘　　要：This study investigates the influences of urban land cover on the extreme rainfall event over the Zhengzhou city in central China on 20 July 2021 using the Weather Research and Forecasting model at a convection-permitting scale[1-km resolution in the innermost domain(d3)].Two ensembles of simulation(CTRL,NURB),each consisting of 11 members with a multi-layer urban canopy model and various combinations of physics schemes,were conducted using different land cover scenarios:(i)the real urban land cover,(ii)all cities in d3 being replaced with natural land cover.The results suggest that CTRL reasonably reproduces the spatiotemporal evolution of rainstorms and the 24-h rainfall accumulation over the key region,although the maximum hourly rainfall is underestimated and displaced to the west or southwest by most members.The ensemble mean 24-h rainfall accumulation over the key region of heavy rainfall is reduced by 13%,and the maximum hourly rainfall simulated by each member is reduced by 15–70 mm in CTRL relative to NURB.The reduction in the simulated rainfall by urbanization is closely associated with numerous cities/towns to the south,southeast,and east of Zhengzhou.Their heating effects jointly lead to formation of anomalous upward motions in and above the planetary boundary layer(PBL),which exaggerates the PBL drying effect due to reduced evapotranspiration and also enhances the wind stilling effect due to increased surface friction in urban areas.As a result,the lateral inflows of moisture and high-θe(equivalent potential temperature)air from south and east to Zhengzhou are reduced.

关 键 词：URBANIZATION extreme rainfall convection-permitting ensemble simulation land-atmosphere interaction boundary layer water vapor transport 

分 类 号：P426.62[天文地球—大气科学及气象学]