Understanding Simulated Causes of Damaging Surface Winds in a Derecho-Producing Mesoscale Convective System near the East China Coast Based on Convection-Permitting Simulations  

作　　者：Liping LUO Ming XUE Xin XU Lijuan LI Qiang ZHANG Ziqi FAN 

机构地区：[1]College of Civil Aviation,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China [2]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [3]Key Laboratory of Mesoscale Severe Weather/Ministry of Education and School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China [4]Center for Analysis and Prediction of Storms and School of Meteorology,University of Oklahoma,Norman,Oklahoma 73072,USA [5]Civil Aviation North China Air Traffic Management Bureau Meteorological Center,Beijing 100621,China

出　　处：《Advances in Atmospheric Sciences》2024年第11期2112-2130,共19页大气科学进展（英文版）

基　　金：primarily supported by the Ministry of Science and Technology of the People's Republic of China (MOST)(Grant No. 2018YFC1507303);National Natural Science Foundation of China (Grant Nos. 419505044,41941007, and 42230607);by the Talent Research Start-Up Fund of Nanjing University of Aeronautics and Astronautics(Grant No. 1007-90YAH22046);supported by The High Performance Computing Platform of Nanjing University of Aeronautics and Astronautics。

摘　　要：A mesoscale convective system(MCS) occurred over the East China coastal provinces and the East China Sea on 30April 2021, producing damaging surface winds near the coastal city Nantong with observed speeds reaching 45 m s^(–1). A simulation using the Weather Research and Forecasting model with a 1.5-km grid spacing generally reproduces the development and subsequent organization of this convective system into an MCS, with an eastward protruding bow segment over the sea. In the simulation, an east-west-oriented high wind swath is generated behind the gust front of the MCS. Descending dry rear-to-front inflows behind the bow and trailing gust front are found to feed the downdrafts in the main precipitation regions. The inflows help to establish spreading cold outflows and enhance the downdrafts through evaporative cooling. Meanwhile, front-to-rear inflows from the south are present, associated with severely rearward-tilted updrafts initially forming over the gust front. Such inflows descend behind(north of) the gust front, significantly enhancing downdrafts and near-surface winds within the cold pool. Consistently, calculated trajectories show that these parcels that contribute to the derecho originate primarily from the region ahead(south) of the east-west-oriented gust front, and dry southwesterly flows in the low-to-middle levels contribute to strong downdrafts within the MCS. Moreover, momentum budget analyses reveal that a large westward-directed horizontal pressure gradient force within the simulated cold pool produced rapid flow acceleration towards Nantong. The analyses enrich the understanding of damaging wind characteristics over coastal East China and will prove helpful to operational forecasters.

关 键 词：damaging surface winds convection-permitting simulations mesoscale convective system gust front cold pool 

分 类 号：P445[天文地球—大气科学及气象学]