摘要
利用天气研究与预报模式3.6版(weather research and forecasting model 3.6,WRF3.6)耦合单层城市冠层模式对武汉市2015年7月23日极端降水事件(简称“7.23”暴雨)进行了模拟研究,分析了武汉城镇下垫面扩张对暴雨过程的影响并探究其潜在机理。对比2001年和2015年武汉地区不同程度城镇化下垫面条件的模拟结果,发现城镇化改变并加剧了武汉市暴雨进程,导致暴雨范围和暴雨中心降雨量增大,暴雨持续时间缩短。在城镇面积增长了约81%的条件下,武汉市“7.23”极端暴雨24 h累积降水大于50 mm的区域增加了503.2 km^(2),特大暴雨事件面积在高城镇化条件下增长了81.8 km^(2),暴雨时长缩短了约1 h。城镇化水平显著提高后,反映低层大气稳定状况的K指数偏大,整个武汉地区更易发生极端暴雨事件;影响暴雨的最大不稳定能量范围扩大,消耗更加迅速,低层大气温度的升高也为对流运动提供了充足的热力条件,导致城市上方对流运动更加剧烈,缩短了暴雨持续时间的同时加剧了整场暴雨事件的强度。
With the acceleration of urbanization,the impact of urbanization on extreme rainfall events has attracted more and more attentions in recent years.In this study,the weather research and forecasting 3.6 model(WRF3.6)coupled with single-layer urban canopy model(UCM)is adopted to simulate the extreme precipitation event occurred on July 23,2015(the“7.23”extreme rainstorm for short)in Wuhan City,and to analyze the impact of urban underlying surface expansion on the rainstorm process and explore its potential mechanism.By comparing the simulation results of underlying surface conditions of different urbanization levels in Wuhan City in 2001 and 2015,it is found that urbanization changes and intensifies the rainstorm process in Wuhan City,leading to the increase of rainstorm range and rainstorm center rainfall,and the shortening of rainstorm duration.As the urban area increased by about 81%from 2001 to 2015,the area with 24 h cumulative precipitation greater than 50 mm increased 503.2 km^(2) under the condition of the“7.23”extreme rainstorm in Wuhan City.Under the high urbanization condition,the area of extreme rainstorm event increased by 81.8 km^(2) and rainstorm duration decreased by about 1 h.With the significant increase of urbanization level,the K index reflecting the stability of the lower atmosphere is slightly larger,and the whole study area is more prone to extreme rainstorms.As an important parameter affecting rainstorms,the convective available potential energy(CAPE)under increased urbanization expands to larger area and consumes more rapidly.The rising temperature of lower atmosphere provides sufficient thermal conditions for convection movement,resulting in more intense convective movement over the city,which shortens the duration of the rainstorm,and exacerbates the intensity of the entire rainstorm event.
作者
张怀谷
程磊
刘攀
夏倩
程淑婕
ZHANG Huaigu;CHENG Lei;LIU Pan;XIA Qian;CHENG Shujie(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China;Hubei Key Laboratory of Water System Science for Sponge City Construction(Wuhan University),Wuhan 430072,China)
出处
《武汉大学学报（工学版）》
CAS
CSCD
北大核心
2023年第6期669-678,共10页
Engineering Journal of Wuhan University
基金
国家自然科学基金项目(编号:41890822
51879193
51961145104)。
关键词
城镇化
WRF
武汉
暴雨
潜在机理
urbanization
WRF
Wuhan City
rainstorm
underlying mechanism
