太行山地形在“7·19”华北持续性低涡暴雨中的作用  

The role of Taihang Mountain topography in“7·19”persistent low vortex rainstorm in North China

作　　者：林慧敏 闵锦忠[1] 朱利剑 徐渊 陶雅琴 LIN Huimin;MIN Jinzhong;ZHU Lijian;XU Yuan;TAO Yaqin(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster,Ministry of Education,Nanjing University of Information Science&Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室,南京210044

出　　处：《气象科学》2023年第1期46-58,共13页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(42192553)。

摘　　要：本文对2016年“7·19”华北特大暴雨进行观测分析和数值模拟,并设置了改变地形高度的敏感性试验,以探究该过程降水系统的发生发展机制以及太行山地形的作用。结果表明:(1)本次强降水过程发生在“东高西低”的有利环流形势下,受太行山地形和平原环流系统影响,低层东风急流造成强的对流性降水和低涡作用的叠置造成“7·19”华北地区持续性暴雨的维持和加强;(2)第一阶段为对流性降水,太行山东麓大气对流不稳定能量释放,大气逐渐转为稳定层结;第二阶段为低涡降水,涡度收支分析表明水平散度项和扭转项对低涡维持和发展起到了主要的正贡献,同时伴随有较强的上升运动和垂直风切变,垂直风切变的增强促使水平涡度向垂直涡度转变;(3)太行山地形在持续性暴雨中对两阶段降水、低涡和水汽的作用存在差异。地形高度敏感性试验中,地形高度增高对低层气流的阻挡和强迫抬升作用增强,使得地形降水增强,低涡路径东移,且强度增大。水平散度项使得对流层低层辐合上升运动增强,造成涡度的垂直输送,这是低涡发展和维持的重要原因之一。太行山地形阻挡截留东部平原水汽,且水汽回流加强,有利于太行山东麓水汽的输送与辐合。Based on ERA-Interim reanalysis data,data from CMORPH and China Automatic station,the observational analysis and numerical simulation of the process were carried out.The sensitivity test of Taihang Mountain topographic height was set up to explore the occurrence and development mechanism of precipitation system and the important role of Taihang Mountain topographic height.Results show that:(1)the heavy rainfall occurred in the favorable circulation situation of“high in the east and low in the west”.Influenced by the topography of Taihang mountain and plain circulation system,the superposition of strong convective precipitation and low vortex caused by low-level easterly jet lead to the maintenance and intensification of persistent heavy rain in North China on July 19.(2)In the first stage of convective precipitation,the unstable convective energy of the atmosphere at the eastern piedmont of Taihang Mountain is released,and the atmosphere gradually turns into stable stratification.The second stage of vortex precipitation begins.The horizontal divergence term and torsional term play a major positive role,accompanied by strong upward movement and vertical wind shear.The enhancement of vertical wind shear promotes the transformation from horizontal vorticity to vertical.(3)The topography of Taihang Mountain has different effects on precipitation,vortex and water vapor in the two stages of continuous heavy rain.In the topographic height sensitivity test,the elevation of topographic height enhances the blocking and forced uplift of low-level airflow,which enhances the topographic precipitation,and the vortex path moved eastward and its intensity increased.The horizontal divergence term of relative vorticity enhances the convergence ascending movement in the lower troposphere,resulting in vertical vorticity transportation,which is one of the important reasons for the development and maintenance of low vorticity.The topography of Taihang Mountain blocks and intercepts water vapor in the eastern plain,and water vapor

关 键 词：华北暴雨 持续性 数值模拟 太行山地形 低涡 

分 类 号：P426.611[天文地球—大气科学及气象学]