新疆伊犁河谷2016夏季一次对流性短时强降水个例分析  

A case study of convective short-time heavy rain in Xinjiang Ili valley in 2016

作　　者：翟芃 明杰[1,2,3] ZHAI Peng;MING Jie(Key Laboratory of Mesoscale Severe Weather of Ministry of Education,School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China;Joint Center for Atmospheric Radar Research of Centre of Modern Analysis/Nanjing University(CMA/NJU),Nanjing 210023,China;Lianyungang Institute of High-Tech Research,Nanjing University,Jiangsu Lianyungang 222000,China)

机构地区：[1]南京大学大气科学学院/中尺度灾害性天气教育部重点实验室,南京210023 [2]中国气象局—南京大学天气雷达及资料应用联合开放实验室,南京210023 [3]南京大学连云港高新技术研究院,江苏连云港222000

出　　处：《气象科学》2024年第4期655-662,共8页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(42265003);国家重点研发计划重点专项资助项目(2018YFC1507103);新疆维吾尔自治区自然科学基金资助项目(2022D01C359);中央高校基本科研业务费专项资金(020714380171,020714380177)。

摘　　要：利用四维变分同化系统对ERA5再分析资料、地面站观测资料和天气雷达数据进行同化,得到了新疆伊犁河谷2016年6月17日一次对流性降水全生命史的高时空分辨率全变量分析场,并利用其对对流系统的触发和发展机制进行了分析。结果表明:此次降水过程发生在“两槽两脊”背景环流形势下,中亚低涡截断了向新疆输送的脊前西北气流,使西南气流与西北气流在新疆中部辐合,为降水提供良好的背景条件。伊犁地区南北被高山包围,产生狭管效应,吹入的西风风速增大,激发了滚涡,使上升气流位置气块不断升高,最终形成多个对流单体,产生降水。对流单体前进过程中受到山地阻挡减速,与后续单体发生合并,使对流增强,造成降水的加强。随着地形继续抬升,对流消亡。By using a four-dimensional variational assimilation system to assimilate ERA5 reanalysis data,observation data from ground station,and weather radar data,a high spatiotemporal resolution all variable analysis field of the entire life history of convective precipitation in the Ili River Valley of Xinjiang on June 17,2016 was obtained.The triggering and development mechanisms of the convective system were analyzed using this field.Results show that this precipitation process occurred under the background circulation pattern of“two troughs and two ridges”.The central Asian low vortex intercepted the northwest airflow in front of the ridge that was transported to Xinjiang,causing the southwest airflow and northwest airflow to converge in the central part of Xinjiang,providing a good background condition for precipitation.The northern and southern parts of the Ili region are surrounded by high mountains,resulting in a narrow tube effect.The westerly wind speed increases,triggering rolling vortices and causing the upward airflow position continuously rise,ultimately forming multiple convective cells and generating precipitation.During the process of advancing convective cells,they were obstructed,slowed down by mountains,and then they merged with subsequent cells,enhanced convection and resulted in increasing precipitation.As the terrain continues to rise,convection disappears.

关 键 词：伊犁河谷 对流性降水 四维变分同化 

分 类 号：P426.6[天文地球—大气科学及气象学]