四川盆地不同落区的三次强降水过程多尺度特征分析  

Analysis of Multi-scale Characteristics of Three Different Types of Heavy Rainfall in Sichuan Basin

作　　者：陈双 孙继松 何立富[1] CHEN Shuang;SUN Jisong;HE Lifu(National Meteorological Centre,Bejing 100081;Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210009,Jiangsu,China;State key Laboratory of Server Weather,Chinese Academy of Meteorological Science,Beijing 100081,China)

机构地区：[1]国家气象中心,北京100081 [2]南京气象科技创新研究院,江苏南京210009 [3]中国气象科学研究院灾害天气国家重点实验室,北京100081

出　　处：《高原气象》2022年第5期1190-1208,共19页Plateau Meteorology

基　　金：国家重点研发计划项目(2018YFC1507201);国家自然科学基金重点项目(91937301);公益性行业(气象)科研项目(GYHY201506006)。

摘　　要：利用ERA-5逐小时再分析资料,结合加密自动站、常规探空、组网雷达资料等对2013年夏季四川盆地三次落区不同的暴雨过程进行对比分析,揭示了不同尺度天气系统在地形和不同大气稳定度环境条件下的动力学过程对对流系统移动传播、结构演变等方面的影响.结果表明:6月19-20日的"盆地西部型"暴雨过程,由夜间加强的700 hPa偏南暖湿气流沿川西高原陡坡地形触发,初始对流系统表现为沿高原边坡的细长直线型回波带,受沿盆地边沿对流冷池与低层暖湿东南气流的相互作用影响,成熟期的MCSs(中尺度对流系统)表现为具有后向传播特征的右移风暴,向盆地中部方向发展并逐渐远离高原地形,当对流系统前侧的暖湿入流显著减弱后,对流系统减弱消散;6月29日至7月1日的"盆地中部型"暴雨过程,是一次长生命史对流降水过程,与"西南涡"系统演变有关,对流系统首先在盆地700 hPa暖湿舌轴线上、沿着低层浅薄暖性低涡外侧(850 hPa以下)的斜压锋区上被触发,并沿对流层中层低空急流轴线的左侧组织成线状对流系统,对流生成后其南端产生的浅薄冷池出流,在环境暖湿气流作用下,触发新的对流,并向θ_(se)(假相当位温)高值区发展,对流系统由"线型"逐渐演变为"弧线型",后期随着涡旋状气流向对流层中层倾斜发展,假相当位温锋区上的气旋式辐合流场不断触发新生对流,对流系统逐渐演变为位于盆地中部的类似于螺旋雨带分布,当对流层中低层随高度倾斜分布的低涡中心逐渐重合,螺旋状对流雨带逐渐向低涡中心收缩并最终消失;7月4-5日的"盆地周边型"暴雨过程,与冷空气越过秦岭-大巴山、从盆地西北侧侵入盆地的过程直接相关,对流系统最先通过冷空气沿盆地西部边沿陡峭地形触发形成,随着冷空气向南推进,对流"移动"至盆地西南部地形边沿地带,随着盆地冷空气在盆地西部堆积�By using ERA-5 reanalysis data,combined with intensive automatic stations,conventional soundings,and networked radar data,a comparative analysis of three different rainstorm processes in Sichuan Basin during the summer of 2013 is made and the influence that different scale weather systems on the movement,propagation and structural evolution of convective systems under different atmospheric stability conditions and topography is revealed.Results show that:the heavy rain process occurred in the western of Sichuan Basin from19th to 20th June(hereinafter referred to the Western Basin Type case)was triggered by the 700 hPa southerly warm and wet airflow that strengthened at night along the steep slope of the Chuanxi Plateau.The convective system appeared as a slender linear pattern along the plateau slope at the initial stage,then it was affected by the interaction between the convective cold pool along the edge of the basin and the low-level warm and wet southeast airflow.The mature MCSs(Meso-scale Convective Systems)manifested as a rightward shifting storm with backward propagation characteristics,which developed toward the middle of the basin and gradually moved away from the plateau topography.As the warm and wet inflow on the front side of the convection system significantly weakened,the convection system weakened and dissipated.The heavy rain process occurred in the central of sichuan basin from 29th June to 1st July(hereinafter referred to the Central Basin Type case)was a long-life history convective precipitation process,which was related to the evolution of the southwest vortex system.The convective system was triggered on the baroclinic front area outside the low-level shallow warm vortex(below 850hPa)along the 700 hPa warm and wet tongue,and it was organized into a linear convection system along the left side of the low-level jet axis in the middle troposphere.After convection was generated,through the interaction between the outflow of the shallow cold pool generated from the southern part of the convecti

关 键 词：四川盆地 强降水 中尺度对流系统 对流冷池 

分 类 号：P458.2[天文地球—大气科学及气象学]