2016年7月四川持续性强降水的中尺度滤波分析  

Mesoscale Filtering Analysis of Persistent Heavy Rainfall in Sichuan in July 2016

作　　者：黄瑶 肖天贵[1] 刘思齐[1] HUANG Yao;XIAO Tian-gui;LIU Si-qi(College of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,China)

机构地区：[1]成都信息工程大学大气科学学院,四川成都610225

出　　处：《成都信息工程大学学报》2018年第3期307-317,共11页Journal of Chengdu University of Information Technology

基　　金：国家自然科学基金资助项目(91337215;41575066);国家科技支撑计划资助项目(2015BAC03B05)

摘　　要：为研究四川持续性强降水期间不同尺度系统相互作用机理和中尺度系统在其中扮演的重要角色,利用四川气象站点降水资料和欧洲中心再分析资料对四川省2016年7月18-23日持续性强降水天气过程进行了综合诊断分析。并运用Barnes带通滤波方法进行中尺度滤波,实现了中小尺度与大尺度的隔离。结果表明:500 h Pa副高两次西伸和东退,高原东传浅槽两次在盆地加深加强,高低空急流耦合,为降水提供大尺度环流背景。两次东移的西南涡是强降水的直接影响系统,流场上表现为低层中尺度气旋和高层中尺度反气旋,而降水间歇期则为中尺度高压控制。对降水场进行综合诊断分析可知,强降水期间层结处于高能不稳定状态,且水汽充沛,涡度和散度表现为低层气旋式辐合高层反气旋式辐散,配合深厚的垂直上升运动,为强降水提供有利的动力条件。This paper presents a comprehensive diagnostic analysis of the persistent heavy precipitation from July 18 to 23 of 2016 in Sichuan with precipitation data which from Sichuan meteorological station and reanalysis data from the European Center to study the interaction mechanism of different scale systems and the important role of mesoscale system in the continuous heavy rainfall in Sichuan. And Barnes band-pass filtering method for mesoscale filteringisusedto achieve the small and medium-sized and large-scale isolation. The results show that the 500 h Pa subtropical high extends westward and retreats eastward twice,the eastward shallow groove in the plateau deepens and intensifies twice in the basin,and the upper and lower air jets couple to provide large-scale circulation background for precipitation. The two southwestern vortexes moving eastward are the direct impact systems of heavy precipitation. The flow field shows low-level mesoscale cyclone and high-level mesoscale anticyclone,while the diapause is controlled by mesoscale high pressure. According to the comprehensive diagnosis and analysis of the precipitation field,it is found that the stratified layer is in a state of high energy instability during heavy precipitation,and the water vapor is abundant. The vorticity and divergence manifest as high-level anticyclonic divergence and low-level cyclonic convergence with a deep vertical upward movement,providing favorable dynamic conditions for heavy rainfall.

关 键 词：大气科学 天气动力学 持续性强降水 Barnes滤波 中尺度 

分 类 号：P467[天文地球—大气科学及气象学]