一次高原低涡诱发西南低涡耦合加强的动力诊断分析  

Dynamic diagnosis of the strengthened Southwest Vortex coupling induced by the Plateau Vortex

作　　者：刘晓冉[1] 李国平[2] 胡祖恒 李永华[1] LIU Xiaoran;LI Guoping;HU Zuheng;LI Yonghua(Chongqing Climate Center,Chongqing 401147,China;School of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225,China)

机构地区：[1]重庆市气候中心,重庆4011472 [2]成都信息工程大学大气科学学院,成都610225

出　　处：《气象科学》2020年第3期363-373,共11页Journal of the Meteorological Sciences

基　　金：国家重点研发计划项目(2018YFC1507200);国家自然科学基金资助项目(41675057,41765003);中国气象局气候变化专项(CCSF202020);重庆市气象局重点业务建设项目。

摘　　要：利用2013年6月29日-7月2日期间逐6 h的NCEP 0. 5°×0. 5°全球预报场再分析GFS (Global Forecast System)资料,对一次引发特大暴雨的西南低涡和高原低涡耦合贯通加强过程进行动力诊断分析,结果表明:西南低涡和高原低涡耦合区上方在不同阶段均维持正涡度柱,呈现低空辐合和高空辐散的特征,并伴有强烈上升运动。垂直运动在耦合开始阶段最强,正涡度柱在耦合强盛阶段显著增强,高原低涡和西南低涡耦合贯通后,改变了涡度的垂直特征。西南低涡发展维持的涡动动能主要源于水平通量散度项和涡动动能制造项,摩擦耗散项和垂直通量散度项是其主要消耗项。高原低涡发展维持的涡动动能主要源于垂直通量散度项和区域平均动能与涡动动能之间的转换项,涡动动能制造项出现负值是其涡动动能减弱的主要原因。耦合期间强烈垂直运动将西南低涡的涡动动能向高原低涡输送,西南低涡对高原低涡发展维持有重要动力作用。By using the NCEP 0.5°×0.5°GFS(Global Forecast System)data from June 29 to July 2 in 2013,the dynamic diagnostic process coupled with a Southwest Vortex and a Plateau Vortex was analyzed.The main results show that:The coupling region of the Southwest Vortex and the Plateau Vortex remains the positive vorticity column,low level convergence and high level divergence characteristics,and a strong upward motion at various stages.The vertical movement is strongest at the beginning state of the coupling process.The positive vorticity column significantly enhance at the powerful stage of the coupling process.The vertical characteristics of vorticity are changed after the coupling of the Southwest Vortex and the Plateau Vortex.The eddy kinetic energy of the development and maintenance of Southwest Vortex mainly due to the horizontal flux divergence term and the generation term of kinetic energy.The dissipation term and vertical flux divergence term are the main consumption items of the Southwest Vortex.The eddy kinetic energy of the development and maintenance of the Plateau Vortex mainly due to vertical flux divergence term and the conversion term.The negative generation term is the main weakness reason of the Plateau Vortex eddy kinetic energy.During the coupling period,strong vertical motion transports the eddy kinetic energy of the Southwest Vortex to the Plateau Vortex,which plays an important dynamic role in maintaining the development of the Plateau Vortex.

关 键 词：西南低涡 高原低涡 强降水 动力诊断 

分 类 号：P435[天文地球—大气科学及气象学]