两次不同生命史东移高原涡的动力结构与成因分析  

Analysis of the Dynamical Structure and Genesis of Two Different Life-History Eastward Moving Plateau

作　　者：屠妮妮[1,2] 郁淑华 李跃清[1,2] TU Nini;YU Shuhua;LI Yueqing(Chengdu Institute of Plateau Meteorology,Chengdu 610072,Sichuan,China;Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province.China Meteorological Administration,Chengdu 610072,Sichuan,China)

机构地区：[1]中国气象局成都高原气象研究所,四川成都610072 [2]高原与盆地暴雨旱涝灾害四川省重点实验室,四川成都610072

出　　处：《高原气象》2024年第1期73-87,共15页Plateau Meteorology

基　　金：国家自然科学基金项目(91937301)

摘　　要：利用NCEP再分析资料对2008年6月25-27日和2013年6月4-10日两次东移出高原的高原涡过程进行结构特征和演变机制的诊断分析,探讨两次长、短路径高原涡过程的结构特征和造成不同生命史的影响因子。结果表明:(1)路径短的扎多涡活动过程中,南亚高压呈扁平状,高空急流偏南,高原涡处在下滑槽中移出高原;路径长的曲麻莱涡活动过程中,南亚高压有些北拱,高原涡处在南亚高压脊前西北气流下空,副高偏南,高原涡随低槽东移加强,并伴有西南涡东移。(2)两次高原涡过程结构特征差异明显,主要表现在扎多涡在高原上增强时、曲麻莱涡与西南涡耦合及之后再度加强时的结构特征,前者低涡处在600~350 hPa较深厚的正涡度、上升运动层内,还具有对流层高层强辐散的结构特征;后者具有对流层高、中、低层正涡度贯通、对流层内为上升运动、对流层低层辐合,对流层高层弱辐散的结构特征,其中对流层低层由整个对流层内为最强正涡度,演变为整个对流层内为最强正涡度、最强上升运动、最强辐合。(3)总涡度收支诊断表明,散度项变化对低涡总涡度变率变化起决定性作用。扎多涡的强度变化与散度项变化一致。曲麻莱涡在与西南涡伴行过程中,垂直输送项、水平平流项的影响在加强。(4)涡中心区500 hPa正涡度变率的收支分析看出,高原涡在没有西南涡活动时,对高原涡的500 hPa正涡度变率贡献的主要是涡度辐合造成的;在有西南涡活动时,随着与西南涡垂直方向叠合、伴行,正涡度垂直输送显得更加重要。The NCEP reanalysis data were utilized to diagnose the structural characteristics and evolutionary mechanisms of two plateau vortex processes that moved eastward out of the plateau on June 25-27,2008 and June 4-10,2013.The data were also used to explore the structural characteristics of the two long and short track plateau vortex processes and the influencing factors that caused their different life histories.The results show that:(1)During the Zhaduo vortex activity with a short path,the South Asian high pressure is flattened,the upper-level jet stream is southward and the plateau vortex moves out of the plateau in the slump trough.During the Qumalai vortex activity with a long path,the South Asian high pressure has a north arch,the plateau vortex is in the northwest airflow under the South Asian high-pressure ridge,the subtropical high is southward and the plateau vortex is strengthened with the eastward movement of the trough,accompanied by the eastward movement of the southwest vortex.(2)The two plateau vortex processes exhibit distinct structural characteristics,especially when the Zhaduo vortex is strengthened on the plateau and when the Qumalai vortex is strengthened again after coupling with the southwest vortex.The former vortex is in the deeper positive vorticity and upward motion layer at 600~350 hPa and also has the structural characteristics of strong divergence in the upper troposphere.The latter has the structural characteristics of high,middle,and low positive vorticity penetration in the troposphere,ascending movement in the troposphere,and weak divergence in the troposphere.(3)The diagnosis of total vorticity budget shows that the change of divergence term plays a decisive role in the change of total vorticity variability of low vortices.The strength change of Zhaduo vortex is consistent with the divergence term change.The influence of vertical transport term and horizontal advection term are strengthened during the accompaniment of Qumalai vortex with the southwest vortex.(4)Regarding the budge

关 键 词：高原低涡 结构特征 涡度收支 

分 类 号：P458[天文地球—大气科学及气象学]