南亚高压次季节尺度东西振荡对我国长江流域降水及水汽输送的影响  

The influence of subseasonal zonal oscillation of South Asian High on precipitation and moisture transportation over Yangtze River Valley

作　　者：葛家荣 任雪娟[1] GE Jiarong;REN Xuejuan(School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学大气科学学院

出　　处：《气象科学》2019年第6期711-720,共10页Journal of the Meteorological Sciences

基　　金：国家重点研发计划(2018YFC1505903);国家自然科学基金资助项目(41675067;41621005)

摘　　要：使用常规资料及HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory Model)模式,分析了早夏和晚夏期间南亚高压次季节尺度异常偏东事件和异常偏西事件发生时,我国长江流域降水及水汽输送异常特征。结果表明:早夏期间当南亚高压异常东伸时,西太平洋副热带高压可西伸至我国东南沿岸,此时,降水正异常场主要位于我国东部地区,表现为江淮区域降水异常偏多;而晚夏期间当南亚高压异常东伸时,西太平洋副热带高压的西脊点更偏东,降水正异常区位置比早夏偏西,表现为四川盆地的降水异常偏多。早夏期间,与南亚高压异常偏西事件相比,南亚高压异常偏东事件有利于更多的水汽从南方的水汽源地输送到我国江淮区域,加上此时江淮流域存在异常上升运动,动力和水汽条件共同使得江淮流域降水偏多。晚夏四川盆地地区有类似的结论。Using regular datasets and HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory Model)model,this paper investigated the characteristics of precipitation and water vapor transport in Yangtze River Valley(YRV)during anomalous eastward and westward extension events of South Asian High(SAH)on sub-seasonal time scales in early and late summers.The results show that when SAH extended eastward during early summer,the western Pacific subtropical high stretch would extend westward towards East Asian land area.In the meantime,the positive rainfall was anomaly located in eastern China with enhanced precipitation in Yangtze-Huaihe River Valley(YHRV).However,when SAH extended eastward in the late summers,the west ridge point of Western Pacific Subtropical High(WPSH)was further eastward and the positive rainfall anomaly moved more westward to middle China than in early summers,inducing the enhanced precipitation in Sichuan Basin.In the early summers,compared with the SAH s westward extension events,the SAH s eastward extension events were more conducive to water vapor transportation from south China to YHRV.The associated anomalous upward motion in YHRV together with the water vapor conditions led to the enhanced rainfall in this region.Results over Sichuan Basin in late summers were similar.

关 键 词：南亚高压 次季节尺度振荡 降水 水汽输送 轨迹 

分 类 号：F434.5[经济管理—产业经济]