Vertical structure of variabilities in the tropical easterly jet and associated factors  

作　　者：Ye Yao Yuanyuan Guo Zhiping Wen Sihua Huang 

机构地区：[1]Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences,Fudan University,Shanghai,China [2]CMA-FDU Joint Laboratory of Marine Meteorology,Shanghai,China [3]Shanghai Key Laboratory of Ocean-land-atmosphere Boundary Dynamics and Climate Change,Fudan University,Shanghai,China [4]Jiangsu Collaborative Innovation Center for Climate Change,Nanjing,China

出　　处：《Atmospheric and Oceanic Science Letters》2023年第5期81-87,共7页大气和海洋科学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China [grant numbers 42030601 and 42205019];supported by a project funded by the China Postdoctoral Science Foundation [grant number 2022M710715]

摘　　要：热带东风急流为热带上对流层-下平流层内夏季出现的一支强东风带,其垂直范围为300-70hPa,目前其垂直结构的变化特征有待研究.本文利用经验正交函数分解研究了热带东风急流纬向垂直剖面的主要模态。第一模态表现为垂直方向上急流强度的一致变化.ENSO对第一模态的年际分量具有主导贡献,而大西洋年代际振荡和太平洋年代际振荡可能调制其年代际分量第二模态表现为热带东风急流垂直位移的年际变化.热带平流层准两年振荡不同位相的相继下传既可以直接影响对流层顶的纬向风异常,也可以通过改变海洋性大陆附近的对流异常影响热带东风急流的垂直位置.The tropical easterly jet(TEJ)is an easterly jet stream that occurs from the upper troposphere to lower stratosphere in boreal summer.Owing to its wide vertical extension from 300 to 70 hPa,the TEJ may exhibit distinct characteristics at different levels,the details of which remain thus far unclear.In this study,two empirical orthogonal function(EOF)modes of the year-to-year variability in the vertical structure of the TEJ were investigated.The leading EOF mode represents a consistent strengthening or weakening of the TE's main body in the vertical direction and varies on both interannual and interdecadal time scales.It has been suggested that ENsO can modulate this vertically consistent mode interannually,whereas the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation can influence its interdecadal variability.In contrast,the second EOF mode exhibits an out-of-phase relationship between the zonal wind anomalies of the upper troposphere and lower stratosphere,linked with the changes in the TEJ's vertical movement and dominating on the quasi-biennial time scale.The Quasi-Biennial Oscillation could contribute to variations in the TEJ's vertical movement by changing the tropopause winds as a direct pathway and inducing anomalous convection over the tropical Indian Ocean and Maritime Continent as an indirect pathway.

关 键 词：热带东风急流 垂直结构 年际变化 年代际变化 厄尔尼诺-南方涛动 平流层准两年振荡 

分 类 号：P442[天文地球—大气科学及气象学]