QBO and ENSO Effects on the Mean Meridional Circulation, Polar Vortex, Subtropical Westerly Jets, and Wave Patterns During Boreal Winter
QBO and ENSO Effects on the Mean Meridional Circulation, Polar Vortex, Subtropical Westerly Jets, and Wave Patterns During Boreal Winter
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DOI：
10.1029/2022jd036691
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发表时间：
2022-08-16
影响因子：
4.4
通讯作者：
Hitchman, Matthew H.
中科院分区：
文献类型：
--
作者：
Kumar, Vinay;Yoden, Shigeo;Hitchman, Matthew H.
通过 40 年（1979-2018）月平均 ERA-中期再分析，研究了平流层准两年期振荡（QBO）和厄尔尼诺南方涛动（ENSO）对北半球冬季极地涡旋、副热带西风急流（STJ）和波浪模式的联合影响。华莱士等人的方法。 (1993)，用于进行 QBO 相位角扫描。然后，QBO 西风 (W) 和东风 (E) 合成图像根据 ENSO 相位进行分离。描述了 QBO 平均经向环流 (MMC) 影响北冬半球的两条路径。 “平流层路径”通过霍尔顿-坦机制调节平流层行星波吸收。 “对流层路径”调节热带和副热带对流层上层和平流层下层。 QBO MMC 异常在温度上表现出棋盘图案，在纬向风中表现出拱形结构，延伸到中纬度地区，并且在冬季一侧更强。在 QBO W 期间，极涡和 STJ 增强。拉尼娜期间，极涡中的 QBO 信号会被放大。在厄尔尼诺和 QBO W 期间，出现最强的 STJ，并发现暖极/波二模式。在厄尔尼诺和 QBO E 期间，欧亚大陆上空出现一个槽，北大西洋上空出现一个脊，呈第一波模式。厄尔尼诺现象减少了热带平流层的QBO异常，并降低了QBO MMC的极地范围和幅度，从而影响了平流层路径。对北半球冬季的影响归因于 QBO 和 ENSO 通过两条路径的综合影响。
The joint influence of the stratospheric quasi-biennial oscillation (QBO) and the El Nino Southern Oscillation (ENSO) on the polar vortex, subtropical westerly jets (STJs), and wave patterns during boreal winter is investigated in 40 years (1979-2018) of monthly mean ERA-Interim reanalyses. The method of Wallace et al. (1993), is used to conduct a QBO phase angle sweep. QBO westerly (W) and easterly (E) composites are then segregated by the phase of ENSO. Two pathways are described by which the QBO mean meridional circulation (MMC) influences the northern winter hemisphere. The "stratospheric pathway" modulates stratospheric planetary wave absorption via the Holton-Tan mechanism. The "tropospheric pathway" modulates the tropical and subtropical upper troposphere and lower stratosphere. QBO MMC anomalies exhibit a checkerboard pattern in temperature and arched structures in zonal wind which extend into midlatitudes, and are stronger on the winter side. During QBO W, the polar vortex and STJs are enhanced. QBO signals in the polar vortex are amplified during La Nina. During El Nino and QBO W, the strongest STJs occur, and a warm pole/wave two pattern is found. During El Nino and QBO E, a trough is found over Eurasia and a ridge over the North Atlantic, in a wave one pattern. El Nino diminishes QBO anomalies in the tropical stratosphere and reduces the poleward extent and amplitude of the QBO MMC, thereby influencing the stratospheric pathway. Effects on the boreal winter hemisphere are attributed to the combined influence of the QBO and ENSO via both pathways.