Influence of the Quasi‐Biennial Oscillation on the Spatial Structure of the Wintertime Arctic Oscillation
Influence of the Quasi‐Biennial Oscillation on the Spatial Structure of the Wintertime Arctic Oscillation
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DOI：
10.1029/2021jd035564
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发表时间：
2022-04
期刊：
影响因子：
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通讯作者：
Qingyu Cai;Wen Chen;Shangfeng Chen;Tianjiao Ma;C. Garfinkel
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文献类型：
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作者：
Qingyu Cai;Wen Chen;Shangfeng Chen;Tianjiao Ma;C. Garfinkel
研究表明，准两年生振荡（QBO）对北方冬季北极振荡（AO）的空间结构有显著影响。特别是在QBO的西风相（WQBO）期间，AO的北太平洋中心（NPC）比QBO的东风相（EQBO）更强。换句话说，尽管总体变率对QBO期不敏感，但WQBO年与北太平洋AO相关的变率比EQBO年强。QBO主要通过调节平流层极涡的强度来影响冬季AO的空间格局，其中WQBO年平流层极涡较EQBO年强。一个较强的平流层极涡可以导致更多的行星波折射，并促进波活动通量从中纬度北太平洋向东传播到北大西洋。因此，建立了北太平洋和北大西洋大气变率之间的增强联系，并且在WQBO年出现了更突出的AO NPC。此外，QBO和相关物理过程对AO结构的调制得到了CNRM‐CM6‐1模式输出的支持。结果表明，在基于AO的北美季节气候预测中，WQBO的可预测信号较大，而EQBO的可预测信号较弱。
This study reveals that the Quasi‐Biennial Oscillation (QBO) has a marked impact on the spatial structure of the Arctic Oscillation (AO) in boreal winter. In particular, the North Pacific center (NPC) of the AO is stronger during the westerly phase of the QBO (WQBO) than the easterly phase of the QBO (EQBO). In other words, the variability associated with the AO over the North Pacific is stronger in WQBO years than EQBO years, even though the overall variability is insensitive to QBO phase. The QBO is suggested to influence the spatial pattern of the winter AO mainly via modulating the intensity of the stratospheric polar vortex, with a stronger stratospheric polar vortex during WQBO than EQBO years. A stronger stratospheric polar vortex can lead to more planetary wave refraction and facilitate the eastward propagation of wave activity flux from the mid‐latitude North Pacific to the North Atlantic. Thus an enhanced connection between North Pacific and North Atlantic atmospheric variability is established, and a more prominent NPC of the AO occurs in WQBO years. In addition, the modulation of the AO structure by the QBO and the associated physical process is supported by output from the CNRM‐CM6‐1 model. Our results indicate that, for seasonal climate prediction in North America based on the AO, WQBO leads to a larger predictable signal while EQBO leads to reduced skill.