Impact of the Atlantic multidecadal oscillation (AMO) on the interannual relationship between the El Niño‐Southern Oscillation (ENSO) and East Asian early summer monsoon (EAESM) is investigated using observations and community atmosphere model (CAM) outputs. We find that the interannual ENSO–EAESM relationship displays a prominent decadal variation during 1951–2018, which is consistent with the AMO phase change, that is, a high ENSO–EAESM correlation appears during the negative AMO phase, while no significant correlation is found during the positive AMO phase. Further analyses reveal that the AMO‐related sea surface temperature anomalies (SSTAs) in the western North Pacific, rather than in the North Atlantic, modulate the interannual relationship between the El Niño and EAESM. These SSTAs can prolong the existence of the anomalous western North Pacific anticyclone (WNPAC) from the ENSO mature winter to the subsequent early summer, thus affecting the ENSO–EAESM relationship for the El Niño events. In contrast, the AMO modulates the interannual relationship between the La Niña and EAESM through the North Atlantic and North Pacific. The North Atlantic warming‐induced anomalous anticyclone weakens the background cyclone over the western North Pacific during the positive AMO phase, and the mid‐latitude air–sea interaction in the North Pacific also influence the anomalous cyclone. The observed AMO's impact on the interannual relationship between the ENSO and EAESM is confirmed by atmosphere general circulation model simulations using the CAM.

中文翻译：

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大西洋年代际振荡对ENSO与东亚初夏季风之间年际关系的影响

大西洋多年代际振荡（AMO）对厄尔尼诺-南方涛动（ENSO）与东亚初夏季风（EAESM）之间的年际关系的影响是利用观测和社区大气模型（CAM）的输出进行的。我们发现，1951-2018年期间年际ENSO-EAESM关系显示出显着的年代际变化，这与AMO相变一致，也就是说，在负AMO阶段出现了高ENSO-EAESM相关性，但未发现显着相关性在积极的AMO阶段。进一步的分析表明，在北太平洋西部而不是北大西洋，与AMO有关的海表温度异常（SSTA）调节了厄尔尼诺现象与EAESM之间的年际关系。从ENSO成熟的冬季到随后的初夏，这些SSTA可以延长北太平洋西部反气旋（WNPAC）异常的存在，从而影响厄尔尼诺事件的ENSO-EAESM关系。相反，AMO通过北大西洋和北太平洋调节拉尼娜和EAESM之间的年际关系。在积极的AMO阶段，北大西洋变暖诱发的反气旋异常减弱了北太平洋西部的本底旋风，并且北太平洋中纬度的海-气相互作用也影响了异常旋风。通过使用CAM进行的大气总体环流模型模拟，可以确认观测到的AMO对ENSO和EAESM之间的年际关系的影响。