The ENSO modulation on the relationship between the Madden‐Julian Oscillation (MJO) and major stratospheric sudden warming (SSW) in the Northern Hemisphere winter is analyzed. The results indicate that the statistical relationship between the MJO and SSWs is robust during La Niña years but almost nonexistent during El Niño years. During La Niña years, a significant response of stratospheric temperature appears after certain MJO phases with a distribution consistent with MJO periodicity, whereas the response becomes nonsignificant during El Niño years. Further analysis indicates that ENSO influences the MJO‐related geopotential height anomalies in middle to high latitudes of the upper troposphere, which leads to an increase in wavenumber 2 in La Niña winters. And wavenumber 2 plays a key role in generating the strong heat flux anomalies in the stratosphere. The results may help to explain the more frequent occurrence of extreme events in the stratosphere, such as SSW during La Niña winters.

中文翻译：

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ENSO对平流层突然变暖与马丹－朱利安振荡之间关系的调制

分析了北半球冬季Madden-Julian涛动（MJO）与平流层突然增温（SSW）之间关系的ENSO调制。结果表明，MJO和SSW之间的统计关系在拉尼娜年期间是稳健的，但在厄尔尼诺年期间几乎不存在。在拉尼娜年期间，在某些MJO阶段之后，平流层温度出现了显着响应，其分布与MJO周期一致，而在厄尔尼诺年期间，该响应变得不显着。进一步的分析表明，ENSO影响了对流层中高纬度地区与MJO相关的地势高度异常，这导致拉尼娜冬季的2波数增加。2号波在平流层中产生强烈的热通量异常中起着关键作用。结果可能有助于解释平流层极端事件的发生频率，例如拉尼娜冬季的南太平洋。