Liang Yu, Xie Shang-Ping, Fedorov Alexey, Yeager Stephen G
Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA.
Sci Adv. 2025 Sep 12;11(37):eadv8621. doi: 10.1126/sciadv.adv8621. Epub 2025 Sep 10.
The El Niño-Southern Oscillation (ENSO) is a key driver of global climate variability. Early-season westerly wind bursts (WWBs) have long been suggested to be important for ENSO evolution and diversity, with the Madden-Julian Oscillation (MJO) among the main sources of WWBs. However, MJO's contribution to ENSO evolution has been difficult to quantify. Here, using an ensemble hindcast approach specifically designed to isolate internal atmospheric variability, we evaluate the influences of March MJO on subsequent ENSO development. Our results show that the March MJO, under favorable background conditions, by itself has limited impacts on ENSO due to weak equatorial air-sea coupling in spring. In comparison, the North Pacific Oscillation-induced meridional mode exerts a more sustained influence on ENSO evolution. A cyclonic circulation anomaly over Hawaii, associated with the Pacific-North American pattern, also plays a role. These findings suggest that March MJO activity alone may not be a reliable predictor for ENSO evolution, but underscore the importance of North Pacific atmospheric variability.
厄尔尼诺-南方涛动（ENSO）是全球气候变率的一个关键驱动因素。长期以来，早季西风爆发（WWBs）被认为对ENSO的演变和多样性很重要，其中马登-朱利安振荡（MJO）是WWBs的主要来源之一。然而，MJO对ENSO演变的贡献一直难以量化。在此，我们使用一种专门设计用于分离内部大气变率的集合后报方法，评估3月MJO对随后ENSO发展的影响。我们的结果表明，在有利的背景条件下，由于春季赤道海气耦合较弱，3月MJO本身对ENSO的影响有限。相比之下，北太平洋涛动引起的经向模态对ENSO演变有更持续的影响。与太平洋-北美型态相关的夏威夷上空的气旋环流异常也起到了一定作用。这些发现表明，仅3月MJO活动可能不是ENSO演变的可靠预测指标，但强调了北太平洋大气变率的重要性。
