Diverse NPMM conditions deviate the 2023/24 El Niño from the 1997/1998 and 2015/2016 extreme El Niño events
Abstract The 2023/24 El Niño commenced with an exceptionally large warm water volume in the equatorial western Pacific, comparable to the extreme 1997/98 and 2015/16 events, but did not develop into a super El Niño. This study highlights the critical role of contrasting Northern Pacific Meridional Mode (NPMM) conditions in this divergence. Warm NPMM conditions during the 1997/98 and 2015/16 events created a positive zonal sea surface temperature (SST) gradient in the equatorial western-central Pacific and enhanced Madden-Julian Oscillation (MJO) propagation, driving sustained westerly wind bursts (WWBs) and downwelling Kelvin waves that intensified both events. In contrast, the cold NPMM during 2023/24 induced a negative SST gradient and suppressed MJO activity, resulting in weaker WWBs and limited eastward wave activity, preventing the event from reaching super El Niño intensity. A 2,200-year CESM1 pre-industrial simulation corroborates these observational findings, underscoring the importance of NPMM interference in improving El Niño intensity predictions.
Authors
- Ting‐Hui Lee (ORCID: https://orcid.org/0009-0004-4073-2596)
- Jin‐Yi Yu (ORCID: https://orcid.org/0000-0001-6156-7623)
- Ruiqiang Ding (ORCID: https://orcid.org/0000-0003-4139-3843)
- Jiepeng Chen (ORCID: https://orcid.org/0000-0002-1720-6836)
- Min‐Hui Lo (ORCID: https://orcid.org/0000-0002-8653-143X)
- Huang‐Hsiung Hsu (ORCID: https://orcid.org/0000-0001-9919-4404)
- Fei Zheng (ORCID: https://orcid.org/0000-0001-6135-6148)
- Xin Wang (ORCID: https://orcid.org/0000-0002-8839-8345)
- Lingling Liu (ORCID: https://orcid.org/0000-0002-5308-1321)
- Chau-Ron Wu
- Mengyan Chen (ORCID: https://orcid.org/0000-0001-7626-3542)
- Yong-Fu Lin
Institutions
- National Taiwan Normal University (TW)
- National Taiwan University (TW)
- Chinese Academy of Sciences (CN)
- University of California, Irvine (US)
- Beijing Normal University (CN)
- Institute of Oceanology (CN)
- South China Sea Institute Of Oceanology (CN)
- Irvine University (US)
- Research Center for Environmental Changes, Academia Sinica (TW)
- Institute of Atmospheric Physics (CN)
- Academia Sinica (TW)
Publication Details
- Journal
- npj Climate and Atmospheric Science
- Published
- 2025-03-31
- DOI
- https://doi.org/10.1038/s41612-025-01013-z
- Citations
- 3
- Primary Topic
- Climate variability and models
- Type
- article
- Field-Weighted Citation Impact
- 3.32