Srinivas G. auteur aut IRD Vialard Jérôme auteur aut IRD Liu F. auteur aut IRD Voldoire A. auteur aut IRD Izumo Takeshi auteur aut IRD Guilyardi E. auteur aut IRD Lengaigne Matthieu auteur aut IRD text journalArticle eng text/pdf reformatted digital access Extreme El Nino events have outsized impacts and strongly contribute to the El Nino Southern Oscillation (ENSO) warm/cold phase asymmetries. There is currently no consensus on the respective importance of oceanic and atmospheric nonlinearities for those asymmetries. Here, we use atmospheric and oceanic general circulation models that reproduce ENSO asymmetries well to quantify the atmospheric nonlinearities contribution. The linear and nonlinear components of the wind stress response to Sea Surface Temperature (SST) anomalies are isolated using ensemble atmospheric experiments, and used to force oceanic experiments. The wind stress-SST nonlinearity is dominated by the deep atmospheric convective response to SST. This wind-stress nonlinearity contributes to similar to 40% of the peak amplitude of extreme El Nino events and similar to 55% of the prolonged eastern Pacific warming they generate until the following summer. This large contribution arises because nonlinearities consistently drive equatorial westerly anomalies, while the larger linear component is made less efficient by easterly anomalies in the western Pacific during fall and winter. Overall, wind-stress nonlinearities fully account for the eastern Pacific positive ENSO skewness. Our findings underscore the pivotal role of atmospheric nonlinearities in shaping extreme El Nino events and, more generally, ENSO asymmetry. specialized El Nino La Nina SST Rainfall Wind stress Atmospheric nonlinearities Asymmetries PACIFIQUE 021 14 1 8122 [12 p.] 2024 2045-2322 https://www.documentation.ird.fr/hor/fdi:010090580 10.1038/s41598-024-58803-3 2045-2322 [F B010090580] https://www.documentation.ird.fr/hor/fdi:010090580 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2024-06/010090580.pdf IRD - Base Horizon / Pleins textes 2024-06-12 2025-11-06 fdi:010090580 fre