Non-linearity in the pathway of El Niño-Southern Oscillation to the tropical North Atlantic

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ID Serval
serval:BIB_AE1A110FEEDC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Non-linearity in the pathway of El Niño-Southern Oscillation to the tropical North Atlantic
Périodique
Journal of Climate
Auteur⸱e⸱s
Casselman Jake W., Taschetto Andréa S., Domeisen Daniela I.V.
ISSN
0894-8755
1520-0442
Statut éditorial
Publié
Date de publication
02/06/2021
Peer-reviewed
Oui
Pages
1-54
Langue
anglais
Résumé
El Niño–Southern Oscillation can influence the tropical North Atlantic (TNA), leading to anomalous sea surface temperatures (SSTs) at a lag of several months. Several mechanisms have been proposed to explain this teleconnection. These mechanisms include both tropical and extratropical pathways, contributing to anomalous trade winds and static stability over the TNA region. The TNA SST response to ENSO has been suggested to be nonlinear. Yet the overall linearity of the ENSO–TNA teleconnection via the two pathways remains unclear. Here we use reanalysis data to confirm that the SST anomaly (SSTA) in the TNA is nonlinear with respect to the strength of the SST forcing in the tropical Pacific, as further increases in El Niño magnitudes cease to create further increases of the TNA SSTA. We further show that the tropical pathway is more linear than the extratropical pathway by subdividing the interbasin connection into extratropical and tropical pathways. This is confirmed by a climate model participating in the CMIP5. The extratropical pathway is modulated by the North Atlantic Oscillation (NAO) and the location of the SSTA in the Pacific, but this modulation insufficiently explains the nonlinearity in TNA SSTA. As neither extratropical nor tropical pathways can explain the nonlinearity, this suggests that external factors are at play. Further analysis shows that the TNA SSTA is highly influenced by the preconditioning of the tropical Atlantic SST. This preconditioning is found to be associated with the NAO through SST-tripole patterns.
Mots-clé
Dynamics, ENSO, Teleconnections, Tropical variability
Web of science
Création de la notice
07/10/2022 18:23
Dernière modification de la notice
09/07/2024 16:26
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