Tropospheric pathways of the late-winter ENSO teleconnection to Europe

Autor: Bianca Mezzina, Javier García-Serrano, Tercio Ambrizzi, Daniela Matei, Elisa Manzini, Ileana Bladé
Přispěvatelé: Barcelona Supercomputing Center
Rok vydání: 2022
Předmět:
Zdroj: Climate Dynamics
ISSN: 1432-0894
0930-7575
DOI: 10.1007/s00382-022-06508-6
Popis: The late-winter signal associated with the El Niño-Southern Oscillation (ENSO) over the European continent is unsettled. Two main anomalous patterns of sea-level pressure (SLP) can be identified: a “wave-like” pattern with two opposite-signed anomalies over Europe, and a pattern showing a single anomaly (“semi-isolated”). In this work, potential paths of the tropospheric ENSO teleconnection to Europe and their role in favoring a more wave-like or semi-isolated pattern are explored. Outputs from historical runs of two versions of the MPI-ESM coupled model, which simulate these two types of patterns, are examined. A novel ray-tracing approach that accounts for zonal asymmetries in the background flow is used to test potential propagation paths in these simulations and in observations; three source regions are considered: the tropical Pacific, the North America/North Atlantic, and the tropical Atlantic. The semi-isolated pattern is suggested to be related to the well-known Rossby wave train emanating from the tropical Pacific, either via a split over northern North America or via reflection due to inhomogeneities in the background flow. The wave-like pattern, in turn, appears to be related to a secondary wave train emerging from the tropical Atlantic. The competition between these two pathways contributes to determining the actual surface response. B.M. and J.G.-S. were supported by the “Contratos Predoctorales para la Formación de Doctores” (BES-2016-076431) and “Ramón y Cajal” (RYC-2016-21181) programmes, respectively. Tercio Ambrizzi was supported by the National Institute of Science and Technology for Climate Change Phase 2 under CNPq Grant 465501/2014-1, 301397/2019-8; FAPESP Grants 2014/50848-9 and 2017/09659-6. This study also received funding from the Spanish ATLANTE project (PID2019-110234RB-C21). We acknowledge the World Climate research Programme’s Working Group on Coupled Modelling, which is responsible for CMIP. Technical support at BSC (Computational Earth Sciences group) is sincerely acknowledged. We also thank the two anonymous reviewers for their valuable insights.
Databáze: OpenAIRE
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