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Experimental evidence of long-term oceanic circulation reversals without wind influence in the North Ionian Sea

Authors :
M. E. Negretti
Boris Petelin
Miroslav Gačić
Laura Ursella
Vlado Malačič
Mirko Orlić
Angelo Rubino
Davide Zanchettin
Vanessa Cardin
Vedrana Kovačević
Manuel Bensi
Giuseppe Civitarese
Giuseppe Siena
Milena Menna
Joël Sommeria
Ricardo Viana Barreto
Department of Environmental Sciences, Informatics and Statistics [Venezia]
University of Ca’ Foscari [Venice, Italy]
Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS)
Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI)
Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )
Université Grenoble Alpes (UGA)
Source :
Scientific Reports, Scientific Reports, Nature Publishing Group, 2020, ⟨10.1038/s41598-020-57862-6⟩, Scientific Reports, Vol 10, Iss 1, Pp 1-9 (2020)
Publication Year :
2020

Abstract

Under the emerging features of interannual-to-decadal ocean variability, the periodical reversals of the North Ionian Gyre (NIG), driven mostly by the mechanism named Adriatic-Ionian Bimodal Oscillating System (BiOS), are known as impacting on marine physics and biogeochemistry and potentially influencing short-term regional climate predictability in the Eastern Mediterranean. Whilst it has been suggested that local wind forcing cannot explain such variability, aspects of the alternative hypothesis indicating that NIG reversals mainly arises from an internal ocean feedback mechanism alone remain largely debated. Here we demonstrate, using the results of physical experiments, performed in the world’s largest rotating tank and numerical simulations, that the main observed feature of BiOS, i.e., the switch of polarity of the near-surface circulation in the NIG, can be induced by a mere injection of dense water on a sloping bottom. Hence, BiOS is a truly oceanic mode of variability and abrupt polarity changes in circulation can arise solely from extreme dense water formation events.

Details

Language :
English
ISSN :
20452322
Database :
OpenAIRE
Journal :
Scientific Reports, Scientific Reports, Nature Publishing Group, 2020, ⟨10.1038/s41598-020-57862-6⟩, Scientific Reports, Vol 10, Iss 1, Pp 1-9 (2020)
Accession number :
edsair.doi.dedup.....3ea92165840285091b51dc7d502a9cf6
Full Text :
https://doi.org/10.1038/s41598-020-57862-6⟩