Abrupt warming and salinification of intermediate waters interplays with decline of deep convection in the Northwestern Mediterranean Sea

Margirier, Félix; Testor, Pierre; Heslop, Emma; Mallil, Katia; Bosse, Anthony; Houpert, Loïc ORCID: https://orcid.org/0000-0001-8750-5631; Mortier, Laurent; Bouin, Marie-Noëlle; Coppola, Laurent; D’Ortenzio, Fabrizio; Durrieu de Madron, Xavier; Mourre, Baptiste; Prieur, Louis; Raimbault, Patrick; Taillandier, Vincent. 2020 Abrupt warming and salinification of intermediate waters interplays with decline of deep convection in the Northwestern Mediterranean Sea. Scientific Reports, 10 (1), 20923. https://doi.org/10.1038/s41598-020-77859-5

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Official URL: http://dx.doi.org/10.1038/s41598-020-77859-5

Abstract/Summary

The Mediterranean Sea is a hotspot for climate change, and recent studies have reported its intense warming and salinification. In this study, we use an outstanding dataset relying mostly on glider endurance lines but also on other platforms to track these trends in the northwestern Mediterranean where deep convection occurs. Thanks to a high spatial coverage and a high temporal resolution over the period 2007–2017, we observed the warming (+0.06 ∘C year−1) and salinification (+0.012 year−1) of Levantine Intermediate Water (LIW) in the Ligurian Sea. These rates are similar to those reported closer to its formation area in the Eastern Mediterranean Sea. Further downstream, in the Gulf of Lion, the intermediate heat and salt content were exported to the deep layers from 2009 to 2013 thanks to deep convection processes. In 2014, a LIW step of +0.3 ∘C and +0.08 in salinity could be observed concomitant with a weak winter convection. Warmer and more saline LIW subsequently accumulated in the northwestern basin in the absence of intense deep convective winters until 2018. Deep stratification below the LIW thus increased, which, together with the air–sea heat fluxes intensity, constrained the depth of convection. A key prognostic indicator of the intensity of deep convective events appears to be the convection depth of the previous year.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1038/s41598-020-77859-5
ISSN:	2045-2322
Date made live:	10 Dec 2020 13:03 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/529129

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1038/s41598-020-77859-5

ISSN:

2045-2322

Date made live:

10 Dec 2020 13:03 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/529129