Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic

Type Article
Date 2020-01
Language English
Author(s) Holliday N. Penny1, Bersch Manfred2, Berx Barbara3, Chafik Léon4, Cunningham Stuart5, Florindo-López Cristian1, Hátún Hjálmar6, Johns William7, Josey Simon A.1, Larsen Karin Margretha H.6, Mulet Sandrine8, Oltmanns Marilena9, Reverdin Gilles10, Rossby Tom11, Thierry VirginieORCID12, Valdimarsson Hedinn13, Yashayaev Igor14
Affiliation(s) 1 : National Oceanography Centre, Southampton, UK
2 : Institute of Oceanography, University of Hamburg, Hamburg, Germany
3 : Marine Scotland Science, Aberdeen, Scotland, UK
4 : Department of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
5 : Scottish Association for Marine Science, Oban, Scotland, UK
6 : Faroe Marine Research Institute, Tórshavn, Faroe Islands
7 : Department of Ocean Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Coral Gables, FL, USA
8 : CLS, Ramonville-Saint-Agne, France
9 : Ocean Circulation and Climate Dynamics, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
10 : Sorbonne Université, CNRS/IRD/MNHN (LOCEAN), Paris, France
11 : Graduate School of Oceanography, University of Rhode Island, Kingston, USA
12 : Ifremer, Univ. Brest, CNRS, IRD, Laboratoire d’Océanographie Physique et Spatiale, IUEM, France
13 : Marine and Freshwater Research Institute, Reykjavik, Iceland
14 : Bedford Institute of Oceanography, Dartmouth, NS, Canada
Source Nature Communications (2041-1723) (Springer Science and Business Media LLC), 2020-01 , Vol. 11 , N. 1 , P. 585 (15p.)
DOI 10.1038/s41467-020-14474-y
WOS© Times Cited 25
Abstract

The Atlantic Ocean overturning circulation is important to the climate system because it carries heat and carbon northward, and from the surface to the deep ocean. The high salinity of the subpolar North Atlantic is a prerequisite for overturning circulation, and strong freshening could herald a slowdown. We show that the eastern subpolar North Atlantic underwent extreme freshening during 2012 to 2016, with a magnitude never seen before in 120 years of measurements. The cause was unusual winter wind patterns driving major changes in ocean circulation, including slowing of the North Atlantic Current and diversion of Arctic freshwater from the western boundary into the eastern basins. We find that wind-driven routing of Arctic-origin freshwater intimately links conditions on the North West Atlantic shelf and slope region with the eastern subpolar basins. This reveals the importance of atmospheric forcing of intra-basin circulation in determining the salinity of the subpolar North Atlantic.

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Holliday N. Penny, Bersch Manfred, Berx Barbara, Chafik Léon, Cunningham Stuart, Florindo-López Cristian, Hátún Hjálmar, Johns William, Josey Simon A., Larsen Karin Margretha H., Mulet Sandrine, Oltmanns Marilena, Reverdin Gilles, Rossby Tom, Thierry Virginie, Valdimarsson Hedinn, Yashayaev Igor (2020). Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic. Nature Communications, 11(1), 585 (15p.). Publisher's official version : https://doi.org/10.1038/s41467-020-14474-y , Open Access version : https://archimer.ifremer.fr/doc/00606/71816/