Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic
Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic
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.
Holliday, N. Penny
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Bersch, Manfred
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Berx, Barbara
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Chafik, Léon
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Cunningham, Stuart
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Florindo-lópez, Cristian
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Hátún, Hjálmar
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Johns, William
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Josey, Simon A.
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Larsen, Karin Margretha H.
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Mulet, Sandrine
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Oltmanns, Marilena
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Reverdin, Gilles
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Rossby, Tom
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Thierry, Virginie
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Valdimarsson, Hedinn
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Yashayaev, Igor
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29 January 2020
Holliday, N. Penny
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Bersch, Manfred
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Berx, Barbara
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Chafik, Léon
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Cunningham, Stuart
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Florindo-lópez, Cristian
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Hátún, Hjálmar
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Johns, William
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Josey, Simon A.
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Larsen, Karin Margretha H.
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Mulet, Sandrine
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Oltmanns, Marilena
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Reverdin, Gilles
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Rossby, Tom
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Thierry, Virginie
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Valdimarsson, Hedinn
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Yashayaev, Igor
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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 and Yashayaev, Igor
(2020)
Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic.
Nature Communications, 11 (1), [585].
(doi:10.1038/s41467-020-14474-y).
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.
Text
s41467-020-14474-y
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Accepted/In Press date: 4 December 2019
Published date: 29 January 2020
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Funding Information:
The idea for this analysis emerged from the Iceland-Faroe-Scotland-Ridge Exchanges Workshop organised by Henrik Søiland, Jan Even Nilsen, Tom Rossby, Bee Berx and Karin Margretha H. Larsen, and held at the Bjerknes Centre, University of Bergen in September 2017. N.P.H. was supported by UK NERC National Capability programmes ACSIS (NE/N018044/1), the Extended Ellett Line and CLASS (NE/R015953/1), and NERC Large Grant UK OSNAP (NE/K010875/1). N.P.H., B.B., H.H., M.O. and K.M.H.L. are supported by the Blue-Action project (European Union’s Horizon 2020 research and innovation program, grant: 727852). G.R. was supported by CNRS for his contribution to SNO SSS (http://www.legos.obs-mip.fr/observations/sss/datadelivery/products). W.J. was supported through NSF OSNAP grants OCE1259398 and OCE1756231. L.C. acknowledges support through the Swedish National Space Agency (SNSA; Dnr 133/17) and the FiNNESS project. M.O. was supported by the AtlantOS project (European Union’s Horizon 2020 research and innovation program, grant: 633211) and the project RACE-Synthesis—Regional Atlantic Circulation and global Change (03F0824C) from the German Federal Ministry of Education and Research (BMBF). S.M. has been funded by the European Copernicus Marine Environment Monitoring Service. V.T. was supported by Ifremer, and the GEOVIDE (ANR-13-BS06-0014-02) and BOCATS (CTM2013-41048-P) project co-funded by the Fondo Europeo de Desarrollo Regional 2014–2020 (FEDER).
Publisher Copyright:
© 2020, The Author(s).
Identifiers
Local EPrints ID: 437874
URI: http://eprints.soton.ac.uk/id/eprint/437874
ISSN: 2041-1723
PURE UUID: 6e7898b5-f188-4ee7-8630-eaeb67a59f62
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Date deposited: 21 Feb 2020 17:31
Last modified: 05 Jun 2024 18:47
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Contributors
Author:
N. Penny Holliday
Author:
Manfred Bersch
Author:
Barbara Berx
Author:
Léon Chafik
Author:
Stuart Cunningham
Author:
Cristian Florindo-lópez
Author:
Hjálmar Hátún
Author:
William Johns
Author:
Simon A. Josey
Author:
Karin Margretha H. Larsen
Author:
Sandrine Mulet
Author:
Marilena Oltmanns
Author:
Gilles Reverdin
Author:
Tom Rossby
Author:
Virginie Thierry
Author:
Hedinn Valdimarsson
Author:
Igor Yashayaev
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