Atlantic origin of observed and modelled freshwater anomalies in the Nordic Seas.

Gleßmer, Mirjam S. , Eldevik, Tor, Våge, Kjetil, Øie Nilsen, Jan Even and Behrens, Erik (2014) Atlantic origin of observed and modelled freshwater anomalies in the Nordic Seas. Nature Geoscience, 7 (11). pp. 801-805. DOI 10.1038/ngeo2259.

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Abstract

Between 1965 and 1990, the waters of the Nordic Seas and the subpolar basins of the North Atlantic Ocean freshened substantially1. The Arctic Ocean also became less saline over this time, as a consequence of increasing runoff1, 2, 3, 4, but it is not clear whether flow from the Arctic Ocean was the main source of the Nordic Seas salinity anomaly. As a region of deep-water formation, the Nordic Seas are central to the Atlantic meridional overturning circulation, but this process is inhibited if the surface salinity is too low2. Here we use the instrumental record of Nordic Seas hydrography, along with a global ocean–sea-ice model hindcast simulation, to identify the sources and magnitude of freshwater that has accumulated in the Nordic Seas since 1950. We find that the freshwater anomalies within the Nordic Seas can mostly be explained by less salt entering the southern part of the basin with the relatively saline Atlantic inflow, with seemingly little contribution from the Arctic Ocean. We conclude that hydrographic changes in the Nordic Seas are primarily related to changes in the Atlantic Ocean. We infer that if the Atlantic inflow and Nordic Seas both freshen similarly, this would render the Atlantic meridional overturning circulation relatively insensitive to Nordic Seas freshwater content.

Document Type: Article
Additional Information: WOS:000344812100011
Keywords: REVISED CIRCULATION SCHEME; NORTHERN NORTH-ATLANTIC; DENMARK STRAIT; SUBPOLAR GYRE; VARIABILITY; SALINITY; OVERFLOW; CLIMATOLOGY; OCEAN; FLUX
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
Kiel University
Refereed: Yes
Open Access Journal?: No
Publisher: Nature Publishing Group
Date Deposited: 03 Nov 2014 13:22
Last Modified: 03 Apr 2018 12:04
URI: https://oceanrep.geomar.de/id/eprint/25937

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