The annual salinity cycle of the Denmark Strait Overflow

Opher, Jacob G., Brearley, J. Alex, Dye, Stephen R. ORCID: https://orcid.org/0000-0002-4182-8475, Pickart, Robert S., Renfrew, Ian A. ORCID: https://orcid.org/0000-0001-9379-8215, Harden, Ben E. and Meredith, Michael P. (2022) The annual salinity cycle of the Denmark Strait Overflow. Journal of Geophysical Research - Oceans, 127 (4). ISSN 2169-9275

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Abstract

The Denmark Strait Overflow (DSO) is an important source of dense water input to the deep limb of the Atlantic Meridional Overturning Circulation (AMOC). It is fed by separate currents from the north that advect dense water masses formed in the Nordic Seas and Arctic Ocean which then converge at Denmark Strait. Here we identify an annual salinity cycle of the DSO, characterized by freshening in winter and spring. The freshening is linked to freshening of the Shelfbreak East Greenland Current in the Blosseville Basin north of the Denmark Strait. We demonstrate that the East Greenland Current advects fresh pycnocline water above the recirculating Atlantic Water, which forms a low salinity lid for the overflow in Denmark Strait and in the Irminger Basin. This concept is supported by intensified freshening of the DSO in lighter density classes on the Greenland side of the overflow. The salinity of the DSO in the Irminger Basin is significantly correlated with northerly/northeasterly winds in the Blosseville Basin at a lag of 3–4 months, consistent with estimated transit times. This suggests that wind driven variability of DSO source water exerts an important influence on the salinity variability of the downstream DSO, and hence the composition of the deep limb of the AMOC.

Item Type:	Article
Additional Information:	Submitted as "Wind-driven seasonal freshening of the Denmark Strait Overflow" title changed for accepted/published.
Faculty \ School:	Faculty of Science > School of Environmental Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Collaborative Centre for Sustainable Use of the Seas Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Depositing User:	LivePure Connector
Date Deposited:	10 Feb 2022 12:30
Last Modified:	22 Dec 2022 01:43
URI:	https://ueaeprints.uea.ac.uk/id/eprint/83402
DOI:	10.1029/2021JC018139

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