Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier Ltd. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 79 (2013): 20-39, doi:10.1016/j.dsr.2013.05.007.
Description:
The circulation and water mass transports north of the Denmark Strait are investigated using recently collected and
historical in-situ data along with an idealized numerical model and atmospheric reanalysis fields. Emphasis is placed
on the pathways of dense water feeding theDenmark StraitOverflowWater plume as well as the upper-layer circulation
of freshwater. It is found that the East Greenland Current (EGC) bifurcates at the northern end of the Blosseville
Basin, some 450 km upstream of the Denmark Strait, advecting overflow water and surface freshwater away from the
boundary. This “separated EGC” flows southward adjacent to the previously identified North Icelandic Jet, indicating
that approximately 70% of the Denmark Strait Overflow Water approaches the sill along the Iceland continental slope.
Roughly a quarter of the freshwater transport of the EGC is diverted offshore via the bifurcation. Two hypotheses are
examined to explain the existence of the separated EGC. The atmospheric fields demonstrate that flow distortion due
to the orography of Greenland imparts significant vorticity into the ocean in this region. The negative wind stress curl,
together with the closed bathymetric contours of the Blosseville Basin, is conducive for spinning up an anti-cyclonic
gyre whose offshore branch could represent the separated EGC. An idealized numerical simulation suggests instead
that the current is primarily eddy-forced. In particular, baroclinic instability of the model EGC spawns large anticyclones
that migrate offshore and coalesce upon reaching the Iceland continental slope, resulting in the separated
EGC. Regardless of the formation mechanism, the recently obtained shipboard data and historical hydrography both
indicate that the separated EGC is a permanent feature of the circulation north of the Denmark Strait.
Description:
Support for this work was provided by the Norwegian Research Council (KV), the European Union 7th Framework Programme (FP7 2007-2013)
under grant agreement n.308299 NACLIM Project (KV), US National Science Foundation grants
OCE-0959381 (RP, MS, DT) and OCE-0850416 (MS), and the Natural Sciences and Engineering
Research Council of Canada (KM).
Keywords:
Denmark Strait
;
East Greenland Current
;
North Icelandic Jet
;
Blosseville Basin
;
Denmark Strait Overflow Water
;
Arctic freshwater export
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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