The Beaufort Gyre Analysis

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The Beaufort Gyre, a major anticyclonic circulation feature in the Arctic Ocean, hosts a substantial fraction of the overall Arctic freshening citep{haine2015arctic}. The large-scale gyre circulation has been directly linked to its freshwater content (FWC) via the process of Ekman pumping that converges relatively fresh surface waters and deepens the halocline citep[e.g.][]{proshutinsky2002role}. The Ekman pumping arises due to transient anticyclonic winds that cause significant gyre variability on interannual and longer time scales. However, observations indicate that the halocline depth (roughly equivalent to the FWC) varies, but does not always mimic, the variability in the strength of the anticyclonic wind stress citep[e.g][]{proshutinsky2009beaufort,giles2012western}. …show more content…
A key assumption of the GM parameterization, which is to be challenged in this manuscript, is that the eddy fluxes at a particular point in time and space depend only on the large-scale state of the ocean at the same point in time and space.

The assumption of temporal and spatial locality can be questioned from both observational and numerical modeling evidence. Observations suggests that mesoscale eddies (in a form of coherent vortices) can persist in the open ocean for years, propagating large distances from their formation regions citep{chelton2011global}. With respect to the Arctic Ocean, using a numerical model citet{spall2008western} discuss how shelf-break eddies propagate away from their formation region, and can be further transported by the mean current of the Beaufort Gyre. citet{manucharyan2013generation} discuss a self-propagation mechanism of sub-mixed layer Arctic eddies that are observed to advect the buoyancy and potential vorticity anomalies up to 500 km away from their presumed formation regions citep{Timmermans2008eddies}. Thus, it is reasonable to assume that a large-scale eddy field does not only depend on a current state of the ocean but carries a finite memory of its past states and a history of dissipative

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