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Wind‐driven freshwater buildup and release in the Beaufort Gyre constrained by mesoscale eddies
Author(s) -
Manucharyan Georgy E.,
Spall Michael A.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065957
Subject(s) - ocean gyre , halocline , ekman transport , mesoscale meteorology , eddy , anticyclone , geology , oceanography , beaufort scale , climatology , environmental science , atmospheric sciences , meteorology , turbulence , subtropics , geography , upwelling , salinity , fishery , biology
Recently, the Beaufort Gyre has accumulated over 20,000 km 3 of freshwater in response to strong anticyclonic atmospheric winds that have prevailed over the gyre for almost two decades. Here we explore key physical processes affecting the accumulation and release of freshwater within an idealized eddy‐resolving model of the Beaufort Gyre. We demonstrate that a realistic halocline can be achieved when its deepening tendency due to Ekman pumping is counteracted by the cumulative action of mesoscale eddies. Based on this balance, we derive analytical scalings for the depth of the halocline and its spin‐up time scale and emphasize their explicit dependence on eddy dynamics. Our study further suggests that the Beaufort Gyre is currently in a state of high sensitivity to atmospheric winds. However, an intensification of surface stress would inevitably lead to a saturation of the freshwater content—a constraint inherently set by the intricacies of the mesoscale eddy dynamics.