Abstract:
The anti-cyclonic Beaufort Gyre is the dominant circulation of the Canada Basin and the largestfreshwater reservoir in the Arctic Ocean. During the first part of the 2000s the gyre intensifiedexpanded, and accumulated freshwater. Using an extensive hydrographic dataset from 20032019, together with updated satellite dynamic ocean topography data, we find that over the pastdecade the Beaufort Gyre has transitioned to a quasi-stable state in which the increase in seasurface height of the gyre has slowed and the freshwater content has plateaued. In additionthe cold halocline layer, which isolates the warm/salty Atlantic water at depth, has thinnedsignificantly due to less input of cold and salty water stemming from the Pacific 0cean and theChukchi Sea shelf, together with greater entrainment of lighter water from the easternBeaufort Sea. This recent transition of the Beaufort Gyre is associated with a southeastwardshift in its location as a result of variation in the regional wind forcing. Our results imply thatcontinued thinning of the cold halocline layer could modulate the present stable state, allowingfor a freshwater release. This in turn could freshen the subpolar North Atlantic, impacting theAtlantic Meridional Overturning Circulation.
