Enhanced eddy activity in the Beaufort Gyre in response to sea ice loss

The Beaufort Gyre freshwater content has increased since the 1990s, potentially stabilizing in recent years. The mechanisms proposed to explain the stabilization involve either mesoscale eddy activity that opposes Ekman pumping or the reduction of Ekman pumping due to reduced sea ice–ocean surface stress. However, the relative importance of these mechanisms is unclear. Here, we present observational estimates of the Beaufort Gyre mechanical energy budget and show that energy dissipation and freshwater content stabilization by eddies increased in the late-2000s. The loss of sea ice and acceleration of ocean currents after 2007 resulted in enhanced mechanical energy input but without corresponding increases in potential energy storage. To balance the energy surplus, eddy dissipation and its role in gyre stabilization must have increased after 2007. Our results imply that declining Arctic sea ice will lead to an increasingly energetic Beaufort Gyre with eddies playing a greater role in its stabilization.
The freshwater content of the Beaufort Gyre in the Western Arctic Ocean has increased in response to almost two decades of persistent anti-cyclonic winds. Here, the authors found that dramatic loss of sea ice and acceleration of surface currents after 2007 led to a net annual wind energy input to the Beaufort Gyre, and anticipate that continued sea ice decline will lead to an increasingly energetic Beaufort Gyre.