One mechanism contributing to co-variability of the Atlantic inflow branches to the Arctic.

The two-branched inflow of warm and saline Atlantic Water to the Arctic is the major contributor of oceanic heat to the Arctic climate system. However, while the Atlantic Water entering the Arctic through the Fram Strait retains a large part of its heat as it flows along the Arctic continental slope, the branch flowing through the shallow Barents Sea releases a substantial amount of heat to the atmosphere. Hence, the pathway of the Atlantic Water into the Arctic to a large degree determines the short term fate of its heat. Here we show events in which the relative strengths of the two branches are affected by wind-induced Ekman-transport off the northern Barents Sea shelf. The resulting decrease in sea surface height induces a cyclonic circulation anomaly along the slope encircling the northern Barents Sea shelf area, which enhances the flow through the Barents Sea while weakening the branch flowing along the Arctic continental slope.