Nordic and Barents Seas Cooling – Where Does the Heat Go?
The Barents Sea heat loss (~75 TW) is a dominant heat source for the Arctic atmosphere and here there has been a direct conversion of AW into dense water contributing ~30% of the GSR overflow. Until 2010 this Barents Sea “cooling machine” – warmer Atlantic inflow, less sea ice, more regional ocean heat loss – operated steadily – but this has now changed. Most of the Barents Sea is now open AW and any additional heat loss from more open water is relatively marginal.
Utilizing coupled climate model simulations, ocean re-analysis and more than 100 years of observations, the ocean heat transport and heat loss variability over the Nordic and Barents Seas will be evaluated, based on current-state of the art understanding of heat loss, dense water formation, sea ice loss and melting of marine-terminating glaciers. Initial results show large decadal-scale variability of the AW inflow dictated by the Atmospheric forcing, but also that there is a significant warming over the recent decades along the entire AW Nordic Seas inflow path. This recent warming is larger than the warm period in the 1920’s and 1930’s – and appears most strongly in the Barents Sea that today dominates both the variability and mean ocean heat transport towards the ocean beneath the Arctic sea ice. The portion of the AW heat that re-circulates in Fram Strait and is available for melting the exported Arctic sea ice and Greenland glaciers has likely also increased, but what drives changes in this re-circulation is under present investigation.