Abstract

Water mass transformation processes in the Barents Sea and their interannual to decadal variability (1948-2007) are studied using a regional coupled ice-ocean model and observational data. Variations in ocean heat transport associated with the Atlantic inflow modulate both the Barents Sea mean temperature (heat content) and the sea ice extent. Strong Atlantic inflow and higher temperatures (heat content) are compensated by an increase in the open ocean area (less sea ice) and larger oceanic heat loss, establishing the Barents Sea as an adjustable and robust ocean cooler. Cooling of the Atlantic throughflow is an important processes for the water mass transformation within the Barents Sea and thus to the properties of the water entering the Arctic Ocean. It is shown that ~70% of the warm inflow is transformed into cold, dense water which is exported into the deep Arctic Ocean. However, during anomalously warm periods like the recent decade cooling of the Atlantic water has not been sufficient and the temperature of the outflowing waters has increased. This might have a profound impact on the heat transport to the Arctic Ocean. The increased ocean temperatures during the last decades have also lead to a reduced sea ice cover in the Barents Sea, i.e. an “Atlantification” of the region.