A research team from the Alfred Wegener Institute has for the first time gained insights into a current in the Barents Sea which affects Arctic sea ice.
A research team from the Alfred Wegener Institute has for the first time gained insights into a current in the Barents Sea which affects Arctic sea ice.
In the last few decades, the Arctic sea ice has receded ever further, including increasingly in winter when the extent of sea ice is at its most prominent. One of the main drivers of this development is thought to be the warming of Atlantic water that flows from Europe’s Norwegian Sea into the Arctic Ocean, passing through the Barents Sea and the Fram Strait in the process. However, not all the Atlantic water flowing into the Barents Sea reaches the sea ice. Part of the Atlantic water recirculates, i.e. by changing direction and flowing back into Europe’s Norwegian Sea as an independent current without coming into direct contact with the sea ice. To date, however, it has not been possible to sufficiently investigate the indirect effect of this current carrying inflowing Atlantic water back out of the Barents Sea on the sea ice of the Barents Sea. A research team from the Alfred Wegener Institute has now discovered - using model simulations - that this return flow from the Barents Sea has an appreciable impact on the amount of sea ice forming in the Barents Sea in winter. The researchers published their results in the journal Nature Communications.
Besides the Fram Strait, the Barents Sea is one of two gateways through which warm, saline water from the Atlantic flows into the Arctic Ocean. If the inflowing Atlantic water is warmer than the long-term average or if an extraordinarily large volume of Atlantic water flows in, the Barents Sea warms up and the ice coverage in winter is lower. If the Atlantic water is cooler or the inflow is weak, a great deal of ice may result. However, before the Atlantic water is transported to the sea ice by the currents in the Barents Sea, part of it recirculates away from the sea ice and is carried back into Europe’s Norwegian Sea. Consequently, this recirculated portion can no longer affect the sea ice. To date, however, it has not been possible to adequately measure the strength and fluctuations of this return flow although these factors might play a vital part in determining how much Atlantic water actually reaches the sea ice. “There are a few observations that strongly suggest that this return flow carries a substantial proportion of the Atlantic water directly back out of the Barents Sea. Therefore, it seemed to make sense that naturally occurring fluctuations and any possible long-term trend in this current could be important factors for the sea ice”, says Dr. Finn Heukamp, lead author of the study by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research. “The volume of Atlantic water flowing into the Barents Sea, while leaving it again immediately as a result of recirculation may have a substantial effect on the formation of sea ice from year to year but also over the long term.
Read more at Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
Image: View across the ocean. With course to the northeast, across the Barents Sea, the German Polarstern research vessel leaves the harbour of Tromsø. (Credit: Alfred-Wegener-Institut/Stefan Hendricks)
