Linked freshwater variability of the Arctic Ocean and North Atlantic

Recently, freshwater changes have been observed both in the Arctic Ocean and the subpolar North Atlantic. Aiming on investigating possible links we compare the freshwater contents of both regions and find a distinct multidecadal anti-correlation. Furthermore these changes are correlated with the dominant atmospheric oscillation indices (AO and NAO).  To further investigate the involved processes we show results from a simulation using a global finite-element sea-ice ocean model. These results suggest changing freshwater exports from the Arctic Ocean to be responsible for the anti-correlation. We propose Arctic freshwater accumulation and release as a response to multidecadal alternations of the dominant large-scale atmospheric variability as the main driver. According to the present phase of this large-scale atmospheric variability, the freshwater accumulated during the previous decades in the Arctic Ocean might be released into the sub-Arctic Seas in the coming years. This has the potential to impact on the North Atlantic meridional overturning circulation.