Satellite-derived sea ice export and its impact on Arctic ice mass balance
Sea ice volume export is affecting the Arctic ice mass balance, and certainly the multiyear ice volume variability. Climate relevance is also given by the significant fresh water input into the North Atlantic, affecting the thermohaline circulation. The Fram Strait represents the main sea ice export gate in the Arctic. Here, we present the first estimates of winter sea ice volume export through the Fram Strait using CryoSat-2 sea ice thickness retrievals and three different drift products for the years 2010 to 2017. The export rates vary between 20 and 550 km3/month. We find that sea ice drift is the main driver of seasonal and interannual ice volume export variability. Moreover, 79% of the interannual variability can be explained by the relation to the North Atlantic Oscillation index (NAO). The seasonal trend, however, is driven by the mean ice thickness, associated with the thermodynamic ice growth, which is typically peaking in March. Considering Arctic winter multiyear ice volume changes, 50% of the seasonal variability can be explained by the ice volume export through the Fram Strait.