Barents Sea ice volume budget in a 40-member historical ensemble of a global climate model

The decrease of Arctic sea ice affects the future climate in the Arctic and beyond. Therefore, it is important to understand the drivers of sea ice variability and trends. The variability of the Arctic-wide winter sea ice extent is largely determined by that in the Barents Sea. The relative impact of oceanic and atmospheric processes has been discussed controversially in the literature for different time scales. Here, we provide a volume budget analysis over the period from 1960 to 2014 based on a 40-member ensemble with the Hadley Centre global climate model HadGEM3 using a horizontal resolution of around 10km in the Arctic. Sea ice gain is Arctic-wide dominated by sea ice growth with a net contribution from sea ice advection and divergence generally below 10%. However, in the Barents Sea this contribution reaches 100% with significant ice growth only taking place on the northern edge of the Barents Sea. Locally up to 5m of annual sea ice are advected in certain place of the Barents Sea. Consequences for the importance of atmospheric and oceanic drivers on variability and trend will be analysed.