Arctic Ocean 1 Arctic ocean 1 Arctic sea ice 1 Climate 1 Climate models 1 Earth (planet) 1 Earth system modeling 1 Earth system models 1 Global warming 1 Ice-free arctic ocean 1 Initial condition ensembles 1 Internal variability Large initial condition ensemble 1 Modified model 1 Sea ice 1 Surface melt 1 climate 1 climate change 1 ice cover 1 ice thickness 1 ice-free Arctic Ocean 1 ice-ocean interaction 1 internal variability 1 large initial condition ensemble 1 sea ice 1 surface melt 1