Inherent sea ice predictability in the rapidly changing Arctic environment of the Community Climate System Model, version 3

Abstract Seasonal predictions of Arctic sea ice have typically been based on statistical regression models or on results from ensemble ice model forecasts driven by his-torical atmospheric forcing. However, in the rapidly changing Arctic environment, the predictability character-istics of summer ice cover could undergo important transformations. Here global coupled climate model sim-ulations are used to assess the inherent predictability of Arctic sea ice conditions on seasonal to interannual time-scales within the Community Climate System Model, version 3. The role of preconditioning of the ice cover versus intrinsic variations in determining sea ice conditions is examined using ensemble experiments initialized in January with identical ice–ocean–terrestrial conditions. Assessing the divergence among the ensemble members reveals that sea ice area exhibits potential predictability during the first summer and for winter conditions after a year. The ice area exhibits little potential predictability during the spring transition season. Comparing experi-ments initialized with different mean ice conditions indi-cates that ice area in a thicker sea ice regime generally exhibits higher potential predictability for a longer period of time. In a thinner sea ice regime, winter ice conditions provide little ice area predictive capability after approxi-mately 1 year. In all regimes, ice thickness has high potential predictability for at least 2 years.