Impact of Blue Arctic on Climate at High Latitudes

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The global warming is enhanced in the Arctic where surface air temperature has increased twice as much as the global average in recent decades, also called Arctic amplification. Arctic warming implies melting of sea ice, but its dynamic-thermodynamic resp onse is neither straightforward nor necessarily linear, nor is the response of the atmosphere to sea ice reductions. Satellite observations (1979 to present) show that the Arctic sea ice cover has declined over the past three decades, with a record-low su mmer ice extent in 2007. Furthermore, the projections from the IPCC AR4 models show that the summer Arctic sea ice could disappear by the end of 21st century. Recent studies suggest that the summer Arctic Ocean can be ice-free faster than the projections of the coupled climate models. This will have severe consequences for climate, environment and human activities in high latitudes. Although previous studies show that the variability of atmospheric circulation plays a dominant role in sea ice variability , some observation-based studies also suggest that Arctic sea ice change will have impact on the atmosphere circulation. Numerous simulations (atmosphere-only models, not coupled climate models) have been performed to investigate the potential impact of s ea ice on the atmosphere where sea ice is used as a fixed boundary. The objective of this project is to explore the impact of a summer ice-free Arctic Ocean on the high-latitude climate. The project will consist of comprehensive data analysis and use of t he Bergen Coupled Climate Model and the atmosphere-only model. For the coupled model simulation, a special technique, the so-called partial coupling will be used. The project will compare a Blue Arctic Ocean high latitude climate scenario with the present climate situation in order to quantify and assess the future changes. Improved knowledge about climate change at high latitudes is essential for planning and policy making.