(AC)³: A Transregional Collaborative Research Center to study Arctic Amplification

Within the last 25 years a remarkable increase of the Arctic near–surface air temperature exceeding the global warming by a factor of two has been observed. This phenomenon is commonly referred to as Arctic Amplification. The warming results in rather dramatic changes of a variety of Arctic climate parameters. For example, the Arctic sea ice has declined significantly. This ice retreat has been well identified by satellite measurements. However, coupled regional and global climate models still fail to reproduce it adequately; they tend to systematically underestimate the observed sea ice decline. Although several causes of the recent Arctic climate changes are known, their combined influence and relative importance for Arctic Amplification are complicated to quantify and difficult to disentangle. As a result, there is no consensus about the mechanisms dominating Arctic Amplification. To investigate these problems we combine the scientific expertise and competency of three German universities and two non–university research institutes in the framework of the Transregional Collaborative Research Centre TR 172. The presentation will give an overview of the planned activities within TR 172. In particular the role of clouds in Arctic Amplification will be discussed.