Influence of Warm, Moist and Cloudy Air on the Arctic Climate

The Arctic is the region of the globe where the most dramatic climate change is occurring and is expected to continue. There is increasing observational evidence that the Arctic winter climate is strongly controlled by filamentary intrusions of moist, warm air which cross the entire basin. This presentation discusses the statistical distribution of these intrusions and how they are affected by large-scale atmospheric circulation, particularly midlatitude storm-track activity, blocking events, and possibly by interaction with the stratosphere. How these features and events as well as clouds are represented in CMIP5 models will also be presented and how biases and future changes in model-simulated large-scale circulations are reflected in moist intrusion statistics and surface climate in the Arctic basin.