Work package MAR 1: Decadal Variability and Global Change
There are various physical mechanisms that control the observed atmospheric circulation patterns in the Arctic and their related global consequences for decadal scale climate variability. The observed variations of Arctic circulation patterns can be attributed to changes in the polar energy budget caused by internal nonlinear dynamics and external forcing factors. Most important are forcing factors which influence the excitation and propagation of large-scale planetary waves due to e. g. changed temperature patterns of the tropical ocean, greenhouse warming of the tropical atmosphere, changed radiation budget due to changed stratospheric ozone and regional polar feedbacks. An improved understanding of the variations of Arctic circulation patterns and their feedback mechanisms with the global circulation will us enable to distinguish between natural and anthropogenic contributions to the observed climate variations and hence, to deliver realistic climate scenarios on the decadal time scale and to improve the prediction capabilities.