The principal goal of the atmospheric modelling-team at the KUP is to deepen our understanding of climate variability including extreme events and to explore the underlying processes. The focus is set to the specific periods like the Last Glacial Maximum, last millennium and the next 100 yr. Regional-scale climate behavior is strongly affected by the natural variability of large-scale atmospheric circulation as well as the interaction with the synoptic-scale variability. Thus, one research focus is set to the interaction of large-scale low-frequency atmospheric circulation with the high-frequency weather-scale features. Thereby, long-term variations involve components of the climate system, which have memory, such as the ocean and the sea ice. Thus, another research activity concentrates on large- and regional-scale atmospheric processes and their interaction with the ocean and sea ice. As the spatial and time scales involved span within a wide range, a set global and regional models to quantitatively simulate processes of the climate system in the past, present and future is applied. This research group has strong links to the other Earth System modelling groups: Climate Dynamics and BGC as well as to measurements (Past Climate and Biogeochemical Studies of Ice Cores).