Northern Hemisphere Climate Variability

The impact of the extra-tropical Atlantic Ocean on the climate variability of the Northern Hemisphere is still unclear. From observations possible forcing patterns of SST and sea ice distribution are defined. Both modern datasets (e.g. instrumental and Reanalysis datasets) and Paleo records have been used to derive these patterns. In addition, sensitivity experiments with the atmospheric general circulations model (AGCM) APREGE have been carried out. The AGCM APREGE has been forced by individual SST and sea-ice patterns derived from the combined - past and present - observations. We will shed light on if the mid-latitudinal atmosphere responds to extra-tropical Atlantic forcing and isolate the signatures of the oceanic forcing on the atmospheric variability.