Reduced winter land sea contrast and its effects on mid-latitude atmospheric variability

Long term projections of the Northern Hemisphere winter climate show an overall increase of surface temperatures that is particularly amplified at Arctic latitudes. On top of this, projections agree in predicting a faster temperature increase on land than on sea surface, therefore a reduced winter land-sea contrast in the mid latitudes. Despite the robustness of this feature in climate projections, the response of the atmospheric system to a strongly reduced winter land-sea contrast has been scarcely investigated. Here, we study how it affects the low and high frequency variability in the extratropics using a simplified GCM, with a focus on the Atlantic and Pacific jets. Moreover, different sea surface temperatures are applied to the North Atlantic and North Pacific basins in order to simulate the presence of a differential warming, as in the well-known scenario of a North-Atlantic warming hole.