The phenomenon of Arctic amplification has a suite of causes, which include various interconnected processes and feedbacks, such as sea ice loss and albedo feedback, meridional atmospheric and oceanic energy fluxes, and radiation-climate feedbacks linked with temperature, water vapor, clouds and ozone. The relative importance of these different feedback mechanisms is still subject of debate. In parallel, climate models have difficulties in reproducing the observed drastic Arctic climate changes and the uncertainty in Arctic climate projections is large. That arises, in large part, from gaps in our understanding of key Arctic processes and feedbacks.
A large body of evidence demonstrates how changes in the climate of the Arctic impact lower latitudes (Cohen et al., 2014). For example, the decline in Arctic summer sea ice concentration is connected with atmospheric circulation responses in the following winter months and linked to anomalous cold winters over Eurasia and other regions of the Northern Hemisphere (Jaiser et al., 2013, 2016; Handorf et al., 2015). The Arctic is coupled with lower latitudes via horizontal advection of heat and moisture as well as through planetary waves in the coupled troposphere-stratosphere system. However, the coupling and impacts of the Arctic climate system to lower latitudes is not fully understood. To disseminate the knowledge on Arctic-midlatitude linkages we gained through our research we are contributing to the Earth System Knowledge Platform (ESKP) of the Helmholtz Association of German Research Centres.