They have now published three overview articles on the MOSAiC atmosphere, snow and sea ice, and ocean programs in the journal Elementa, highlighting the importance of examining all components of the climate system together. These results present the first complete picture of the climate processes in the central Arctic which is warming more than two times as fast as the rest of the planet - processes which affect weather and climate worldwide.
Diminishing sea ice is a symbol of ongoing global warming: in the Arctic, its extent has almost halved in summer since satellite records began in the 1980s. Less well studied but equally relevant are the thickness and other properties of the ice. The question of what this means for the future Arctic and how these changes will affect the global climate were the impetus for the historic MOSAiC expedition with the German research icebreaker Polarstern from September 2019 to October 2020. With these results coming out now the researchers are building the most complete observation-based picture of climate processes in the Arctic, where the surface air temperature has been rising more than two times as fast as on the rest of the planet since the 1970s. To study the relevant processes for a full year required a special concept, in part because the Central Arctic Ocean is still ice-covered in winter and therefore difficult to access. During the expedition, the icebreaker froze to a large ice floe and drifted with the natural transpolar drift across the Arctic Ocean. And this is where the first surprises came. "We found more dynamic and faster drifting pack ice than expected. This not only challenged the teams on the ground in their daily work, but above all resulted in changed sea-ice properties and sea-ice thickness distributions," reports Dr Marcel Nicolaus, sea-ice physicist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and co-leader of Team Ice in the MOSAiC project.
One of the reasons for the rapid drift is provided by the analysis of the atmospheric research team: "Near the surface there were particularly low temperatures and associated persistent strong winds in the winter months that pushed Polarstern faster than expected. Large-scale atmospheric pressure and wind patterns in January to March led to a particularly strong polar vortex around the Arctic, in addition to a record ozone hole in the Arctic stratosphere," explains Dr Matthew Shupe, atmospheric scientist at CIRES at the University of Colorado and NOAA and co-leader of Team Atmosphere.
