Climate research of extremes

"You only experience this once," enthuses Torsten Sachs from the Helmholtz Centre Potsdam - German Research Centre for Geosciences GFZ, "and on so many levels - scientific, personal, group dynamic and psychological. He is one of the many researchers who boarded the research icebreaker "Polarstern" and whose energetic commitment made the largest Arctic expedition of all time possible. Scientists from all over the world are involved in MOSAiC to explore the warming of the Arctic in a yearly cycle. The project of global importance is led by the Alfred Wegener Institute (AWI). 

The marine ecosystem under extreme conditions

Scientists of GEOMAR - Helmholtz Centre for Ocean Research Kiel were on board of the "Polarstern" on the trail of life under the ice. During the polar night from December to February they took water samples and examined them for bacteria and phytoplankton. In this way, they wanted to find out how the marine ecosystem functions under extreme conditions and how it changes due to global warming. The focus of their research was on studies of microorganisms that live below the Arctic sea ice. Julia Gosse from GEOMAR performed the measurements on board.

For more than ten years now, Anja Engel's GEOMAR working group, together with scientists from AWI, has been observing how the production and decomposition of organic matter in the ocean, especially in polar regions, is changing in the long term. However, the experts have so far only been able to measure between early summer and autumn and mostly work in subpolar regions such as the Fram Strait between Greenland and Spitsbergen. Therefore, the investigations during the MOSAiC expedition were a real highlight for the research team

Meanwhile, DLR atmospheric researchers are concentrating on the question of how Arctic clouds are formed. Since the beginning of September, they have been using their high-resolution aerial camera on board the research aircraft Polar 5 and Polar 6. It is known from previous studies that clouds contribute significantly to the rapid warming of the Arctic - but modern atmospheric models underestimate the influence of clouds and simulate it imprecisely. For this reason, the research team is measuring the air masses over a large area above the Arctic Ocean and investigating all factors relevant to cloud formation. "On board Polar 5, we are measuring microphysical cloud properties such as drop size distribution, phase, ice and liquid water content, and ice crystal shapes," explains Valerian Hahn from the DLR Institute of Atmospheric Physics. The data collected will help to improve climate models.

Joining forces for success

A total of about 500 people are involved in MOSAiC - mainly researchers, but also pilots and captains, cooks and engineers. The Arctic expedition of superlatives would not have been possible without the successful cooperation and the international research community, which has the greatest common denominator in curiosity. "We work together with over 80 institutions from 20 countries. Just the number of people taking part in the expedition goes beyond all dimensions," explained Markus Rex, head of the expedition, at the launch of MOSAiC. Now the "Polarstern" will return to Bremerhaven on October 12th. In her luggage: countless climate data collected under extreme conditions by researchers from all over the world.