Multidisciplinary drifting Observatory for the Study of Arctic Climate



The Swiss Polar Institute has co-funded Swiss teams to take part in the MOSAiC expedition, one of the largest scientific expeditions ever organised in the Arctic. Prof. Julia Schmale (Paul Scherrer Institute) and Dr. Martin Schneebeli (WSL) acted as the PIs for these projects which were selected by the MOSAiC organisation. Researchers from over 19 countries took part in the expedition.

Following in the footsteps of Fridtjof Nansen’s ground-breaking expedition with his wooden sailing ship Fram in 1893-1896, the MOSAiC expedition brought a modern research icebreaker close to the North Pole for the first time in polar winter. The data gathered will be used by scientists around the globe to take climate and ecosystem research to a new level.

In autumn 2019, the German research icebreaker Polarstern set sail from Tromsø, Norway, to spend a year drifting through the Arctic Ocean – trapped in ice. The expedition was led by the Alfred Wegener Institute AWI with the support of international partners.

The updates about the MOSAiC expedition can be followed on Twitter (@MOSAiCArctic) and on Instagram (@mosaic_expedition) using the hashtags #MOSAiCexpedition, #Arctic and #icedrift.

Lay summaries of the Swiss projects on board

Measurement-Based Understanding of the aeRosol budget in the high Arctic and its Climate Effects (MBRACE)

PI: Dr. Julia Schmale

Clouds are a critical element for the energy transfer between the atmosphere and the surface. They can cool the surface by blocking sunlight, but they can also warm the surface by reflecting the warm, infrared radiation of Earth. Opposed to most other regions on Earth, clouds in the Arctic tend to have a warming effect. In order to form, clouds require small particles in the air, aerosols, that function as seeds for cloud droplets and ice crystals. However, to date we know very little about the sources and abundance of these cloud seeds, particularly during polar night, because such measurements were simply not possible before MOSAiC.

The MBRACE project aims to find out (a) which are the natural processes that produce particles, e.g. phytoplankton blooms or sea ice movement, that influence clouds, and (b) which are the human-made sources such as air pollution transported over long distances to the central Arctic Ocean. The project will also try to investigate how the changing Arctic environment, e.g. diminishing sea ice or blooming algae under thin sea ice, will change the aerosol population and with that future Arctic clouds. For that purpose, we deploy more than a dozen state-of-the-art instruments in the Swiss aerosol container which measure particles and trace gases in real time.

Together with observations from other MOSAiC projects which are closely related, such as SnowMOSAiC, our data will help to improve atmospheric and climate models for better predictions of the Arctic future and weather patterns over Europe.


PI: Dr. Martin Schneebeli

The MOSAiC expedition, which enables continuous measurements and sample collection in the Arctic Ocean throughout a full year, represents an unprecedented opportunity to measure the ocean – ice – snow – atmosphere interaction. A key factor of these processes is the snow covering the sea ice and its properties. The SnowMOSAiC project investigates these complex interactions with high-tech instrumentation.

SnowMOSAiC studies the spatial thickness and its changes over time using terrestrial laser scanning, the microwave properties using a special radiometer, and its microstructure using the SnowMicroPen and computed micro-tomography. These unique measurements will lead to a dataset of unprecedented precision and size, opening new opportunities to improve models.

As for the MBRACE project, the data collected by the Swiss team will be used in conjunction with data collected by other projects participating in the MOSAiC expedition. This interdisciplinary approach will lead to an improved understanding of the sea ice in the Arctic.


The presentation of the Swiss projects on MOSAiC is also available in German and French.