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MOSAiC Expedition: Dr. Gunnar Spreen Starts His Adventure in the Ice

It is the most important scientific work of his career: Dr. Gunnar Spreen, Institute of Environmental Physics, University of Bremen, is taking part in MOSAiC, the biggest Arctic expedition ever. On September 20, 2019, he will depart from Tromsø (Norway) to carry out month-long research in the ice.

The leader of the Remote Sensing of Polar Regions working group at the Institute of Environmental Physics (IUP) at the University of Bremen, is, in fact, a little nervous. After all, after months of preparation, it now begins: Dr. Gunnar Spreen is part of the first group of 600 scientists and crew who are involved in MOSAiC – the most significant Arctic expedition to have ever taken place.

Drifting towards Europe

“Never before has a research vessel been frozen, in order for it to then drift thousands of kilometers in the ice across the North Pole and towards Europe,” explains the 43-year-old with regard to this extraordinary mission. On the one hand, this means persevering in the dark and cold for weeks for the scientists. On the other hand, it also means that there will be enough time for experiments and research that will, for the first time, occur under such conditions. “No one has ever researched the local conditions for a longer period of time during the Arctic polar night. All previous – and notably shorter – expeditions were mainly carried out during the lighter period of the year,” says Gunnar Spreen.

The expedition project has the acronym MOSAiC, which stands for Multidisciplinary drifting Observatory for the Study of Arctic Climate. The German research vessel Polarstern will drift for one year after it has been frozen in the Arctic Ocean in October 2019. The Polarstern will then spend the winter in a region that is widely unreachable during the polar night. The 600 scientists and crew will pitch their research camp on an ice floe. They will not do this in unison but rather in varying constellations and in six stages. MOSAiC is an international project of extraordinary dimensions. For the first time ever, data will be measured in a period, in which has been impossible to carry out measurements to date.

Better and More Reliable Results

Gunnar Spreen is in one of the first groups that will begin their work. He will mainly work with a microwave radiometer. “There is basically no recent data from young ice, spanning from the process of sea formation over the Arctic winter to the thawing,” according to the environmental physicist. “For one year, we will investigate the ice type, thickness, the snow characteristics and a great deal more.” The researchers will then compare this data to the measurements that they have been taking for several years via satellites at a height of 800 km. The comparison of data from space with the detailed microwave measurements on site should lead to the development of significantly improved methods for future expeditions. These are already planned and will be carried out by the space organization ESA, under the direction of the EU. Spreen states: “For one year, we can investigate up close what we have so far only seen from a great distance. This will lead to results that are better and more reliable.”

After departure from Tromsø on September 20, it will take quite a time for the vessel to reach the polar region. “We will need to hurry when we set up our equipment because we should use the hours of sunlight that remain for a few days. We will be in complete darkness from October 15,” explains the 43-year-old. He will be relieved of his position his birthday, December 15. The Russian research icebreaker Kapitan Dranitsyn will then transport the next research group onto the ice and will collect the “pilot group.”

At that point, Gunnar Spreen will hand over his research job in the Arctic to Markus Huntemann from the Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research (AWI). Huntemann is part of the cooperative junior research group Remote Sensing of Sea Ice, which is led by Gunnar Spreen and was established by the University of Bremen and AWI.

Christmas at Sea

After his “collection” by Kapitan Dranitsyn, quite a time at sea will pass until the environmental physicist will be on solid ground again. The icebreaker needs around three weeks to reach Tromsø and will arrive in the new year. “It is scheduled for January 2, 2020,” according to Gunnar Spreen, “but how long the icebreaker will really take is uncertain. There are several uncertainties that come with such an expedition.” It is certain, however, that the scientist and his companions will celebrate Christmas and New Year at sea.

Another researcher from the University of Bremen will go into the ice as part of the fourth researcher group in April 2020: The physicist Natalia Sukhikh from the working group Oceanography, which is led by IUP professor Monika Rhein, will take water samples from the varying layers underneath the ice. Subsequently, the gas content of these layers will then be determined at the University of Bremen, in order to better understand the exchange between warmer and colder currents.

About the MOSAiC Expedition

The MOSAiC expedition, led by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) entails unprecedented challenges. An international fleet of 4 icebreakers, helicopters and aircraft will supply the team on its epic voyage. A total of 600 international participants, half of which are researchers, will be part of the mission.

Markus Rex, Head of MOSAiC, Alfred Wegener Institute, Germany, says: “This mission is ground breaking. Never before has there been such a complex Arctic expedition.  For the first time we will be able to measure the climate processes in the Central Arctic in winter. And so for the first time we will be able to understand this region and correctly represent it in climate models. The Arctic is the epicentre of global warming and has already undergone dramatic changes. And it is the weather kitchen for our weather in North America, Europe, and Asia. Extreme weather conditions like outbreaks of cold Arctic air here in winter, or heat waves in summer are linked to the changes in the Arctic. At the same time, the uncertainties in our climate models are nowhere bigger than in the Arctic. There are no reliable prognoses of how the Arctic climate will develop further or what that will mean for our weather. Our mission is to change that.”

The budget for the expedition is roughly 140 million euros. During the course of the year, circa 300 researchers from 17 countries will be on board, from Belgium, Canada, China, Denmark, Finland, France, Germany, Great Britain, Japan, the Netherlands, Norway, Poland, Russia, Spain, Sweden, Switzerland and the USA. They will be supported on land by researchers from Austria and South Korea. The questions that the researchers will be investigating during the expedition are closely linked. Together they will study the entire climate system in the Central Arctic for the first time. They will gather data on five subareas: atmosphere, sea ice, ocean, ecosystems and biogeochemistry, in order to gain insights into the interactions that shape the Arctic climate and life in the Arctic Ocean.

You can find the latest news from the Arctic via the MOSAiC channels on Twitter (@MOSAiCArctic) and on Instagram (@mosaic_expedition) using the hashtags #MOSAiCexpedition, #Arctic and #icedrift. There is more information on the expedition at: The MOSAiC web app allows you to follow Polarstern’s drift route live:

Further information:


Available by phone until September 20:

Dr. Gunnar Spreen
Institute of Environmental Physics (IUP)
University of Bremen
Phone: +49 163 8033583

From September 21, onwards:

Prof. Dr. Justus Notholt
Institute of Environmental Physics (IUP)
University of Bremen
Phone: +49 421 218-62190

Gunnar Spreen
From September 20, 2019, Dr. Gunnar Spreen from the Institute of Environmental Physics at the University of Bremen will be taking part in MOSAiC, the biggest Arctic expedition of all time. Photo credit: Dr. Gunnar Spreen / University of Bremen