MOSAiC Expedition: The largest polar mission in history

The MOSAiC Expedition started in September 2019 after more than a decade of planning and will last for a whole year. It is the largest polar expedition in history. The research ship Polarstern, following the footsteps of Fritjof Nansen’s Fram Expedition 1893-96, will spend the year drifting, trapped in the Arctic ice close to the North Pole. The goal is to better understand the Arctic climate system and global climate change. Linde delivers several gases for advanced measurements.

The harshest and darkest time of year on the North Pole starts during Autumn. The sun dips down beyond the horizon and doesn’t return till Spring. Temperatures become inhumanely low and the ice so thick that no icebreaker can penetrate it. Research vessels flee south to avoid being caught, while the icebreaker Polarstern does quite the opposite. The Arctic Winter is exactly what these researchers are seeking.

 World's largest polar expedition
Polarstern drifts with the Arctic ice. Photo: Alfred-Wegener-Institut (CC-BY 4.0)
MOSAiC Expedition: understanding the Arctic
The Mosaic expedition researchers use several types of gas when carrying through advanced measurements of the atmosphere, the ocean and ecological systems. Photo: Alfred-Wegener-Institut / Mario Hoppmann (CC-BY 4.0)

MOSAiC Expedition: understanding the Arctic

Late in September 2019 they left the Norwegian northern town of Tromsø, to East Siberia, towards the North Pole. The captain steers the ship into massive ice, kills the engines and lets Polarstern freeze in place for a whole year. In biting cold up to minus 45° C.

The expedition is named MOSAiC (Multidisciplinary Drifting Observatory for the Study of Arctic Climate), and is managed by Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Germany. They will collect data from sea ice and ecosystems contributing to new knowledge about climate change in the Arctic.

By doing advanced measurements the researchers hope to uncover important aspects of the Arctic systems: The drifting ice, the turbulent ocean, atmosphere, ecosystems and biogeochemical cycling. They among others search for answers to whether the Arctic Ocean captures more greenhouse gasses than it releases due to phytoplankton, absorbing carbon dioxide through photosynthesis. All in order to better understand Arctic weather and climate and the impact on global weather conditions.

Gases used in measurements

A temporary research camp on the ice is established, where they have a range of advanced sensors, weather balloons and research drones to measure the atmosphere and remote sensing instruments to measure ice and snow properties.

The various instruments need gases in advanced chemical measuring processes. Linde was contacted by the University of Colorado, through their partner the University of Tromsø, and has guaranteed regular deliveries of gasses to the supply ships leaving Tromsø harbour to Polarstern.

Linde delivers helium and oxygen for measuring a range of volatile organic and halogenated compounds to better understand chemical reactions that may be important precursors to aerosol and cloud formation. Clouds are thought to be one of the most important, but poorly understood influences on radiation and energy budget in the Arctic.

Argon is used as a carrier gas for gaseous elemental mercury measurements. Mercury is ubiquitous throughout the environment, and the atmosphere is able to transport mercury in gaseous form for hundreds of kilometres. In other words, from source areas as coal power plants or volcanoes at lower latitudes, all the way to the Arctic. The chemistry of the Arctic atmosphere – particularly in the springtime – is such that the Arctic surface can act as a strong sink for atmospheric mercury, acting as the final link in a chain of transport of this dangerous pollutant from source regions to the Arctic food web.

Carbon dioxide/methane is used as standards for instruments that measure the well-known greenhouse gases, to research the balance of production and destruction of these gases taking place in the Arctic, to better understand the global balance of sources and sinks.

Nitrogen is used as an important tool in quality control of instruments and to ensure that all instruments are synced in time.

Nitric oxide is used for measuring ozone, being very important for chemical reactions related to cloud/aerosol formation and for deposition of pollutants such as mercury. Ozone depletion and atmospheric mercury depletion events are related to each other. Nitric oxide (NO) is also used as a standard for measuring nitrogen compounds (NO, NOx, NOy), which again are important parts of the atmospheric chemistry system.

Ice bears checking out the research station flags
Ice bears checking out the research station flags. Photo: Alfred-Wegener-Institut / Esther Horvath (CC-BY 4.0)
The Russian icebreaker and supply ship on its way to Polarstern. Alfred-Wegener-Institut / Manuel Ernst, Dieter Stürmer (CC-BY 4.0)

International and multidisciplinary

MOSAiC is an international project with more than 300 researchers from 70 institutions across 20 countries. They are driven to understand our planet´s most mysterious and least hospitable regions, gathering vast amounts of data for future generations.


  • The expedition’s planned duration is 388 days from 20 September 2019, planned end 12 October 2020.
  • RV Polarstern will be resupplied by additional icebreakers from China and Russia.
  • The ice drifts at an average speed of 7 km a day.
  • 20 nations are involved in the expedition.
  • During the expedition, 600 experts will be on board and 300 people will work in the background to make the expedition possible.
  • RV Polarstern will travel about 2 500 km.
  • The Polar night with no sun continues for 150 days.
  • 6 people are assigned as “polar bear watch” to ensure researchers´ safety.
  • In winter, temperatures down to -45 degrees Celsius are expected.
  • The expedition´s operating costs alone are 200 000 euro per day. Not including the cost of instruments and researchers.
  • There will be monitoring stations as far as 50 km from Polarstern.
  • The sea ice must be at least 1.5 m thick for necessary infrastructure to be set up on the surface.
  • Measurements will be taken at altitudes up to 35000 m and depths of 4000 m below the surface.
  • To date, there has never been a comparable expedition in the central Arctic.

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Follow the MOSAiC Expedition on Instagram @mosaic_expedition

Text: Ingalill Sandal

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