The MOSAiC Expedition

Adventure in the Ice

Climate Researchers’ Plans for the Polarstern
[01. March 2017] 

Two-and-a-half years from now, the research vessel Polarstern will depart on an adventurous expedition. For an entire year, the ship will drift through the Arctic, stuck in the pack ice. Using this approach, the researchers hope to gain new insights into climate change. The project was recently presented to a broader audience at the Annual Meeting of the AAAS in Boston, USA.

It’s been more than 120 years since a research crew has ventured such an undertaking. In 1893 the Norwegian polar researcher Friedtjof Nansen intentionally allowed his research ship, the Fram, to become trapped in the ice, in the hopes that natural ice drift – which he hypothesized existed – would take it to the North Pole. Nansen and his crew didn’t reach the North Pole; further, their attempts to cover the remaining distance to the Pole using ski equipment and sled dogs failed as well. Nevertheless, today the expedition is still considered one of the most daring and most successful of its kind.

And it won’t be long before a new expedition follows in Nansen’s historic footprints: in 2019 the German research vessel Polarstern will depart for the East Siberian Sea, where it will allow itself to become frozen solid in the northern ice, using the drift to traverse the central Arctic. The fact that this is even possible is one of the most important findings of Nansen’s Fram expedition. Granted, this time the goal will consist of more than reaching the North Pole; the team of researchers, led by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), intends to explore the Arctic climate more comprehensively than ever before. To date, they have primarily gathered data during the Arctic summer, but the bold new expedition should now give them an unparalleled opportunity to do so in the Arctic winter. This is important, not only to better understand the Arctic, but also the highly complex climatic processes at work around the globe.

“We’re currently observing a particularly intense warming of the Arctic and a dramatic level of ice retreat. But we still don’t adequately understand these processes. We hope the new data will yield fundamentally new insights into global climate change,” says Markus Rex of the AWI, who is coordinating the international project from the Institute’s facilities in Potsdam. The project was recently presented to a broader audience at the Annual Meeting of the AAAS in Boston, USA.

The plans for the expedition were developed under the auspices of the International Arctic Science Committee. Its official title: MOSAiC – an acronym for Multidisciplinary drifting Observatory for the Study of Arctic Climate. The projected costs will be more than 60 million euros, which will be provided by roughly a dozen polar research organisations and other sponsors from around the world. “And it’s money well spent,” Rex is convinced. “Our research will contribute to a quantum leap in climate research.”

“In the course of the year-long expedition, the focus will be on carrying out countless experiments and measurements on site.” One of the researchers’ goals is to better grasp the complex interplay between ocean, ice, atmosphere and ecosystem. Accordingly, they will set up an entire network of stations on the ice, in a ca. 50-km radius around the Polarstern. In these camps, small research teams will take extensive measurements, in some cases using helicopters for resupply. In essence, the camps will drift on the ice alongside the research vessel. According to Rex, “It will definitely have its fair share of logistical challenges.”

“We’re going to measure everything the climate researcher’s heart desires,” says Rex. An additional focus will be on sea ice and the processes that lead to its formation. Another aspect that is important to understanding climate processes, but which remains unclear, is the flow of energy between the ocean and the atmosphere. “Ocean currents transport massive amounts of energy from the warmer latitudes to the Arctic. Once there, it reaches the atmosphere through small eddies in the ocean and atmosphere, and through cracks in the sea ice, greatly shaping the Arctic’s energy balance,” explains Rex. Lastly, the researchers are also interested in learning more about sea-ice transport and deformation processes during the winter, as well as the melting process in the spring.

“What do the krill do under the ice in winter?” asks Rex, before answering his own question: “That’s yet another question we still can’t clearly answer. We know that krill and plankton overwinter, and that, when the ice breaks up in the spring, we see large plankton blooms in the Arctic.” But what exactly transpires under the ice, and how could things change if ice retreat intensifies? As he explains, there are many important processes that simply can’t be observed using satellites, like which type of plankton is swimming in a meltwater pool, or what the smallest-scale turbulences in the atmospheric boundary layer look like. The list of questions the researchers still have could fill pages – and by the time the expedition departs, two-and-a-half years from now, it will surely be even longer.

No-one knows exactly which route the Polarstern will follow; statistical methods only allow the researchers to make approximate predictions. There are a number of possible routes. If all goes as planned, in 2020 they’ll emerge from the ice again somewhere between Svalbard and Greenland. It could become problematic if the Polarstern drifts too close to northern Greenland. “If that happens, the ship won’t be able to break free under her own power,” says Rex. Though he stresses that the risk has been minimised by carefully modelling and selecting the starting point for the drift trajectory, drifting is, after all, drifting: for the duration of her journey, the Polarstern’s engines will be shut down, and the ship will be frozen solid amidst the massive ice. “From that point on, where we go will depend entirely on how the ice drifts. That’s an aspect we simply have to accept; we might not always like where it takes us, but like it or not, that’s where we’re going.”

Rex himself will be there at the start of the journey and again in the spring of 2020. All participating researchers will spend two or three months on board, and the entire crew will be switched out five to six times in the course of the year-long project. Russian long-range helicopters will fly them in – with the help of a refuelling station set up on Bolshevik Island specifically for the expedition. In addition, partner icebreakers will occasionally replenish the Polarstern’s fuel supply. Why does the ship need fuel if it’s adrift? Even in standby mode, it consumes 15 tonnes of fuel a day – just to keep the heating and electronic systems up and running.

The icebreakers will also convey the first research findings to Potsdam. “We’re confident that we’ll make important findings even as we drift,” says Rex. He expects corresponding publications to follow soon after – and above all, a significantly deeper understanding of our global climate system.

This text was published at first, author: Roland Koch



Markus Rex

Press Office

Folke Mehrtens