Mosaic resupplied despite adverse conditions

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Experts from 20 nations are studying the Arctic on the Mosaic expedition. All that research works up an appetite, and no amount of sea ice was going to stop the resupply mission.

For days, fast sea ice had slowed the progress of the resupply icebreaker Kapitan Dranitsyn; bound for the North Pole, her mission was to support the second exchange of researchers and crew in the Mosaic expedition. Nevertheless, she steadily drew closer to her destination, and finally, at 12:20pm (CET) on Friday, February 28, dropped anchor 970m from Polarstern, moored to the same floe. While the handover is in full swing on the Mosaic  floe, in Russia another icebreaker will soon leave port in order to supply Kapitan Dranitsyn with additional fuel on her return trip.

This past week there were not one but two new records in the history of polar research, as the University of Cambridge’s Scott Polar Research Institute has reported: on February 24, Polarstern’s drift took her to 88°36’ north, just 156km from the North Pole. Never before had a ship ventured so far north during the Arctic winter. And two days later, the Russian icebreaker Kapitan Dranitsyn, shortly before her rendezvous with Polarstern at 88°28’ north, reached the northernmost position on her mission, marking the first time a ship had made it so far north under her own power, so early in the year.

“These records represent milestones in the Mosaic expedition. They demonstrate the success of the logistical concept and provide the basis for the unprecedented scientific data that is being gathered during the expedition,” says leader of the Mosaic expedition Prof. Markus Rex, from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Potsdam.

“My hat goes off to Captain Alexandr Erpulev for successfully navigating the icebreaker Kapitan Dranitsyn through the Arctic winter and virtually to the North Pole,” adds Polarstern Captain Stefan Schwarze, underscoring this nautical achievement.

“Given the current sea-ice situation, the delay is absolutely in keeping with what had to be expected,” Rex emphasizes. Following the first few months of the expedition, Rex returned from the Arctic on board Kapitan Dranitsyn and will return to Polarstern in April.

Together with the Logistics Division of the Alfred Wegener Institute, he’s spent the past several days working out how to provide the resupply icebreaker with additional fuel.

Since the fast sea ice forced Kapitan Dranitsyn to consume more fuel than originally planned, the icebreaker Admiral Makarov is expected to depart from Murmansk on March 3, and follow an intercept course with Kapitan Dranitsyn, so as to refuel the latter in the Arctic sea ice.

The exchange of staff and equipment is taking place on foot, with snowmobiles and with snowcats hauling heavily laden sledges. On board Polarstern and in the Ice Camp, the new expedition members are being instructed on various tasks by their predecessors. Extreme caution is the prime rule, especially when working on the ice, where the wind-chill temperature can now reach 58° below zero Celsius.

Thanks to these extreme temperatures, only a day after her arrival, the channel of open water left behind by Kapitan Dranitsyn had refrozen so rapidly and intensively that the researchers could walk on it. The temperatures also pose a problem when it comes to transferring provisions; for example, fresh produce has to be transported in heated containers. It’s still too soon to say how long the transfer of crew and equipment will take to complete, partly because the two ships’ cranes only work very slowly in the frigid conditions.

Shortly before beginning the journey home, Prof. Christian Haas from the Alfred Wegener Institute, chief scientist for the second leg, took stock of the situation.

According to the sea ice expert, “Over the past few months, we’ve been able to observe winter at the North Pole more consistently and precisely than ever before. The ice thickness has doubled to an average of 160cm since December, which corresponds to a growth rate of roughly 10cm per week.”

In addition, with the aid of helicopter laser-scanner readings, Polarstern’s radar system, and buoys, the researchers were able to observe how the ice deformed, and channels opened and closed again. Thanks to the warming of the Arctic Ocean, smaller and thinner ice floes are becoming more common.

Driven by the wind, they can collide and overlap, producing pack ice hummocks up to 4m tall. Since a great deal of their mass lies underwater, some hummocks are 20m to 30m thick – a phenomenon that now represents a challenge for the resupply icebreakers.

In contrast, readings taken on the ice, on board ship and with weather balloons, revealed that the air temperature just above the ice was far lower than at a height of 20m. In the lowermost 10m there can be temperature differences of more than 4°C, which has a major influence e.g. on the increase in ice thickness. Lastly, ROV dives showed how life under the ice goes on, even in the long polar night.

“We’ve never had the opportunity to study the zooplankton and polar cod up here so extensively at this time of year. In February we even repeatedly saw a seal under the ice, which is apparently finding sufficient food, despite being practically at the North Pole. And on the surface, we sighted a polar bear and several Arctic foxes,” says Christian Haas, summarizing recent observations.

Sometime in the next few days Prof. Torsten Kanzow from the Alfred Wegener Institute, who arrived on Polarstern by helicopter last Wednesday (February 26), will take over as chief scientist for the third leg of the journey.

This phase of the expedition will in part be characterized by the return of daylight. Even now, there is a perceptible several-hour-long phase of twilight each day, which also makes the cargo transfer a bit easier to manage. Over the next few weeks the sea ice will become even denser, which is why the next exchange, in April, will most likely be done by plane.

For this purpose, the snowcats were used to prepare a 900m-long airstrip on the ice. In addition to the flights for exchanging staff and crewmembers, the third leg will also include scientific missions with the research airplanes Polar 5 and Polar 6, which will then be based in Svalbard and are slated to make flights to the still drifting Polarstern.

The expedition in numbers

From December 13, 2019, to February 27, 2020, the Transpolar Drift carried Polarstern a total distance of 672km; however, given the meandering course of the drift, the ship only covered a linear distance of 406km.

In the same period, the top drift speed, 1.7km per hour, was reached on February 1, 2020.

The expedition came within 156km of the North Pole.

Using snowcats, engineers created a 900m-long airstrip on the ice.

On February 1, the air temperature plummeted from an unseasonably warm minus 11.4°C to -38.2°C, the most intense cold snap observed during this leg of the expedition.

During the second leg of the journey, the expedition members and crew consumed 8,100 eggs, 1,360kg of potatoes, and 86 jars of Nutella. Needless to say, that’s not all they ate.

The longest excursion was a ski tour to an automated monitoring station roughly 10km from Polarstern. The entire tour was completed in total darkness.

Only one polar bear was sighted during this leg – at night, by an automated camera that just happened to snap a photo while the bear was sniffing the instruments at the remote sensing station.

Due to fog and a major snowstorm, there were three days on which work out on the ice had to be suspended.

The experts gathered 34.3TB of data.

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