Exploring Greenland’s 79 North Glacier

“By taking measurements in the area right in front of the cavity, where warm Atlantic water flows in and colder water flows out, our goal is to monitor the strength of this circulation, and to determine how much heat from the Atlantic water is made available for melting the glacier tongue within the cavity,” explains Prof Torsten Kanzow, an AWI oceanographer and chief scientist of the expedition. To do so, last year he and his team had installed moorings equipped with sensors, both directly in front of the glacier cavity and at other key sites of the circulation of Atlantic water on the continental shelf of Greenland. By pursuing this approach, the researchers hope to trace the circulation of this watermass from Fram Strait to the coast of Northeast Greenland and toward the 79 North Glacier, to determine how variable the circulation is and to infer what the physical causes of the fluctuations are.

“Based on our data, we can now show that warm Atlantic water has been flowing into the glacier cavity continuously since last summer,” says Kanzow. That being said, the flow hasn’t been constant, but has waxed and waned. As the oceanographer explains: “For example, we’re not sure why the inflow suddenly increased at the end of 2016, but we expect that it was likely due to some factor outside the cavity.” The oceanographers also found periods marked by unusually warm Atlantic water inflow in the cental part of the continental shelf. “We can’t say yet, how much of this water actually made its way into the glacier cavity – we’ll conduct the corresponding computer-based analyses back in Bremerhaven,” adds Kanzow.

Torsten Kanzow recalls one of the expedition’s highlights: “We were on the edge of our seats during one of the AUV dives near the glacier. It encountered densely packed ice when it was finally resurfacing, and it was only owing to the crew’s skill that we managed to safely retrieve it.” And that wasn’t the only memorable aspect. Comparing the conditions this time around with his last expedition toward the coast of Greenland, which was in August 2016, he adds, “This September we could clearly feel the coming winter. The massive amount of newly formed ice off the coast made our work much harder: any equipment that came into contact with the seawater was immediately coated in ice. It was also a bit dicey recovering the moorings while surrounded by dense ice and heavy fog, which once again shows how much our success depended on the outstanding skill and experience of the crew of Polarstern.”

Polarstern left her homeport for this year’s Arctic season on 24 May 2017. The first four segments of its journey chiefly took the research vessel to different parts of the Svalbard archipelago, before the final expedition took her to northeast Greenland. The ship will remain at the Lloyd Werft shipyards in Bremerhaven until shortly before Christmas. During this time she’ll be fitted with a new generator and be treated to a fresh underwater coating before she departs again, on a course to the Antarctic.