The overall aim of the project was to study the structure and dynamics of the sea ice cover in a critical region of the Arctic Ocean, north of Greenland, and to relate these to longer-term records of climate variability retrieved from sediment cores.

The ice cover in the region is among the thickest in the Arctic, as the sea ice is forced against the north coast of Greenland and the Canadian Archipelago by the transpolar drift stream. This thick and heavily-deformed ice prevents access by even the most powerful icebreakers and has resulted in an almost complete lack of ice, ocean or geological data from the region. The challenge was to determine in what way ice conditions are changing as part of the overall pattern of retreat and thinning seen elsewhere in the Arctic, and at the same time to determine from seabed coring whether such a heavy ice regime, deep inside the ice limits, was ever free of ice during the past two glacial cycles.

The project was an integrated programme of measurements, remote sensing and modelling. Three winter field measurement campaigns were carried out:

• Fieldwork in 2003 was aimed at trialling systems and methods for the main ice camp the following year. Efforts centred on the AWI vessel Polarstern, specifically during a two-week period when she was moored to a drifting ice floe in the Yermak Plateau area. Aerial campaigns were conducted with the AWI helicopter-borne electromagnetic induction system (HEM) and the KMS swath laser profilometer, mounted on a Twin Otter aircraft. Activities on the ship included intensive ground-truthing using in situ thickness measurements, both by drilling (ice augers, hot water drill) and sledge-borne EM. The drift also allowed the development of thickness monitoring buoys based on the measurement of the spectrum of flexural-gravity waves in the ice. Concurrent data were obtained from an ice camp (APLIS) north of Alaska, providing long-range comparisons of waves necessary for testing the buoy concept.

• 2004 saw the project team install and occupy an ice camp in the Lincoln Sea, north of Greenland, using Twin Otter aircraft. The camp was a novel, low-cost, lightweight effort, which provided an excellent platform for science in this otherwise inaccessible region. The camp was placed 280 km north of Alert (85°N,65°W), and occupied by 10 scientists for two weeks in May. Activities at the camp included geological investigations of the seabed and sub-seafloor, a co-ordinated aerial thickness measurement campaign, in situ measurements of ice thickness and properties, and the deployment of an array of buoys designed to measure both path-integrated ice thickness and drift, hence deformation over the lifetime of the project and beyond.
• The opportunity was taken to repeat the HEM and laser measurements north of Alert with a limited campaign in 2005, to examine temporal as well as spatial ice thickness variability in the region.