Ice mass budget of Greenland -a process study in Qaanaaq drainage basin-

Qaanaaq drainage basin
Our study site is a drainage basin extending to the east of Qaanaaq, a small village in the northwestern Greenland. The basin consists of inland accumulation area, recently darkening ablation area, and numbers of fast flowing outlet glaciers, forming a typical drainage basin in Greenland. The location (77-78° N) is far from relatively more populated southern Greenland, and thus only a few field measurements have been carried out in this region. Another important aspect is many ice caps and glaciers physically isolated from the ice sheet, existing in the coastal regions of the basin. These ice bodies are losing mass very quickly, but details are not known as compared to the ice sheet itself. We study surface mass balance and calving processes of the ice sheet, as well as mass budget of ice caps and glaciers in the coastal regions, to evaluate their contributions to ice mass change in Greenland.

Qaanaaq ice cap
In the summer 2012, we visit Qaanaaq for field measurements on Qaanaaq ice cap, approximately 20-km-wide ice cap covering an elevation range from 250 to 1000 m a.s.l. We established survey profile from the ice cap summit down to the terminus of one of the outlet glaciers. Using stakes installed along the profile, we measured melt rate and ice flow speed during the summer period. The stakes will be maintained for the next several years for annual mass balance and ice flow measurements. Ice thickness and surface elevation were surveyed along the profile with ice radar and GPS devices. These field data are used to develop a two-dimensional thermomechanical glacier model.

Calving glaciers
Another focus of our study in Qaanaaq region is outlet glaciers calving into Inglefield Bredning. Our satellite data analyses show most of the glaciers are retreating over the last decades. Some of the large glaciers, including Tracy Glacier located at inner most part of the fjord, are rapidly retreating and speeding up after 2000. Following aerial reconnaissance in 2012, field campaign is planned in the summer 2013 to investigate calving glacier dynamics and ice-ocean interaction. Ice discharge from these glaciers are very important for the mass budget of the ice sheet as well as ocean environment and processes in the fjord.

From left to right; Qaanaaq ice cap, study site in 2012 field campaign, two-dimensinal glacier model, and ice speed of calving glaciers.