June 22 to July 26, 2005
Recent studies of the Greenland Ice Sheet show that the largest changes are taking place near the ice sheet margins. These changes include an increase in the spatial extent, seasonal duration, and intensity of surface melting, as well as rapid ice sheet thinning in the catchments of several large outlet glaciers. Outlet glacier thinning might be related to an increase in flow speeds due to enhanced lubrication caused by a greater amount of surface meltwater reaching the bed. If this hypothesis is correct, climate change might lead to relatively rapid changes in ice dynamics and ice sheet volume.
click on image to view full size We are visiting East Greenland this summer to conduct a program of measurements that will help us understand the processes driving ice sheet change. The field program is related to our NASA-funded study of Arctic glaciers and ice caps using modern satellite imagery. In that study, we use repeat ASTER imagery to map flow velocities of large outlet glaciers, and compare the results with field measurements of velocity made by our Danish collaborators in the 1960s and 1970s to detect changes in flow speed over time.
One of the objectives of this summer's field program is to revisit many of the original Danish measurement locations and obtain new measurements of velocity using GPS techniques. The results will enable a direct comparison with the archival field measurements and will also be used to validate the results of our remote sensing analysis. We will also visit local ice caps to excavate shallow snow pits to study the frequency of melt events, and to measure snow properties for improving our understanding of features observed in satellite imagery.
click on image to view full size Our logistics platform will be the Arctic Sunrise . The trip begins in Isafjordur in northwest Iceland. From there, we will cross the Denmark Strait to the east coast of Greenland. The ship will take us deep into the Scoresbysund fjord system (the largest fjord system on Earth). We plan to access Daugaard Jensen Gletscher, Graah Gletscher and the Renland Ice Cap using the ship's helicopter. After leaving Scoresbysund, the vessel will sail south along the east coast of Greenland. Ice and weather conditions permitting, we will also conduct measurements on Kangerlussuaq Gletscher and Hellheim Gletscher. We will disembark Arctic Sunrise in the small village of Kulusuk and, from there, fly to Iceland and onward to the United States.