Flow Pattern of the North East Greenland Ice Stream – Niels Bohr Institute - University of Copenhagen

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Flow Pattern of the North East Greenland Ice Stream

Master thesis colloquium
Mai Winstrup
Center for Ice and Climate, Niels Bohr Institute

A characteristic feature on surface elevation maps of the Greenland ice sheet is a large fan-like depression, which extends from the central part of the ice sheet and broadens symmetrically towards the north eastern margin. This feature is due to the North East Greenland Ice Stream, which is draining the inner part of the ice sheet into outlet glaciers at the margin.

By use of radio-echo data obtained by the Kansas ice-penetrating radar, we have composed a profile of the internal layering of the ice along the North East Greenland Ice Stream from central Greenland to the ice fiord. Each layer in the profile is an isochrone, and the layers were traced to the NorthGRIP drilling site in northern Greenland to obtain an accurate dating of the layers. We have then used a simple flow model to estimate accumulation rate, basal melting and changes in flow pattern along the profile. A peculiar pattern of localized large basal melt rates was found, which may be attributed to local geothermal heat sources. The effect of the basal melting and the basal topography on the dynamics of the ice stream is discussed. A better understanding of the physical processes controlling the behaviour of such ice streams might offer the possibility for future incorporation of the dynamics of ice streams into current ice and climate models.