Talks by Henrik Skov, Århus University and Knut A. Christianson, Kansas University – Niels Bohr Institute - University of Copenhagen

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Talks by Henrik Skov, Århus University and Knut A. Christianson, Kansas University

We have two talks Friday 05.04 2013

HRS. 13:00
Henrik Skov,
Århus University, will give a presentation on the future research station in North Greenland from where there will be studies on climate change and its impact on the air, sea, geology, fauna and flora in the High Arctic region.

In english

HRS. 14:00
Knut Andrew Christianson, University of Kansas,
 will give a talk on his findings at NEGIS.

Self-Stabilizing Ice Stream Flow in the Upstream Portions of Northeast Greenland Ice Stream from Radio-Echo Sounding and Seismic Surveys

Abstract: We present radio-echo sounding (RES), global positioning system (GPS), and active-source seismic data from the central portion of the Northeast Greenland Ice Stream (NEGIS) showing that the dynamic effects of the streaming flow limit ice-stream extent. NEGIS widens downglacier from a small region of high geothermal flux near the ice-divide. Our data reveal water-saturated till lubricating the ice-stream, with the ice-stream widening toward the coast. Ice accelerates and thins as it flows into NEGIS, producing marginal troughs in surface topography. These troughs create steep gradients in the subglacial hydropotential that generate parallel ‘slippery’ and ‘sticky’ bands beneath margins. The ‘sticky’ bands limit ice entrainment across the margin and thus restrict further widening, producing the long, narrow, and relatively stable ice-stream. Age-depth relations from internal radar layering reveal that high basal melt rates, approximately 2 times background rates, correlate well with streaming flow extent; this suggests that shear-heating induced basal melt of ~5 cm/a provides an important additional source of basal lubricant to further promote self-stabilizing streaming flow.