PRESENTER: William Colgan, CIRES

TITLE: The influence of hydrology on the ice flow of the Greenland Ice Sheet

ABSTRACT: Abundant observational evidence supports a link between surface meltwater production and basal sliding velocity of the Greenland Ice Sheet over a variety of timescales. Anticipated increases in surface meltwater production over the next century therefore provide an impetus to assemble physically-based models of ice sheet hydrology. We present a 1D hydrology model that calculates temporal change in hydraulic head to a flowline of the Greenland Ice Sheet. Water input is prescribed from observed surface ablation rates and water output occurs through conduits at the ice-bed interface whose geometry evolves through time. The model achieves a quasi-steady-state hydrologic cycle that accurately reproduces limited in situ hydraulic head observations. Generally, ice sheet hydrology models require complex parameterization to deal with spatially variable supra- to sub-glacial travel time and episodic lake drainage events. We present fresh remotely sensed observations of the Greenland Ice Sheet that provide insight into how these particular processes may evolve in the feature.

http://cires.colorado.edu/~colganw