The Influence of Hydrofracture and Surface Melt Variability on Greenland Ice Sheet Flow

Hydrofracture events associated with lake drainages in Greenland create surface-to-bed conduits through which surface melt reaches the bed at rates ranging from that of summer-long melt-stream discharge to that of large, transient pulses during sudden lake drainages. While recent work suggests that enhanced seasonal lubrication may have less of a destabilizing effect on the Greenland Ice Sheet than once feared, the interaction between surface melt and ice flow remains poorly constrained and its influence is not well represented in current ice-sheet models. This project aims to contribute toward improving future sea-level rise assessments by achieving a firm, physically based understanding of ice-sheet hydrofracture, and by characterizing the influence of surface melt on ice-sheet flow over seasonal and inter-annual time scales. Acquisition of this knowledge is an important step toward integrating the influence of increased surface melt in model-derived sea level projections. The investigators will use an experimental design of integrated ground- and satellite-based observations coupled to numerical models to determine the processes that govern hydrofracturing and use this understanding to determine whether the area of the Greenland Ice Sheet?s bed exposed to surface meltwater will increase substantially in a warming climate. The results of this research will be disseminated to the public through extensive ongoing efforts of these investigators including K-12 activities and public lectures. The direct involvement of a photographer-writer team will also bring a local dimension to understanding and communicating the impact of climate change on Greenland communities. Our results will also be of immediate interest to scientists working to understand past and future changes to the Greenland Ice Sheet, including theoretical and modeling studies. This project will also include direct graduate student involvement in field and research activities at both WHOI and UW.