Movement of basal meltwater beneath the ice sheet is fundamental to the dynamics and stability of ice sheets. Depending on the movement of meltwater along the ice base, water can lubricate different areas of the bed, and in turn, modify the responses of an ice sheet to influxes of meltwater. Ice-penetrating radar is a powerful tool that can directly observe the ice-bed interface and constrain basal water. So far, radar sounding has been primarily applied to map the locations of standing water. However, emerging techniques allow us to track the temporal signals of meltwater drainage by merging radar with ice-sheet modeling.
In this talk, I discuss some of the challenges we face in using radar sounding to detect meltwater underneath the Greenland Ice Sheet. I demonstrate how by merging ice-sheet models with observations we can address some of these challenges and extract new information from multi-seasonal radar data. I show some examples of applying this joint radar-model technique across the Greenland Ice Sheet. These include estimating the amount of basal water storage, constraining englacial firn aquifer thickness, and examining the seasonal switching and piracy of basal meltwater between neighboring glaciers. I demonstrate variability in basal water drainage could explain some of the spatiotemporal patterns observed from offshore sediment export and seasonal ice velocity changes across the Greenland Ice Sheet.