Subglacial water flux routing for the 79°N Glacier, Greenland

Abstract:

The hydrological regime of Greenland is of major importance for the ice dynamics, as water acts as lubricant for ice flow. The 79°N Glacier is feed by two branches, one southern coming from the North East Greenland Ice Stream (NEGIS) and one northern branch.

We have applied a flux routing type of hydrological model to this area prior to an airborne ice penetrating radar campaign that has been carried out in June 2015. Flux routing scheme can be used to distribute the basal water down the static hydraulic potential. In this study, local sinks in the potential field were filled using a priority flooding approach, which allows a more realistic continuation of water flow across the sinks.

One distinct sink was found in the NEGIS branch, indicating a potential lake location. In the northern branch, the water flux appeared to be concentrated with a clear transition to a potentially dry area. We show the subglacial water fluxes for constant basal melt rates, as well as for spatially varying melt rates taken from the Parallel Ice Sheet Model (PISM). Using the PISM output allows assessing the likely drainage pathways with a more realistic availability of water. The airborne campaign was covering cross sections over these two locations, of which we will present the radar sections.