Seasonal Evolution of Greenland Ice Sheet Hydrology
Matt Charette, Marine Chemistry & Geochemistry
Arctic Research Initiative
2011 Funded Project
The Greenland Ice Sheet (GrIS) is the Northern Hemisphere’s largest terrestrial permanent ice mass; melting the entire ice sheet would raise the ocean’s surface more than seven meters. However, surprisingly little is known about how surface warming controls ice sheet loss or if the composition of meltwater-derived chemical fluxes will remain unchanged. One important control is thought to be the internal hydrology of the GrIS, which dictates how fast it travels to the ocean. Here, I propose to test a new isotope mixing model to determine the seasonal evolution of meltwater flow paths in the GrIS. Naturally occurring radioisotopes will be used to quantify two important aspects of the subglacial discharge: (1) the basal meltwater component and (2) the supraglacial meltwater transit time from the surface to the bed. These mechanisms have a direct bearing on ice sheet advection rates as well as subglacial chemical fluxes and composition; they will be addressed via a time series study of a large land-terminating outlet glacier during the course of the melting season.