Impact of subglacial hydrology recharge location and intensity on ice dynamics.

Abstract

As temperatures continues to increase, a larger amount of snow and ice is melting at the surface of ice sheets and glaciers. It is now clear that this increase in meltwater availability has a direct impact on ice dynamics on a seasonal timescale, and there are strong presumption that this is also the case on longer timescales. The recent evolution of subglacial hydrology models now allows them to be directly coupled to ice dynamics model to perform long term simulation of this systems and provide the link between ice dynamics and the evolution of climate. There is however still a large number of open questions to answer in order to provide long term realistic simulations of this coupled system. One of those questions is the impact of the recharge location an intensity of the subglacial hydrological system on ice dynamics, or whether the injection of water in the system needs to pass through Moulins or can be approximated as a uniform source. The impact of the recharge strategy on subglacial hydrology model alone has yielded contrasted results with a potential impact on short timescale but a limited influence once integrated over a full season. Here we want to investigate the direct effect of this recharge scenarios on the ice dynamics itself.We apply the Ice-sheet and Sea-level System Model (ISSM) to a synthetic glacier with a geometry similar to a Greenland ice sheet land terminating glacier. Using a range of moulin density (or uniform input) for the recharge of the subglacial hydrology model we observe the response of the ice dynamics itself both on short and longer timescales. Those simulations provide an insight into the importance of recharge location and intensity of the subglacial drainage system directly on the ice dynamics, and so provide a baseline for the choice of recharge style for more realistic simulations.