A Model for Subglacial Conduits on Erodible Beds

Abstract

The fast movement of many ice streams and glaciers is due to sliding at the ice/bed interface. The ease of sliding is determined by the effective pressure at the bed (the difference between ice overburden pressure and water pressure). The effective pressure is determined by the movement of water at the base of the glacier. However, only few models of subglacial hydrology on soft (i.e. deformable and erodible) beds exist. One of these models was developed by Ng (1998), who proposes that water can flow in subglacial conduits eroded into the ice and deformable bed. Here we analyze the model presented by Ng (1998) to determine how melting and viscous deformation of the ice and erosion, deposition, and sediment fluxes along the bed shape these conduits. We numerically determine the relationship between conduit discharge and effective pressure for a range of representative glacier morphologies.