Sack Lunch Seminar (SLS)

Outlet glaciers lying in deep troughs are responsible for a large fraction of the ice loss of present and past ice sheets by discharging ice to the ocean. However, the reasons for their fast flow, up to 15km per year, are still poorly understood. Here I present modelling work which offers a possible mechanism for their fast flow: high basal water pressures in the trough leading to enhanced sliding. Somewhat surprisingly, the hydraulic effects leading to the high pressures are due to the pressure dependence of the melting point of ice (e.g.
underneath 1500m of ice the melting point is reduced to approximately -1°C). I will explain and illustrate these effects by showing model results from the 2D subglacial hydrology model GlaDS applied to Jakobshavn Isbrae, one of Greenland's largest outlet glaciers.