Flow simulation of a firn-covered cold glacier

Abstract

A numerical simulation of the flow of the cold glacier of Dôme du Goûter (4304 m, Mont Blanc, France) is presented. Owing to the large thickness of the firn layer, the simulation was done by using a rheological model for porous ice derived from a model for ceramic sintering and adapted to fit available data on in situ measured density profiles and firn mechanical behaviour. The flow calculation was made under the assumptions of axisymmetric geometry and stationary conditions, by solving a coupled problem. For a given density field, the velocities were obtained by the finite-element method. Then the integration of the mass-conservation equation along the streamlines derived from this velocity field gave the corresponding stationary densities. The results of the numerical simulation, besides the velocity and density fields, are the age of the ice along the streamlines. They are compared with observation and field data.