Steady-state thermomechanical modelling of ice flow near the centre of large ice sheets with the finite-element technique

Annals of Glaciology, Vol. 23, p. 116-123, 1996 

C.S. Hvidberg 
Departement of Geophysics, The Niels Bohr Institute of Astronomy, Physics and Geophysics, University of Copenhagen.

A finite-element model is developed in order to calculate the coupled ice and heat flow and the surface topography ij cold, steady-state ice sheets. The model decouples the heat-flow equation and the surface mass-balance condition from the rest of the equations and solves the problem by an iterative method. The model is used to examine the thermomechanics of ice divides. Initial studies of a symmetric, plane ice divide and an axisymmetric ice divide have led to the following conclusions, which are consistent with previous results. The ice-divide zone is a narrow region, only a few ice thicknesses wide, where the surface slope drops to zero and the flox solution changes. The longitudinal strain rate is high, especially in the upper layers, and the vertical velocity is smaller than away from the divide. This causes the basal temperatures in increase and the isochrones to rise. Divergent-flow conditions widen the ice-divide zone, whereas they do not influence the solution at the ice divide.