Marco Picasso

Title:
Numerical simulation of Rhone's glacier from 1874 to 2100

Abstract:
The numerical simulation of the motion of Rhone's glacier in the Swiss Alps is performed from 1874 to 2007, and then from 2007 to 2100. Given the shape of the glacier, the velocity of ice is obtained by solving a 3D nonlinear Stokes problem with a nonlinear sliding law along the bedrock-ice interface. Then, the shape of the glacier is updated by computing the volume fraction of ice
which satisfies a transport equation. A source term acting only on the ice-air interface accounts for the accumulation or ablation of ice due to snow falls or melting.

A decoupling algorithm allows the two above problems to be solved using different numerical techniques. The nonlinear Stokes problem is solved on a fixed, unstructured finite element mesh made of tetrahedrons. The transport equation is solved using a fixed, structured grid made of smaller cells.

The numerical simulation between 1874 and 2007 is compared to measurements. Then, three different climatic scenario are considered in order to predict the shape of the glacier from 2007 until 2100.