FROZEN - ICE SHEET MODELING
The project is a topical continuation of project SNIC 2015/1-311 and 2016/1-175 We simulate grounded ice sheets and attached floating ice shelves, on timescales ranging from 100 to 100.000 years. The equations which govern ice dynamics and which need to be solved are the full Stokes equations for the velocity field of the ice , coupled to a transport equation for the elevation of the surface of the ice. The Stokes equations have a nonlinear viscosity and are discretized by a finite element method. A simplification of the equations is possible in parts of the ice domain called the shallow ice equations. The combined method is implemented in Elmer/Ice, and is now referred to as the ISCAL method (Ahlkrona, J., Lötstedt, P., Kirchner, N., Zwinger, T.,(2016). Dynamically coupling the non-linear Stokes equations with the Shallow Ice Approximation in glaciology: Description and first application of the ISCAL method. Journal of Computational Physics 308, 1-19,doi:10.1016/j.jcp.2015.12.025). ISCAL has been run succesfully on Beskow in the past, and we plan to extend ISCAL to include also a coupling of the Stokes equations to those parts of the ice sheet where it is sufficient to solve the simpler shallow shelf approximation equations. This will allow simulate grounding line migration of an ice sheet, a process which receives much attention and poses considerable numerical challenges, especially when performed over the long timescales of natural ice sheet behavior. The team consists of one PhD student at the Division of Scientific Computing at Uppsala University (UU), and a MSc student at the Dept. of Physical Geography at Stockholm University (SU). Also, three senior researchers (2 from UU, 1 from SU) are part of the team.