The Utrecht Finite Volume Ice-Sheet Model: UFEMISM

Improving our confidence in future projections of sea-level rise requires models that can simulate ice-sheet evolution both in the future and in the geological past. A physically accurate treatment of large changes in ice-sheet geometry requires a proper treatment of processes near the margin, like grounding line dynamics, which in turn requires a high spatial resolution in that specific region. This leads to a demand for computationally efficient models, where such a high resolution can be feasibly applied in simulations of 10⁵ – 10⁷ yr in duration. To solve this, we developed UFEMISM, a new ice-sheet model that solves the hybrid SIA/SSA approximation of the stress balance on a fully adaptive, unstructured triangular mesh. This strongly reduces the number of grid points where the equations need to be solved, making the model much faster than the square-grid models that are typically used in paleo-ice-sheet research. We will discuss some of the difficulties in developing such a model, and the solutions we came up with. We will show that the model successfully performs several common schematic benchmark experiments for ice-sheet models, and we will take a look at some preliminary results of realistic experiments.