Towards a 3-D model for large-scale glacier simulations

Glaciers outside the two major ice sheets are key contributors to sea level rise, act as important sources of freshwater, and have great touristic value. To simulate the temporal evolution of these ice masses at regional- to global scale, simplified models are typically used that rely on volume scaling approximations or parameterizations based on observed glacier changes. These approaches rely on minimal data and are fast, but they do not account for mass redistribution through ice flow. More recently, efforts have been undertaken to represent ice dynamical processes in flowline models that can be applied at large spatial scales. These flowline approaches represent the mass transfer within a glacier in a more realistic way, but fail at reproducing the evolution of large glaciers, which are typically not confined by the local topography and do not have a pronounced elongated shape as represented in flowline models.

Here we present our first efforts to develop a 3D coupled surface mass balance – ice flow model that can be used to model the temporal evolution of an ensemble of glaciers. The main goal of such a model is to be able to simulate the temporal evolution of glaciers with distinct shapes and situated in various climatic regimes in an automated way. By relying on a 3D model architecture we aim to better represent processes crucial for glacier evolution, such as glacier calving and convergent flow from several tributaries. Here, we will present first tests with a prototype version of the model by reproducing steady state geometries of selected glaciers, and by simulating the evolution of these ice bodies under idealised forcing scenarios.