Integrating 3D remeshing in the iceberg-calving model of Elmer/Ice at St Andrews

Author: Guest blogger
Posted: 19 Nov 2019 | 17:10

Eef van Dongen visited the University of St Andrews from 23 September–11 October 2019 through the HPC-Europa3 transnational access programme. In this post she describes her work on improving iceberg-calving simulation techniques.

Hi! My name is Eef van Dongen. I am a PhD student in glaciology at ETH Zurich. This autumn I visited Dr Joe Todd in the research group of Professor Doug Benn based at the University of St Andrews for three weeks with HPC-Europa3. My research focuses on iceberg-calving – the breaking off of icebergs at the edge of glaciers into the sea – which is responsible for approximately half of the ice mass loss of the Greenland ice sheet.

Calving mechanisms are still not entirely understood. An improved understanding of iceberg calving will help to better constrain the future contribution of ice sheets to sea level rise. The goal of my PhD is to use numerical modelling to improve our knowledge of calving by studying a particular glacier in Northwest Greenland, Bowdoin Glacier. Joe Todd has developed a 3D iceberg-calving model in the Finite Element code Elmer/Ice. However, after an iceberg is predicted to calve off, the model domain needs to be remeshed, which is currently limited to 2D such that the 3D model must first be turned into a representative footprint, extruded and deformed to match potentially non-vertical regions of the newly formed glacier terminus. For reasons of model flexibility, robustness and efficiency, it is desirable to be able to remesh arbitrarily in 3D, with no dependence on vertically structured meshes.

The aim of my visit was to continue development of a 3D remeshing routine for calving in Elmer/Ice, which can deal with the change of topology of the glacier resulting from the detachment of icebergs in a robust way. Even though my visit was short, Joe and I managed to couple the 3D remeshing routine successfully to the existing calving routines, such that icebergs are cut out of the mesh based on the modeled 3D stress state of the glacier.

It was my first visit to Scotland and I very much enjoyed going for a hike with my colleagues in the Cairngorms National Park (despite the very Scottish weather). It was also great to combine work with running and orienteering training in and around St Andrews, my office was even on one of the available maps! During my compass training in Tentsmuir forest I also got lucky enough to stumble upon some chanterelles.