A statistical fracture model for Antarctic ice shelves and glaciers

Antarctica and Greenland hold enough ice to raise sea level by more than 65 m if they were to melt completely. Predicting future ice sheet mass balance depends on our ability to model these ice sheets, which is limited by our current understanding of several key physical processes, such as iceberg calving. Large-scale ice flow models either ignore this process or represent it crudely. To model fracture formation, which is an important component of many calving models, Continuum Damage Mechanics as well as Linear Fracture Mechanics are commonly used. However, these methods applied across the Antarctic continent have a large number of uncertainties. Here we present an alternative, statistics-based method to model the most probable zones of nucleation of fractures. We test this approach on all main ice shelf regions in Antarctica, including the Antarctic Peninsula. We can model up to 99 % of observed fractures, with an average rate of 84 % for grounded ice and 61 % for floating ice and mean overestimation error of 26 % and 20 %, respectively, thus providing the basis for modelling calving of ice shelves. We find that Antarctic ice shelves can be classified into groups based on the factors that control fracture location. The factors that trigger fracturing as well as sustain existing fractures advected from upstream vary from one ice shelf to another.