A viscoelastic phase-field model for calving and fracture in ice

Iceberg calving due to fracture accounts for around half of the ice lost annually from Antarctica, but physically based models representing this process are not currently included in ice sheet models. By using a phase-field viscoelastic model for fracture we can model both slow deformation of ice and the distribution and evolution of cracks leading to calving. The model solves equations for non-linear viscous flow, elastic displacement and a phase-field variable which allows cracks to nucleate and propagate in response to the evolving stress field. Without making any assumptions about the type of calving, we apply this model to a simulate fracture of an iceberg. We explore how the calving rate is influenced by changing a range of parameters, and find it is particularly sensitive to the water level inside the cracks.