Combining physics-based and statistics-based approaches to model calving in Antarctica

• Main Author: Emetc, Veronika
• Format: Thesis
• Language: English
• Published: The Australian National University 2019
• Subjects: Antarctica; ice shelves; ice sheet; calving; fractures; crevasses; basal; modelling; ISSM; Antarctic; The Antarctic; Antarc*; Ice Sheet; Ice Shelves; Iceberg*
• Online Access: https://dx.doi.org/10.25911/5c765954dc1a1; https://openresearch-repository.anu.edu.au/handle/1885/156513

Surface and basal crevasses are deep fractures in ice that are observed on the surface and the base of the Antarctic ice sheet/ice shelves, respectively. They are a direct pre- cursor of formation of rifts in ice shelves and a consequent calving or breaking off of icebergs. Modelling of calving is crucial for better estimation of the ice mass balance in Antarctica because ice shelves act like a supporting mechanism for the inland ice preventing it from accelerating into the ocean. While there have been a number of studies that attempted to parameterise calving, each of them has limitations that do not allow to apply them to all the Antarctic ice shelves on a large scale. A more comprehensive calving model needs to include not only parameterisation of calving at ice fronts, but also the history of fracturing of the ice that led to a calving event such as formation, advection and propagation of both surface and basal crevasses. Towards improving a calving parameterisation in ice sheet models we constructed a set of sub-models for predicting surface and basal fracturing, vertical and horizontal propagation as well as advection. Combining statistics-based and physics-based ap- proachers we developed a preliminary calving model that includes the full history of rifts and crevasses, from their initiation to the final break off at the ice front.