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

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 c...

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Bibliographic Details
Main Author: Emetc, Veronika
Format: Doctoral or Postdoctoral Thesis
Language:English
Subjects:
Online Access:http://hdl.handle.net/1885/156513
https://doi.org/10.25911/5c765954dc1a1
https://openresearch-repository.anu.edu.au/bitstream/1885/156513/4/Emetc%20Thesis%202019.pdf.jpg
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Summary: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.