Preprints
https://doi.org/10.5194/egusphere-2023-807
https://doi.org/10.5194/egusphere-2023-807
08 Jun 2023
 | 08 Jun 2023

A leading-order viscoelastic model for crevasse propagation and calving in ice shelves

Maryam Zarrinderakht, Christian Schoof, and Thomas Zwinger

Abstract. We use a leading-order viscoelastic model for crevasse evolution, in which a purely viscous model for the deformation of the domain couples with linear elastic fracture mechanics models through a viscous pre-stress. The fracture mechanics model conversely couples with the viscous model by inserting cracks into the domain, which viscous flow subsequently pulls apart. By contrast with prior work, we solve the fracture mechanics problem on the actual domain geometry using a boundary element method, coupled with a finite element solution of the Stokes equations describing the viscous flow. We study a periodic array of surface and basal crevasses on an ice shelf being stretched at a prescribed rate. We find that calving can either occur instantly for large enough stretching rates or sufficiently high surface water levels or through feedbacks between partial fracture propagation and subsequent viscous deformation and adjustment of the viscous pre-stress acting on crack faces. Our results show that purely stress-based calving laws cannot robustly describe the process of calving, since they cannot account for the gradual evolution of local crevasse and surface geometry, which can be understood at the large scale as being more akin to the evolution of a damage variable. Future work will need to coarse-grain the type of process model we describe here in order to make it applicable to ice sheet simulations.

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Maryam Zarrinderakht, Christian Schoof, and Thomas Zwinger

Status: closed (peer review stopped)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-807', Jeremy Bassis, 08 Sep 2023
  • RC2: 'Comment on egusphere-2023-807', Anonymous Referee #2, 15 Oct 2023

Status: closed (peer review stopped)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-807', Jeremy Bassis, 08 Sep 2023
  • RC2: 'Comment on egusphere-2023-807', Anonymous Referee #2, 15 Oct 2023
Maryam Zarrinderakht, Christian Schoof, and Thomas Zwinger
Maryam Zarrinderakht, Christian Schoof, and Thomas Zwinger

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Short summary
We used a model to study how crevasses propagate in ice shelves. Our model combines a viscous model and a fracture mechanics model. We studied periodic crevasses on an ice shelf being stretched. We show that existing models based only on stress cannot fully explain how crevasses grow and lead to iceberg calving. This model can be a useful tool to train a low-dimensional representation calving law for an ice sheet model.