A Maxwell-Elasto-Brittle model for the drift and deformation of sea ice

• Main Author: Dansereau, Véronique
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes, Jérôme Weiss, Pierre Saramito
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2016
• Subjects: Discontinuous Galerkin methods; Viscous stress relaxation; Elastic interactions; Brittle mechanics; Maxwell-Elasto-Brittle rheology; Sea ice deformation; Méthodes Garlerkin discontinues; Relaxation visqueuse; Intéractions élastiques; Mécanique élasto-Fragile; Rhéologie Maxwell-Élasto-Fragile; Déformation de la banquise; [PHYS.MECA]Physics [physics]/Mechanics [physics]; [PHYS.MECA.SOLID]Physics [physics]/Mechanics [physics]/Solid mechanics [physics.class-ph]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; banquise; Sea ice
• Online Access: https://tel.archives-ouvertes.fr/tel-01316987; https://tel.archives-ouvertes.fr/tel-01316987/document; https://tel.archives-ouvertes.fr/tel-01316987/file/DANSEREAU_2016_archivage.pdf

In recent years, analyses of available ice buoy and satellite data have revealed the strong heterogeneity and intermittency of the deformation of sea ice and have demonstrated that the viscous-plastic rheology widely used in current climate models and operational modelling platforms does not simulate adequately the drift, deformation and mechanical stresses within the ice pack.A new alternative rheological framework named ''Maxwell-Elasto-Brittle” (Maxwell-EB) is therefore developed in the view of reproducing more accurately the drift and deformation of the ice cover in continuum sea ice models at regional to global scales. The model builds on an elasto-brittle framework used for ice and rocks. A viscous-like relaxation term is added to a linear-elastic constitutive relationship together with an effective viscosity that evolves with the local level of damage of the material, like its elastic modulus. This framework allows for part of the internal stress to dissipate in large, permanent deformations along the faults/leads once the material is highly damaged while retaining the memory of small, elastic deformations over undamaged areas. A healing mechanism is also introduced, counterbalancing the effects of damaging over large time scales.The numerical scheme for the Maxwell-EB model is based on finite elements and variational methods. The equations of motion are cast in the Eulerian frame and discontinuous Galerkin methods are implemented to handle advective processes.Idealized simulations without advection are first presented. These demonstrate that the Maxwell-EB rheological framework reproduces the main characteristics of sea ice mechanics and deformation : the strain localization, the anisotropy and intermittency of deformation and the associated scaling laws. The successful representation of these properties translates into very large gradients within all simulated fields. Idealized numerical experiments are conducted to evaluate the amount of numerical diffusion associated with the advection of these ...