Development of a viscoelastic model of ice shelf dynamics

• Main Author: Zimmermann, Astrid Margit
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université Grenoble Alpes 2020-., University of Swansea (Swansea (GB)), Emmanuel Lemeur, Stephen Cornford
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2023
• Subjects: Rheology; Snow study; Modelling; Antarctica; Antarctique; Modélisation; Nivologie; Travail de terrain; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Antarc*; Antarctic; Antarctique*; Ice Shelf; Ice Shelves
• Online Access: https://theses.hal.science/tel-04099198; https://theses.hal.science/tel-04099198/document; https://theses.hal.science/tel-04099198/file/ZIMMERMANN_2023_archivage.pdf

Climate Change has already caused large losses on natural occurring ice in the last decades and continues to do so. Antarctica, the largest source of land ice, contains an equivalent of several tens of meters of sea water level rise, which is induced not only by melting but also by out flow into ice shelves, the floating tongues of glaciers. In the last decades with recorded longer melt seasons and warming water in Antarctica, ice shelves are thinning and breaking up. With that, speed up of shelf inflowing glaciers are recorded, highlighting the buttressing force ice shelves have on glaciers and therefore their importance to the Antarctic Ice Sheet.Many factors play a roll in the integrity of ice shelves, besides melting on the surface and from below, waves, tides and pressure imbalances at the calving front (buoyancy force) induce bending moments on short time scales.While ice is mainly studied as purely viscous, elastic or even plastic material. Certain ice shelf behaviour, like the tidal deformation near the grounding line or drainage of melt ponds, can only be sufficiently simulated with an viscoelastic model - representing the viscous thinning of ice as well as short term elastic bending deformations.Viscoelastic studies of ice so far have used commercial proprietary software, which require expensive licences and often lack inside in the used algorithms or flexibility to adapt the code as needed.In this thesis a viscoelastic model was developed in the open source FEM C++ environment Rheolef. Le changement climatique a engendré des pertes considérables pour les glaces continentales au cours de ces dernières décennies et perdure toujours aujourd'hui. L'Antarctique, la plus grande réserve de glace naturelle recèle à lui seul l'équivalent d'une hausse potentielle du niveau marin mondial de plusieurs dizaines de m, laquelle résulte non seulement de la fonte mais aussi de l'écoulement de la glace au travers les plateformes flottantes des glaciers émissaires, les 'ice shelves'. Depuis les dernières décennies ...