Modélisation 3D de l'écoulement des calottes glaciaires : application à la calotte du Groenland et aux calottes de l'hémishère nord au dernier maximum glaciaire

• Main Author: Fabre, Adeline
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-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 Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-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 Joseph-Fourier - Grenoble I, Catherine Ritz
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 1997
• Subjects: calotte glaciaire; modelisation 3D; Groenland; écoulement; reconstruction; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDE.MCG]Environmental Sciences/Global Changes; Greenland; Ice Sheet
• Online Access: https://tel.archives-ouvertes.fr/tel-00766870; https://tel.archives-ouvertes.fr/tel-00766870/document; https://tel.archives-ouvertes.fr/tel-00766870/file/These-Fabre-1997.pdf

The earth's climatic system consists in several components which strongly interact (atmosphere, ice sheets, oceans, lithosphere and biosphere). Numerical modelling is one among the appropriate tools for studying these interactions. In this work, the flow of several ice sheets is modelled and particular interest is given to the interface between the ice sheet surface and the atmosphere. This interface is governed by the altitude of the ice sheet surface, the surface temperatures and the accumulation. A 3D ice sheet model is developped and tested on a theoretical ice sheet, within the scope of a European project concerning ice sheet model intercomparison. Then it is applied to the Greenland ice sheet, by simulating the ice sheet response under climates different from today's climate, and by studying its evolution during the last interglacial-glacial cycle. The model sensitivity to the accumulation parameterization is emphasized. The model is at last applied to the reconstruction of the Last Glacial Maximum (about 21 000 years before present) ice sheets in the Northem hemisphere. Three methods are used to compute the climatic conditions in input to the mode!. In the first two methods, these conditions come from a parameterization calibrated of the present values: the results thus obtained are not satisfactory. The third method uses surface temperatures and precipitations coming from the simulations of the Last Glacial Maximum climate, performed with the LMD atrnospheric general circulation mode!. The "coupling" between both models requires a complex data treatrnent, but the ice sheets obtained are in better agreement with geological data on ice sheets extension and thickness at that time. Le système climatique terrestre est fondé de plusieurs composantes qui interagissent étroitement (atmosphère, calottes de glace, océans, lithosphère et biosphère). La modélisation numérique permet d'étudier ces interactions. Dans ce travail, l'écoulement de plusieurs calottes glaciaires est modélisé et on s'attache ...