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Développement d'un modèle d'hydrologie sous-glaciaire dédié à la simulation du glissement basal des glaciers.

Abstract : Modeling glacier dynamics needs proper knowledge of a number of processes which are responsible for the displacement observed at the surface of glaciers. Some of these mechanisms are well known and yet implemented into ice-flow models. On the other hand, processes that work at the base of the glaciers are much less controlled. Thus, even if glacier sliding has been observed since the early twentieth century its accurate modeling is still a current issue. In order to determine glacier sliding, friction laws that are currently used in ice flow models are only depending upon the basal shear stress. This simple relationship needs a precise fitting of the parameters which vary both in time and space so as to yield surface velocities compatible with data. Field observations also show that subglacial water pressure plays a crucial role in glacier dynamics. Furthermore, water pressure is closely related to the volume of water present at the bed of the glacier and, therefore to the production of water. The objective of this thesis is to develop a subglacial hydrological model which enables the computation of water pressure at the base of glaciers and to couple it to an ice flow model through a friction law. We choose to implement an equivalent porous media which, according to the choose parameters, features both efficient and inefficient components of the system. The sensitivity experiments show that the proposed method can reproduce the characteristics of a subglacial drainage system. Finally, the robustness of the model arose from its ability to qualitatively reproduce an extreme glaciological phenomenon under the form of a jökulhlaup.
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https://tel.archives-ouvertes.fr/tel-00541108
Contributor : Basile de Fleurian <>
Submitted on : Monday, November 29, 2010 - 6:38:08 PM
Last modification on : Thursday, November 19, 2020 - 3:54:26 PM
Long-term archiving on: : Thursday, March 30, 2017 - 3:15:12 AM

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  • HAL Id : tel-00541108, version 1

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Basile de Fleurian. Développement d'un modèle d'hydrologie sous-glaciaire dédié à la simulation du glissement basal des glaciers.. Sciences de la Terre. Université de Grenoble, 2010. Français. ⟨tel-00541108⟩

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