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Amélioration de la modélisation de la calotte de glace Antarctique à partir de la topographie de la surface

Abstract : Modelling of the polar ice sheets is important to reconstruct its past, understand its current state and predict its evolution in the context of the global warming and rising sea levels. There are numerous mechanisms involved in the dynamics of ice sheets and these are climate-dependent. In particular there are two very important opposing mechanisms: the increase in the temperature which is supposed to lead to increased precipitation and thickening of the ice, and increased melting of the ice, which tends to reduce the mass of the ice sheets. To study these two mechanisms, we followed two approaches: characterize the ice sheets from direct observations (i.e., surface topography and ice flow velocities) or indirect observations (i.e., flow balance), and model it with GRISLI (Grenoble Ice Shelf and Land Ice), taking into account the dynamics of ice streams and their precise locations, to better understand the active mechanisms involved in the ice sheets. The subject of this thesis is to improve the modelling of ice sheets from the available data, especially those based on the first and second derivatives of the surface (slope and curvature respectively), and to link with the ice drainage, and velocity structure outcome. This data has allowed us to develop methods to model ice flows, subsequently introduce them into the GRISLI. We then made several sensitivity studies of the ice sheets, to localize ice streams, geothermal data flow and the parameters that control the slip and deformation of the ice. Finally, we compare the observed and modelled structures of the ice sheets, and show that model results are not far from the actual observed structures.
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Submitted on : Monday, December 5, 2011 - 4:17:27 PM
Last modification on : Thursday, November 19, 2020 - 3:54:27 PM
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  • HAL Id : tel-00648409, version 1



Giuliat Navas. Amélioration de la modélisation de la calotte de glace Antarctique à partir de la topographie de la surface. Sciences de la Terre. Université de Grenoble, 2011. Français. ⟨NNT : 2011GRENU034⟩. ⟨tel-00648409⟩



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