Les glaciers du Haut Arc (Savoie) : caractérisation et impacts de la décrue post-Petit Age Glaciaire

Abstract : The glacial recession post-Little Ice Age in the valley of Haute Maurienne is studied by three complementary points of view. In the first time, the evolutions of the glacial rate in the watershed of the Haut Arc have been reconstructed on the sample of thirty glaciers. The method carried out is based on GIS software supplied by various documentations (old maps, aerophotography, geomorphological records). The maps of glacier's extension and the diagrams of the relative area, obtained by this approach, lead to a classification of the different type of glacial recession. These results are interpreted as a high degree of interaction between the climate forcing and the glacier response. The last ten years are charactezised by a synchronous increase in the glacial recession on all glaciers in the watershed.
The second part of this study concerns the consequences of the glacial recession on the high mountain environment. The analyses on glacial discharge the Avérole river case-study show a significant evolution of the proglacial hydrology of the river on the last ten years.
The mechanisms of the glacial recession processes are investigate through a high frequency systemic analysis of atmospheric parameters and pro-glacial discharge. In this aim, the Baounet glacier has been instrumented since 2002 with a monitoring station to record the environmental parameter. The measurements are modelled to characterize the development and the evolution of glacial drainage networks. The results show an increase in drainage system efficiency during the ablation season. It's interpreted as the recording of the climate forcing on the glacial drainage structure. In the last time, the analyses of the daily hydrographs with this method lead to the quantification of the daily intensity of the melting processes on the glacier. This new tool can be used to link the glacial surface processes to the internal structure the drainage patterns.
The impacts of the glacier's surface evolution on the mountain environment are studied by the glacial hazards approach. We show that the last ten years are characterized by the increase of the glacial hazards in the Haut Arc watershed. The case studies of supra-glacial lakes are developed to explain the mechanisms.
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Submitted on : Saturday, December 24, 2005 - 12:53:03 PM
Last modification on : Thursday, January 11, 2018 - 6:20:38 AM
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Sylvain Jobard. Les glaciers du Haut Arc (Savoie) : caractérisation et impacts de la décrue post-Petit Age Glaciaire. Géographie. Université de Savoie, 2005. Français. ⟨tel-00011264⟩

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