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Reconstruction du bilan de masse des glaciers alpins et impact d'un changement climatique

Abstract : A new physically-based distributed surface mass balance model is presented for Alpine glaciers. It is based on the CROCUS prognostic snow model. The model resolves both the temporal (1-hour time-step) and the spatial (200 m grid-step) variability of the energy and mass balance of glaciers. Mass balance reconstructions for the 1981-2004 period are produced using meteorological reconstruction from the SAFRAN meteorological model for St Sorlin and Argentière glaciers (French alps). Both glaciers lost mass at an accelerated rate in the last 23 years. The spatial distribution of precipitation within the model grid is adjusted using field mass balance measurements. This is the only correction made to the SAFRAN meteorological input to the glacier model, which otherwise also includes surface atmospheric temperature, moisture, wind, and all components of downward radiation. Independent data from satellite imagery and geodetic measurements are used for model validation. With this model, glacier sensitivity to climate change can be separately evaluated with respect to a full range of meteorological parameters, contrary to simpler models like degree-days which only account for temperature and precipitation. We provide results both for mass balance and equilibrium line altitude using a generic Alpine glacier. In particular, the sensitivity of the equilibrium line altitude to air temperature alone is found to be 125 m.°C-1, or 160 m.°C-1 if concurrent (Stefan-Boltzman) long-wave radiation change is taken into account.

Long time simulations are done over the 1800-2165 period, using IPCC AR4 GCM output. ST Sorlin glacier is likely to vanish before 2100
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https://tel.archives-ouvertes.fr/tel-00011324
Contributor : Martin Gerbaux <>
Submitted on : Monday, January 9, 2006 - 1:25:45 PM
Last modification on : Thursday, November 19, 2020 - 3:54:26 PM
Long-term archiving on: : Saturday, April 3, 2010 - 7:24:35 PM

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  • HAL Id : tel-00011324, version 1

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Martin Gerbaux. Reconstruction du bilan de masse des glaciers alpins et impact d'un changement climatique. Climatologie. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00011324⟩

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