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This project aims at better understanding the impact of climate change on the morphologic and environmental processes in the Mont-Blanc Massif (MBM), with particular focus on the reduction of glacier surface-area, rock-fall increase related to permafrost warming and downstream changes in water and sediments fluxes. Adequately tackling the environmental and societal challenges arising from the acceleration of these processes requires: 1) a careful documentation of the spatio-temporal evolution of the involved components, i.e. local climate, rock faces, glaciers, sediment production and hydrological regimes; and 2) an accurate understanding of the complex interactions between these components. To address these issues, we formed a team of climatologists, geophysicists, geomorphologists, glaciologists, permafrost specialists and hydrologists. A first workpackage is dedicated to the coordination aspects; we will perform a systemic approach within the other work packages focuses on the study of the spatio-temporal changes of the different components influencing the evolution of the MBM: climate, hydrology, permafrost, erosion products and present-day and Holocene glacier dynamics. To investigate the complex interplay between the parameters, active exchange between work packages will assure cross-analysis of the resulting data. The project is based on both observations (field measurements, remote sensing and geochemistry) and modeling. Direct field observations will benefit from the contributions of: 1) the GLACIOCLIM observatory (LGGE-LTHE) regarding the glacio-hydrological processes in the studied areas; 2) expertise of the EDYTEM laboratory in permafrost studies; and 3) expertise of the ISTerre laboratory in erosional processes. Climate modeling will be performed by the Centre de Recherche de Climatologie of BioGeoscience. Remote sensing will benefit from the expertise of the LISTIC in satellite images processing while the study of longterm glacial and peri-glacial processes is based on cosmogenic nuclides, including notably the new dating tool in-situ produced 14C, currently implemented at CEREGE. Several modeling approaches will be applied for the present-day (~ 30 to 50 last years) period: the 1979- today regional climate variability around the MBM will first be analyzed through kilometer-scale numerical climate modeling, compared with statistically downscaled fields derived from atmospheric reanalyses and general circulation models. In addition to climate analysis (mostly focused on local orographic effects), the derived high-resolution data will be used to feed hydrological, permafrost and glacier models. Glaciohydrological discharge will rely on a glacio-hydrologic model (GSM-Socont); glacier modeling will be based on functions linking mass balance and surface elevation changes; thermal permafrost evolution will be inferred from statistical GIS-modeling to simulate the mean annual rock surface temperature distribution; and present-day sub-glacial erosion will be estimated as a function of the basal-ice velocity. Holocene glacier fluctuations, and in particular glacier retreat during past warm periods will be studied using in-situ cosmogenic (14C and 10Be) measurements. Based on this data, a Holocene erosion/ice cover history will be deduced from modeled glacier mass balance, and sub-glacial erosion functions will be calibrated with the present-day period and forced by different Holocene climate scenarii. Projections of the environmental evolutions till the end of the 21st century will be achieved through a statistical downscaling of climate change simulations using IPCC scenarios (CMIP5 simulations). The reliability of the regionalized climate will be evaluated through comprehensive comparisons with observations under present conditions before applying the downscaling technique to a multi-model, multiscenario (RCP2.6 and 8.5 radiative forcings) ensemble of global climate models throughout the century. Projection of the glacier extents and permafrost changes till at least the mid-21st century will be statistically deduced from the multi-scenario climatic ensemble applied to the mass balance and thermal models

Appli Clim

L'Appli Clim du CRC

Analysez l’évolution climatique des 50 dernières années !

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Université de Bourgogne