1. Executive Summary of the Proposal

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

Acronym VIP –MONT-BLANC

VItesses des Processus contrôlant les évolutions morphologiques et Titre du projet environnementales du massif du Mont-Blanc Rates of the processes controlling the morphologic and Proposal title environmental changes in the Mont-Blanc massif

Evaluation panel 1.1.

 Basic Research Type of research

International cooperation  No grant asked

Grant requested 498 931 € Projet duration 48 mois

Mugnier Jean-Louis Coordinator ISTerre, UMR 5275 (CNRS-UdS, UJF), partner Université de Savoie

No Link with a project of the Investment for the Future programme

1. EXECUTIVE SUMMARY OF THE PROPOSAL ...... 3 2. CONTEXT, POSITION AND OBJECTIVES OF THE PROPOSAL ...... 3 2.1. Objectives, originality and novelty of the project ...... 4 2.2. State of the art ...... 5 3. SCIENTIFIC AND TECHNICAL PROGRAMME, PROJECT ORGANISATION ...... 9 3.1. Scientific programme and project structure ...... 9 3.2. Description by task ...... 10 3.3. Tasks schedule ...... 20 4. DISSEMINATION AND EXPLOITATION OF RESULTS, INTELLECTUAL PROPERTY ...... 21 5. CONSORTIUM DESCRIPTION ...... 22 5.1. Partners description, relevance and complementarity ...... 22 5.2. Qualification and contribution of each partner ...... 23 6. SCIENTIFIC JUSTIFICATION OF REQUESTED RESSOURCES ...... 26 6.1. Partner 1 : ISTerre UMR 5275 ...... 26 6.2. Partner 2 : EDYTEM UMR 5204 ...... 26 6.3. Partner 3 : LGGE-LTHE UMR 5183-5564 ...... 27 6.4. Partner 4 : Biogeoscience UMR 6282 ...... 27 6.5. Partner 5 : CEREGE UMR 7330 ...... 27 6.6. Partner 6 : LISTIC EA 3703 ...... 28 7. REFERENCES ...... 28

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

People involved in the project: (In red : funding request in this ANR) Involv Etablissement / Current Contribution to the project Last name First name ement Organisation position (PM) Coordinator of the project DR2 ISTerre, UMR 5275 Mugnier Jean-Louis 28 Scientific and technics responsible (partner n°1) CNRS Participation to WP3 CR1 Scientific and technics responsible (partner n°2) EDYTEM, UMR 5204 Ravanel Ludovic 24 CNRS Coordinator workpackage WP2 LGGE, UMR 5183 Rabatel Antoine Phys.ad 12 Scientific and technics responsible (partner n°3) BioGéosciences, CR2 Scientific and technics responsible (partner n°4) Pohl Benjamin 14 UMR 6282 CNRS Coordinator workpackage WP1 Scientific and technics responsible (partner n°5) PrCE1 CEREGE UMR 7330 Bourlès Didier 8 Coordinator workpackage WP4 AMU Systematic of the cosmogenic nuclides. LISTIC EA CNRS- Scientific and technics responsible (partner n°6) Vernier Flavien MC 5 UdS 7703 Distributed computation and image processing ISTerre Vassallo Riccardo MC2 12 Geomorphology and dating of sub-glacial surface IR2 Systematic of the cosmogenic nuclides. Rockfall ISTerre Carcailet Julien 12 CNRS dating ISTerre Crouzet Christian MC2 4 Holocene sediment and glacier morphology ISTerre Romeyer Olivier IE 1 Hydro-sedimento data logger (Data transmission) ISTerre Guillon Herve PhD High resolution DEM interpretation ISTerre XXXX XXXX IE 3 Data transmission and acquisition EDYTEM Deline Philip MC 4 Geomorphology EDYTEM Bodin Xavier CR2 4 Permafrost modelling EDYTEM Malet Emmanuel AI 6 Field campaigns; measurements EDYTEM Astrade Laurent MR 4 Topographic and sedimentary changes of the streams EDYTEM Magnin Florence PhD 12 Permafrost modelling EDYTEM XXXX XXXX Postdoc 12 Relation climate-rockfalls since the LGM EDYTEM Berthet Johan PhD 12 High resolution DEM acquisition “Modelling future permafrost distribution in the MBM EDYTEM XXXX XXXX PhD 18 and the associated instabilities” LGGE Vincent Christian IR1 8 Glaciological measurements and modeling (partner 3) LGGE Six Delphine Phys.ad 8 Glaciological measurements and modeling (partner 3) LGGE Réveillet Marion Ph.D 10 Glaciological measurements and modeling (partner 3) LGGE (LTHE) Condom Thomas CR1 8 Glacio-hydrological modeling (partner 3) LGGE (LTHE) Belleudy Philippe PR 1 Sediment transport modeling (partner 3) LGGE XXXX YYYYY Postdoc 13 Glaciological modeling BioGéosciences Buoncristiani Jean- MC uB 12 Meltwater Sediment yield; glacial geomorphology and François sedimentology BioGéosciences Joly Daniel DR1 14 Statistical downscaling of recent and future climate CNRS variability BioGéosciences Tolle Florian MC UFC 14 Climate variability and associated effects on glaciers BioGéosciences Bernard Eric CR2 14 Climate variability and associated effects on glaciers CNRS BioGéosciences XXXX YYYYY Postdoc 12 Climate modeling CR2 Systematic of the cosmogenic nuclides. Development CEREGE (partner 5) Schimmelpfennig Irene 24 CNRS of the in situ produced C-14 methodology CDD CEREGE Rieu Patricia 7,2 Project administration for CEREGE (adm) Ing./Ch CEREGE Arnold Maurice 8 Cosmogenic nuclides measurements at ASTER CEA IE2 CEREGE Aumaître Georges 8 Cosmogenic nuclides measurements at ASTER CNRS AI CEREGE Keddadouche Karim 8 Cosmogenic nuclides measurements at ASTER CNRS Cosmogenic nuclide related physico-chemical CEREGE Guillou Valery ASI 12 preparation of the samples. Development of the in situ produced C-14 CEREGE/ISTerre XXXX YYYYY PhD 36 methodology. “Quantification of past and present sub-glacial erosion”

LISTIC Trouvé Emmanuel Pr1 5 Satellite image processing And seven masters (28 months) distributed between ISTerre, EDYTEM, BIOGEO and LISTIC

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

1. EXECUTIVE SUMMARY OF THE PROPOSAL 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 long- term 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. Glacio- hydrological 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, multi- scenario (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

2. CONTEXT, POSITION AND OBJECTIVES OF THE PROPOSAL This project deals with sub-challenge 1 (sober management of the resources and the adaptation to the climate change) of “the fundamental societal challenges”. Our project proposes to simultaneously contribute to: (i) a better understanding of the impact of regional versus global climate variability on the cryosphere at the scale of a mountain massif; (ii) a better understanding of the water and sediment cycles in the foreland of the Alpine cryosphere; and (iii) new scenarii of the environmental and morphologic evolutions of a partly glacierized mountain range. These three points are explicitly quoted in the sub-division of the Axe: «understand and plan the evolutions of the environment» of the ANR call for project.

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

High mountain areas have a great vulnerability to climate warming. This project deals with the impact of global warming on the processes that control the relief and the environmental evolutions of a mountain massif. The study area we chose to tackle this fundamental issue is the Mont-Blanc massif (MBM), located at the border between France, Switzerland and Italy and hosting the highest summit of the European Alps, the Mont-Blanc (~4810 m). The main evidence of climate change impact on the MBM are the rapid changes in glacierized areas. Future projections predict that at the end of the 21st century, French glaciers will mainly be restricted to the highest parts of the MBM. Understanding and preparing for the environmental and societal challenges resulting from this evolution in the touristic valley of Chamonix requires answering to the following questions: (1) How will the environment evolve and what will remain of the present-day scenic high mountain landscape? (2) How will the tourism management have to adjust to preserve the interest for this exceptional environment, in particular the glacierized zones of the MBM? (3) Which mitigation and adaptation strategies need to be developed facing the expected hazards and environmental changes? The ultimate goal of this research project is to provide answers to question (1). The results will supply the key elements to better assess question (2), which concerns the choices of long-term development and the future management of such attractive places of touristic and recreational interests. The municipalities of the valley of Chamonix expressed indeed the need of a global long-term vision: parts of the infrastructure, used by millions of tourists, started to be developed at the beginning of the 20th century, when the glaciers reached down into the valleys. Since then, the “Mer de Glace” retreated by 2.7 km, and Vincent et al. (2014) showed that it might retreat further by more than 1 km in the next 30 years. How to adapt the tourism infrastructures sustainably to these fast-paced changes? Concerning point (3), many risks (floods, glacier outbursts, and gravitational instabilities…), are related to high mountain domains. Several projects have already been granted by Europe or local collectivities to assess specific and well identified risks (flood risk in Chamonix, water cavity inside the Tête Rousse Glacier, seracs fall of the Taconnaz Glacier). With regard to these projects (described in Table 4, section 5.3), we propose a complementary approach, which is based on a comprehensive, long-term understanding of all the processes involved in the risk assessment.

2.1. OBJECTIVES, ORIGINALITY AND NOVELTY OF THE PROJECT This project deals with the global warming impacts on the processes that control the relief and environmental changes of a mountain massif affected by the decrease of its glacierized surface areas. The resulting data will clearly be useful for decision makers about the sustainable development of the MBM area, because the understanding of the long-term evolution of the MBM is of prime importance for the society: how to conciliate a sustainable development of this area- mainly based on tourism- with the dramatic evolution the mountain environment is currently subjected to?; and which long-term land planning is necessary to anticipate the occurrence of more serious and frequent natural hazards? Regional scale modeling of the glacier mass balance in the European Alps suggests a dramatic reduction the glacier surface-area during the 21st century (Huss, 2012), and about 4-18% of the present-day glacierized area would be preserved (Fig. 1) at the highest altitude, for all the climatic scenarios proposed by the IPCC-2007 report.

Fig. 1: Evolution of glacier mass balance and cumulated volume change in the Alps for the next century (from Huss, 2012).

Nonetheless, strong uncertainties remain and more accurate studies are now indispensable to increase our understanding of the complex influence of the local scale topographical effect on the future shrinkage of glaciers in the highest altitude zones of Europe. 4

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

The project involves downscaling modeling of the General Circulation Models (GCMs) proposed by IPCC (2013), mass-balance studies at the scale of glaciers, and coupling between glacier and its environment. Indeed, environmental changes in a glacierized massif are not only defined by the extent of glaciers, but also by the thermal and physical evolutions of the rock faces and debris slopes close to the glaciers and by the erosion/transport processes affecting the foreland slopes downstream the glaciers. All the processes are tightly linked by numerous retro-actions. The aim of the project is to assess the past and current rates of changes of the different components in a glacierized massif in order to better understand the linkages that will ultimately drive the long-term evolutions forced by the future worldwide climate warming. The MBM is one of the most suitable areas to analyze the morphologic and environmental changes of a glacierized mountain massif: MBM is the highest one in the Alps and numerous glaciological, geographical and morphological studies have already been performed in this zone of nearly 750 km2, constituting a large database of present-day and past observations. Studies started earlier in the MBM than in any other range, with the pionner works of de Saussure (1796); since the 1960s, the French Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE) increasingly focused on this study area, and various studies currently deal with the MBM (see section 5.3 for a detailed list). In this project, our team proposes to produce a comprehensive data framework including newly acquired and existing data on past and present processes in the MBM, which will be fed into a coherent modeling approach of quantifying the past, present and future rates of the different processes involved in the evolution of the MBM. Furthermore, our team will be able to rapidly perform comparisons with the intensively studied neighbor Swiss massifs, comparisons that will allow deciphering the influences of altitude, relief and massif-size. The variations at regional scale will be evidenced from the present-day evolutions but also from the past ones: e.g. Goehring et al. (2012) have shown that the Rhone Glacier (Switzerland) was shorter than presently during half of the Holocene period and its length was momentary less than half of the current one; did the MBM glaciers undergo the same evolution? We develop this interdisciplinary project on the MBM through a consortium of laboratories internationally recognized for their specialities: LGGE for glaciology, LTHE for hydrology and sediment transport, CEREGE for cosmogenic nuclide dating, ISTerre for erosion processes, EDYTEM for permafrost study and CRC (Biogéoscience) for climate downscaling and analysis. The project is not a sum of independent studies but a real effort for interactions between partners summarized in Fig. 5. Special attention will be devoted to the analysis of the model uncertainties at local and regional scales and will govern the choice of modeling strategies especially for evolutions throughout the next century. All the tasks have their own identified deliverables that are detailed in the following. One task will be devoted to the transmission of results from one task to the other and to the broad diffusion of the results to the general public. This integrated approach has the potential to produce detailed understanding of the mountain system, and we aim at more than 15 international publications. The main expected results of VIP-Mont-Blanc are the following: 1- Assessment of the climate variability induced by the orographic effect of the MBM, in respect to the wordwide evolution. 2- Assessment of the impacts of the climatic scenarios on the reduction of the glaciers size and downstream hydrologic fluxes. Projections of environmental evolutions will be achieved by constraining the mass balance glacier models by statistically downscaled climate simulations using IPCC scenarios, throughout the century. 3- Evaluation of the influence of the current and future warming on rockfalls’ occurrence linked to permafrost evolution. 4- Present fluctuation quantification of the sedimentary fluxes downstream of a de-glaciated catchment area. 5- Determination of the local climate evolution, its synchronicity with the regional and global scale throughout the Holocene until the present.

2.2. STATE OF THE ART The relationships between climate, morphogenesis and environmental changes in glacierized high mountain ranges have been studied for a long time, and pioneer works have been performed on the MBM (e.g. De Saussure, 1796). In the past few decades, interactions between these processes have become a scientific priority to better decipher the climatic evolution: it has been shown (e.g. Vincent, 2002) that the mass balance time-series for a glacier represents a good indicator of climate, and the SO/SOERE 5

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

GLACIOCLIM has been developed around this concept in the MBM (http://www-lgge.ujf-grenoble.fr/ ServiceObs/ SiteWebPOG/index.htm). Nonetheless the study of the sensitivity of glaciers to climate variables has still to be improved. Knowledge of the future glacier evolution. The future evolution of surface mass balance is the main uncertainty in glacier volume projections, but the role of ice dynamics by transferring mass from accumulation to ablation zones cannot be disregarded. Different approaches have been used in former studies on mountain glaciers. Empirical approaches do not aim to reproduce glacier dynamics and fluctuations with great fidelity and details and rely on more or less complex parameterizations (e.g. Oerlemans et al., 1998; Vincent et al., 2000; Sugiyama et al., 2007; Huss et al., 2010; Vincent et al., 2014). Physical approaches rely on the use of numerical ice flow models that solve the equations governing the flow of ice. Numerous ice- flow models with different degrees of complexity have been developed and applied to both real and synthetic applications (e.g. Hubbard et al., 1998; Le Meur and Vincent, 2003; Schaefer and Le Meur, 2007, Gudmundsson, 1999; Le Meur et al., 2007; Jouvet et al., 2011). A drawback of the physical approaches is that it requires numerous in-situ observations to calibrate and validate the model. The question is: which complexity in the glacial modeling and in the estimation of the parameters controlling the mass balance is necessary to obtain significant results? Regional climate Statistical Regional climate Worldwide Linear models RCM downscaling of with a physical climatic SIMPLE atmospheric ENSEMBLES climate modeling base (RCM scenario (GCM,

Climate Climate warming (12 kilometers (~250 m kilometric

Modeling Modeling (1° resolution) resolution) resolution) resosution) Glacier modeling COMPLEX Regional statistics (3) mass balance Fig. 1 relationships Parameterized model This project This project (1) of the characteristics (scenario for (present-day Fig.2 of one glacier future) parameters)

Physical models of COMPLEX mass balance and  (2) (4) (5) glacier flow dynamics Table 1: Strategy of coupling between glacier modeling and climate modeling inputs for future scenarios of glacier changes. (1) Oerlemans et al., 1998; Vincent et al., 2000; Sugiyama et al., 2007; Huss et al., 2010; Vincent et al. (2014); (2) Giesen and J. Oerleman (2010); (3) e.g. Huss (2012) ; (4) Hubbard et al., 1998 ; Le Meur and Vincent, 2003 ; Schaefer and Le Meur, 2007 ; Gudmundsson, 1999 ; Le Meur et al., 2007 ; Réveillet et al., submitted;. (5) Jouvet et al. (2011). Table 1 illustrates different modeling strategies that have already been used, with different complexities. The comparison of three different methods with different levels of complexity to simulate future glacier changes in the Swiss Alps (Linsbauer et al., 2013) indicates that the different glacier-modeling approaches lead to rather similar results with respect to the overall long-term evolution; the choice of the climate scenario produces the largest spread in the final results. For complex modeling strategies, like those of Réveillet et al. (submitted), the largest difference in glacier volume changes for the next century is also related to the considered worldwide climatic scenario rather than to the used climate model. Nonetheless, the simplest large-scale strategy (Fig. 1, Huss, 2012) misses to evidence the long-term influence of the climatic scenarios. Climate input, Regional Climate Models (RCMs) can be used to physically increase the resolution of GCM. Jouvet et al. (2011) used the results of the “ENSEMBLES” RCM performed at European scale (http://www.ensembles-eu.org/). As the MBM is at the transition between the humid climatic domain of northern Europe controlled by oceanic influences and the Mediterranean domain that will become warmer and probably dryer with more extreme events, large incertainties at continental scale nonetheless affect climatic scenario in this area. Because RCM are computationally expensive, they are usually not used at small scales (less than 10 km) and Statistical Downscaling Models (Maraun, 2010) are frequently preferred; we will use this empirical approach to characterize and rank the magnitude of the uncertainties at the scale of the MBM through a systematic downscaling of CMIP5 climate change simulations (multi-model and multi- RCP approach). 6

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

A study of model uncertainty components in future hydrometeorological projection (Lafaysse et al., in press) indicates that GCM uncertainty prevails for temperature, whereas, GCM and Statistical Downscaling Models uncertainty components are of the same order for precipitation. Salzmann et al. (2007b) also illustrate the added-value of RCM in mountainous regions compared to coarser-resolution global models, in spite of persisting biases. In order to better assess, at least on the present-day period, the modulation of the large scale climate variability by the local surface conditions, a physically based regional climate modeling approach will be performed; using the Weather Research and Forecasting (WRF) meso-scale model (Skamarock et al., 2008), it will allow to separate the regional climate variability in a “chaos vs. large scale forcings” at a kilometer scale. The following strategy will therefore be applied: (1) the use of a medium–scale complexity parametrized glacier model following the approach of Vincent et al. (2014) on the Mer de Glace. This approach will use: (i) the parametrization of the relationship between the annual surface mass balance and the glacier surface lowering at different elevations using the field observations acquired through the GLACIOCLIM observatory; (ii) the glacier thickness quantification; and (iii) the future annual mass balance, simulated from a positive degree-day model. By using the set of climate scenarios inferred from the multi-models and multi-RCP provided by the statistical downscaling approach, we therefore expect to provide uncertainty domains and median scenarios for the glacier extent evolution during the 21st century.

Fig. 2: Simulated thickness and snout fluctuations in 2003, 2008 and 2012 (dashed lines correspond to measurements) and in 2020, 2030 and 2040 (with a temperature increase of 0.02 °C yr-1 (yellow line) and 0.04 °C yr-1 (red line)). From Vincent et al., 2014. Yellow dot for the location of the sub-glacial gallery (EDF), possible site for applying the methods developed by Goehring et al. (2011, 2012) and based on measuring the couple of cosmogenic isotopes in situ 14C and 10Be (section 4.2). The past changes of glaciers are usually determined from glacier landform dating (moraines, roches moutonnées, peatbog …), providing results about maximum glacier extents. Due to recent methodological development of the cosmogenic nuclide dating tool “in situ 14C”, a new geochronological approach now allows studying periods of glacier retreat based on the combined measurements of cosmogenic in situ 10Be and 14C in recently deglaciated bedrock (Goehring et al., 2011, see also description of WP4 of this proposal). The exposure duration of the bedrock (glacier retracted), burial duration (glacier advance) and a mean subglacial abrasion rate may be deduced for the period of the Holocene (past ~12,000 yr) in the case of a simple advance scenario (Goehring et al., 2011). The results can also be used to simulate more complex glacier evolutions; to simulate paleo configurations of the Rhone Glacier (Fig. 3), Goehring et al. (2012) employed a simple 1-D shallow-ice model, based on that described in Vacco et al. (2009), and determine the best-fitting erosion rates in response to different paleoclimate scenarios by minimizing a misfit statistic between the measured and modeled nuclide concentrations. Fig. 3: Simulated Rhone Glacier length for a model-forcing experiment, based on a Dongee Cave Speleothem  18O record (from Goehring et al., 2012). The vertical dashed line indicates modern Rhone Glacier length. The region to the right of the dashed line indicates the simulated Rhone Glacier is smaller than modern and vice- versa for the region to the left. Time runs vertically towards the present. Nonetheless most glacial erosion models assume that sub-glacial erosion rates are proportional (erodability coefficient) to ice-sliding velocity (or to an exponent of the velocity) rather than being a constant (Harbor et al., 1988). Furthermore, recent studies have shown that water plays a major role in modulating sliding velocities (Herman et al., 2011), although the potential impact on erosion rates is still unclear. One difficulty in testing the erosional 7

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

model is the small number of databases concerning erosion rate estimates and the dispersion concerning the estimates although sediment flux in a subglacial stream was one the most usual methods to estimate the sub- glacial erosion (e.g. Hallet, 1996). In order to better constrain the past modeling of a glacier evolution in the MBM, we will therefore develop the following new strategy: (1) Develop a methodology to estimate the erodability coefficient of the substratum from present-day observations of sediment fluxes (Guillon et al., 2013), and estimation of the mean annual velocity of the glacier. This latter is classically annually measured locally from stake displacements (SO/SOERE GLACIOCLIM) but can be estimated from SAR images in the case of a glacier with lot of crevasses (e.g. Fallourd et al., 2011), on short (few days) periods. (2) Measure the double isotope system (in situ 10Be and 14C) as close as possible to the glacier (Goehring et al., 2011) and in one case (hydro-electric gallery) beneath it. (3) Model the glacier evolution and isotope concentration in the substratum by adapting the Goehring et al. (2012) approach in order to take into account the velocity of the glacier and basal erodability in the quantification of sub- glacial erosion rate. The periglacial domain is also affected by warming. Due to their steep topography, rock slopes in high mountains are affected by significant rockfalls in supraglacial areas. It is one of the most hazardous geomorphological processes because of its high speed and the related risks for infrastructure and population in the valley floors through cascading effects (Ravanel et al., 2012). The hypothesis of a relationship between climate and rock slope stability was born in 1970 in Switzerland, but it took several decades for it to be validated from a study in the MBM (Ravanel, 2010). Indeed, this link (Fig. 4) has mainly been shown from the photo-comparison-based study (Ravanel and Deline, 2011) since the end of the Little Ice Age (~ 1850). The climate control involves the current permafrost degradation and in a lesser extent the glacial debuttressing due to glacier shrinkage. Permafrost degradation corresponds to the warming of bedrock whose temperature remains at or below 0°C for at least two years, and generates physical changes of the potential interstitial ice and increases the hydraulic permeability of the fractured rock masses. Nonetheless a major question arises: will the rockfall hazard continue to significantly increase during the 21st century or is the observed increase a transient state?

Fig. 4: Comparative evolution of the number of rockfalls (> 500 m3) in the west face of the Drus and on the north side of the Aiguilles de Chamonix with changing air temperature in Chamonix since 1930 (from Ravanel, 2010). The distribution of the permafrost is of prime importance to understand its role on rock slope stability and is a challenging task due to topographical constraints, difficulties of instrumentation, and the fact that it is a largely invisible phenomenon. Modeling based on thorough process understanding is therefore necessary for estimating permafrost spatial distribution patterns today and in the future (Harris et al., 2009). Modeling capability for mountain areas has progressively improved over the past decade. Empirical–statistical models have been developed for regional scales; process-oriented numerical approaches are more relevant on local scales (terrain geometry, surface and subsurface properties or snow cover strongly influence thermal processes), particularly under future scenarios (Salzmann et al., 2007a). At the MBM scale, benefiting from downscaled climatic scenario (WP1) will be a great advantage. Concerning sediment transfer. Denudation rates at the scale of the Alps probably varied by a factor greater than 10 during a glacial/interglacial cycle (Hinderer, 2001), but the basic processes that cause this increase remain unclear. The MBM gives the opportunity to study the present-day influence of the glacier shrinkage on the

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

morphologic evolution of the streams and their sedimentary fluxes at the outlet of partly glaciated watersheds. More specifically, the evolution of sedimentary sources (clasts provenance) will be studied, as well as the discontinuities of the sedimentary transit in systems where the river geometry quickly evolves due to glacial fluctuations. First results show a disconnection of the high watersheds with the bottom of valley: downstream of big valley glaciers like Mer de Glace, the glacial retreat reveals new zones of sedimentary supplies (erosion of the lateral moraines) and at the same time zones of sedimentary storage interrupt the transit (Berthet et al., 2013, Godon, 2013). For the streams downward glaciers located on large rocky surfaces (like for the Bosson Glacier), the river system evolves by abandonment of channels that induces important variations in the distribution of the hydro-sedimentary flows. Finally, while the transport in streams is essentially made by bed-load, torrential lavas can initiate from morainic bastion of glacier systems. The major remaining questions are the following: what are the rate and role of sedimentary buffering along the streams? Does sedimentation along the streams reduce the peaks of sediment transport and/or does it form an available stock for catastrophic mass flow events? These fundamental questions have major implications concerning the mitigation of aleas linked with floods. The results of this project will be of great interest for the SM3A (Syndicat Mixte de l’Arve et ses Abords) and EDF (Environment and DPIH Services); contacts have already been taken with these public and industrial organisms that have already granted projects on to the flood risk in Chamonix town and bed-load transport experimental facility on the Arve river, respectively.

3. SCIENTIFIC AND TECHNICAL PROGRAM, PROJECT ORGANIZATION

3.1. SCIENTIFIC PROGRAM AND PROJECT STRUCTURE This collaborative project involves an interdisciplinary consortium of laboratories internationally recognized in their specialties, and the presented project intends to be a real incentive for improving interactions between partners. To organize the work, the tasks are distributed in 4 work packages that are transverse to several partners and focused on the following scientific objectives: (WP1) Climate variability at a kilometer scale; (WP2) Present and future evolution of permafrost-related slope dynamics; (WP3) Present and future variations of the glacio-hydro-sedimentary fluxes; (WP4) Holocene extend of glaciers. Each work package is organized in several tasks (see Table 2) and a specific work package (WP0) is devoted to the management of the project, the exchanges between the work packages and the dissemination to the public of the project results. In this project, we develop: - the sustainability of observational efforts already performed in the area (9 data acquisition tasks, see Fig. 5); some data acquisitions will be performed at the massif scale, like the 1952 to 2013 mass balance study (WP3.1) that will allow to complete the SO/SOERE GLACIOCLIM observations realized in the MBM; other acquisitions will focus on single sites (Fig. 7) in order to constrain a specific process, like the case of the hydro-sedimentological data-logger stations exclusively located on meltwater sub-streams of the Bossons Glacier (WP3.3) or the sampling of glacially polished surfaces for in situ cosmogenic 14C and 10Be measurements (WP4.2). - the integration of field data in models in order to take into account the simultaneous influence of climate at kilometer scale, the changes in glacier size, the evolution of the morphologies induced by the permafrost dynamics, the fast erosion of the foreland slopes and the incision/deposition along the proglacial streams (seven modeling tasks, Fig. 5). These modeling tasks have been selected in order to develop a coherent modeling framework in order to take into account the data acquired in this project and those already acquired. Finally the four major goals of the project can be summarized in one point: What will be the implications of the climate evolution on the reduction of the glacier extent, the destabilization of the permafrost and the downstream changes in the water and sediment fluxes?

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Future ( 2100 AD) Present (30 last years) Past (Holocene)

CMIP5 and Euro‐CORDEX simulations ERA‐Interim re‐ analyses Meteo‐France data, glacio‐clim, Crea Climatic records: GISP2 , EPICA Dome C, Dongue cave, alpine lakes, MBM dendrochronology Statistical downscaling Regional climate modeling Climate Rockwall instability monitoring Modeling the potentially unstable rock slopes Cliffs and paleo‐rock fall scarps dating slopes Upward

Modeling the evolution of the glaciers in MB massif In situ 14C/10Be surface exposure/ Volume and area‐surface burial dating of proglacial bedrock changes at the MBM scale Surface velocity of the ice Modeling the fluctuations

Glaciers Sub‐glacial erosion modeling of one glacier Sub‐glacial sedimentary Quantifying the fluxes erosion of a Erosion of moraines Moraines dating

watersheed Sediment transit time in zones streams Downward Impacts of the climatic scenarios on the warming of the slopes, Influence of the Fluctuations of the sedimentary Was climate evolution in the Alps reduction of the glaciers size and warming on the rock flux downstream of a partly de‐ synchronous with that on global downstream hydrologic flux. glaciated catchment area. fall occurrence. scale during the Holocene? Figure 5: Tasks and relationships between them. The tasks are distributed from past to future (right to left in the diagram) and from atmosphere to glacier foreland areas through upward zones and glaciers (top to bottom in the diagram): Yellow boxes for tasks devoted to data acquisition in addition to the present database; green boxes for tasks devoted to modeling; thin lines for data incorporated in models; thick lines for interconnections between models.

3.2. DESCRIPTION BY TASK WP0 Coordination and diffusion As the project coordinator, J.L. Mugnier has the overall responsibility for this project. He will coordinate the work of all participants and delegate the implementation of the envisioned tasks to the scientific and technical managers of the six partners involved in this project. He will continually make certain that the work is progressing steadily towards attaining the project goals. To this end, Jean-Louis Mugnier will ensure that all participants are well informed about the project status through frequent information transfer. A strict timetable is set with all tasks and actions, and regular deadlines will be defined for the fulfilment of precise objectives and the assessment of results. As delays or faster-than-expected progress may occur, these deadlines will be re-adjusted accordingly. The coordinator will also be in close and regular contact with the scientific managers of the six partners and specific meetings will be organized between them to discuss technical developments and transfer important information such as new data, results and synthesis documents. Meetings with all participants (~35 people) will be held about every year, which will allow the deadlines to be communicated and give the opportunity to discuss the technical and scientific evolution of the project and to re-adjust strategies. Six key specific meetings are also planned concerning: (1) the compilation of meteorological and climate data useful for present-day regional climate modelling (beginning of the project), ); (2) coordination with the public organism managing the touristic developments and hazard mitigation in the Chamonix valley (month 1); (3) development of the dissemination websites (month 2); (4) dissemination of climate variability results in order to model glacier and permafrost evolution (month 8), (5) glacier modelling and sub-glacial erosion (month 15) and (6) dissemination of glacier change modelling results in scenario of environmental changes (month 22). To ensure a fruitful collaboration, trips common to the different work packages are envisioned. Jean-Louis Mugnier will participate in the recruitment of the PhD and Postdoc students whose experience, interests and skills fit the project. During the project, meetings between, the PhD or Postdoc students, their

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scientific manager and Jean-Louis Mugnier will be held every three months or more often if necessary to ensure optimal mentoring and a steady progress of the tasks, in which the student will be involved. The actions of diffusion and dissemination to the general public are detailed in chapter 4 and the budget for the internal coordination and external diffusion will be ~12% of the total budget of VIP-Mont-Blanc.

WP1 Climate variability at a kilometer scale (Coordinator B. Pohl, BioGéosciences, Dijon) WP1.1 Statistical downscaling climatic modelling (Joly, Bernard, IE CNRS, MasterStudent 1 and Post- Doc 1) Quantifying climate change at fine spatial scales is a challenging issue. Numerical climate models require huge computation costs to reach sub-kilometer spatial resolutions, making such tools inappropriate for a small region such as the MBM if we wish to consider uncertainties linked with the global climate model (ESM for Earth System Model) and radiative forcing scenarios (the "Representative Concentration Pathways", or RCP, used for the latest IPCC report). We propose thus to use the so-called statistical downscaling methods, forced by large-scale climate variability derived from the ESMs used in the IPCC 5th Assessment Report (AR5) published in 2013-14, that use local predictors (mostly derived from the digital elevation model) to estimate local climate variability at fine scales (EUR 23461 -COST Action 719-, 2008). The uncertainties associated with the anthropogenic emissions of greenhouse gases and the ESMs' physics are addressed through a multi-model, multi-scenario approach. The forcing large-scale climate data consist in daily temperature and precipitation fields produced by roughly ten to twenty ESMs involved in the 5th Coupled Model Intercomparison Project (CMIP5) database used for IPCC AR5, forced by two opposite RCPs (2.6 and 8.5) over the whole 21st century. Historical runs (on the last 3 decades) will also be processed in order to evaluate the climate models' biases under present conditions against state-of-the-art reanalyses ERA-Interim. The targeted resolution for statistically downscaled temperature and precipitation fields is 150-200m over the MBM and its surroundings (Salzmann and Mearns, 2012). Their realism will be assessed through extensive inter-comparisons (under present-day conditions), with in situ observations, ERA-Interim reanalyses statistically downscaled over the same grid (Gao et al., 2012), and regional climate simulations performed at a kilometer scale (W1-2). In situ measurements (obtained from the national weather services and local observatories such as GLACIOCLIM, in collaboration with the LGGE partner) will be pre-processed at Biogéosciences by a permanent CNRS engineer (ongoing recruitment). This approach enables ranging the magnitude of the uncertainties (either due to the forcing model or the radiative forcing) and provides high- resolution estimates of climate evolutions through the century, useful for the work packages using climate conditions as a forcing.

Deliveries WP1.1 High-resolution statistically downscaled climate evolutions over the 21st century (with quantification of the uncertainties due to the climate models and radiative forcing scenarios) leading to one publication on the evolution of the MBM climate during the 21st century.

WP1.2 Regional climate modeling (B. Pohl, MasterStudent 2 and Post-Doc 1 funding requested to ANR ) For the 1979-today period, the non-hydrostatic regional climate model WRF (Weather Research and Forecasting; Skamarock et al., 2008) will be forced by ERA-Interim reanalyses (Dee et al., 2011) to regionalize climate variability at a kilometer scale over the MBM. Three one-way nested domains will be used, which are respectively centered over France and surrounding countries (~ 19km resolution), the northern part of French Alps (~ 4km) and the MBM and neighbouring areas (~ 1km). A multi-member ensemble simulation (ideally, 10 members) will be performed, using perturbed initial conditions. Large computation times will be required (roughly 8 months, for 10 x 64 = 640 processors), so the task will be launched as early as the launch of the project.

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Fig. 6: Probable simulation domains for WRF simulations. Domain #1 is at a 18.75km resolution. Inner black boxes represent the location of nested domain #2 (3.75km resol.) and #3 (kilometer resol.). At this resolution, the top of the Mont-Blanc and the major valleys (Mer de Glace, Chamonix Valley) are clearly defined.

This experimental set-up offers the opportunity to use probabilistic approaches when analyzing WRF-simulated regional climate variability (e.g., probability for frost or snow, etc.), depending on the large-scale forcings (common to all experiments) and the irreproducible fraction of climate variability, materializing the chaotic component of the atmosphere regionally. The aims of these series of numerical simulations are: (i) to disentangle the fraction of local climate variability associated with large-scale synoptic configurations and that are driven by local (mostly orographic) forcings. This work is of primary importance to predict the local effects of large-scale flows on the MBM climate at fine scales, and to determine how they are modulated by the topography and land surface conditions; (ii) to provide a high-resolution climate dataset, together with the weather observational network, to evaluate the reliability of statistically-downscaled climate simulations under present conditions (WP1-1), the ultimate goal being to determine which scales need to be downscaled dynamically with WRF, and which ones can be downscaled statistically with a similar skill, in order to reduce computation costs; (iii) to feed the glacier, hydrological and thermal models used in WP2.3 and WP3.1, the ensemble approach enabling us to quantify the local errors in temperature and rainfall estimated based on a physical approach resolving the equations of the atmosphere thermodynamics regionally. The range of the produced uncertainties can be seen as a benchmark for future climate conditions. In other words, the ensemble approach used for present-day climate conditions can give an estimate of the amplitude of local uncertainties, which can next be compared with the magnitude of local climate changes due to increased greenhouse effect and anthropogenic activities. One can thus determine a threshold (or a precise year) for which the local changes induced by anthropogenic emissions exceed in magnitude the internal variability of the regional climate system.

Deliveries workpackage WP1.2 A multi-member ensemble climate simulation at a kilometer scale over the MBM under present climate conditions (30 yrs) leading to a publication on the current climate variability in the MBM (chaotic vs. large-scale forcings)

WP2 Permafrost and rock slope evolution (Coordinator L. Ravavanel, EDYTEM, Chambery) WP2.1 Relationship between climate and rockfalls Participants: J. Carcaillet, L. Ravanel, P. Deline, E. Malet. Collaborations: M. Egli, M. Schaepman (Univ. Zurich). In continuation of: (i) a pilot study carried out at the Aiguille du Midi validating the use of cosmogenic dating (10Be) on the Mont-Blanc granite (Böhlert et al., 2008); and (ii) the measurement of the exposure time of 15 rock samples (paper in prep.), this task pursues the goal to date the rockfall scarps and evaluate the effect of permafrost evolution on rockfall triggering. These dates will be compared to climate changes since the Last Glacial Maximum (LGM, past ~22,000 yr.). We envision direct comparison of the results with those obtained in WP4 on the Holocene glacier dynamics, as both rockfalls and glacier fluctuations in the past are mainly a function of climate variability. This task will be organized in 4 points: - Dating rockfall scarps with various scarp orientations (10Be surface exposure dating) in the Géant basin - 25 samples; - Dating scarps with inscreasingly bearing rock varnish (redness) – 15 samples; - Measuring the spectroscopic characteristics of the samples (Böhlert et al., 2008) in laboratory in order to: (i) assess a color-age relationship: the more the rock surface is varnished, the older exposure age should be measured; for this approach, we will also take care of orientation of the exposed faces and the mineralogy of the samples; (ii) indirectly date other rockwalls with the established color-age law, thereby increasing the amount of available data. - Indentifying high frequency rockfalls periods out of the recent decades.

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Fig. 7: Location of the studied zones: Red zone: Glacier changes WP3.1; Green zone: Sub-glacial erosion WP3.2; purple zone: proglacial evolution WP3.3; White square: moraine dating WP4.1; Red pins: Holocene erosion and exposition WP4.2, (see also Fig. 8); Blue pins: hydro-sedimentological monitoring WP3.3; purple camera: monitoring ice velocity WP3.2; Green arrow: rockfall dating WP2.1; Purple circle: rockfall monitoring WP2.2. (Figure detail available with google earth at: http://climatologie.u-bourgogne.fr/documents/Sites3.kmz) WP2-2 Rockfall monitoring Participants: Ludovic Ravanel, Philip Deline. Collaboration: Christian Huggel (Univ. Zurich). The destabilization of rock masses with permafrost and glacier retreat is a path-dependent process linked with their geologic, tectonic, geomorphologic, hydraulic and thermal characteristics. Research is therefore needed to characterize the current evolution of the MBM rock walls. This identification in terms of space/time distribution and processes is here associated with two proven methodologies in the Mont-Blanc since 2005: - HR remote sensing techniques which allow pre- and post-failure assessment of rock instability (Ravanel et al., 2014); Within the Interreg Alcotra-projet PERMAdataROCK (2006-08) and the Interreg AlpineSpace- project PermaNET (2008-11), a large amount of data on rockfalls were collected but it is necessary to continue the monitoring effort to: (i) better characterize and quantify the parameters involved in rockfall triggering; and (ii) get a long-term monitoring, essential to assess the effects of global warming. Annual terrestrial laser scanning (TLS) on 9 rockwalls will allow getting high-resolution 3D models. The diachronic comparison of those models makes possible quantifying the detached rock mass and understanding the rock- structural context. - A network of observers (guides, hut keepers and climbers; Ravanel et al., 2010) identify all events that occur in the central part of the massif (60% of its surface is covered). This participatory science action, with very satisfactory results (more than 350 documented events), will be enhanced with rely on a smartphone app developed within the framework of the Interreg Alcotra-project PrévRisk Mont-Blanc. The network of observers set up in 2005; it will be reactivated every spring and the data will be verified, completed and analyzed each fall. WP2.3 Modeling the permafrost distribution and the associated instabilities Participants: L. Ravanel, Ph. Deline, F. Magnin, X. Bodin, Ch. Vincent, A. Rabatel, E. Malet. 1 PHD (half- grant asked ANR). Collaboration: S. Gruber (Carleton Univ.), J. Noetzli (Univ. of Zurich). Permafrost in high-alpine bedrock is characterized by great spatial variability driven by high gradients in topography, surface and subsurface characteristics. We thus have to develop permafrost modeling in order to extend knowledge to situations in space (locations with no existing measurements) and time (future rock 13

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temperature evolution for a given climate scenario downscaled in WP1) which are not monitored. With such models, we will then propose scenarios of rockfall susceptibility for the future (2050). This task, which will be mainly developed through a Geographic Information System (GIS) and will benefit from rockfall data acquired since 2003,results of the PhD thesis on permafrost modeling in the MBM (Magnin et al., 2013), data of rock surface temperature and temperature at depth (up to 10 m) which are acquired at the Aiguille du Midi (3842 m a.s.l.) since 2005 thanks to the Interreg Alcotra-projet PERMAdataROCK (2006 - 2008) and the Interreg AlpineSpace-project PermaNET (2008-2011). Modeling the rockfall susceptibility today and in the future needs: - Modeling and improving by in-situ measurements the current permafrost distribution by employing physically based models; existing modeling approaches (Gruber and Haeberli, 2007; Harris et al., 2009) and parameterisations are successful at a terrain model resolution and can serve to assess general permafrost conditions in release areas at a decameter scale; - Modeling the permafrost distribution in the future by forcing the latter model with temperatures outputs from the statistical downscaling climatic modelling WP1-1; - Crossing this permafrost distribution model with the rockfall triggering parameters – after having computed their relative importance – to map the most susceptible areas (potentially unstable rock slopes) for the future for 2100 or 2050 depending the uncertainties related to the climate scenario. Deliveries WP2 - An approach of the climate-rockfall relationship since the LGM: 10Be surface exposure dates in rock walls and Rock color - surface exposure age relationship tested. - Systematic annual survey of rockfalls in the central part of the MBM and characterization of the triggering parameters for each collapse. - Production of an advanced permafrost distribution model for the Mont Blanc massif for the current period and simulations for 2025, 2050 or 2100. - Production of rockfall occurrence susceptibility maps for the same dates.

WP3 Changes in glacier extent and hydro-sedimentary fluxes on a recent time scale WP3.1: Surface-area and volume changes of the glaciers at the scale of MBM (Coordinator A. Rabatel, LGGE, Grenoble) Task 3.1.A: Quantification of glacier changes from 1952 to 2013 Participants: A. Rabatel, C. Vincent, D. Six, M. Réveillet, 1 post-doc This task will benefit from both in-situ measurements available on several glaciers of the study areas (mass balance, glacier surface flow velocities) through the SO/SOERE GLACIOCLIM and the “Arve project”, and photogrammetric data acquired through the Labex OSUG@2020 (aerial photographs from 1952).  In-situ measurements. Additional measurements to those realized within the SO/SOERE GLACIOCLIM on Argentière and Mer de Glace glaciers will be performed to quantify the glacier thickness using ground penetration Radar (GPR). All these data will be used for the parameterization of the modeling of glacier thickness at the massif scale (Task 3.1.B).  Surface and volume change reconstruction. Historical extensions of glaciers at the scale of the Mont- Blanc massif will be reconstructed from 1952 aerial photographs and 2013 high resolution Pleiades satellite images. These data will serve to reconstruct recent glacier changes in terms of both surface-area and volume (volume changes will be computed by subtracting digital elevation models made using photogrammetric techniques). Results from this task will be used in the task 3.1.2 and other WPs by providing information of the past extension of the glaciers and the surfaces exposed to erosion processes. Task 3.1.B: Modeling the glacier shrinkage over the 21st century in the Mont-Blanc massif Participants: A. Rabatel, C. Vincent , D. Six, M. Réveillet, T. Condom , 1 post-doc ANR This task will benefit from a recent work on the Mer de Glace (Vincent et al., 2014) which applied the conceptual modeling approach we propose to use at the scale of the Mont-Blanc massif.

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 Calibration of the function linking mass balance and surface elevation changes at the massif scale. This function is the basis of the conceptual approach proposed here. Such a function has been yet calibrated on the Mer de Glace (Vincent et al., 2014). Volume changes at the scale of the Mont-Blanc massif (Task 3.1.1) will be used to calibrate this relationship for all the glaciers considering their morpho- topographical variables (aspect, slope, size). The advantage of this conceptual approach is to implicitly consider the glacier ice flow.  Glacier thickness quantification. To simulate the future evolution of glaciers, the ice thickness needs to be known. We propose to compute glacier-specific distributed thickness by applying an approach based on an inversion of surface topography using the principles of flow dynamics (Huss & Farinotti, 2012). Results of this modeling will be validated using the GPR measurements performed in Task 3.1.A.  Mass balance simulation for the 21st century. On the basis of IPCC scenarios and results of downscaling from WP1 for temperature and precipitation evolution during the coming decades, we will apply a positive degree-day model to compute the annual mass balance of each glacier over the 21st century, as it has already been done for the Mer de Glace by Vincent et al. (2014), but for a shorter period, i.e. until 2030.  The three above mentioned points will be used all together to simulate the evolution of glaciers until 2100. Annual mass balance will allow quantifying the glacier surface elevation changes yearly for all the glacier elevation ranges. Subtracting these annual elevation changes to the current glacier thicknesses will give us the remaining glacier for each year until the end of the study period. Deliveries WP3.1 - Production of the digital elevation models for 1952 and 2013. - Quantification of glacier surface-area and volume changes at the scale of the Mont-Blanc massif between 1952 and 2013. - Simulation of the glacier changes at annual scale for the 21st century using: 1) available climate scenarios from the CMIP5 project (IPCC AR5); and 2) the downscaled climate data performed by the WP1 when available: i.e. during year 3 of the current ANR project. WP3.2 Sub-glacial erosion (Coordinator J.F. Buoncristiani, BioGéosciences, Dijon) (F. Vernier, E. Trouvé, J.L. Mugnier, L. Astrade, J. Berthet, O. Romeyer, J.F. Buoncristiani, H. Guillon, coll. F. Herman) (1 M2R and 1 IE funding requested in thisANR) Sub-glacial erosion beneath temperate glaciers are studied in this task by using the Bossons Glacier as a present-day observatory allowing to test and to estimate the parameters values of erosion laws. This work will complete the work already performed on the erosion beneath the cold part of the glacier des Bossons (Godon et al., 2013); it will benefit from the results of W3.1 concerning the glacier dynamics and W4.2 concerning long term sub-glacial erosion. Two specific data acquisitions will be performed in order to constrain modelization. Task 3.2.A: Glacier velocity Space data: The three-dimensional (3D) glacier surface velocity (beneath the altitude of 3200 m) has already been deduced from high resolution (HR) SAR (Synthetic Aperture Radar) images provided by TerraSAR-X satellite (See Fallourd et al. (2010; 2011) for the methodology developed in the frame of ANR EFIDIR). Taking into account the new data acquired in 2012 (Ponton et al., in press) and 2013, at least ~40 velocity fields on 11- day periods will be calculated in this project on the Bossons Glacier. Ground-based data (Geodesy by GPS): a permanent GPS, granted by UdS (AAP Mont-Blanc, 2011), has already measured the displacement of the Bossons Glacier in 2011. This receiver will be re-installed during 3 successive summer seasons in order to obtain fluctuation at high resolution of the velocity at one site, as it has already been performed on the Argentière Glacier (Ponton et al., in press). Ground-based data (Change detection by photogrammetry): 2 digital cameras were funded by the Mont- Blanc Savoie University project (2011) and were installed on the right bank of the Argentière Glacier in a stereoscopic configuration. An operating chain is currently being developed to compute the glacier flow velocity (see Pham , 2014; submitted). These digital cameras will be re-installed to monitor the Bossons Glacier. The objectives are to compute the 3D glacier velocities from the stereoscopic installation. Spatio-temporal data mining techniques allow combining different data and extracting useful information from multiple origins data. These technics will be developed in the project DIM (a project submitted to the “défi Données massives, connaissances, décision, calcul haute performance et simulation numérique” of the ANR 15

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2014) to estimate displacement of gravitational mass flow from various monitoring (ground-based, airborne, spaceborne); they will be tested on the heterogenic data set above presented for the Bosson Glacier, in order to better estimate the mean annual ice velocity and its fluctuations. Task 3.2.B: Suspended load of sub-streams The three outlets of the Bossons Glacier are already instrumented and hydro-sedimentological stations continuously monitor water-flux, turbidity and conductivity. Two station installations were supported by ANR ERD ALPS (2010-2013) (Godon, 2013) and one supported by SM3A (Syndicat Mixte Aménagement de l’Arve et Abords). The continuous monitoring of water-fluxes and turbidity will be prolonged in the frame of this project in order to estimate the sediment yield and hydrologic budget of the Bossons Glacier. The respective extent of the three sub-glacial watersheds will be estimated using the procedure detailed in Godon et al. (2013, supplementary data). This method is a comparison between discharge measured continuously at the station and best fit discharge modeling deduced from the GSM-Socont (Glacier and SnowMelt – SOil CONTribution model, Schaefli et al., 2005) by varying the surface of the sub-glacial shed. Task 3.2.C: Sub-glacial erosion rate Seasonal fluctuations: Theoretical modeling suggested (Herman et al., 2011) that erosion might mainly occur during melting seasons, when subglacial water pressure is large and effective pressure is low (Hildes et al., 2004) (i.e., before the channels fully develop (Boulton et al., 2007); furthermore a temporary sediment storage beneath the glacier during winter (Collins 1989; Darrel et al., 2005) may increase the number of abrasive agents. A multi- parameters statistical analysis of glacier velocity fluctuations, yield of suspended load in the sub-glacial shed, stream flows and meteorological parameters will be performed in order to model the influence of the basal water and the seasonal development of conduits in the sediment yield fluxes. Modeling annual erosion: Most glacial erosion models assume that erosion rates are proportional to ice- sliding velocity (e.g. Herman et al., 2011) but are poorly constrained. The proportionality coefficient (erodability of the substratum beneath the temperate part of the glacier) will be calculated from integration, during annual periods, of sediment flux (task W3-2A) and spatial integration of mean annual basal velocity. Basal velocity will be computed from the measured surface velocity (Task W3.2B) and difference between surface and basal velocities of the glacier deduced from the approach (Huss & Farinotti, 2012) developed in task W3.1. The erodability of the substratum deduced in this task will be used for Modeling Holocene erosion in WP4.3.

Deliveries workpackage W3.2: - Analysis of the role of basal water and seasonal development of conduits in the sediment yield fluxes. - Quantification of the erodability coefficient in sub-glacial erosion laws for present-day Bosson glacier. WP3.3 Erosion and sediment transfert in a partly glaciated watershed (Coordinator L. Astrade) (P. Belleudy, T. Condom, H. Guillon, J.L.Mugnier, L. Astrade, J. Berthet, 1 AI (funding requested in this ANR) The work will be focused on the pro-glacial melt-waterstreams of the Arveyron of the Mer de Glace and the Creuse, Crosette and Bossons streams located in the watershed of the glacier des Bossons. Creuse and Arveyron streams are highly influenced by man (hydroelectric deviations in the case of the Mer de Glace, impoundment, strand zones of deposits and cleaning operations for the protection of the MB tunnel road in the case of the Creuse stream), whereas the Bossons and Crosette streams are less influenced by man and not at all in their upper part. The understanding of the dynamics of these rivers is focused on: a) the sediment supply/erosion/storage in the upper part close to the glacier, and b) on the downstream evolution, characterized by incision, transit or sedimentation close to the confluence with the Rave river Two methods will be used: the first one is the diachronic study of the past dynamics from various types of archives; the second is the monitoring of the current dynamics and the regular re-iteration of high-resolution topographic measurements. Task 3.3.A) Past moraine and river bed stability Various types of archives allow a diachronic study of the past dynamics: aerial photos, iconography, handwritten archives… the chronicles of the valley of Chamonix were remarkably supplied for a mountainous territory but have only been used for glacier extent studies (e.g. Nussbaumer et al., 2011). The aim of this task is: a) to realize diachronic morphological maps of the sediment source zones: steep moraines potentially mobilizable and temporary storage zones formed by terraces, riverbeds and cones;

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b) to compare high resolution Digital Elevation Models (DEM) in order to estimate the volume of the stored sediment or the amount of incision. The work will be mainly based on the analysis of ortho-rectified aerial photos: - 20 aerial photo campaigns (Institut Geographic National) are available for the 1983-2013 period of glacier extents decrease, and 32 aerial photos campaigns are available for the period 1951-1983 characterized by a phase of glacier advances; - at least 3 DEM will be performed ; the present-day DEM will be based on aerial Lydars acquired in collaboration with SM3A, and the others (In 1983 and 1952) by photogrammetry; the DEM of 1952 will be performed in collaboration with the task W3.1 that deals with the realization of a large scale 1952 DEM. The study of the older periods will be mainly based on cadastral documents, iconography and handwritten archives; It will mainly focused on the Little Ice Age (last major glacier advance) around 1850. Task 3.3.B) Present-day Sediment flux and transit time In this task, the present-day sediment transport dynamics, the evolution of the sedimentary sources and the link between river transport processes and hill slope erosion will be quantified from : - High-resolution topographic surveys of riverbeds, slopes producing sediments and storage zones. Since 2008 High resolution aerial LiDAr DEM are regularly acquired by different agency (IRSTEA/Espace Mont Blanc, SM3A), and ground campaigns will be regularly performed on local zones using terrestrial LiDAR. - monitoring of the streams ; hydro-sedimentology stations already continuously monitor the suspended load and water flux of the studied streams (see W3.2.A). Complementary observation systems are on the way to being installed in collaboration with SM3A to detect boulder motion by stereo-photography and the camera will be piloted by geophones detecting mass flows; A methodology is developed in the upper shed of the Bossons stream (« plan des eaux ») in order to estimate the precise total sediment/transport budget of a zone ; it combines (1) re-iteration of high resolution DEM of the steep slope (moraines) performed by pixel automatic correspondence of a set of ground-based photography (IGN MicMac software) ; (2) re-iteration of DEM of the rather flat river bed zone by differential kinematic GPS campaigns; (3) estimation of the silt production of the slope by difference between suspended load measured with hydro-sedimentology stations at different sites along the Bossons stream ; (4) estimation of the transit time of marked pebbles (with radiofrequency (RFID) tags) of different granulometries (from 2cm to 30 cm « b » axe) using a mobile antenna for campaigns regularly performed since 2010, and a fixed antenna through the whole stream downstream of the studied zone. All this instrumentation will allow to quantify the motion and transit time of different granulometries and to determine the process of motion – bed-load or mass flow- and their link with the precipitation and water discharge. This detailed set of data will be used to test the applicability of different physical models of transport. Acquisition of significant data with this instrumentation will necessitate several years of monitoring. Therefore, a participation by the ANR to the engineer’s salary is requested, this will be included in the mutualized pool of technical support of the observational services of ISTerre. Task 3.3.C) Moraine and river bed stability in the future For the area that will be free of ice during the 21st century (inferred from the median scenario issue from W3.1), a morphological map will be performed to indicate the sedimentation zones, unstable zones (moraine or scree) and rock outcrops. This classification will be based on a slope analysis of the bedrock geometry beneath the present-day glacier (issue from the glacier thickness estimation of WP3.1.B), and on the sediment dynamics rules evidenced in WP.3.3.B.

Deliveries workpackage W3.3 - Geomorphologic evolution of river profiles and moraines during a phase of glacier retreat (since 1983) and a phase of glacier advance (before 1983) ; - Annual budget (during ~a decade) of the sediment of « plan des eaux » : transit time, annual storage and origin (glacier/moraines) for the different granulometries - Morphological map of the area that will be free of ice during the 21eme century, indicating the sedimentation zones, unstable zones (moraine or scree), rocks outcrops.

WP4. Holocene extent of the glaciers (coordinator D. Bourles, CEREGE, Aix-en-Provence) Investigating the local glacier extents during the past thousands of years is necessary to understand the long- term morphological and environmental evolution of the MBM. WP4 aims at establishing a chronology of glacier 17

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dynamics throughout the current interglacial Holocene (past ~11,600 years). Further, a novel approach will allow quantifying Holocene subglacial abrasion rates. Because glacier fluctuations are driven by the local climate, the results will allow reconstructing key events in the Holocene climate evolution at the MBM, benefitting from the glacier models calibrated with data from the recent past (WP3.1). The results on the Holocene glacier-climate variations and associated abrasion rates will be of considerable interest for WP2.1, WP3.2, and WP3.3. WP4.1 Timing and extents of Holocene advanced glaciers Participants: P. Deline, I. Schimmelpfennig, 1 PhD (funding 2 requested in this ANR) Pre-historic fluctuations of mid-latitude glaciers as a consequence to climate changes, in particular variations in temperature and precipitation (e.g. Oerlemans, 2005), are globally documented by moraines. Moraines were deposited along the margins of an advancing or stagnating glacier just before it started retreating due to warmer/dryer conditions. Mapping and dating moraines thus provide us with information on the timing of past glacier extents, but only for large glacier extents, as moraine deposits of shorter extents have been run over and destroyed by later, more extensive advances. Over the last years, transformational improvements in the sensitivity of surface exposure dating using the cosmogenic nuclide 10Be have been attained allowing for better resolved Holocene moraine records at various sites in the world (e.g. Schaefer et al., 2009; Jomelli et al., 2011; Schimmelpfennig et al., 2014). At the national French accelerator mass spectrometry facility ASTER (CEREGE) 10Be moraine samples as young as the Little Ice Age (~700-150 yr) have already been measured. A new ion source will be installed at the beginning of 2015 allowing for low uncertainties (~5%) of such young ages. In the MBM, Le Roy (2012) obtained pioneering Holocene moraine ages based on 10Be dating, dendrochronology and radiocarbon dating, indicating at least ten glacier advances between 3.6 kyr ago and the late LIA. More 10Be data from the Belledonne and Ecrins massif further south evidence large Holocene advances prior to 9.3 kyr as well as from the Neoglacial period on 4.2 kyr ago (Le Roy, 2012). We envision complementing the existing moraine record from the MBM (Jaillet and Ballandras, 1999, Deline and Orombelli, 2005; Le Roy, 2012) with additional data in three different catchments, the Nant Blanc and Talèfre Glaciers (two reactive glaciers in the Mer de Glace basin), and Bossons Glacier (Fig. 8). These sites feature moraine ridges slightly outboard of late LIA limits, presumably of Holocene age. The ridges will be mapped and sampled according to up-to-date procedures (e.g. Schimmelpfennig et al., 2014). We plan 40 measurements. WP4.2 Period of retracted glaciers and subglacial abrasion rates (Holocene) Participants: R. Vassallo, I. Schimmelpfennig, D. Bourles, 1 PhD (funding 2 requested in this ANR) Reconstructing past periods of retracted glaciers has remained difficult, even though quantitatively characterizing these periods is crucial to understanding the fate of mountain glaciers in the light of future climate predictions. In the Swiss Alps, evidence from radiocarbon-dated fossil trees that grew up-valley of the modern glacier terminus and were killed during a subsequent re-advance revealed that glaciers were shorter than today for most of the early and mid-Holocene (e.g. Hormes et al., 2006; Joerin et al., 2006). During this period, no moraines are preserved at the MBM, suggesting that its glaciers, too, were retracted. The current glacier retreat allows now exploring a new archive to investigate periods of retracted glaciers: proglacial bedrock, accessible for analyzing its cosmogenic nuclide inventory produced during periods of retracted glaciers. Exposure-dating glacially scoured bedrock relies on a novel approach developed at LDEO (New York, USA) and so far applied in only one pioneering study (Rhone Glacier, Switzerland): Goehring et al. (2011) combined measurements of 10Be with those of the new cosmogenic tool ‘in situ 14C’ in the same mineral fraction (quartz) (Lifton et al., 2001) to quantify the cumulative durations during the Holocene of how long the proglacial bedrock was exposed (i.e. the glacier was retracted), and how long it was buried by ice (i.e. the glacier was large). The use of only one cosmogenic nuclide would largely underestimate the exposure duration of the bedrock, because during periods of advanced glacier positions, the ice abrades the rock surface, reducing the nuclide inventory produced before. The combined-nuclide approach is illustrated by these two equations: 10 14 where Nx are the nuclide concentrations at time t (x for Be and C, respectively), Px are the production rates, te is the exposure duration, 14 tb is the burial duration, λ14 is the decay constant of C, and ε is the abrasion rate. Due to the very different half-lives of the two nuclides (14C: 5.73 kyr; 10Be: 1.4 Myr), their concentrations evolve differently as a function of exposure, burial and abrasion, and their combined measurements allow for simultaneous determination of the Holocene exposure duration te, burial duration tb and a

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mean abrasion rate ε at a given site. Because here we only consider the period of the Holocene (duration of ~11,600 yr), we make the assumption that tb = 11,600 yr - te, thus dealing only with two unknowns, te and ε. The first French laboratory for in situ 14C extraction from quartz is now being implemented at CEREGE, based on the knowledge Irene Schimmelpfennig is transferring from her postdoc period at LDEO (2010-2012) to CEREGE (e.g. Schimmelpfennig et al., 2012). I. Schimmelpfennig has been ranked eligible for a permanent CR2 CNRS position this year. Routine acquisition of in situ 14C data at CEREGE is expected for end of 2015. In the case of significant delays, in situ 14C extractions could be performed at LDEO. According to Goehring et al. (2011) above described innovative method, we envision collecting samples from recently deglaciated bedrock on transects parallel to the termini of the following MBM glaciers (Fig. 6): 1) the Bossons Glacier, where preliminary 10Be measurements of two samples imply an exposure duration of the surface for at least 1200 years (Prud’homme, 2013); 2) the Trè la Tête Glacier, and 3) the Glacier du Tour (Fig. 8). We will focus on one of the two latter candidate sites depending on preliminary 10Be data. Further, we have obtained a sample from subglacial bedrock underneath the Mer de Glace, ~800 m behind the current terminus through access of a temporary “EDF” gallery (courtesy of the Direction de la Mission Concessions, Eau Territoire à l'Unité de Production Alpes) (Location on Fig.2). In total, we plan ~15 samples for the in situ 14C/10Be approach. Following Goehring et al. (2011) strategy, we will additionally measure the cosmogenic nuclides 26Al and 36Cl in a few selected samples, to test if 10Be concentrations could be “inherited” from exposure periods pre-dating the Holocene. Nuclides with different half-lives from 10Be (26Al: 0.7 Myr, 36Cl: 0.3 Myr) yield discordant results if previous exposure periods followed by substantial burial are not accounted for.

Fig. 8: Glaciers targeted to investigate Holocene glacier dynamics. Left panel: locations in the MBM with glacier names. Middle panel: example for a moraine dating site; moraines indicated as white lines. Right panel: example for a bedrock dating site; potential sampling profile indicated as red line.

WP4.3 Modelisation of Holocene glacier-climate fluctuations (I. Schimmelpfennig, J.L. Mugnier, C. Crouzet, 1 PhD (funding 2 requested in this ANR) Combining the dating and mapping results from moraine and glacial bedrock, we will reconstruct a well- defined chronology of Holocene glacier behavior at the MBM. Because the preserved geomorphic features do not represent a complete high-resolution archive, but rather key extents of advanced glaciers and the total duration of glacier retraction over the Holocene, we will model a scenario of continuous glacier fluctuations, which best fits our geochronological and geomorphic data. For this, we will follow the approach by Goehring et al. (2012) who modeled the Holocene dynamics of the Rhone Glacier using independent paleoclimate records as templates for paleo-equilibrium line altitude variations; the validity of the most adequate of four paleoclimate records was evaluated by comparing theoretical geochemical and erosion data associated with the modeled glacier configurations to the measured values. We envision complementing this approach by: 1) assuming an erosion law proportional to velocity (deduced from the flux, thickness and basal sliding factor, in collaboration with task 3.2B) rather than a constant erosion rate; 2) taking into account the calibration between mass balance and surface elevation changes performed in task W3.1; the ability of this calibration to simulate glacier extents will be tested for the Little Ice Age, which is well described till 1570 AD for the Chamonix valley (e.g. Nussbaumer et al., 2011), and during which the glacier largely exceeded the present-day state and was rather. The results obtained for the Holocene will be compared to independent regional Holocene paleoclimate records from close-by sites, such as lake level reconstructions (e.g. Magny, 2004), pollen assemblages (Peyron et al., 2011) or results from the project Dove (drilling overdeepened alpine valley) deposited to ICDP (Isere valley).

Deliveries workpackage WP4 - Dating and mapping of Holocene key extents of advanced glaciers - Quantification of cumulative period of galcier retractation during the Holocene - Modeling of local Holocene glacier-climate dynamics and subglacial abrasion rates

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3.3. TASKS SCHEDULE

Table 2: Synthetic table of the tasks progression. 2015 2016 2017 2018 Task Wi Sp su au Wi Sp su au Wi Sp su au Wi Sp su au WP1 Climate variability at a kilometer scale Statistical downscaling climatic modeling X X X X WP 1.1 Compilation of Present-day climate data X X WP 1.2 Regional climate modeling X X X X X X WP2 Permafrost and rock slope evolution Past rockfalls : Sampling X WP2.1 10Be preparation X X X Rockwall instability TRS monitoring X X X WP3.2 Network of observers X X X WP3.3 Modeling of the permafrost distribution X X X X X X X X X X X X WP3.1 surface-area and volume changes of the glacier at the scale of MBM In-situ measurements MBM glaciers X X WP3.1A DEM 1952- DEM 2013 of the MBM glaciers X X X X Calibration of the functions linking mass balance X X

WP3.1B & surface elevation changes Glacier thickness quantification X X X Mass balance simulation for the 21st century X X X X Simulate the evolution of glaciers until 2100 X X X W3.2 Sub-glacial erosion Glacier velocity: GPS record X X X X X X WP 3.2A GPS processing X X X Stereo-camera X X X X X X Satellite image processing X X X X X X X X X X X X X X X X WP 3.2B Flux records at 3 Bossons subglacier streams GSM-Socont modelisation X Multicorrelation analysis of velocity, flux, meteo X X X X WP 3.2C Annual sub-glacial erosion modeling X X X X W3.3 Erosion and sediment transfert in a partly glaciated sheed Present to 1951 moraine topography modification X X X WP3.3 A 1983 to 1951 moraine topography modification X X X X Pre-1951 chronics X X X X River topography Creuse, Bossons, Arvey. X X X

Moraine high resolution DEM (Lydar ) X X X Very coarse sediment transit: camera, Creuse X X X X X X X X X WP3.3 B X X X X X X Coarse sediment : RFID in Bossons river WP3.3B Physical model of transport X X X X Comparison sediment flux, climatic parameters X X X X WP3.3 C Slope analysis of the new surfaces X X X Prevision of the sediment buffering zones X X X X WP 4 Holocene extend of the glaciers Holocene advanced glaciers : moraine sampling X X WP 4.1 10Be sample preparation X X Retracted glaciers : preliminary 10Be sampling X X WP 4.2 10Be sample preparation X X Drilling and main sampling phase X X 14C preparation samples X X X X Modeling depth attenuation and retracted duration X X WP 4.3 Modeling of past glacier fluctuations X X X X

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4. DISSEMINATION AND EXPLOITATION OF RESULTS, INTELLECTUAL PROPERTY A total budget of ~56 000€ is devoted to interactions between work packages and external disseminations: Table 3: Budget devoted to interactions between work packages and external disseminations (in Euros): ISTerre EDYTEM LGGE BioGéosc. CEREGE LISTIC Internal Working meeting 2000 1000 2000 3000 2000 1500 dissemination Data Formatting (PostDoc) 3915 Dissemination publication (Editing) 1000 2500 2000 1000 1000 to the scientific Presentations to conference 1500 1500 5800 1500 1000 1000 community Organisation and participation 1500 1500 1500 1500 1500 toa EGU special session Dissemination Atlas du Mont Blanc 8000 to the public The OSUG web‐site 7000 Dissemination to the scientific community. - Scientific publications will be the main support for scientific communication. We will give priority to high quality open access journals, without neglecting the visibility. Our results will be published in leading journals in Glaciology (e.g., Journal of Glaciology, The Cryosphere), Hydrology (Journal of Hydrology, Advances in Water Resources), geomorphology (Geomorphology), geophysics (Journal of Geophysical Journal) and atmospheric sciences (Climate Dynamics, Journal of Climate) and hopefully in generalist journals. A total of more than 15 scientific papers is expected. - A special session on the « future of the alpine glacier: return to the Holocene optimum conditions? » will be organized in the frame of the EGU meeting (2017) and results will be also presented at international conferences (AGU, EGU, INQUA ...) as well as “regional/local” conferences. The internal dissemination between the members of the consortium will be done through informal discussions, and organised meetings (see above description in paragraph 3.2 of the project gestion). The dissemination within our universities and research centers will be done through seminaries and conferences. Dissemination to the public. - Film 90 minutes: « Mont-Blanc 2015, Exploration en cordée »: for ARTE, producer: Guillaume Pérès Grand Angle Productions and Marine Jacquemin Ethic Prod Pitch: A scientific rope climbing the Mont Blanc will explain the geological and glaciological history of this mountain from the observed landscape and from clip on laboratory experiments. This film illustrates all the WP proposed in this project and will furnish high standard scientific vulgarization diffusion. - Pedagogic web site: On top of PIs experience to communicate with the Medias (see below) and the public (popular articles and videos, exhibitions) the dissemination of project results to the society will be realized in collaboration with the CREA (Centre de Recherche des écosystèmes d’altitude). A specific budget of 13000 Euros is planned for the dissemination of our results through the already popular ATLAS MONT BLANC Initially granted by the « plan integre transfrontalier de l’espace Mont-Blanc » and driven by the CREA. (See http://www.atlasmontblanc.org/accueil/) The following maps will be added to the Atlas Mont Blanc with scientific explanations: (1) Climatic maps issue from WP1: Mean precipitation and mean temperature for 1984, 2014; for 2050 and 2100, different scenarios will be shown; (2) Synthetic maps of the mer de glace, Bosson and Argentiere glacier extents issues from WP3.1: min- max and most probable extension for 2050 and 2100; (3) Synthetic morphological map of the area keep free of ice between 2014 and 2100 issue from WP2 and WP3.3.and indicating the sedimentation zones, unstable zones (moraine or « pierriers »), rocks outcrops. - Scientific web site: a webpage will be constructed on the OSUG dedicated to our project. This page will be performed in collaboration with the communication service of the OSUG and part of the work will be performed by the CREA diffusion team. Formation of students. The focus of the current project is highly multidisciplinary with WPs dedicated to the different components of the high-altitude ecosystems. The team is comprised of research scientists with different competences in relation with the different components. The works realized in each WP will be done by associating Master, PhD students and post-docs from the different Universities. Over the four years of the project and for the four WPs, we have planed 7 Master students, 2 PhD students and 2 post-docs. Depending 21

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on the WP in which each student will be involved, he/she will develop competences in glaciology, climatology, geomorphology, geophysics, with in-situ and or satellite observations, or also in modeling. The students will be part of the team (which represents an additional motivation for them), be involved in the meetings organized during the project to participate to the discussions and present their results. Along the project duration, we plan to postulate to other PhD grants distributed by the "Doctoral School of the University of Grenoble" (Ministry of Research) for the best Master students. Furthermore, a half grant for a PhD student will be asked in complement to the half part asked to ANR for WP2; the subject concerning thermics and mechanics of rockfalls is highly transversal to several laboratories of the Grenoble Observatory and could be granted by the Labex OSUG@2020 (OSUG-UJF-Grenoble) whereas its regional focus could interest the “Association des Pays de Savoie” (Conseil general des départements Savoie-Haute Savoie). Dissemination to the public services: The dissemination and coordination of our project with the actions developed by the public services (Syndicat Mixte d'Aménagement de l'Arve et de ses Abords, community of municipalities of the Chamonix valley, Rhône Alpes region.…..) (See table of section 5.3) will be ensured through the simultaneous implication of the researchers in this project ANR and in these projects concerning specifically the risks.

5. CONSORTIUM DESCRIPTION

5.1. PARTNERS DESCRIPTION, RELEVANCE AND COMPLEMENTARITY We develop this interdisciplinary project on the MBM through a consortium of internationally recognized laboratories in their specialties: LGGE for glaciology, LTHE for hydrology, CEREGE for cosmogenic dating, ISTerre for erosion processes, CRC (Biogéoscience) for climate downscaling and analysis, EDYTEM for permafrost study and LISTIC for images and teledetection theme. The » Institut des Sciences de la Terre » (ISTerre) (UMR 5275 CNRS/Université de Savoie/UJF is a multi- disciplinary laboratory regrouping roughly 265 persons. Main research topics are based on the study of the couplings between observation, and modeling of complex natural processes. For the VIP-Mont-Blanc project, Jean-Louis Mugnier (geologist, CNRS) is coordinator and WP3 task leader. Julien Carcaillet (geochimist, CNRS), Riccardo Vassallo and Christian Crouzet (geologists, UdS) are respectively involved in WP1, WP3 and WP4 on geochronology and erosion aspects. EDYTEM (Environnements, DYnamiques et TErritoires de la Montagne) is a research laboratory belonging to Université de Savoie and CNRS (UMR 5204), that deals with mountain thematic in geosciences and social sciences thanks to an interdisciplinary approach. EDYTEM includes ~ 75 persons and has adequate infrastructure and equipment (field equipment, analysis laboratories, monitoring/topometric instruments, and working stations) to enable the success of tasks in which the laboratory is involved. Within the VIP-Mont-Blanc project, Ludovic Ravanel (geomorphologist) is WP2 leader. 3 other permanent researchers (geomorphologist) and 3 PhD students or post-doc are involved: Philip Deline (WP2 & 4), Xavier Bodin (WP2) and Laurent Astrade (WP3). The Laboratory of Glaciology and Environmental Geophysics: LGGE (UMR 5183, Univ. Grenoble Alpes / CNRS) gathers about 140 persons. Main research topics include: mountain glaciers and ice sheets processes and changes, paleoclimatoly, ocean-atmosphere modeling, snow and ice chemistry and physics. Antoine Rabatel (glaciologist, Univ. Grenoble Alpes), Delphine Six (glaciologist, Univ. Grenoble Alpes), Christian Vincent (glaciologist, CNRS), and Marion Réveillet (Ph.D. student in glaciology) are involved in the WP3.1. In this group, two scientists come from the LTHE (UMR5564, Univ. Grenoble Alpes/CNRS/IRD/INP) specialized in hydrology and sediment transport processes in rivers in close collaboration with LGGE: Thomas Condom (glacio- hydrologist, IRD) and Philippe Belleudy (geomorphology, Univ. Grenoble Alpes) Biogéosciences (UMR6282 CNRS / université de Bourgogne) is a multi-disciplinary laboratory regrouping roughly 110 persons. Main research topics include climate sciences, geology, paleontology and ecology. Benjamin Pohl (climatologist, CNRS) and Jean-François Buoncristiani (geologist, univ. Burgundy) are respectively involved in the WP1 (task leadership) and WP3. Three researchers from ThéMA (Daniel Joly and Eric Bernard, CNRS, Florian Tolle, univ. Franche-Comté) are also part of the consortium and form a common partner with Biogéosciences. ThéMA is a laboratory mostly composed of geographers; the persons involved in VIP-Mont-Blanc are specialized in glacier environments (Alps and Spitsbergen). 22

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement (CEREGE), CNRS-IRD-Collège de France UM 34, a leading institution for the utilization of cosmogenic nuclides in Earth Sciences, hosts ASTER (Accélérateur pour les Sciences de la Terre, Environnement, Risques) enacted the French national AMS facility since 2006. The “Laboratoire National des Nucléides Cosmogéniques” team involved in this project has a recognized expertise in the development, implementation and monitoring of the use of cosmogenic nuclides for a large variety of settings, and in particular those relevant for this proposal (e.g. Rinterknecht et al., 2014; Schimmelpfennig et al., 2014). For the VIP-Mont-Blanc project, Didier Bourlès (task leader, physicist, Aix-Marseille University) and Irene Schimmelpfennig (CR2, CNRS) are involved in the the scientific development of WP4, and will be supported by a technician team. Laboratoire d’Informatique, Systèmes, traitement de l’Information et de la Connaissance (LISTIC) (EA 3703 CNRS / université de Savoie) is a multi-disciplinary laboratory regrouping roughly 70 persons. The main research topics are based on data fusion and include images and remote sensing, information fusion for decision support and distributed software systems. Emmanuel Trouvé (images and remote sensing) and Flavien Vernier (distributed software systems) involved in WP3 on the computation of 3D glacier flow monitoring.

5.2. QUALIFICATION AND CONTRIBUTION OF EACH PARTNER Qualification of the project coordinator and scientific responsible for partner 1: Jean-Louis Mugnier, 56 yr-old, DR2 CNRS at ISTerre, Savoie. Geologist, specialist in erosion, interactions between relief and tectonics, seismic hazard. Publications: - 90 International publications; 170 abstracts to meetings; Edition of 1 book; list of publications at: http://www.researcherid.com/rid/E-7241-2011. Sum of time cited: 1538; H index: 21. Administration of Science 1993-2001 and 2006-2009: deputy-director of the laboratory "LGCA" (~ 40 persons). 1989- 2009: Head of the team "mesure et modèlisation des mouvements récents" (~ 18 persons of LGCA). 2004-2009: Member of the "administration comity" of the "Observatoire de Grenoble" Since 2013: Deputy director of the scientific committee of “Observatory of the climate evolution in Savoy” Direction of programs: 1990-2004: "Inter-action between tectonics and climate"; contract with the "Institut Français du Petrole. 2004-2006: " Flux tectonique et relief de l’Himalaya : une approche par thermo-chronologie détritique et géomorphologie " ; granted by INSU (Relief project). 2011-2014: “Mont-Blanc observation”; granted by INSU and Univ. Savoie. Student Direction: 3 post-docs, 15 Phd students, 14 Masters, 25 BsE students, 3 visiting scientists. Five latest relevant papers: Godon, C., Mugnier, J.L. Buoncristiani J.F. et al., 2013, The Glacier des Bossons protects Europe's summit from erosion, Earth and Planetary Science Letters. Commented at: http://www.nature.com/news/mont-blanc-growing-with-help-from-glaciers-1.13357 Mugnier, J.L. et al., 2013, Structural interpretation of the great earthquakes of the last millennium in Central Himalaya, Earth-Science Reviews, 127, 30-47. Lupker M., France-Lanord C., Lavé J., Bouchez J., Galy V., Métivier F., Gaillardet J., Lartiges, B., Mugnier J.L. (2011) Integrating the chemical composition 1 of river sediments: Composition of the Ganga and Himalayan erosion fluxes. JGR, 116, F04012, doi:10.1029/2010JF001947 Mugnier, J.L., Huyghe, P Gajurel, A.,. Upreti, B.et Jouanne F., 2011, seismites in the Kathmandu basin and seismic hazard in central Himalaya, Tectonophysics, doi:10.1016/j.tecto.2011.05.012 Fallourd, R. Harant, O., Trouve, E., Nicolas, J.-M., Gay, M., Walpersdorf, A., Mugnier, J.-L., Serafini, J., Rosu, D., Bombrun, L., Vasile, G., Cotte, N., Vernier, F., Tupin, F., Moreau, L. and P. Bolon. 2011. Monitoring Temperate Glaciers by Multi-Temporal TerraSAR-X Images and Continuous GPS Measurements, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 4, 372-386. Qualification of the partner scientific responsables Partner 2: Ludovic Ravanel, Ph.D., 32 yr-old, CR1 CNRS at EDYTEM lab, Le Bourget du Lac. Researcher specialized in slope movements in mountain and their related risks, he has received three awards for his PhD thesis supported in 2010 and has participated in several European research projects: PERMAdataROC, PermaNET, GlaRiskAlp, RiskNat, PermaSense and PrévRisk Mont-Blanc. 14 publications in peer-reviewed international journals; 107 abstracts in meetings; 16 students supervised or co- supervised. Five latestrelevant publications: Ravanel L., Allignol F., Deline P., Gruber S., Ravello M. (2010). Rock falls in the Mont Blanc Massif in 2007 and 2008. Landslides, 7: 493-501. Ravanel L., Deline P. (2011). Climate influence on rockfalls in high-Alpine steep rockwalls: the North side of the Aiguilles de Chamonix (Mont Blanc massif) since the end of the Little Ice Age. The Holocene, 21: 357-365. Ravanel L., Deline P., Lambiel C., Vincent C. (2012). Instability of a highly vulnerable high alpine rock ridge: the lower Arête des Cosmiques (Mont Blanc massif, France). Geografiska Annaler A, DOI: 10.1111/geoa.12000. 23

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

Ravanel L., Bodin X., Deline P. (2014). Using terrestrial laser scanning for the recognition and valorisation of high-alpine geomorphosites. Geoheritage. DOI 10.1007/s12371-014-0104-1 Ravanel L., Deline P. (2013). A network of observers in the Mont Blanc massif to study rockfalls from high alpine rockwalls. Geografia Fisica e Dinamica Quaternaria, 36: 151-158 DOI 10.4461/GFDQ.2013.36.12. Partner 3: Antoine Rabatel, 35 yr-old, is a scientist at the LGGE (Univ. Grenoble / CNRS) since 2009 (PhD in 2005). He currently coordinates the GLACIOCLIM Observatory and more specifically is in charge of the Andean part of the observatory. He is the French correspondent of the international GLIMS project (Global Land Ice Measurements from Space). He has obtained several scientific awards (Prix La Recherche 2006, Elsevier Top Reviewer 2009, Medal of Honor of Merit of the University National of Huaraz – Peru 2011, Prize of Scientific Excellence of the University of Grenoble 2013). He has published thirty articles in peer-reviewed journals, many of them in some of the most influent journals of glaciology (Journal of Glaciology, The Cryosphere) and Geophysics (Journal of Geophysical Research, Geophysical Research Letters). He has also published eight popular articles, and has co-authored five book chapters. He has given more than thirty oral presentations in international conferences (AGU, EGU, IGARSS, AGM, ...) and has served as chair of an EGU session since 2013. Several of his publications received broad coverage in the media both nationally (Le Monde, Pour la Science, La Recherche, France 5) and internationally (press releases by EGU, Nature, BBC news, La Razon ...). He is currently supervising two PhD students, and during recent years has supervised ten Masters and ten undergraduate students. He has reviewed: one national project (ANR) and one international project (FWF), more than twenty-five papers for peer-reviewed journals, and the chapter on the cryosphere for the latest IPCC AR5. Partner 4: Benjamin Pohl, Ph.D., 34 yr-old, CR1 CNRS at CRC / Biogéosciences, Dijon. Researcher with expertise in observed and simulated climate variability (Africa, Indian Ocean, Europe, Antarctica), regional climate modeling, statistics and signal analysis. 31 publications in peer-reviewed international journals. Full list available at: http://climatologie.u-bourgogne.fr/perso/bpohl/Publications.html Direction of programs: WP coordinator for ANR ACASIS project. Direction of students: 3 post-docs, 2 Ph.D. students, 5 MSc students, 4 visiting scientists. Five relevant publications: Marteau R, Y Richard, B Pohl & T Castel (in press) High-resolution rainfall variability simulated by the WRF RCM: Application to Eastern France. Climate Dynamics, in press. doi:10.1007/s00382-014-2125-5 Morel B, B Pohl, Y Richard, B Bois & M Bessafi (in press) Regionalizing rainfall at very high resolution over La Réunion island using a regional climate model. Monthly Weather Review, in press Pohl B & J Crétat (in press) On the use of nudging techniques for regional climate modeling: Application for tropical convection. Climate Dynamics, in press. doi:10.1007/s00382-013-1994-3 B Pohl, M Rouault & SS Roy (in press) Simulation of the annual and diurnal cycles of rainfall over South Africa by a Regional Climate Model. Climate Dynamics, in press. doi:10.1007/s00382-013-2046-8 Boulard D, B Pohl, J Crétat & N Vigaud (2013) Downscaling large-scale climate variability using a regional climate model: the case of ENSO over Southern Africa. Climate Dynamics, 40, 1141-1168. doi:10.1007/s00382-012-1400-6 Partner 5: Pr. Didier Bourlès, 59 yrs, [email protected]; Present position: Professor CareerPath  Exp1 – 1982-1998 : Researcher CNRS (CSNSM, Campus Orsay)  Exp2 – 1998-actual : Professor (Aix-Marseille Université) Scientifics kills/Striking points  Point 1: Nuclear physics – Development of the Accelerator Mass Spectrometry technique  Point 2: Geochemistry – Development of the use of atmospherically and of in-situ produced cosmogenic nuclides for dating and environmental purposes.  Point 4: Earth sciences – Development of applications using the cosmogenic nuclides aiming at quantifying the processes modeling the Earth’s surface. Publications  183 publications, 2409 citations, h-index : 31 (isiweb of science) Five recent and significant articles since 2009 V. Godard, D. W. Burbank, D. L. Bourlès, B. Bookhagen, R. Braucher and G. B. Fisher - Impact of Glacial Erosion on 10Be Concentrations in Fluvial Sediments of the Marsyandi Catchment, Central Nepal - Journal of Geophysical Research - Earth Surface 117, F03013, doi:10.1029/2011JF002230, 2012. S.G. Arzhannikov, R. Braucher, M. Jolivet, A.V. Arzhannikova, R.Vassallo, A. Chauvet, D.L. Bourlès and F. Chauvet - History of Late Pleistocene Glaciations in the Central Sayan-Tuva Upland (Southern Siberia) – Quaternary Science Reviews 49, 16-32, 2012. R. Delunel, P.A. van der Beek, D.L. Bourlès, J. Carcaillet and F. Schlunegger - Transient Sediment Supply in a High-Altitude Alpine Environment Evidenced Through a 10Be Budget of the Etages Catchment (French Western Alps) - Earth Surface Processes and Landforms, DOI: 10.1002/esp.3494, 2013. 24

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

V. Rinterknecht, A. Börner, D.L. Bourlès and R. Braucher - Cosmogenic 10Be Dating of Ice Sheet Marginal Belts in Mecklenburg-Vorpommern, Western Pomerania (Northeast Germany) – Quaternary Geochronology 19, 42-51, 2014. V. Godard, D.L. Bourlès, F. Spinabella, D.W. Burbank, B. Bookhagen, G. Burch Fisher, A. Moulin and L. Léanni - Dominance of Tectonics Over Climate in Himalayan Denudation – Geology 42(3), 243-246, 2014. Partner 6: Flavien Vernier, Ph.D., 37 yr-old, Assistant professor at Université de Savoie/LISTIC. Computer scientist, specialist in algorithm and distributed systems. Publications: 1 book chapter, 7 publications in peer-reviewed international journals and 10 conference articles in peer-reviewed international proceedings. List available at “http://hal.archives- ouvertes.fr/autlab/vernier/listic/” Direction of students: 3Ph.D. students, 2 Master students. Five latest relevant publications: Pham H.T., Vernier F., Trouvé E., Benoit L., Moreau L., Girard B. Analyse de ''Time Lapse'' stéréo pour la mesure de déformation 3D, application au suivi du glacier d'Argentière. Congrès nationnal sur la Reconnaissance de Formes et l'Intelligence Artificielle, France 2014.s Yan Y., Pinel V., Vernier F., Trouvé E. Displacement measurements. In Remote Sensing Imagery (2014) pp.251-185 Vernier F., Fallourd R., Friedt, Yan Y., Trouvé E., Nicolas J.M., Moreau L.Glacier flow monitoring by digital camera and space-borne SAR images. In 3rd International Conference on Image Processing Theory, Tools and Applications (2012) Turkey. Vernier F., Fallourd R., Friedt J.-M., Yan Y., Trouvé E., Nicolas J.M., Moreau L. Fast correlation technique for glacier flow monitoring by digital camera and space-borne SAR images. EURASIP Journal on Image and Video Processing 2011 11 Fallourd R. et al. Monitoring Temperate Glacier Displacement by MultiTemporal TerraSAR-X Images and Continuous GPS Measurements. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 4, 2 (2011) pp. 372-386

5.3. POSITION OF THE VIP MONT-BLANC PROJECT IN RESPECT TO OTHERS PRESENT OR RECENT PROJECTS Table 4: projects recently or presently performed and that deal with the study of the MBM or with methods applied in this project. The complementary and difference with the VIP-Mont-Blanc project is indicated in the right-most column. Type Responsable Scientific aim complementarity ‐difference with VIP Mont‐Blanc VIPMB in the continuity of: SO‐SOERE Six ; Rabatel Glacier mass balance monitoring VIPMB will highlight this data base GLACIOCLIM 2002‐2020 ANR VanderBeek Evolution of the Alpine relief at different VIPMB will prolongate observational studies of glacial erosion ERD‐Alps 2009‐2013 time scale initiated in this project ANR EFIDIR E. Trouvé Methodology for the processing of SAR Difference: development of processing tools applied on a data‐base (LISTIC) images to measure Earth surface of SAR images. Complementarity: 2D and 3D displacement fields 2008‐2012 displacement. gathered over Chamonix‐Mont‐Blanc test site.. Atelier bservation Schoeneich Monitoring the permafrost thermal VIPMB will highlight this data base (OSUG) evolution in the French Alps PermaFrance World Climate Giorgi Dynamical downscaling of IPCC's AR5 Comparisons with lower‐resolution (50km) climate evolutions over Research Program Beginning climate change simulations Europe (WCRP) CORDEX 2009‐ Labex OSUG@2020 Rabatel Realization of a digital elevation model VIPMB will benefit from the 1952 in WP3.1 Glacier volume 2014 from 1952 aerial photographs of the MBM change ANR Déqué Regional climate change in mountainous VIPMB will use, in a first step, the SCAMPEI data before proposing a SCAMPEI 2008‐2012 regions; 12km resolution) of climate more precise down‐scaling evolutions over the French Alps ANR RIWER2030 Hingray Water resource and regional climate 2008‐2012 evolutions (1960‐2030) INTERREG Deline, Monitoring of the permafrost thermal VIPMB will use and extend these data AlpineSpace Schoeneich evolution, and the rockfall and rock glacier PermaNET 2008 ‐2011 activity in the MBM INTERREG ALCOTRA Ravanel Awareness and information about risks in Development of a smartphone app for the documentation of PrévRisk Mont‐ 2011‐2013 the Mont Blanc massif dangerous natural events in high mountain Blanc INTERREG ALCOTRA Deline Digital inventory of the glaciers in the VIPMB will use these data GlaRiskAlp (A 1) 2010 ‐2013 French Alps in 1860, 1970 and 2008 INTERREG ALCOTRA Vincent Study and monitoring of Taconnaz and Tête VIPMB will use these data in order to take into account the cold to GlaRiskAlp (A 2) 2010 ‐2013 Rousse Glaciers temperate glaciers transition VIPMB in parallel to others regional studies ERC project Thuiller Development of new generation of Use of the statically downscaled climate scenarios and glacial TEEMBIO 2012‐2016 biodiversity models and scenarios retreat models available by VIPMB for feeding biodiversity models. Local collectivity Six Flood study of the Arve river at Chamonix VIPMB will benefit from glaciological, hydrological and high « Arve project » 2014‐2017 Mont Blanc resolution topographic measurements performed within this project GIS Zone Atelier Anne Clemens VIPMB will furnish hydro‐sedimento estimates of the flux provided Bassin du Rhone by the upper catchment 25

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

ORECC (Observatoire DREAL Rhône‐ Improve and spread the knowledge on the VIPMB will furnish a coherent information about the regional régional des effets du Alpes climate, the effects of its evolutions in climate evolution changement Begin: 2013 Rhône‐Alpes climatique) Observatoire savoyard CG Savoie Transfer of the knowledge on the evolution VIPMB will furnish a coherent information about the regional des effets du Head of coPil : of the alpine climate towards local climate evolution changement Mugnier authorities to manage the adaptation policy climatique VIP‐Mont‐Blanc in parallel to methodological studies BIO‐THAW funded Rabatel for Biodiversité et interactions d'usage des sols An example for VIPMont‐BLANC: How to transfer fundamental by FRB and FFEM LGGE vis‐à‐vis de la disponibilité d'eau des research about environmental evolution towards societal problems. 2013‐2017 glaciers dans les Andes tropicales humides CNES‐ TOSCA FerroFamil Caracterisation and Spatio‐Temporal Analysis of remote sensing data, especially SAR images, use of CESTENG (IETR) Trouvé Evolution of Snow and Ice Environments regular Sentinel‐1 coming images for LISTIC 2013‐2015 ANR DIM Meger Data mining‐based model Inversion for VIPMB will test the DIM approach on a peculiar gravitational mass (défi Société de 2014‐2018 gravitational Mass flow monitoring, flow: the Bossons glacier l'information et de la submited communication) EDF Project Malavoi EDF‐ Development and intercomparison of The facility will be located on the Arve River immediately experimental facility DPIH methods for the measurement of sediment donwnstream of the confluence with the torrent des Bossons. It will on the Arve River Begin: 2015 transport. allow the continuous measurement of the bedload transport. DOVE ICDP Crouzet for Drilling overdeepened Alpine Valley to This international project will propose new synthesis of the ISterre reconstruct Quaternary erosion and climate Holocene climate in the Alps that will be compared with results of (2015) Asked WP4 of VIP Mont‐Blanc

6. SCIENTIFIC JUSTIFICATION OF REQUESTED RESSOURCES

6.1. PARTNER 1: ISTERRE, UMR 5275 • Staff - 1 Master student will be funded by VIP-Mont-Blanc, during yrs 2-3 4 x 420= 1680 € - 3 months “Ingenieur d’étude” (Mutualised pool of maintenance of ISTerre) 9786 € - A common PhD subject about « past and present estimation of the sub-glacial erosion » is asked with Partner 5. (CEREGE) It will be administratively supervised by this partner. • Operating costs External service providers: Helicopter (36 €/mn) 1/2 H. each year for material transport) 4320 € Data processing in SIG format and diffusion on the Atlas du Mont Blanc by the CREA 13000€ Drilling operators for sampling at depth to study the 10Be attenuation 500 Euros/ m x 12 m= 6000 € Trips Internal meeting of the ANR 2000€ Field work (60 €/day, 12 missions for three peoples every year) 8640€ Two participations at international meetings (EGU) 3000 € Internal charges Chemical extraction of 10 Be from the samples 20 analysis are already granted by INSU (2014); 20 others are asked: 220 € x 20= 4400 € Others charges Publications (professional editing and supplement for long papers in peer reviews) 1000 € RFID passive transponders for detection of clast displacement 2040 € Batteries- solar pannels for two sites 2000 €

6.2. PARTNER 2: EDYTEM, UMR 5204 • Equipement (6700 €) - WP2-2: laser telemeter Trupulse 360 2050 € - WP2-1&2: mountaineering and sampling equipment 1650 € - WP2-3: computer and softwares 3000 € • Staff (61026 €) - WP2-1: 1 Master student: 10Be dating of rockwalls stability 4 months × 436 € = 1744 € - WP2-2: 1 Master student: rockfall triggering parameters 2 months × 436 € = 872 €

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

- WP3-3: 1 PhD student will be half-funded for “Modelling permafrost distribution in the Mont Blanc massif, according to IPCC scenarios, and the associated instabilities” - the second half will correspond to a CIFRE or APS or equivalent founding 58410 € • Operating costs (33 800 €) External service providers (13 780 €) - WP2-1&2: helicopter to access the sampling sites and other remote study sites (not reachable by cable-car and/or basic alpinism) 255 minutes × 36 € = 9180 € - WP2-1&2: Guides to ensure the security for field work in high mountain 12 days × 325 € = 3900 € - WP2-2: Development of a smartphone app 700 € Internal charges (10 000 €) - Measurement of the spectroscopic characteristics and chemical extraction of 10Be from rock samples 40 rock samples × 250 € = 10 000 € Trips (7520 €) Internal VIP-Mont-Blanc ANR meetings 1000 € Field campaigns (~60 €/day, 30 missions for 2 peoples) 3520€ International conferences (e.g. EGU, IAEG) 3000 € Others charges: Publications 2500 €

6.3. PARTNER 3: LGGE (UMR 5183) – LTHE (UMR 5564) • Equipment (6000 €) Other expenses: 2 personal computers and 2 laptops will be required 6000 €. • Personnel / Staff (50 895 €) 1 year post-doc position specialized in glacier modeling 46980 €. 1 month post-doc position in data formating between WP1 and WP3 3915 €. • Operating cost (20300 €) Budget for the missions (Internal VIP-Mont-Blanc ANR meetings): 2000 € Field works in the Mont-Blanc massif for W3.1 (glacier thickness measurements by GPR) will generate a total of 60 man-days over the whole project duration, covering transportation from LGGE-Grenoble to Chamonix and per-diem. corresponding to a cost evaluated to 4000 € Helicopter fees for transportation on the glacier of people and material have to be added 5000 €. Budget is also requested to attend international conferences (EGU, AGU) over the project duration: 7300 € and publication fees for two publications in peer review journals 2000 €.

6.4. PARTNER 4: BIOGEOSCIENCE, UMR 6282 • Equipment Instead of paying the effective cost of calculation hours for WRF simulations (6 euro cents / hour CPU) we propose to increase the calculation capabilities of the supercomputer owned by the univ. of Burgundy, through one Dell C6220 computation server (64 cores, 1.5Tflops) 17755€ • Staff - One 12-month post-doctoral position (for candidates having a Ph.D. in atmospheric sciences) will be shared by the 2 labs constituting the Biogéosciences group. The recruited person will contribute to the analysis of high- resolution WRF simulations and CMIP5 model outputs statistical downscaling 43200€ - 3 Master students will be funded by VIP-Mont-Blanc, during yrs 1-2-3 3 x 4 x 420= 5040€ • Operating costs - 2 international conference (e.g. EGU): 3000€ - 10 working meetings (coordination between the 2 labs of WP1 and other partners of the project): 3000€ - Missions in Chamonix (for WP3 - erosion): 7250€ - Publication 1000€ - Others expenses: 4000€

6.5. PARTNER 5: CEREGE, UMR 7330 • Personnel / Staff A PhD student who will be shared with Partner 1 (ISTerre UMR 5275). Devoted to the systematic of the cosmogenic nuclides and, more specifically, to the development of the in situ produced C-14 methodology, the 27

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

aim of his/her work will be at the forefront of the geosciences and will be the now possible “quantification of past and present sub-glacial erosion” thanks to the new and still ongoing developments allowing the measurements of minute quantities of in situ-produced C-14. 114 940 € • Operating costs Mission (7000 Euros) Internal meeting of the ANR 2000€ Field work 2500€ 2 international congres: 2500€ Others charges (22770 Euros) Functioning of the 14C extraction line 11000€ Chemical extraction of 10 Be 9900€ Small Equipment 1870€

6.6. PARTNER 6: LISTIC, EA 3703 • Equipment To develop algorithms and chains to extract and to fusion information from image (SAR/Optic) time series, an efficient computer is required (PowerEdge T620 20 Cores): 4000 Euros. In fine, the algorithms and chains will be deployed on the cluster “Must” of the Université de Savoie. • Staff - 1 Master student will be funded by VIP-Mont-Blanc, during yrs 2 (6 x 450) 2700€ • Operating costs - 1 international conference: 1000€ - 10 working meetings in France (coordination with other VIP-Mont-Blanc partners): 1500€ - Missions in Chamonix (for WP3 – optic acquisition): 2000€ - Publication 1000€ - Other expanses (batteries for cameras, equipment for the installation of acquisitions...): 3000€

7. REFERENCES Berthet J., Astrade L., Ployon L. (2013) Dynamic of sediments assessment by terrestrial laserscanner, application to quantify sediment yield of four streams in French Alps. Mountain Under Watch 2013 conference, 20-21 fevrier 2013 Aoste. Böhlert R., Gruber S., Egli M., Maisch M., Brandová D., Haeberli W., Ivy-Ochs S., Christl M., Kubik P.W., Deline P. (2008). Comparison of exposure ages and spectral properties of rock surfaces in steep, high alpine rock walls of Aiguille du Midi. Proceedings of the 9th International Conference on Permafrost, 143-148. Bosson J.B., Lambiel C., Deline P., Bodin X., Schoeneich P., Gardent M., Baron L. In revision. Ground ice occurrence in high-mountain proglacial areas since the Little Ice Age and its influence on geomorphic dynamics: the case of Rognes and Pierre Ronde proglacial areas (Mont Blanc range, France). Earth Surface Processes and Landforms. Boulton, G.S., et al., 2007. Subglacial drainage by groundwater-channel coupling, and the origin of esker systems: part 1 — glaciological observations. Quat. Sci. Rev. 26, 1067–1090. Collins 1989. Seasonal development of subglacial drainage and suspended sediment delivery to meltwaters beneath an Alpine glacier. Annals of glaciology 13, 45-50. Darrel A. et al. 2005. Seasonal evolution of runoff from Haut Glacier d’Arolla, Switzerland and implications for glacial geomorphic processes. Journal of hydrology 309, 133-148. Dee DP, et al. (2011) The ERA-Interim reanalysis : configuration and performance of the data assimilation system. Q J R Meteorol Soc 137:553–597. De Saussure H.-B.,1796, Voyages dans les Alpes, précédés d'un essai sur l'histoire naturelle des environs de Genève, 4 tome, published in Neuchâtel. Deline, P. and Orombelli, G., 2005 Glacier ﬂuctuations in the western Alps during the Neoglacial, as indicated by the Miage morainic amphitheatre (Mont Blanc massif, Italy). Boreas, Vol. 34, pp. 456–467. Fallourd, R., Vernier, F., Yan, Y., Nicolas, J.M., Walpersdorf, A., Cotte, N., Mugnier, J.L et al. 2010. Alpine glacier 3D displacement derived from ascending and descending TerraSAR-X images on Mont-Blanc test site, EUSAR 2010, Aachen, Germany, June 2010, pp. 556-559. Fallourd, R., Harant, O., Trouve, E., Nicolas, J.M., Gay, M., Walpersdorf, A., Mugnier, J.Let al., 2011. Monitoring Temperate Glaciers by Multi-Temporal TerraSAR-X Images and Continuous GPS Measurements. IEEE J. Selected Topics in Applied Earth Observations and Remote Sensing, 4, 372-386.

Projet VIP –MONT-BLANC DOCUMENT SCIENTIFIQUE

Gao L, et al. (2012) Downscaling ERA-Interim temperature data in complex terrain. Hydrol Earth Syst Sci Discuss 9:5931– 5953. doi: 10.5194/hessd-9-5931-2012 Giesen et al. (2010) Response of the ice cap Hardangerjøkulen in southern Norway to the 20th and 21st century climates, The Cryosphere, 4, 191-213, 2010. Godon, C., Mugnier, J.L. Buoncristiani J.F. et al., 2013, The Glacier des Bossons protects Europe's summit from erosion, Earth and Planetary Science Letters. Godon C. (2013) L'érosion dans les environnements glaciaires: exemple du glacier des Bossons (France), thèse université Grenoble, 244 p. Goehring et al., 2011, The Rhone Glacier was smaller than today for most of the Holocene, Geology, v. 39, p. 679-682. Goehring et aL., 2012, Holocene dynamics of the Rhone Glacier, Switzerland, deduced from ice flow models and cosmogenic nuclides, Earth and Planetary Science Letters, v. 351–352, p. 27–35. Gruber, S. et al. 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