Permafrost distribution in the French Alps : statistical modelling using rock glacier inventory

• Main Authors: Marcer, Marco, Bodin, Xavier, Schoeneich, Philippe
• Other Authors: Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Pacte, Laboratoire de sciences sociales (PACTE), Sciences Po Grenoble - Institut d'études politiques de Grenoble (IEPG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), International Permafrost Association
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2016
• Subjects: [SDE]Environmental Sciences; Ice; permafrost
• Online Access: https://sde.hal.science/hal-01887944

International audience long with a rising temperature trend registeredin the past decades along the European Alps, severalsignals of permafrost degradation have been reportedin the same region, e.g. rock glacier displacementacceleration and thickening of the active layer. Per-mafrost degradation is alarming due to its role in ter-rain destabilization and, in particular, ice-rich debrisslopes are of great concern due to their proximity toinhabited areas. Therefore, in the past years increas-ing efforts have been made either by the scientificcommunity and local authorities in understanding theprocesses and hazards linked to the alpine permafrostdegradation.The first step to manage the risk associated withpermafrost degradation is to know its spatial extent.Since alpine permafrost does not manifest itself on thesurface, exception made for rock glaciers, it is not suit-able for automatic mapping. Therefore distributionmodels are required to infer permafrost occurrence.Traditionally, permafrost distribution models take ad-vantage of rock glaciers as evidence of permafrostto extrapolate statistically its occurrence based oncorrelation with climate variables. Although severalstatistical models have been made at the whole alpinerange scale, only one permafrost distribution map,calibrated on the Combeynot massif and validated onthe Vanoise and Mercantour massifs, was designedspecifically for the French Alps. However, permafroststatistical modeling using rock glacier inventories hasbeen recognized to be biased depending on the datacharacteristics, making permafrost maps inaccurateat local scale when applied to specific areas. Thisis due to the fact that rock glaciers extents are notonly influenced by climate, but also by their dynam-ics, a complex function of local topography, geologyand ice content in the landform. Therefore, the valid-ity of current models in the French Alps is, at least,questionable.To address this issue, the service Restauration desTerrains en Montagne (RTM) in collaboration withthe Institut de Géographie ...