- Edytem laboratory (UMR 5204), University Savoie Mont Blanc, Geography, France (maeva.cathala@yahoo.fr)
In high mountain environments, permafrost in steep slopes has been increasingly studied since the 2000s, driven by the increase of rock slope failure caused by permafrost degradation. In the European Alps, estimating permafrost distribution is a first step in understanding its current state and evolution, evaluating associated hazards, and investigating its impact on infrastructure. The only existing model to map permafrost in steep rock slope has been published in 2012 and is based on a limited number of data mostly collected in the Northern European Alps. However, over the past decade, numerous temperature loggers have been installed in the French Alps, over a latitudinal range for 46° to 44° and the collected data allow to fit a new statistical model to map permafrost in the steep rock wall of the French Alps. This study presents an updated statistical model of permafrost distribution in the steep rock slopes of the French Alps.
To achieve this, we first measured ground surface temperature from 80 temperature sensors installed on steep slope or rockwalls over 22 study sites in the French Alps that provide 176 multi-year temperature points are used to fit a multiple linear regression model explaining the mean annual rock surface temperature (MARST) with the potential incoming solar radiation (PISR) and mean annual air temperature (MAAT). PISR is calculated with GIS tools with a 10 m resolution DEM while the MAAT is interpolated from the reanalysis climate data from the S2M-SAFRAN model of Météo France. The model is then implemented with the MAAT of the 1991-2020 period to map the MARST that is then used to calculated permafrost probability (i.e., the probability of the MARST to be < 0°C). We then analyse the spatial distribution of permafrost over the French Alps and compare it to the previous permafrost map.
This map is an important baseline for any permafrost investigation and hazard assessment from alpine rockwalls in the French Alps.
How to cite: Cathala, M., Magnin, F., Monzie, N., Ravanel, L., and Malet, E.: Statistical modelling of permafrost distribution in steep rock slope, application to the French Alps, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16337, https://doi.org/10.5194/egusphere-egu25-16337, 2025.
