Trends in the annual snow melt-out day over the French Alps and Pyrenees from 38 years of high-resolution satellite data (1986–2023)

Barrou Dumont, Zacharie; Gascoin, Simon; Inglada, Jordi; Dietz, Andreas; Köhler, Jonas; Lafaysse, Matthieu; Monteiro, Diego; Carmagnola, Carlo; Bayle, Arthur; Dedieu, Jean-Pierre; Hagolle, Olivier; Choler, Philippe

doi:https://doi.org/10.5194/tc-19-2407-2025

Articles | Volume 19, issue 7

https://doi.org/10.5194/tc-19-2407-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-19-2407-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 7

Research article

|

04 Jul 2025

Research article |

| 04 Jul 2025

Trends in the annual snow melt-out day over the French Alps and Pyrenees from 38 years of high-resolution satellite data (1986–2023)

Zacharie Barrou Dumont, Simon Gascoin, Jordi Inglada, Andreas Dietz, Jonas Köhler, Matthieu Lafaysse, Diego Monteiro, Carlo Carmagnola, Arthur Bayle, Jean-Pierre Dedieu, Olivier Hagolle, and Philippe Choler

Supplement

https://doi.org/10.5194/tc-19-2407-2025-supplement

Data sets

Snow melt out day in the French Alps and Pyrenees from SPOT, Landsat and Sentinel-2 data, Version v2 Zacharie Barrou Dumont and Simon Gascoin https://doi.org/10.5281/zenodo.15063934

Model code and software

Algorithm theoretical basis documentation for an operational snow cover product from Sentinel-2 and Landsat-8 data (Let-it-snow) (v1.0) Gascoin Simon et al. https://doi.org/10.5281/zenodo.1414452

Short summary

We generated annual maps of snow melt-out days at 20 m resolution over a period of 38 years from 10 different satellites. This study fills a knowledge gap regarding the evolution of mountain snow in Europe by covering a much longer period and characterizing trends at much higher resolutions than previous studies. We found a trend for earlier melt-out with average reductions of 5.51 d per decade over the French Alps and 4.04 d per decade over the Pyrenees for the period 1986–2023.