Black carbon and dust alter the response of mountain snow cover under climate change

Marion Réveillet (1) , Marie Dumont (1) , Simon Gascoin (2) , Matthieu Lafaysse (1) , Pierre Nabat (3, 4) , Aurélien Ribes (3, 4) , Rafife Nheili (1) , Francois Tuzet (1) , Martin Ménégoz (5) , Samuel Morin (3) , Ghislain Picard (5) , Paul Ginoux (6)

1 CEN - Centre d'Etudes de la Neige
2 CESBIO - Centre d'études spatiales de la biosphère
3 CNRM - Centre national de recherches météorologiques
4 GMGEC - Groupe de Météorologie de Grande Échelle et Climat
5 IGE - Institut des Géosciences de l’Environnement
6 NOAA - National Oceanic and Atmospheric Administration

By darkening the snow surface, mineral dust and black carbon (BC) deposition enhances snowmelt and triggers numerous feedbacks. Assessments of their long-term impact at the regional scale are still largely missing despite the environmental and socio-economic implications of snow cover changes. Here we show, using numerical simulations, that dust and BC deposition advanced snowmelt by 17 ± 6 days on average in the French Alps and the Pyrenees over the 1979–2018 period. BC and dust also advanced by 10-15 days the peak melt water runoff, a substantial effect on the timing of water resources availability. We also demonstrate that the decrease in BC deposition since the 1980s moderates the impact of current warming on snow cover decline. Hence, accounting for changes in light-absorbing particles deposition is required to improve the accuracy of snow cover reanalyses and climate projections, that are crucial for better understanding the past and future evolution of mountain social-ecological systems.

Domaines: Climatologie; Interfaces continentales, environnement

Marion Réveillet, Marie Dumont, Simon Gascoin, Matthieu Lafaysse, Pierre Nabat, et al.. Black carbon and dust alter the response of mountain snow cover under climate change. Nature Communications, 2022, 13 (1), pp.5279. ⟨10.1038/s41467-022-32501-y⟩. ⟨hal-03783979⟩