Variabilité de l'enneigement et variations du climat

EnglishThe study ofthe current snow climatology in the French Alps, with series of snow records at selected sites, shows that the spatial and temporal variability of snow cover is very high. In particular, the very poor snow conditions encountered during some recent winters can be compared with those of some winters in the past. The numerical snow modelling is also a good mean to improve our knowledge because it is able to take into account the complex relations between meteorological conditions and snow. Lastly, it was used to simulate the impact of a climate warming on the alpine snow cover. The results show its high sensitivity, which may induce important perturbations in various domains such as hydrology, ecology and economy in these regions. francaisL'etude de la climatologie nivale des Alpes francaises, realisee a partir de series de mesures sur certains sites, montre que la variabilite spatiale et temporelle de l'enneigement est tres grande. En particulier, les conditions de tres faible enneigement rencontrees durant certains hivers recents peuvent etre comparees a celles de certains hivers du passe. La modelisation du manteau neigeux est un moyen efficace pour completer notre connaissance de la climatologie nivale car elle permet de prendre en compte les relations complexes entre conditions meteorologiques et enneigement. Elle a egalement ete utilisee pour simuler l'impact d'un rechauffement du climat sur le manteau neigeux. Les resultats montrent la tres grande sensibilite de l'enneigement, ce qui conduirait probablement a des modifications importantes pour l'hydrologie, l'ecologie et l'economie de ces regions.