Hydrometeorological reconstruction of snow-influenced streamflow series in France since 1871
Reconstruction hydrométéorologique des séries hydrologiques influencées par la neige en France depuis 1871
Résumé
The length of streamflow records is generally limited to the last 50 years. It therefore prevents studying the long-term evolution of streamflow regimes. In order to overcome this limit, this work takes advantage of a 140-year ensemble hydrometeorological dataset over France based on: (i) a probabilistic precipitation and temperature downscaling of the global Twentieth Century Reanalysis over France (Caillouet et al., 2016a), and (ii) a continuous hydrological modelling that uses the high-resolution meteorological reconstructions as forcings over the whole period (Caillouet et al., 2016b). The resulting SCOPE Hydro dataset provides an ensemble of 25 equally plausible daily streamflow time series for a reference network of more than 600 stations in France over the 1871-2012 period. A subset of 184 stations located in all French mountain ranges (Alps, Pyrenees, Massif Central, Jura and Vosges) is specifically targeted here. This work aims at studying the long-term evolution of streamflow in mountainous catchments where the regime is largely influenced by snow accumulation and snowmelt processes. Results show a high interannual variability of the seasonal snowmelt component of streamflow, pondered by a relatively large multidecadal variability highlighting periods with large (1910s) or small (1950s, post-1980 period) snowmelt.