Uncertainty Analysis of Future Projections of Precipitation and Temperature for the Var Basin, France

In order to understand the future changes of water resources and its impact assessments, it is necessary to have reliable projections of temperature and precipitation. A high -resolution regional climate change ensemble is available for Europe within the World Climate Research Program Coordinated Regional Downscaling Experiment (EURO-CORDEX) initiative. These simulations should be validated against observations before they can be used in hydrological models or other assessment tools. The Var catchment, located at the southeast part of France is the largest river basin in the French Mediterranean Alps region. The Var low valley and its unconfined alluvial aquifer is the main water resource for around 600,000 inhabitants who live in the cities and towns near the river mouth such as Nice and St Laurent du Var. Here in this study, the future changes of temperature and precipitation derived from five RCMs. The delta changes approach was used as a downscaling and bias correction method. The results of analysis show that the future temperature might increase, with higher values under RCP 8.5 as it is expected, for all over the basin. The changes are larger for the upstream part of the basin. The results of precipitation changes indicate that in the future period (2031-2050) compared to the baseline (1986-2050), the annual precipitation will might decrease for the most areas of the basin while it is slightly expected to have an increase for the upstream part, under both RCP scenarios.