Climate models and hydrological parameter uncertainties in climate change impacts on monthly runoff and daily flow duration curve in a Mediterranean catchment.

International audienceClimate models and hydrological parameter uncertainties were quantified and comparedwhile assessing climate change impacts on monthly runoff and daily flow duration curve (FDC) in aMediterranean catchment. Simulations of the SWAT model using an ensemble of behaviouralparameter sets derived from the GLUE method were approximated by feed-forward artificial neuralnetworks (FF-NN). Then, outputs of climate models were used as inputs to the FF-NN models.Subsequently, projected changes in runoff and FDC were calculated and their associated uncertaintywas partitioned into climate model and hydrological parameter uncertainties. Runoff and dailydischarge of the Chiba catchment were expected to decrease in response to drier and warmer climaticconditions in 2050s. For both hydrologic indicators uncertainty magnitude increased as moving fromdry to wet period. The decomposition of uncertainty demonstrated that climate models uncertaintydominated hydrological parameter uncertainty in wet period, whereas in dry period hydrologicparametric uncertainty became more important