Hydrological impact of SBMcast nowcasting ensembles

SBMcast is a probabilistic nowcasting technique based on the generation of an ensemble of equiprobable scenarios of rainfall based on radar measurements. Since the simulated scenarios reproduce the space-time structure of the rainfall field, these ensembles fulfill the requirements for its implementation in the framework of probabilistic rainfall-runoff simulation and flow forecasting. The work presented here focuses on investigating the use of the outputs of a high-resolution numerical weather prediction model to constrain the spread of generated SBMcast ensembles. The performances of the basic and this new configuration of SBMcast have been evaluated in terms of rainfall and runoff forecasts. Also, the spread of rainfall and runoff ensembles have been compared for the different configurations. The study has been carried out in the Besòs basin (~1000 km2), located in the vicinity of Barcelona (NE Spain) coupling SBMcast outputs with the distributed rainfall-runoff model DiCHiTop.