Ensemble meteorological forecast for the Upper Rhone River basin

Abstract A semi-distributed hydrological model was developed for the Upper Rhone River basin in Switzerland. It is currently operational for a real-time flood forecast in the Rhone Valley. It simulates the snow and glacier melt, soil infiltration and run-off processes, flood routing in rivers as well as hydropower scheme operations. For the computation of flood prediction, the numerical meteorological forecasts COSMO-LEPS, COSMO-7 and COSMO-2, provided by MeteoSwiss, have been assimilated. The forecast errors are analyzed by comparing the performance on different time periods, regarding the observed and the predicted rainfall and temperature over the entire catchment area as well as in punctual locations. The influence of the lead time is described with the aim of providing an estimation of the forecast error. Aperformance evaluation is achieved considering indexes like Brier Score and Relative Operating Characteristic. Keywords: Deterministic and ensemble meteorological forecast, Brier Score, Relative Operating Characteristic