Short- and medium-range hydrological ensemble forecasts over France

The Safran-Isba-Modcou (SIM) distributed hydro-meteorological modeling suite is developed at Meteo-France. Two ensemble forecasts were tested as input to the SIM suite. The first one was the ECMWF EPS (10-day range, 1.5 degrees grid, 51 members). Then, the Meteo-France PEARP (60-h range, 0.25 degrees grid, 11 members) was used. The methods for disaggregating the EPSs down to the 8-km Isba grid were described. Statistical analysis of the skills of these systems (for rainfall and streamflows) was performed against observations and showed the interests of using these EPSs. The PEARP-based streamflows showed better scores than the ECMWF ones, for low and high flows. Copyright (C) 2010 Royal Meteorological Society