Calibrating a spatially distributed conceptual hydrological model using runoff, annual mass balance and winter mass balance

We modified the well-known HBV-ETH model to develop a partially distributed hydrological model that was able to simulate runoff in a highly glacierised basin. By introducing additional calibration criteria (annual and winter glacier mass balance) we reduced the goodness-of-fit for runoff, but improved the description of the accumulation and ablation processes involved. Final adjustment of the model parameters, after choosing the best out of 10,000 random parameter sets, allowed us to find a parameter calibration with acceptable errors for all criteria, which was then confirmed by good model performance during the validation period. The glacier-wide winter mass balance and the annual mass balance in the ablation area were simulated well, while the annual mass balance in the accumulation area showed inaccuracies. Good simulation of the processes during the 2003 heat wave in Europe proved that the model also delivers reliable results for meteorological conditions different from those used during calibration.