Development and test of the distributed HBV-96 hydrological model

A comprehensive re-evaluation of the HBV hydrological model has been carried out. The objectives were to improve its potential for making use of spatially distributed data, to make it more physically sound and to improve the model performance. The new version, HBV-96, uses subbasin division with a typical resolution of 40 km z, although any resolution can be used. In addition, each subbasin is divided into elevation bands, vegetation and snow classes. Automatic weighting of precipitation and temperature stations was introduced and a new automatic calibration scheme was developed. The modifications led to significant improvements in model performance. In seven test basins the average value of the efficiency criterion R2 increased from 86 to 89%, with improvements in both the calibration and verification periods.