Abstract: This study applies the Hydrologiska Byr?ns Vattenbalansavdelning (HBV) model to simulations of snow and runoff processes in the upper Yalung Zangbu River over its basin above the Nuxia gauging station. We develop a multi-objective optimization method considering river runoff, snow depth, and snow coverage to calibrate the model’s parameters; and compare the simulation results with those considering only river runoff and snow depth. The results show that the HBV model based on measurements of runoff and snow depth simulates the runoff quite well, but its simulations of snow depth are poor. Adding snow coverage to the model calibration can improve the simulation accuracy of snow coverage significantly, and also improves efficiency coefficient of river runoff. Thus, changes in snow and runoff in the study area can be better predicted by this HBV model that is calibrated against the measurements of river runoff, snow coverage, and snow depth.

Key words: hydrological model, runoff simulation, snow simulation, multi-objective calibration