An Energy Balance Based HBV- Model with Application to an Arctic Watershed on Svalbard, Spitsbergen

In several studies of snowmelt using the temperature index method from the original HBV-model, the model fails to predict the timing of the snowmelt and underestimates the intensities on occasions with high solar radiation and low air temperatures. This is especially evident at high latitudes such as catchments on Svalbard, but can also be the case for catchments at lower latitudes but at higher elevations and thus of importance to hydropower production. In this study, an energy balance calculation replaces the simple temperature index model in a spreadsheet version of the HBV-model. Calculation of average snow pack temperatures is included, and a new method is introduced to account for uneven snow distribution and glacial melt. This energy balance based HBV-model gives a better simulation of both snow and glacial melt. It was also found that estimates of sensible heat were improved by using a function with a non-linear wind speed dependency.