Development of a Conceptual Snow Sub-Model: Application in Meteorological Stations, Slovakia

Abstract A semi-distributed rainfall-runoff Approximate Redistributive Balance (ARB) model is currently in development as a tool for the assessment and analysis of the water management balance at the level of micro-basins on the territory of Slovakia. For the winter season, it is necessary to supplement the model with a sub-model for calculating the snow water equivalent (SWE) with a comparatively low amount of the input data necessary. Since SWE models generally operate in a daily time step, a new sub-model was developed and tested in monthly and weekly time steps in 30 meteorological stations in the north of Slovakia. When compared in a weekly time step with the snow sub-model of the HBV rainfall-runoff model and when the impact of switching from a monthly to weekly time step on the quality of the runoff simulation was evaluated, the results showed that the snow sub-model does react to sudden snowmelt better when compared to the modified version of the HBV snow sub-model used. Using a weekly time step for the snow sub-model in a monthly ARB model runoff simulation showed an increase of accuracy (NSE change from 0.89 to 0.92) in one case, while maintaining the same level of accuracy in the second one.