Snowmelt modelling aspects in urban areas

Urban winter hydrology is generally poorly understood, despite the large number of cities which have annual seasonal snow cover and there are only few studies about urban snow and snowmelt rates in the cities. Two specific factors affecting the snow melting rate in urban areas are the degree of urbanization and the urban snow distribution. The net radiation balance of urbanised catchments differs from their rural counterparts. The choice of a snowmelt model for a particular application depends on data availability and snow characteristics. A review of attributes of common snowmelt models is presented for evaluation and selection of the best suited model for simulating snowmelt in a specific area. In snowmelt computations, the challenge is to identify a suitable model for the heterogeneous urban conditions from the existing model categories as TIM, EBM, or their combination as a hybrid method. For rural environments, empirical methods (TIM) have been demonstrated to reproduce a large part of the snowpack variations at both open and forested areas. For heterogeneous urban environments, it is necessary to apply an EBM in order to take into account all the characteristics of urban snow. Snow properties such as density and albedo vary both between urban and rural areas as well as between different urban locations belonging to the same urban agglomeration.