An Energy Budget Approach to Urban Snow Deposit Melt

Abstract

In urban areas in cold regions snow handling is a significant part of municipal activity. The snow is usually ploughed off the streets and then transported to a snow deposit. As a consequence the snow is mechanically blended, packed, polluted and piled up, giving it a characteristic texture, shape, and size. To predict snow deposit melt an energy budget model that uses general meteorological data has been derived. The model is a synthesis of available energy balance terms developed for natural snow covers, and general mass and heat transfer considerations. This approach was found applicable for estimating snow deposit melt. Only geometry, radiation, sensible and latent heat are included to the model. Radiation was found to be the major source of snow deposit melt. Very little difference was found between top and side energy fluxes. Model predictions were compared with measurements of two pilot snow deposits which were constructed with snow collected from the streets of Luleå, Sweden. The degree day approach also seems to be an applicable method to estimate snow deposit melt.

Hydrologic assessment of an urban variable source watershed in the northeast United States

“…The reduced albedo associated with urban areas [Taha, 1997] may also increase the actual ground surface temperature causing increased snowmelt. Additionally, in urban areas snowmelt appears to be dominated by net radiation fluxes, as opposed to sensible heat flux, turbulent exchange, and heat exchange at the soil-snow interface, as in natural systems [Sundin et al, 1999;Valeo and Ho, 2004]. More representative watershed temperatures and the inclusion of solar radiation may improve snowmelt estimates.…”

Observations of urban snow properties in Calgary, Canada

“…The literature has identified a number of gaps in knowledge of urban snow processes when incorporating them into urban snowmelt models. The role of frozen ground in the generation of floods in urban areas has largely been ignored, and there are only a few investigations of the densities of an urban snow cover (Sundin et al, 1999). Sundin et al (1999) studied two snow deposits collected from the streets of the city centre of Luleå, Sweden, and reported initial snow densities exceeding 700 kg m 3 .…”

“…The role of frozen ground in the generation of floods in urban areas has largely been ignored, and there are only a few investigations of the densities of an urban snow cover (Sundin et al, 1999). Sundin et al (1999) studied two snow deposits collected from the streets of the city centre of Luleå, Sweden, and reported initial snow densities exceeding 700 kg m 3 . The optimum time resolution to use in an urban snowmelt runoff model is important for accurate modelling.…”

“…In addition, there have been very few attempts to apply separate energy models to the different snow cover types to achieve accurate modelling of snowmelt in urban areas. Sundin et al (1999) applied an energy budget method to estimate an urban snow pile melt.…”

“…Gray and Male (1981) showed that the initial density of a natural snow cover is usually 100-500 kg m 3 , whereas Sundin et al (1999) indicated that an urban snow pile can have densities up to 700 kg m 3 , which is very close to the density of ice at 917 kg m 1 . Spatial variations in energy fluxes exist over the snowpack due to factors such as longwave radiation from buildings, full-sun/shadow effect, and snow albedo variability (Bengtsson and Westerström, 1992;Semádeni-Davies, 1999).…”