Snow Surface Energy Exchanges and Snowmelt in a Shrub-Covered Bog in Eastern Ontario, Canada.

摘要

The ground heat flux (G) is typically considered a small component of the snowpack energy balance (EB) when compared to radiative and turbulent fluxes. However, in environments where the soil remains above freezing throughout the winter, G may be an important energy input to the snowpack. To assess the role of G in the snow energy budget of such an environment, the EB components of the snowpack in a peatland were measured and modelled using an EB snowmelt model (SNOBAL) during the 2009-2010 winter. When integrated over the pre-melt period, measured G proved to be a large contributor to the total EB (25%). Net radiation and G were under-predicted by the model, while turbulent fluxes were considerably over-predicted. Modelled G was found to be sensitive to the temperature gradient between the soil and the snowpack, while turbulent fluxes could be improved by reducing the roughness lengths for heat and vapour relative to momentum.