Measurements of the Energy Fluxes Involved in the Energy Budget of a Snow Cover

Abstract

Measurements of the various energy components involved in an energy balance of a snow cover were made at the Elora Research Station, University of Guelph during the winter of 1976. A pressure sphere anemometer and a sonic anemometer-thermometer in conjunction with fast response, fine wire, resistance thermometers and Lyman-alpha humidiometers were used to measure the fluxes of sensible and latent heat by eddy correlation techniques. A net radiometer and soil heat flux plates measured the radiative and soil heat fluxes. The data allowed a complete energy budget to be calculated including the energy stored in the snowpack and/or utilized in the fusion process, determined as a residual. The data indicated the absence of any close relationship between the net radiation and sensible and latent heat fluxes during the diurnal cycle. The flux of heat into the snowpack was found to be a major component of the energy balance. Maximum evaporation from the snow surface was observed to occur following the replacement of warm moist air masses by cold dry air masses. During these periods the sensible and latent heat fluxes were greater than the net radiation and resulted in a rapid loss of energy from the snowpack. The determination of evaporation from the snowpack using a Bowen ratio energy balance approach was found to be impractical because the large energy flux into the snowpack could not be independently determined with sufficient accuracy.