Melting of a Prairie Snowpack

Abstract

An energy budget approach is used to study the melt of a prairie snowpack. Air temperature, humidity and wind speed are measured at seven levels in the first 2 m above the snow surface. Evaporation and melt are measured directly with a weighing lysimeter. In the analysis this enables all the terms of the energy budget to be determined independently. On the basis of results from three spring melt periods the net radiation flux is shown to be the major source of energy for the melt of a continuous snowcover. In the absence of local advection, the sensible heat flux is shown to be a function of the energy content of the air mass and more closely related to the 850 mb temperature than to temperatures near the snow surface. The latent heat flux responds to the radiation flux with daytime evaporation and nighttime condensation; however, the net daily flux is usually evaporative.