Surface Energy Balance of a Perennial Snowbank, Melville Island, Northwest Territories, Canada

Abstract

The energy balance of a large perennial snowbank located in the continuous permafrost zone was examined during the summer of 1986. Three meteorological towers allowed energy fluxes to be determined for separate zones of the snowbank. Over the melt season, net radiation accounted for 85% of the energy absorbed by the snow surface, while sensible heat contributed 15% and latent heat was a net loss of 2%. Albedo varied across the snowbank due to an irregular distribution of surface aeolian deposits. Direct measurements of snowmelt from a snow survey compare favorably with calculated values obtained from the energy balance. The net shortwave radiation flux was a significant influence on ablation, explaining on average 77% of the variance in the measured melt. The predominance of the radiant fluxes is attributed to the large size of the snowbank and its sustained melt through the cool arctic summer.