A surface energy exchange model of glacier melt and net mass balance

Abstract

AbstractAn energy balance model of surface climate and melt for a glacierized area is described, and applied to simulate ablation and net mass balance on Peyto Glacier. Surface characteristics are assigned according to general knowledge from physical climatology and experimental data from the glacier itself. A known elevational distribution of snow covers the glacier at the beginning of the ablation season, then melts in response to simulated energy input to the surface, thus exposing an ever increasing area of ice. The end result is the annual net mass balance, which is shown to be very sensitive to annual mean temperature, solar energy input, atmospheric emissivity, surface albedo, and climatic regime. Maritime climates produce steeper elevational gradients of net mass balance than do continental climates, which, in turn, are steeper than those created under Arctic conditions. It is also found that, in addition to lag caused by internal drainage development, there must be delay in peak meltwater production owing to changing surface conditions because, as snowline elevation rises, the glacier evolves into a more effective collector of solar energy.