Ablation patterns of snow cover over smooth first-year sea ice in the Canadian Arctic

We examine the temporal evolution of snow distribution over first-year sea ice from late winter to the period when melt ponds form. Our objectives are to model snowmelt over first-year sea ice and investigate how melt rate affects the transmission of photosynthetically active radiation (PAR). These objectives are a subcomponent of a larger initiative to examine the coupling of physical and biological systems within a changing ocean-sea-ice-atmosphere system (Iacozza J, Barber. 2000. C-ICE 2000 Field Summary. CEOSTEC-2000-12-01. CEOS, University of Manitoba). Results indicate that the melt rate for the snow cover is non-uniform both spatially and temporally, with decreasing rates for increasing snow depths. At depths greater than approximately 16 cm the melt rate is fairly consistent (approximately 3.5% day(-1)). The melt rate was best modelled using a quadratic equation, accounting for 71.5% of the variation in the melt rate. This melt-rate equation was used to estimate the evolution of a statistical snow surface based on Iacozza and Barber (1999. Atinosphere-Ocean 37: 21-51) and to examine the transmission of PAR through the melt period. Analysis of the PAR transmission indicated that, as the melt season progressed, a greater amount of PAR is transmitted through the snow and ice and that this transmission is controlled by the ablation rate of different thicknesses of snow. The variation in PAR over the study area also increased as the melt season progressed. Copyright (C) 2001 John Wiley Sons, Ltd.