Snow processes in a forest clearing and in a coniferous forest

An energy balance approach is applied to simulate snow accumulation and melt in a forest clearing and in a coniferous forest. The study site is located in southern Finland (60.1degreesN) where the winters are mild considering the high latitude. For forest simulations the snow model is coupled with a procedure, which accounts for the effects of the canopy on the driving meteorological variables of the snow model. Model results are first validated against measured values of snow water equivalent and snow temperature in a forested site and in an adjacent clearing. Subsequently differences in snow accumulation, snowmelt, and energy components contributing to snowmelt in open and forested conditions are studied. Effect of the canopy on snow mass balance on the ground can be seen as higher accumulation and more intense snowmelt in the open. Due to these counteracting processes the results show little difference in the annual maximum of the snow water equivalent between the clearing and the forest. The model results suggest that in mid-winter the main source of energy for snowmelt is sensible heat in the open, whereas both sensible heat and net radiation contribute equally to snowmelt in the forest. Solar radiation intensity increases towards the spring, which causes net radiation to become dominant in both sites. (C) 2002 Elsevier Science B.V. All rights reserved.