Simulation of snowmelt in a subarctic spruce woodland: 2. Open woodland model

A model is presented to simulate snowmelt in a subarctic woodland using a Geographic Information System to express the spatial distribution of snow and the pattern of trees and their shifting shadows during the day. The woodland is distinguished into several zone types, including openings under the Sun and in the shade, zones beneath the tree canopy, and the tree trunks. Meteorological data obtained at an open site are transposed to each zone for the calculation of melt rates. The wooded experimental plot is subdivided into 2×2 m 2 grid cells, each with different fractional areas occupied by various zone types. Melt rates at each cell are obtained by weighting the zonal melt with these fractional areas. Despite some limitations the model provides a spatial dimension to snowmelt in the woodland and yields mean melt values that enhance the representation of the forest melt conditions conventionally obtained using calculations for single points.