The effect of a canopy on the snowmelt energy balance

Energy balances over snow in a clearcut, an adjacent mature Engelmann spruce-subalpine fir forest, and a thinned and pruned juvenile lodgepole pine stand are presented. Net irradiance, soil heat flux density, and heat storage within the pack, were combined with eddy correlation measurements of sensible and latent heat flux density to estimate the energy available for snowmelt. When the ripe snow packs were melting, latent and soil heat flux density, and heat storage were negligible. A highly stable lower atmosphere resulted in low sensible heat flux densities. Although distinct differences in magnitude were observed between sites, net irradiance was the largest energy source for snowmelt at all three sites. Daily snowmelt calculated from energy balance measurements agreed well with measurements from snowmelt lysimeters.