Canopy snow influence on water and energy balances in a coniferous forest plantation in northern Japan

Snowfall captured by the forest canopy is an important component of the water and energy balances in forests that are seasonally covered with snow. In the present study, we examined the influence of canopy snow on water and energy balances above a coniferous forest in the Hitsujigaoka Experimental Forest of Japan during winter 1997–1998. Measured data comprised eddy covariance fluxes above the forest, micrometeorological data, and canopy-snow monitoring data obtained from photographs and by weighing a cut tree. The maximum daily canopy snow storage was around 6.9 mm water equivalent. The snow-covered area of the canopy affected the partitioning of the energy balance above the canopy. The quantity of canopy snow strongly influenced canopy surface albedo, canopy surface temperature, and aerodynamic resistance between forest and atmosphere. About 26% of the accumulated snowfall from 1 January 1998 to 31 March 1998 was intercepted by the forest canopy.