ALBEDO OVER THE BOREAL FOREST

Using the Boreal Ecosystem-Atmosphere Study mesonet data, we show the annual cycle of albedo for 1994 and 1995 at 10 sites; two over grass, one over an aspen forest, and an average of seven over coniferous fore sts. Representative daily average albedo values in summer are 0.2 over grass, 0.15 for aspen, and 0.083 for the conifer sites. In winter the corresponding mean albedo for snow-covered grass, aspen, and conifer sites with snow under the canopy are 0.75, 0.21, and 0.13. The jack pi ne sites have a higher mean winter albedo of 0.15 than the predominant ly spruce sites for which mean albedo is only 0.11. Forest albedo incr eases at all sites in winter (with snow on the ground under the canopy ) as the ratio of diffuse to total solar flux increases. The albedo of the conifer sites in winter rarely reaches 0.3.