Energy Balance and Climate of a Snow-Covered Frozen Lake
in the Boreal Forest
R.J. Harding1, C.M. Taylor1, and J. Pomeroy2
Lakes make up nearly 20% of the Canadian boreal forest region. The contrast between the surface
characteristics of coniferous forest and snow-covered lakes is probably the largest that can be found
naturally anywhere. This contrast leads to fluxes of differing sign over the forest and the lake and a
likely advection of heat from the forest to the lake, providing the energy for snowmelt on the lake.
The paper describes measurements of turbulent fluxes and climate made above a snow-covered
lake in the springs of 1994 and 1996, taken as part of the BOREAS experiment. The measurements
show albedos in excess of 85%, decreasing following melt to less than 70%. The roughness lengths
are highly variable, with mean values ranging from 0.01 to 10 mm, with a hint that the roughness
length for heat and water vapor are less than that for momentum. There is a strong diurnal variation
of wind and air temperature on the lake. Air crossing the lake is observed to speed up and cool; this
may result in the melt on the lakes being dependent on their size. These patterns of surface meteo-
rology are a product of interactions with the surrounding forest and enhance the turbulent fluxes
into the snow cover during the daytime and may have important consequences to the onset of melt
on the lake.
1
Institute of Hydrology, Wallingford Oxon., OX10 8BB, United Kingdom
2
National Hydrology Research Institute, Environment Canada, 11 Innovation Boulevard, Saskatoon,
Saskatchewan S7N 3H5, Canada
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