Albedo of wheat during a growing season: Diurnal symmetry and asymmetry

The role of atmospheric and surface controls on the albedo of wheat was assessed during the 2001 growing season in southern Saskatchewan. When surface conditions (crop and soil) and atmospheric conditions (cloudless or overcast) remained constant, the diurnal albedo was symmetrical about solar noon. Albedo asymmetry between morning and afternoon regimes was evident in the early growing season (up to the end of the emergence stage) and was associated with surface wetting in the morning due to the presence of dew. When the crop dominated the surface, the albedo was symmetrical during unchanging sky conditions.