Surface albedo over typical types of surfaces in the North China Plain was observed using a Multi-field Albedo Observation System before and after several snowfalls from 13 to 27 February 2005.Dramatic variations of the surface albedos of bare land,a frozen pond,and withered grassland during that period were analyzed.Under cloudy sky,the mean surface albedo of bare land was about 0.23,but it immediately rose to 0.85 when the surface was covered by fresh snow.The albedo decreased gradually to normal levels afterwards.The melting processes were different depending on the characteristics of the underlying surfaces.For example,over grassland the surface albedo was relatively lower after snowfall,and as a result,more solar energy could be absorbed and consequently the snow melting process was accelerated.Significant variations of surface albedo cannot be easily captured by satellite observations;therefore,detailed measurements of surface albedo and related parameters are essential for determining the impact of snow on the energy budget of the Earth.
