Human-induced changes in winter surface Albedo

Abstract

The surface albedo of snow-covered deforested portions of the United States is approximately twice as high as when naturally vegetated. Moderate increases of up to about 0.20 are found for snow-covered farmland developed from former medium and tall grasslands. These changes may be considered representative of other populated regions in the middle latitudes. As a result, the winter surface albedo and, in turn, boundary-layer climates in these zones have become considerably more sensitive to the presence and duration of snow cover. Results are obtained from two models using satellite derived surface brightness fields, aerial albedo measurements of relatively undisturbed sites representative of past vegetation and global land-cover data sets. They refer to a block between 38° and 43°N latitude and 71° and 105°W longitude.