Effective UV surface albedo of seasonally snow-covered lands A. Tanskanen and T. Manninen Finnish Meteorological Institute, Helsinki, Finland
Abstract. At ultraviolet wavelengths the albedo of most natural surfaces
is small with the striking exception of snow and ice.
Therefore, snow cover is a major challenge for various applications based on
radiative transfer modelling. The aim of this work was to
determine the characteristic effective UV range surface albedo
of various land cover types when covered by snow.
First we selected 1 by 1 degree sample regions that met three criteria:
the sample region contained dominantly subpixels of only one land cover type
according to the 8 km global land cover classification product from the University of Maryland;
the average slope of the sample region was less than 2 degrees according to the USGS's HYDRO1K slope data;
the sample region had snow cover in March according to the NSIDC Northern Hemisphere weekly snow cover data.
Next we generated 1 by 1 degree gridded 360 nm surface albedo data
from the Nimbus-7 TOMS Lambertian equivalent reflectivity data,
and used them to construct characteristic effective surface albedo distributions
for each land cover type. The resulting distributions showed that each land cover type
experiences a characteristic range of surface albedo values when covered by snow.
The result is explained by the vegetation that extends upward beyond the snow cover
and masks the bright snow covered surface.
Citation: Tanskanen, A. and Manninen, T.: Effective UV surface albedo of seasonally snow-covered lands, Atmos. Chem. Phys., 7, 2759-2764, doi:10.5194/acp-7-2759-2007, 2007.