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Armstrong, R.L. and Brodzik, M.J. (2005). Northern Hemisphere EASE-Grid weekly snow cover and sea ice extent version 3. National Snow and Ice Data Center, Boulder (Digital media)
Uploaded on Tuesday 21 Feb 2012
Mean snow-cover extent in the Northern Hemisphere 1966-2006
Hugo Ahlenius, UNEP/GRID-Arendal
Snow occurs predominantly on the northern continents, on the sea ice of the Arctic Ocean and on Antarctica. On the Northern Hemisphere continents, snow covers a maximum mean area of 45.2 million km2, typically in January. The minimum snow-cover extent usually occurs in August and covers a mean area of 1.9 million km2, most of which is snow on the Greenland ice sheet and on mountain glaciers. As a result, snow cover is the surface characteristic responsible for the largest annual and interannual differences in surface reflectivity (albedo) in the Northern Hemisphere.