English: Author, Hugo Ahlenius, UNEP/GRID-Arendal. Full graphic, including sources, referencing etc are available here: http://maps.grida.no/go/graphic/cryosphere

Image donated by author, no restrictions on use.

Notes: Snow cover extent for Northern Hemisphere is represented by the 1966-2005 February average, for Southern Hemisphere by the 1987-2003 August average. Sea ice extent for Northern Hemisphere is represented by the 1979-2003 March average, for Southern Hemisphere by the 1979-2002 September average. Permafrost data for mountain areas and for the Southern Hemisphere are not represented in this map, neither are river and lake ice.

Data sources: Armstrong, R.L. and Brodzik, M.J. (2005). Northern Hemisphere EASE-Grid weekly snow cover and sea ice extent version 3. (Digital media). National Snow and Ice Data Center, Boulder Armstrong, R.L., Brodzik, M.J., Knowles, K. and Savoie, M. (2005). Global monthly EASE-Grid snow water equivalent climatology. (Digital media). National Snow and Ice Data Center, Boulder Brown, J., Ferrians Jr., O.J., Heginbottom, J.A. and Melnikov, E.S. (1998 revised February 2001). Circum-Arctic map of permafrost and ground-ice conditions. (Digital media). National Snow and Ice Data Center/World Data Center for Glaciology, Boulder NGA (2000). Vector Map Level 0. National Geospatial-Intelligence Agency. http://geoengine.nima.mil/ftpdir/archive/vpf_ data/v0soa.tar.gz [Accessed 1 September 2006] Stroeve, J. and Meier, W. (1999, updated 2005). Sea Ice Trends and Climatologies from SMMR and SSM/I. National Snow and Ice Data Center. http://nsidc.org/data/smmr_ssmi_ ancillary/monthly_means.html [Accessed 20 April 2007]