The Cryosphere
Snow
Sea ice
Ice shelves
Ice sheets
Glaciers and ice caps
Permafrost (continuous)
Permafrost (discontinuous)
Permafrost (isolated)
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 perma-
frost 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-Intelli-
Notes:
gence Agency. http://geoengine.nima.mil/ftpdir/archive/vpf_
Snow cover extent for Northern Hemisphere is represented by the 1966–2005 February aver-
data/v0soa.tar.gz [Accessed 1 September 2006]
age, for Southern Hemisphere by the 1987–2003 August average.
Stroeve, J. and Meier, W. (1999, updated 2005). Sea Ice
Sea ice extent for Northern Hemisphere is represented by the 1979–2003 March average, for
Trends and Climatologies from SMMR and SSM/I. National
Southern Hemisphere by the 1979–2002 September average.
Snow and Ice Data Center. http://nsidc.org/data/smmr_ssmi_ Permafrost data for mountain areas and for the Southern Hemisphere are not represented
ancillary/monthly_means.html [Accessed 20 April 2007] in this map.