The circumpolar permafrost and ground ice data contribute to a unified international data set that depicts the distribution and properties of permafrost and ground ice in the Northern Hemisphere (20°N to 90°N). The re-gridded data set shows discontinuous, sporadic, or isolated permafrost boundaries.
Brown, J., O.J. Ferrians, Jr., J.A. Heginbottom, and E.S. Melnikov. 1998, revised February 2001. Circum-arctic map of permafrost and ground ice conditions. Boulder, CO: National Snow and Ice Data Center/World Data Center for Glaciology. Digital media.
National Center for Atmospheric Research Staff (Eds). Last modified 20 Nov 2013. "The Climate Data Guide: Permafrost: Circum-Arctic Map of Permafrost and Ground Ice Conditions." Retrieved from https://climatedataguide.ucar.edu/climate-data/permafrost-circum-arctic-map-permafrost-and-ground-ice-conditions.