Depth to Permafrost - Alaska LandCarbon Project

These data represent the percentage of the map area for which the depth to permafrost is less than or equal to 100 cm. A soil horizon was flagged as having permafrost if the texture modifier for the horizon contained the characters “PF-“, indicating permafrost. A soil component was flagged as having permafrost in the 0-100 cm zone if at least one horizon overlapping that zone was classified as having permafrost. The component percentage represents the percentage of the map unit area represented by the component. The sum of the component percentages for components flagged as having permafrost in the zone was coded at the map unit level, and used to create the spatial data layer. A non-soil component, such as water, ice, or rock at the surface, would not contribute to the total. The prefix “mu_” on the filename indicates that a map unit level variable was being computed. The suffix “_2” on the filename is an arbitrary version number. The file extension “.img” indicates an Erdas Imagine format for spatial data, which can be manipulated by various types of geospatial analysis software, including GDAL (the Geospatial Data Abstraction Library), Erdas Imagine, and ArcGIS.

For more information on the structure of soil data attributes, including definitions of map units, components, and horizons, see http://soils.usda.gov/survey/geography (which redirects to https://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/geo/.

The source of the soil data for Alaska for this project was a revised STATSGO database for Alaska at 1:500,000 scale, dated October 16, 2012. The data are in an Albers Conical Equal Area projection with a central meridian of 154° W and standard parallels at 55° N and 65° N. The cell size is 1000x1000 meter (1-km resolution), with 2012 rows and 3685 columns. The minimum value is 0 and the maximum value is 98 percent.

Data and Resources