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Data Set ID:
GGD318

Circum-Arctic Map of Permafrost and Ground-Ice Conditions, Version 2

The Circum-Arctic permafrost and ground ice map is available via ftp in ESRI Shapefile format and Equal-Area Scalable Earth Grid (EASE-Grid) format. See the Format section for an explanation of the files provided via FTP.

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. Permafrost extent is estimated in percent area (90-100 percent, 50-90 percent, 10-50 percent, <10 percent, and no permafrost). Relative abundance of ground ice in the upper 20 m is estimated in percent volume (>20 percent, 10-20 percent, <10 percent, and 0 percent). The data set also contains the location of subsea and relict permafrost. the gridded data are gridded at 12.5 km, 25 km, and 0.5 degree resolution. The shapefiles were derived from the original 1:10,000,000 paper map (Brown et al. 1997)

Permafrost, or permanently frozen ground, is ground (soil, sediment, or rock) that remains at or below 0°C for at least two years (Permafrost Subcommittee, 1988). It occurs both on land and beneath offshore arctic continental shelves, and underlies about 22 percent of the Earth's land surface.

For more information on the creation of the original map, see Heginbottom et al. (1993). The original paper map also includes information on the relative abundance of ice wedges, massive ice bodies and Pingos, ranges of permafrost temperature and thickness (Brown et al. 1997).

Geographic Coverage

Parameter(s):
  • Frozen Ground > Ground Ice
  • Frozen Ground > Permafrost
Spatial Coverage:
  • N: 90, S: 28, E: 180, W: -180

Spatial Resolution: Not Specified
Temporal Coverage: Not specified
Temporal Resolution: Not specified
Data Format(s):
  • ESRI Shapefile
Platform(s) Not specified
Sensor(s): Not specified
Version: V2
Data Contributor(s): J. Heginbottom, Jerry Brown, Oscar Ferrians, E.S. Melnikov
Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Brown, J., O. Ferrians, J. A. Heginbottom, and E. Melnikov. 2002. Circum-Arctic Map of Permafrost and Ground-Ice Conditions, Version 2. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. [Date Accessed].

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Detailed Data Description

Format

The Circum-Arctic permafrost and ground ice map data set contains the following files:

permaice.avl = ESRI Shaprefile legend file for permaice coverage based on NUM_CODE field in the polygon attribute table
permaice.dbf = attribute data
permaice.prj = projection info
permaice.shp = feature geometry
permaice.shx = feature geometry index
subsea.avl: ESRI Shapefile legend file for subsea coverage
subsea.dbf = attribute data
subsea.prj = projection info
subsea.shp = feature geometry
subsea.shx = feature geometry index
treeline.avl: ESRI Shapefile legend for treeline map
treeline.dbf = attribute data
treeline.prj = projection info
treeline.shp = feature geometry
treeline.shx = feature geometry index
llipa.byte = binary raster file, 0.5 degree by 0.5 degree version
llipa.hdr = header file used to bring the binary raster files into a GIS program
nhipa.byte = binary raster file, 2.5 km by 12.5 km EASE-Grid version
nhipa.hdr = header file
nlipa.byte = binary raster file, 25 km by 25 km EASE-Grid version
nlipa.hdr = header file
readpf.f = fortran program

Each datum within a file is a single byte. Numerical data values are listed below.

Value Definition
0 No information
1 - chf Continuous permafrost extent with high ground ice content and thick overburden
2 - dhf Discontinuous permafrost extent with high ground ice content and thick overburden
3 - shf Sporadic permafrost extent with high ground ice content and thick overburden
4 - ihf Isolated patches of permafrost extent with high ground ice content and thick overburden
5 - cmf Continuous permafrost extent with medium ground ice content and thick overburden
6 - dmf Discontinuous permafrost extent with medium ground ice content and thick overburden
7 - smf Sporadic permafrost extent with medium ground ice content and thick overburden
8 - imf Isolated patches of permafrost extent with medium ground ice content and thick overburden
9 - clf Continuous permafrost extent with low ground ice content and thick overburden
10 - dlf Discontinuous permafrost extent with low ground ice content and thick overburden
11 - slf Sporadic permafrost extent with low ground ice content and thick overburden
12 - ilf Isolated patches of permafrost extent with low ground ice content and thick overburden
13 - chr Continuous permafrost extent with high ground ice content and thin overburden and exposed bedrock
14 - dhr Discontinuous permafrost extent with high ground ice content and thin overburden and exposed bedrock
15 - shr Sporadic permafrost extent with high ground ice content and thin overburden and exposed bedrock
16 - ihr Isolated patches of permafrost extent with high ground ice content and thin overburden and exposed bedrock
17 - clr Continuous permafrost extent with low ground ice content and thin overburden and exposed bedrock
18 - dlr Discontinuous permafrost extent with low ground ice content and thin overburden and exposed bedrock
19 - slr Sporadic permafrost extent with low ground ice content and thin overburden and exposed bedrock
20 - ilr Isolated patches of permafrost extent with low ground ice content and thin overburden and exposed bedrock
21 - g Glaciers
22 - r Relict permafrost
23 - l Inland lakes
24 - o Ocean/inland seas
25 - ld Land

Permafrost extent codes
c = continuous (90-100%)
d = discontinuous (50- 90%)
s = sporadic (10- 50%)
i = isolated patches ( 0 - 10%)

Ground ice content codes
h = high (>20% for "f" landform codes) 
(>10% for "r" landform codes)
m = medium (10-20%)
l = low (0-10%)

Landform (terrain and overburden) codes
f lowlands, highlands, and intra- and intermontane depressions characterized by thick overburden cover (>5-10m)
r mountains, highlands ridges, and plateaus characterized by thin overburden cover (>5-10m) and exposed bedrock
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Projection

Projection for the raster (*.byte) files is:

Projection: Lambert Azimuthal
Units: meters
Spheroid: defined
Major Axis: 6371228.00000
Minor Axis: 6371228.000
Parameters: 
radius of the sphere of reference: 6371228.00000
longitude of center of projection: 0
latitude of center of projection: 90
false easting (meters): 0.00000
false northing (meters): 0.00000

Projection of the shapefiles is:

Projection: Lambert Azimuthal
Datum: none
Units: meters
Spheroid: defined
Major Axis: 6370997.00000
Minor Axis: 0.00000
Parameters:
radius of the sphere of reference: 6370997.00000
longitude of center of projection: 180
latitude of center of projection: 90
false easting (meters): 0.00000
false northing (meters): 0.00000

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Spatial Coverage

Spatial Coverage Map:

spatial coverage map: 25°N - 90°N, 180°W-180°E

spatial coverage map 

legend

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Software and Tools

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Data Acquisition and Processing

Processing Steps

The investigators initialized the Eurasian section of the map at the United Nations Environmental Programme/Global Resource Information Data Base (UNEP/GRID)-Arendal in Norway. The Norwegian Mapping Authority scanned and vectorized the polygon arcs, and georeferenced, corrected, and attributed the vectorized map at UNEP/GRID-Ardenal.

The North America and Greenland sections were also initialized at UNEP/GRID-Ardenal. The investigators manually digitized permafrost boundaries with an Root Mean Square (RMS) error of approximately 1 mm. Any coastline not coinciding with a permafrost unit was digitized as a generalized line. They digitized glacial boundaries as generalized lines and attributed closed polygons. They updated and corrected North America and Greenland at the Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, New Hampshire, and the United States Geological Survey (USGS) in Woods Hole, Massachusetts. They superimposed digital coastline and glacial boundaries using Arc/Info's Identity command, and corrected and updated attributes. Finally, they joined the data set of North America and Greenland with the compiled Eurasian area.

The investigators refined the full map at CRREL and USGS by appending digital coastlines and country lines to the map region south of 50°N. These data only extend down to 25°N, the limit of Northern Hemisphere permafrost. Finally, they superimposed digital data sets of select deep, large lakes with no underlying permafrost.

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Data Source

Following are input data used in processing the digital map:

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References and Related Publications

Contacts and Acknowledgments

Tingjun Zhang
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO, USA

Document Information

DOCUMENT CREATION DATE

February 2001

DOCUMENT REVISION DATE

October 2002

No technical references available for this data set.
No FAQs or How Tos available for this data set.

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