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Thermal state of permafrost in North America: A contribution to the international polar year

Permafrost and Periglacial Processes

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Abstract

A snapshot of the thermal state of permafrost in northern North America during the International Polar Year (IPY) was developed using ground temperature data collected from 350 boreholes. More than half these were established during IPY to enhance the network in sparsely monitored regions. The measurement sites span a diverse range of ecoclimatic and geological conditions across the continent and are at various elevations within the Cordillera. The ground temperatures within the discontinuous permafrost zone are generally above -3°C, and range down to -15°C in the continuous zone. Ground temperature envelopes vary according to substrate, with shallow depths of zero annual amplitude for peat and mineral soils, and much greater depths for bedrock. New monitoring sites in the mountains of southern and central Yukon suggest that permafrost may be limited in extent. In concert with regional air temperatures, permafrost has generally been warming across North America for the past several decades, as indicated by measurements from the western Arctic since the 1970s and from parts of eastern Canada since the early 1990s. The rates of ground warming have been variable, but are generally greater north of the treeline. Latent heat effects in the southern discontinuous zone dominate the permafrost thermal regime close to 0°C and allow permafrost to persist under a warming climate. Consequently, the spatial diversity of permafrost thermal conditions is decreasing over time.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Thermal state of permafrost in North America: A contribution to the international polar year
Series title:
Permafrost and Periglacial Processes
Volume
21
Issue:
2
Year Published:
2010
Language:
English
Publisher:
John Wiley & Sons
Publisher location:
Hoboken, NJ
Contributing office(s):
Geology and Environmental Change Science Center
Description:
19 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Permafrost and Periglacial Processes
First page:
117
Last page:
135
Other Geospatial:
North America