Title Thermal state of permafrost in North America; a contribution to the International Polar Year
Author Smith, S.L.; Romanovsky, V.E.; Lewkowicz, A.G.; Burn, C.R.; Allard, M.; Clow, G.D.; Yoshikawa, K.; Throop, J.
Author Affil Smith, S.L., Natural Resources Canada/Geological Survey of Canada, Ottawa, ON, Canada. Other: University of Alaska- Fairbanks; University of Ottawa, Canada; Carleton University, Canada; Université Laval, Canada; U. S. Geological Survey
Source The International Polar Year, edited by A.G. Lewkowicz. Permafrost and Periglacial Processes, 21(2), p.117-135, . Publisher: Wiley, Oxford, United Kingdom. ISSN: 1045- 6740
Publication Date Jun. 2010
Notes In English. 55 refs. CRREL Acc. No: 65001979
Index Terms active layer; climatic change; permafrost; soils; soil temperature; temperature; thawing; thermal regime; United States--Alaska; Canada; North America; Alaska; climate change; International Polar Year 2007-08; IPY 2007-08 Research Publications; United States
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. Abstract Copyright (2010), Wiley Periodicals, Inc.
URL http://hdl.handle.net/10.1002/ppp.690
Publication Type journal article
Record ID 304403