Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley
The variability of maximum active layer thickness in boreal and tundra environments has important implications for hydrological processes, terrestrial and aquatic ecosystems, and the integrity of northern infrastructure. For most planning and management purposes, the long-term probability distributi...
Published in: | Canadian Journal of Earth Sciences |
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Online Access: | http://dx.doi.org/10.1139/e06-121 http://www.nrcresearchpress.com/doi/pdf/10.1139/e06-121 |
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crcansciencepubl:10.1139/e06-121 2024-06-23T07:44:55+00:00 Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley Woo, Ming-ko Mollinga, Michael Smith, Sharon L 2007 http://dx.doi.org/10.1139/e06-121 http://www.nrcresearchpress.com/doi/pdf/10.1139/e06-121 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 44, issue 6, page 733-743 ISSN 0008-4077 1480-3313 journal-article 2007 crcansciencepubl https://doi.org/10.1139/e06-121 2024-06-13T04:10:51Z The variability of maximum active layer thickness in boreal and tundra environments has important implications for hydrological processes, terrestrial and aquatic ecosystems, and the integrity of northern infrastructure. For most planning and management purposes, the long-term probability distribution of active layer thickness is of primary interest. A robust method is presented to calculate maximum active layer thickness, employing the Stefan equation to compute phase change of moisture in soils and using air temperature as the sole climatic forcing variable. Near-surface ground temperatures (boundary condition for the Stefan equation) were estimated based on empirical relationships established for several sites in the Mackenzie valley. Simulations were performed for typically saturated mineral soils, overlain with varying thickness of peat in boreal and tundra environments. The probability distributions of simulated maximum active layer thickness encompass the range of measured thaw depths provided by field data. The effects of climate warming under A2 and B2 scenarios for 2050 and 2100 were investigated. Under the A2 scenario in 2100, the simulated median thaw depth under a thin organic cover may increase by 0.3 m, to reach 1 m depth for a tundra site and 1.6 m depth for a boreal site. The median thaw depth in 2100 is dampened by about 50% under a 1 m thick organic layer. Without an insulating organic cover, thaw penetration can increase to reach 1.7 m at the tundra site. The simulations provide quantitative support that future thaw penetration in permafrost terrain will deepen differentially depending on location and soil. Article in Journal/Newspaper Active layer thickness Mackenzie Valley permafrost Tundra Canadian Science Publishing Mackenzie Valley ENVELOPE(-126.070,-126.070,52.666,52.666) Canadian Journal of Earth Sciences 44 6 733 743 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
The variability of maximum active layer thickness in boreal and tundra environments has important implications for hydrological processes, terrestrial and aquatic ecosystems, and the integrity of northern infrastructure. For most planning and management purposes, the long-term probability distribution of active layer thickness is of primary interest. A robust method is presented to calculate maximum active layer thickness, employing the Stefan equation to compute phase change of moisture in soils and using air temperature as the sole climatic forcing variable. Near-surface ground temperatures (boundary condition for the Stefan equation) were estimated based on empirical relationships established for several sites in the Mackenzie valley. Simulations were performed for typically saturated mineral soils, overlain with varying thickness of peat in boreal and tundra environments. The probability distributions of simulated maximum active layer thickness encompass the range of measured thaw depths provided by field data. The effects of climate warming under A2 and B2 scenarios for 2050 and 2100 were investigated. Under the A2 scenario in 2100, the simulated median thaw depth under a thin organic cover may increase by 0.3 m, to reach 1 m depth for a tundra site and 1.6 m depth for a boreal site. The median thaw depth in 2100 is dampened by about 50% under a 1 m thick organic layer. Without an insulating organic cover, thaw penetration can increase to reach 1.7 m at the tundra site. The simulations provide quantitative support that future thaw penetration in permafrost terrain will deepen differentially depending on location and soil. |
format |
Article in Journal/Newspaper |
author |
Woo, Ming-ko Mollinga, Michael Smith, Sharon L |
spellingShingle |
Woo, Ming-ko Mollinga, Michael Smith, Sharon L Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley |
author_facet |
Woo, Ming-ko Mollinga, Michael Smith, Sharon L |
author_sort |
Woo, Ming-ko |
title |
Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley |
title_short |
Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley |
title_full |
Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley |
title_fullStr |
Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley |
title_full_unstemmed |
Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley |
title_sort |
climate warming and active layer thaw in the boreal and tundra environments of the mackenzie valley |
publisher |
Canadian Science Publishing |
publishDate |
2007 |
url |
http://dx.doi.org/10.1139/e06-121 http://www.nrcresearchpress.com/doi/pdf/10.1139/e06-121 |
long_lat |
ENVELOPE(-126.070,-126.070,52.666,52.666) |
geographic |
Mackenzie Valley |
geographic_facet |
Mackenzie Valley |
genre |
Active layer thickness Mackenzie Valley permafrost Tundra |
genre_facet |
Active layer thickness Mackenzie Valley permafrost Tundra |
op_source |
Canadian Journal of Earth Sciences volume 44, issue 6, page 733-743 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e06-121 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
44 |
container_issue |
6 |
container_start_page |
733 |
op_container_end_page |
743 |
_version_ |
1802640821940387840 |