| Title | Landscape-scale variations in near-surface soil temperature and active-layer thickness: implications for high-resolution permafrost mapping |
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| Author | Zhang, Y ; Touzi,
R; Feng, W; Hong, G; Lantz, T C; Kokelj, S V |
| Source | Permafrost and Periglacial Processes vol. 32, issue 4, 2021 p. 627-640, https://doi.org/10.1002/ppp.2104 |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210405 |
| Alt Series | Northwest Territories Geological Survey Contribution 0133 |
| Publisher | Wiley |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf; html |
| Province | Northwest Territories |
| NTS | 107B/01; 107B/02; 107B/07; 107B/08; 107B/09; 107B/10; 107B/15; 107B/16; 107C/01; 107C/02; 107C/07; 107C/08; 107C/09; 107C/10 |
| Area | Tuktoyaktuk; Inuvik |
| Lat/Long WENS | -134.0000 -132.5000 69.7500 68.0000 |
| Subjects | surficial geology/geomorphology; Nature and Environment; Science and Technology; permafrost; ground ice; ground temperatures; vegetation; snow; organic deposits; field methods; ecology;
Inuvik-Tuktoyaktuk Highway; Boreal ecosystems; permafrost thaw |
| Illustrations | location maps; photographs; bar graphs; time series; plots; tables |
| Program | Canada Centre for Remote Sensing Remote Sensing Science Program - Optical methods and applications |
| Released | 2021 08 14 |
| Abstract | Soil temperature observations in permafrost regions are sparse, which limits our understanding and ability to map permafrost conditions at high spatial resolutions. In this study, we measured
near-surface soil temperatures (Tnss) at 107 sites from August 2016 to August 2017 in northern boreal and tundra areas in northwestern Canada. Active-layer thickness (ALT), soil and vegetation conditions were also measured at these sites. Our
observations show large variations in Tnss and ALT across an area with a similar climate. This high degree of spatial heterogeneity illustrates the importance of high-resolution mapping of permafrost for infrastructure planning and understanding the
impacts of permafrost thaw. Annual mean Tnss varied by 5-6°C among observation sites, which was mainly due to differences in Tnss in winter and spring, indicating the importance of snow conditions on determining landscape-scale variation in
near-surface ground temperatures. ALT varied from about 30 cm to more than 120 cm. The variation in ALT among sites did not correlate with thawing season Tnss, but was associated with variation in soil conditions, especially the surface organic layer
thickness. Freezing n-factors varied significantly from site to site and among ecotypes, while thawing n-factors were similar among sites, except bare soils. This study shows that ecotypes can be used to map ALT and Tnss at landscape scales in tundra
areas, but the method is not as effective in the northern boreal region. |
| Summary | (Plain Language Summary, not published)
Spatially detailed information about permafrost conditions is critical for land use planning and infrastructure development in permafrost regions. Soil
temperature observations in northern regions are sparse, which limits our understanding and ability to map permafrost conditions at high spatial resolutions. In this study, we measured near-surface soil temperatures (Tnss) at 107 sites from August
2016 to August 2017 in a northern boreal area and a sub-arctic tundra area in northwestern Canada. Active-layer thickness (ALT, or maximum summer thaw depth), soil and vegetation conditions were also measured at these sites. These multi-site
observations show large variations in near-surface permafrost conditions at landscape-scales. The annual mean Tnss varied by 5 to 6 °C among observation sites, which was mainly due to differences of Tnss in winter and spring, indicating the
importance of snow effects. ALT varied from about 0.4 m to more than 1.2 m. The site variation of ALT did not correlate with the Tnss in thawing season but was mainly due to variations in soil conditions. The variation of ALT was also positively
correlated with Tnss in winter and spring, probably because the impacts of local topography and vegetation on snow and on soil conditions were closely associated. This study also shows that vegetation conditions are very useful for mapping permafrost
at land-scape scales in tundra, but not as effective for boreal regions. |
| GEOSCAN ID | 329239 |
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