Landscape‐scale variations in near‐surface soil temperature and active‐layer thickness: Implications for high‐resolution permafrost mapping

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.

Towards a Monitoring Approach for Understanding Permafrost Degradation and Linked Subsidence in Arctic Peatlands

“…We speculate that the high range of motion in 2020 at Stordalen was linked to two winters with soil temperatures at 20 cm depth close to 0 • C preceding the thaw period of 2020, because rising winter soil temperatures contribute to permafrost degradation [19]. This is in line with finding from northwest Canada, where controls on near-surface soil temperatures linked to snow conditions are a good predictor of active layer depth [17]. At this stage, the short time series of the ASPIS-InSAR limits robust comparison between subsidence rates and climate data, but the increasing Sentinel-1 data time series offer this possibility for comparison at a later date.…”

“…Degradation of palsas and peat plateaus in response to climatic changes typically progresses through lateral erosion along the edges, but also through permafrost active layer deepening and the reduction of permafrost body thickness [15,16]. Ground temperature is a key control of permafrost, and local conditions (e.g., snow accumulation) that impact ground temperature contribute to spatial variation in active layer depth and rates of degradation [17][18][19]. The response of palsa peatlands to warmer conditions or altered snow dynamics has already been observed across northern Scandinavia [1,18,20,21] and elsewhere [22].…”

Research on the Applicability of DInSAR, Stacking-InSAR and SBAS-InSAR for Mining Region Subsidence Detection in the Datong Coalfield

“…Differential interferometric synthetic aperture radar (DInSAR), stacking-InSAR and small baseline subset InSAR (SBAS-InSAR) are popular methods for the monitoring of mining subsidence, permafrost-related subsidence, building subsidence and landslide. [11][12][13][14][15][16][17]. DIn-SAR, as an emerging Earth observation method, can measure surface deformation induced by underground mining activities with large spatial coverage, low cost, high accuracy, and all-weather observation capabilities [18].…”

Impacts of ecological succession and climate warming on permafrost aggradation in drained lake basins of the Tuktoyaktuk Coastlands, Northwest Territories, Canada

“…The degradation of permafrost is a transient process with a high degree of spatial variability, and our understanding of the response of permafrost to climate warming remains limited, particularly in areas of continuous permafrost where thermal history, ground ice, latent heat effects, and ecosystem feedbacks have an important influence on rates of degradation 20 . Predicting the impacts of climate warming on permafrost conditions is also made challenging by fine‐scale variability in ground temperatures associated with variation in soil moisture, vegetation, and snow conditions 4,21–23 . A significant lag in the response of continuous permafrost to a changing climate should be anticipated 20,24,25 .…”

“…20 Predicting the impacts of climate warming on permafrost conditions is also made challenging by fine-scale variability in ground temperatures associated with variation in soil moisture, vegetation, and snow conditions. 4,[21][22][23] A significant lag in the response of continuous permafrost to a changing climate should be anticipated. 20,24,25 Conversely, emergent surfaces that have not been preconditioned by a cold Holocene climate and the ecological conditions created by long-term succession (vegetation, organic soils, etc.)…”