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

Author(s):  
Yu Zhang ◽  
Ridha Touzi ◽  
Wanpeng Feng ◽  
Gang Hong ◽  
Trevor C. Lantz ◽  
...  
2021 ◽  
Author(s):  
Y Zhang ◽  
R Touzi ◽  
W Feng ◽  
G Hong ◽  
T C Lantz ◽  
...  

Quantifying and understanding spatial variation in permafrost conditions at the landscape-scale is important for land use planning and assessing the impacts of permafrost thaw. This report documents detailed field data observed at 110 sites in two areas in northwestern Canada from 2016 to 2017. One area is a northern boreal landscape near Inuvik and the other is a tundra landscape near Tuktoyaktuk. The observations include near-surface soil temperatures (Tnss) at 107 sites, and active-layer thickness, soil and vegetation conditions at 110 sites. The data set includes the original Tnss records, the calculated daily, monthly, and annual averages of Tnss, soil and vegetation conditions at these sites, and photographs taken in the field. This data set will be useful for understanding the spatial heterogeneity of permafrost and validating modelling and mapping products.


2020 ◽  
Author(s):  
Bin Cao ◽  
Stephan Gruber ◽  
Donghai Zheng ◽  
Xin Li

Abstract. ERA5-Land (ERA5L) is a reanalysis product derived by running the land component of ERA5 at increased resolution. This study evaluates its soil temperature in permafrost regions based on observations and published permafrost products. Soil in ERA5L is predicted too warm in northern Canada and Alaska, but too cold in mid-low latitudes, leading to an average bias of −0.08 °C. The warm bias of ERA5L soil is stronger in winter than in other seasons. Diagnosed from its soil temperature, ERA5L overestimates active-layer thickness and underestimates near-surface (


2021 ◽  
pp. 1-10
Author(s):  
X.M. Yang ◽  
W.D. Reynolds ◽  
C.F. Drury ◽  
M.D. Reeb

Although it is well established that soil temperature has substantial effects on the agri-environmental performance of crop production, little is known of soil temperatures under living cover crops. Consequently, soil temperatures under a crimson clover and white clover mix, hairy vetch, and red clover were measured for a cool, humid Brookston clay loam under a corn–soybean–winter wheat/cover crop rotation. Measurements were collected from August (after cover crop seeding) to the following May (before cover crop termination) at 15, 30, 45, and 60 cm depths during 2018–2019 and 2019–2020. Average soil temperatures (August–May) were not affected by cover crop species at any depth, or by air temperature at 60 cm depth. During winter, soil temperatures at 15, 30, and 45 cm depths were greater under cover crops than under a no cover crop control (CK), with maximum increase occurring at 15 cm on 31 January 2019 (2.5–5.7 °C) and on 23 January 2020 (0.8–1.9 °C). In spring, soil temperatures under standing cover crops were cooler than the CK by 0.1–3.0 °C at 15 cm depth, by 0–2.4 °C at the 30 and 45 cm depths, and by 0–1.8 °C at 60 cm depth. In addition, springtime soil temperature at 15 cm depth decreased by about 0.24 °C for every 1 Mg·ha−1 increase in live cover crop biomass. Relative to bare soil, cover crops increased near-surface soil temperature during winter but decreased near-surface soil temperature during spring. These temperature changes may have both positive and negative effects on the agri-environmental performance of crop production.


2019 ◽  
Vol 9 (1) ◽  
pp. 20-36 ◽  
Author(s):  
Filip Hrbáček ◽  
Daniel Nývlt ◽  
Kamil Láska ◽  
Michaela Kňažková ◽  
Barbora Kampová ◽  
...  

This study summarizes the current state of the active layer and permafrost research on James Ross Island. The analysis of climate parameters covers the reference period 2011–2017. The mean annual air temperature at the AWS-JGM site was -6.9°C (ranged from -3.9°C to -8.2°C). The mean annual ground temperature at the depth of 5 cm was -5.5°C (ranged from -3.3°C to -6.7°C) and it also reached -5.6°C (ranged from -4.0 to -6.8°C) at the depth of 50 cm. The mean daily ground temperature at the depth of 5 cm correlated moderately up to strongly with the air temperature depending on the season of the year. Analysis of the snow effect on the ground thermal regime confirmed a low insulating effect of snow cover when snow thickness reached up to 50 cm. A thicker snow accumulation, reaching at least 70 cm, can develop around the hyaloclastite breccia boulders where a well pronounced insulation effect on the near-surface ground thermal regime was observed. The effect of lithology on the ground physical properties and the active layer thickness was also investigated. Laboratory analysis of ground thermal properties showed variation in thermal conductivity (0.3 to 0.9 W m-1 K-1). The thickest active layer (89 cm) was observed on the Berry Hill slopes site, where the lowest thawing degree days index (321 to 382°C·day) and the highest value of thermal conductivity (0.9 W m-1 K-1) was observed. The clearest influence of lithological conditions on active layer thickness was observed on the CALM-S grid. The site comprises a sandy Holocene marine terrace and muddy sand of the Whisky Bay Formation. Surveying using a manual probe, ground penetrating radar, and an electromagnetic conductivity meter clearly showed the effect of the lithological boundary on local variability of the active layer thickness.


1992 ◽  
Vol 35 (5) ◽  
pp. 1449-1455 ◽  
Author(s):  
F. B. Pierson ◽  
G. N. Flerchinger ◽  
J. R. Wight

Geophysics ◽  
2016 ◽  
Vol 81 (2) ◽  
pp. H1-H11 ◽  
Author(s):  
Albert Chen ◽  
Andrew D. Parsekian ◽  
Kevin Schaefer ◽  
Elchin Jafarov ◽  
Santosh Panda ◽  
...  

2015 ◽  
Vol 8 (1) ◽  
pp. 715-759 ◽  
Author(s):  
S. Chadburn ◽  
E. Burke ◽  
R. Essery ◽  
J. Boike ◽  
M. Langer ◽  
...  

Abstract. It is important to correctly simulate permafrost in global climate models, since the stored carbon represents the source of a potentially important climate feedback. This carbon feedback depends on the physical state of the permafrost. We have therefore included improved physical permafrost processes in JULES, which is the land-surface scheme used in the Hadley Centre climate models. The thermal and hydraulic properties of the soil were modified to account for the presence of organic matter, and the insulating effects of a surface layer of moss were added, allowing for fractional moss cover. We also simulate a higher-resolution soil column and deeper soil, and include an additional thermal column at the base of the soil to represent bedrock. In addition, the snow scheme was improved to allow it to run with arbitrarily thin layers. Point-site simulations at Samoylov Island, Siberia, show that the model is now able to simulate soil temperatures and thaw depth much closer to the observations. The root mean square error for the near-surface soil temperatures reduces by approximately 30%, and the active layer thickness is reduced from being over 1 m too deep to within 0.1 m of the observed active layer thickness. All of the model improvements contribute to improving the simulations, with organic matter having the single greatest impact. A new method is used to estimate active layer depth more accurately using the fraction of unfrozen water. Soil hydrology and snow are investigated further by holding the soil moisture fixed and adjusting the parameters to make the soil moisture and snow density match better with observations. The root mean square error in near-surface soil temperatures is reduced by a further 20% as a result.


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