scholarly journals Modelling of the thermal regime of permafrost during 1990–2014 in Hornsund, Svalbard

2016 ◽  
Vol 37 (2) ◽  
pp. 219-242 ◽  
Author(s):  
Tomasz Wawrzyniak ◽  
Marzena Osuch ◽  
Jarosław Napiórkowski ◽  
Sebastian Westermann
Keyword(s):  
Thermal Regime ◽  
Environmental Changes ◽  
Thermal State ◽  
Ground Surface ◽  
Temperature Data ◽  
Ground Temperature ◽  
The Arctic ◽  
Transfer Model ◽  
Numerical Heat Transfer ◽  
Air Temperatures

AbstractThe thermal state of permafrost is a crucial indicator of environmental changes occurring in the Arctic. The monitoring of ground temperatures in Svalbard has been carried out in instrumented boreholes, although only few are deeper than 10 m and none are located in southern part of Spitsbergen. Only one of them, Janssonhaugen, located in central part of the island, provides the ground temperature data down to 100 m. Recent studies have proved that significant warming of the ground surface temperatures, observed especially in the last three decades, can be detected not only just few meters below the surface, but reaches much deeper layers. The aim of this paper is evaluation of the permafrost state in the vicinity of the Polish Polar Station in Hornsund using the numerical heat transfer model CryoGrid 2. The model is calibrated with ground temperature data collected from a 2 m deep borehole established in 2013 and then validated with data from the period 1990–2014 from five depths up to 1 m, measured routinely at the Hornsund meteorological station. The study estimates modelled ground thermal profile down to 100 m in depth and presents the evolution of the ground thermal regime in the last 25 years. The simulated subsurface temperature trumpet shows that multiannual variability in that period can reach 25 m in depth. The changes of the ground thermal regime correspond to an increasing trend of air temperatures observed in Hornsund and general warming across Svalbard.

scholarly journals NORPERM, the Norwegian Permafrost Database – a TSP NORWAY IPY legacy

2010 ◽  
Vol 3 (1) ◽  
pp. 27-54 ◽  
Author(s):  
H. Juliussen ◽  
H. H. Christiansen ◽  
G. S. Strand ◽  
S. Iversen ◽  
K. Midttømme ◽  
...  
Keyword(s):  
Thermal State ◽  
Ground Surface ◽  
Temperature Data ◽  
Ground Temperature ◽  
Future Research ◽  
Research Project ◽  
International Polar Year ◽  
Standard Format ◽  
Data Infrastructure ◽  
Data Loggers

Abstract. NORPERM – The Norwegian Permafrost Database was developed at the Geological Survey of Norway during the International Polar Year (IPY) 2007–2009 as the main data legacy of the IPY research project Permafrost Observatory Project: A Contribution to the Thermal State of Permafrost in Norway and Svalbard (TSP NORWAY). This paper describes the structural and technical design of NORPERM. NORPERM follows the IPY data policy of open, free, full and timely release of IPY data, and the borehole metadata description follows the Global Terrestrial Network for Permafrost (GTN-P) standard. The ground temperature data infrastructure in Norway and Svalbard is also presented, focussing on the TSP NORWAY permafrost observatory installations in the North Scandinavian Permafrost Observatory and Nordenskiöld Land Permafrost Observatory, as the data providers for NORPERM. Further developments of the database, possibly towards a regional database for the Nordic area, are also discussed. The purpose of NORPERM is to store ground temperature data safely and in a standard format for use in future research. NORPERM stores temperature time series from various depths in boreholes and from the air, snow cover, ground-surface or upper ground layer recorded by miniature temperature data-loggers, and temperature profiles with depth in boreholes obtained by occasional manual logging. It contains all the temperature data from the TSP NORWAY research project, totalling 32 boreholes and 98 sites with miniature temperature data-loggers for continuous monitoring of micrometeorological conditions, and 6 temperature depth profiles obtained by manual borehole logging. The amount of data in the database will gradually increase as data from older, previous projects are added. NORPERM also provides links to near real-time permafrost temperatures obtained by GSM data transfer.

scholarly journals Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling

2013 ◽  
Vol 9 (1) ◽  
pp. 119-133 ◽  
Author(s):  
D. Mottaghy ◽  
G. Schwamborn ◽  
V. Rath
Keyword(s):  
Surface Temperature ◽  
Thermal Regime ◽  
Climate Changes ◽  
Ground Surface ◽  
Temperature Data ◽  
Ice Age ◽  
Drilling Process ◽  
Past Climate ◽  
Ground Surface Temperature ◽  
Recent Climate

Abstract. This study focuses on the temperature field observed in boreholes drilled as part of interdisciplinary scientific campaign targeting the El'gygytgyn Crater Lake in NE Russia. Temperature data are available from two sites: the lake borehole 5011-1 located near the center of the lake reaching 400 m depth, and the land borehole 5011-3 at the rim of the lake, with a depth of 140 m. Constraints on permafrost depth and past climate changes are derived from numerical simulation of the thermal regime associated with the lake-related talik structure. The thermal properties of the subsurface needed for these simulations are based on laboratory measurements of representative cores from the quaternary sediments and the underlying impact-affected rock, complemented by further information from geophysical logs and data from published literature. The temperature observations in the lake borehole 5011-1 are dominated by thermal perturbations related to the drilling process, and thus only give reliable values for the lowermost value in the borehole. Undisturbed temperature data recorded over more than two years are available in the 140 m deep land-based borehole 5011-3. The analysis of these observations allows determination of not only the recent mean annual ground surface temperature, but also the ground surface temperature history, though with large uncertainties. Although the depth of this borehole is by far too insufficient for a complete reconstruction of past temperatures back to the Last Glacial Maximum, it still affects the thermal regime, and thus permafrost depth. This effect is constrained by numerical modeling: assuming that the lake borehole observations are hardly influenced by the past changes in surface air temperature, an estimate of steady-state conditions is possible, leading to a meaningful value of 14 ± 5 K for the post-glacial warming. The strong curvature of the temperature data in shallower depths around 60 m can be explained by a comparatively large amplitude of the Little Ice Age (up to 4 K), with low temperatures prevailing far into the 20th century. Other mechanisms, like varying porosity, may also have an influence on the temperature profile, however, our modeling studies imply a major contribution from recent climate changes.

scholarly journals Ground thermal regime in the vicinity of relict rock glaciers (Cantabrian Mountains, NW Spain)

Finisterra ◽  
2012 ◽  
Vol 44 (87) ◽  
Author(s):  
Javier Santos-González ◽  
Rosa González-Gutiérrez ◽  
Amélia Gómes-Villar ◽  
José Redondo-Vega
Keyword(s):  
Snow Cover ◽  
Thermal Regime ◽  
Strong Influence ◽  
Temperature Data ◽  
Ground Temperature ◽  
Cantabrian Mountains ◽  
Nw Spain ◽  
Freeze Thaw ◽  
Rock Glaciers ◽  
Frost Penetration

Ground temperature data obtained from 2002 to 2007 in sites near relict rock glaciers in the cantabrian mountains, at altitudes between 1500 and 2300 meters is analysed. Snow cover lasted between 3 and 9 months and had a strong influence on the thermal regime. When snow was present, the soil was normally frozen in the first 5 to 10 cm, but daily freeze-thaw cycles were rare. In well developed soils located at sunny faces frost penetration rarely reached more than 10 cm. on the contrary in shady and windy faces with scarce snow cover, frost penetration reached, at least, 40 cm. In persistent snow patches the temperature was stable at 0 ºc, even in relict rock glaciers, where subnival winter air fluxes appear to have been very rare.

Ground thermal contrasts and variability at an alpine pyramidal peak in central Austria (Innerer Knorrkogel, Venediger Mountains)

2021 ◽  
Author(s):  
Andreas Kellerer-Pirklbauer ◽  
Gerhard Karl Lieb
Keyword(s):  
Snow Cover ◽  
Thermal Regime ◽  
Ground Surface ◽  
Temperature Monitoring ◽  
Ground Temperature ◽  
Freeze Thaw ◽  
Ground Temperatures ◽  
Frost Weathering ◽  
Second Year ◽  
Ridge Flank

<p>Ground temperatures in alpine environments are severely influenced by slope orientation (aspect), slope inclination, local topoclimatic conditions, and thermal properties of the rock material. Small differences in one of these factors may substantially impact the ground thermal regime, weathering by freeze-thaw action or the occurrence of permafrost. To improve the understanding of differences, variations, and ranges of ground temperatures at single mountain summits, we studied the ground thermal conditions at a triangle-shaped (plan view), moderately steep pyramidal peak over a two-year period (2018-2020).</p><p>We installed 18 monitoring sites with 23 sensors near the summit of Innerer Knorrkogel (2882m asl), in summer 2018 with one- and multi-channel datalogger (Geoprecision). All three mountain ridges (east-, northwest-, and southwest-facing) and flanks (northeast-, west-, and south-facing) were instrumented with one-channel dataloggers at two different elevations (2840 and 2860m asl) at each ridge/flank to monitor ground surface temperatures. Three bedrock temperature monitoring sites with shallow boreholes (40cm) equipped with three sensors per site at each of the three mountain flanks (2870m asl) were established. Additionally, two ground surface temperature monitoring sites were installed at the summit.</p><p>Results show remarkable differences in mean annual ground temperatures (MAGT) between the 23 different sensors and the two years despite the small spatial extent (0.023 km²) and elevation differences (46m). Intersite variability at the entire mountain pyramid was 3.74°C in 2018/19 (mean MAGT: -0.40°C; minimum: -1.78°C; maximum: 1.96°C;) and 3.27°C in 2019/20 (mean MAGT: 0.08°C; minimum: -1.54°C; maximum: 1,73°C;). Minimum was in both years at the northeast-facing flank, maximum at the south-facing flank. In all but three sites, the second monitoring year was warmer than the first one (mean +0.48°C) related to atmospheric differences and site-specific snow conditions. The comparison of the MAGT-values of the two years (MAGT-2018/19 minus MAGT-2019/20) revealed large thermal inhomogeneities in the mountain summit ranging from +0.65° (2018/19 warmer than 2019/20) to -1.76°C (2018/19 colder than 2019/20) at identical sensors. Temperature ranges at the three different aspects but at equal elevations were 1.7-2.2°C at ridges and 1.8-3.7°C at flanks for single years. The higher temperature range for flank-sites is related to seasonal snow cover effects combined with higher radiation at sun-exposed sites. Although the ground temperature was substantially higher in the second year, the snow cover difference between the two years was variable. Some sites experienced longer snow cover periods in the second year 2019/20 (up to +85 days) whereas at other sites the opposite was observed (up to -85 days). Other frost weathering-related indicators (diurnal freeze-thaw cycles, frost-cracking window) show also large intersite and interannual differences.</p><p>Our study shows that the thermal regime at a triangle-shaped moderately steep pyramidal peak is very heterogeneous between different aspects and landforms (ridge/flank/summit) and between two monitoring years confirming earlier monitoring and modelling results. Due to high intersite and interannual variabilities, temperature-related processes such as frost-weathering can vary largely between neighbouring sites. Our study highlights the need for systematic and long-term ground temperature monitoring in alpine terrain to improve the understanding of small- to medium-scale temperature variabilities.</p>

scholarly journals Microtopographic control on the ground thermal regime in ice wedge polygons

2018 ◽  
Vol 12 (6) ◽  
pp. 1957-1968 ◽  
Author(s):  
Charles J. Abolt ◽  
Michael H. Young ◽  
Adam L. Atchley ◽  
Dylan R. Harp
Keyword(s):  
Thermal Conditions ◽  
Ground Temperature ◽  
The Arctic ◽  
Near Surface ◽  
Hydrologic Processes ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Ice Wedge ◽  
Prudhoe Bay

Abstract. The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1 ∘C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

scholarly journals New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere: a comparison between permafrost and non-permafrost areas

2019 ◽  
Vol 13 (2) ◽  
pp. 693-707 ◽  
Author(s):  
Olli Karjalainen ◽  
Miska Luoto ◽  
Juha Aalto ◽  
Jan Hjort
Keyword(s):  
Environmental Factors ◽  
Solar Radiation ◽  
Soil Properties ◽  
Northern Hemisphere ◽  
Effect Size ◽  
Thermal Regime ◽  
Thermal State ◽  
Local Scale ◽  
The Arctic ◽  
Active Layer Thickness

Abstract. The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (∼1 km2) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R2 values being ∼0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were ∼1.31 ∘C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6 ∘C, respectively. Soil properties had marginal effects on MAGT (effect size =0.4–0.7 ∘C). For ALT, rainfall (effect size =181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGT ≤0 ∘C and ALT were non-linear and indicated thresholds for covariation. Most importantly, permafrost temperatures had a more complex relationship with air temperatures than non-frozen ground. Moreover, the observed warming effect of rainfall on MAGT≤0∘C reverted after reaching an optimum at ∼250 mm, and that of snowfall started to level off at ∼300–400 mm. It is suggested that the factors of large global variation (i.e. climate) suppressed the effects of local-scale factors (i.e. soil properties and vegetation) owing to the extensive study area and limited representation of soil organic matter. Our new insights into the factors affecting the ground thermal regime at a 1 km scale should improve future hemispheric-scale studies.

scholarly journals Microtopographic control on the ground thermal regime in ice wedge polygons

2018 ◽  
Author(s):  
Charles J. Abolt ◽  
Michael H. Young ◽  
Adam L. Atchley ◽  
Dylan R. Harp
Keyword(s):  
Rapid Change ◽  
Thermal Conditions ◽  
Ground Temperature ◽  
The Arctic ◽  
Near Surface ◽  
Hydrologic Processes ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Ice Wedge

Abstract. The goal of this research is to constrain the influence of ice wedge polygon topography on near-surface ground temperatures. Because ice wedge polygon topography is prone to rapid change in a changing climate, and because cracking in the ice wedge depends on thermal conditions at the top of the permafrost, feedbacks between topography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of subdaily ground temperature observations at five depths and nine locations throughout a cluster of low-centered polygons near Prudhoe Bay, AK, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.2 °C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs, and tracking the effects on ice wedge temperature. The results indicate that deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for reestablishing rims in modern thermokarst-affected terrain will be precluded by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

scholarly journals Permafrost presence and distribution in the Chic-Chocs Mountains, Gaspésie, Québec

2011 ◽  
Vol 33 (3-4) ◽  
pp. 299-316 ◽  
Author(s):  
James T. Gray ◽  
Roger J. E. Brown
Keyword(s):  
Ground Surface ◽  
Drill Hole ◽  
Temperature Data ◽  
Ground Temperature ◽  
Flow Data ◽  
Conductivity Measurements ◽  
Profile Data ◽  
Ground Surface Temperature ◽  
Permafrost Table ◽  
Mean Annual Air Temperature

Ground temperature studies, begun in 1977, revealed the presence of permafrost at the summit of Mont Jacques-Cartier (1270 m), in Gaspésie. Temperature profile data to a depth of 30 m in a drill hole indicates an active layer slightly thicker than 5.75 m, overlying a permafrost body extending beyond the base of the hole. Downward extrapolation of the profile, based on heat flow data and thermal conductivity measurements show that this permafrost body is from 45-60 m thick. That the permafrost is contemporary is indicated by the proximity of the permafrost table to the surface, by the low mean annual air temperature for the site (-3°C to -5°C), and by the lack of a thick insulative blanket of snow in the winter. A mean annual ground surface temperature of -1°C to -1.5°C is estimated for the site. The Mont Jacques-Cartier data enabled a regional lower limit of 1,000 — 1,100 m to be established for extensive permafrost in the Chic-Chocs Mountains in treeless exposed situations. A limited amount of ground temperature data from Mont Logan and Mont Albert tends to confirm the validity of this regional limit, which was then used, in association with our knowledge of the vegetation cover, to map the distribution of extensive permafrost bodies for the entire eastern Chic-Chocs Mountains. Although not observed in this study, permafrost may exist below this regional limit, in either coarse debris accumulations, or in organic terrains at high altitudes subject to sufficiently thick accumulations of peat

scholarly journals Ground surface temperatures indicate the presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

2016 ◽  
Author(s):  
Gonçalo Vieira ◽  
Carla Mora ◽  
Ali Faleh
Keyword(s):  
Snow Cover ◽  
North Africa ◽  
Thermal Regime ◽  
Ground Surface ◽  
Cold Season ◽  
Snow Accumulation ◽  
Landsat 8 ◽  
High Atlas ◽  
Freeze Thaw ◽  
Air Temperatures

Abstract. Relict and present-day periglacial activity have been reported in the literature for the upper reaches of the High Atlas mountains, the highest range in North Africa (Djebel Toubkal – 4,167 m a.s.l.). Lobate features in the Irhzer Ikbi South at 3,800 m a.s.l. have been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess on the possible presence of permafrost, analyse data from June 2015 to June 2016 from two air temperature sites at 2,370 and 3,200 m a.s.l., and from four ground surface temperature (GST) sites at 3,200, 3,815, 3,980 and 4,160 m a.s.l. allowing to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GST were collected at 1-hour intervals and the presence of snow cover at the monitoring sites was validated using Landsat-8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3,210 m showed a regime characterized by frequent freeze-thaw cycles during the cold season but with a small number of days of snow. When snow sets, the ground remains isothermal at 0 °C and the thermal regime indicates the absence of permafrost. The highest sites at 3,980 and 4,160 m a.s.l. showed very frequent freeze-thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the their wind-exposed settings in a ridge and in the summit plateau. The site located at 3,815 m in the Irhzer Ikbi South valley showed a stable thermal regime from December to March with GST varying from −4.5 to −6 °C, under a continuous snow cover. The site's location in a concave setting favours snow accumulation and lower incoming solar radiation due to the effect of a southwards ridge, favouring the maintenance of a thick snow pack. The stable and low GST are interpreted as a strong indicator of the probable presence of permafrost at this site, an interpretation which is supported by the presence of lobate and arcuate forms in the talus deposits. These results are still a first approach and observations through geophysics and boreholes are foreseen. This is the first time that probable permafrost is reported from temperature observations in the mountains of North Africa.

scholarly journals New insights into the environmental drivers of the circumpolar ground thermal regime

2018 ◽  
Author(s):  
Olli Karjalainen ◽  
Miska Luoto ◽  
Juha Aalto ◽  
Jan Hjort
Keyword(s):  
Thermal Regime ◽  
Climatic Factors ◽  
Global Climate ◽  
Thermal Conditions ◽  
Cold Climate ◽  
The Arctic ◽  
Environmental Drivers ◽  
Active Layer Thickness ◽  
Thermal Dynamics ◽  
Air Temperatures

Abstract. The thermal dynamics of permafrost shape Earth surface systems and human activity in the Arctic and have implications to global climate. Improved understanding of the fine-scale variability in the circumpolar ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related circumpolar observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (~1 km2) geospatial data to identify their key environmental drivers. The multivariate models fitted well to MAGT and ALT observations with average R2 values being ~0.94 and 0.78, respectively. Corresponding predictive performances in terms of root mean square error were ~1.31 °C and 87 cm. Freezing air temperatures were the main driver of MAGT in permafrost conditions while thawing temperatures dominated when permafrost was not present. ALT was most strongly related to solar radiation and precipitation with an important influence from soil properties. Our findings suggest that in addition to climatic factors, initial ground thermal conditions and local-scale topography-soil-driven variability need to be considered in order to realistically assess the impacts of climate change on cold-climate geoecosystems.

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