scholarly journals Short-term changes in thermal conditions and active layer thickness in the tundra of the Kaffiøyra region, NW Spitsbergen

2016 ◽  
Vol 11 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Ireneusz Sobota ◽  
Michał Dziembowski ◽  
Tomasz Grajewski ◽  
Piotr Weckwerth ◽  
Marcin Nowak ◽  
...  
Keyword(s):  
Active Layer ◽  
Thermal Conditions ◽  
Weather Conditions ◽  
Active Layer Thickness ◽  
Test Field ◽  
Tidal Channels ◽  
Short Term ◽  
Ground Temperatures ◽  
Layer Increase ◽  
Field Area

Abstract This article describes and discusses the results of observations concerning short-term changes in the thermal conditions and the thickness of the active layer in a test field located in the tundra of the Kaffiøyra (NW Spitsbergen) during the summer season of 2015. One of the objectives was to find a correlation between the dynamic of the changes and the local topography. In recent years, thawing of the active layer in the Kaffiøyra region has been considerably varied in individual summer seasons. The test field area was 100 square meters, comprised 36 measurement points and was situated at approximately 3 m a.s.l. in the tundra. The measurements of the thickness and temperature of the active layer were carried out in July, August and early September of 2015. The greatest thickness of the active layer in the tundra was found near the moraine, in the area with the sharpest slope (156 cm to 212 cm). Ground temperatures were observed to follow the prevailing weather conditions with a delay, which amounted to about 24 h at a depth of 25 cm, and as much as 48 h at a depth of 75 cm. A greater thickness of the active layer was found in the western part of the test field, in the vicinity of a tidal channel, and in the eastern part of the field, bordering on the foot of the Aavatsmarkbreen’s moraine. A considerable sloping of the land, combined with increased surface runoff and infiltration at the time of precipitation, makes the water penetrating into the active layer increase its temperature. This demonstrates that the local land forms (tidal channels and terminal moraines) have a substantial influence on the extent and rate of changes which occur in the active layer.

scholarly journals Transient modeling of the ground thermal conditions using satellite data in the Lena River Delta, Siberia

2016 ◽  
Author(s):  
Sebastian Westermann ◽  
Maria Peter ◽  
Moritz Langer ◽  
Georg Schwamborn ◽  
Lutz Schirrmeister ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Layer Thickness ◽  
Active Layer ◽  
Thermal Conditions ◽  
River Delta ◽  
Active Layer Thickness ◽  
Lena River ◽  
Ground Temperatures ◽  
Lena River Delta

Abstract. Permafrost is a sensitive element of the cryosphere, but operational monitoring of the ground thermal conditions on large spatial scales is still lacking. Here, we demonstrate a remote-sensing based scheme that is capable of estimating the transient evolution of ground temperatures and active layer thickness by means of the ground thermal model CryoGrid 2. The scheme is applied to an area of approx. 16 000 km2 in the Lena River Delta in NE Siberia for a period of 14 years. The forcing data sets at 1 km spatial and weekly temporal resolution are synthesized from satellite products (MODIS Land Surface Temperature, MODIS Snow Extent, GlobSnow Snow Water Equivalent) and fields of meteorological variables from the ERA-interim reanalysis. To assign spatially distributed ground thermal properties, a stratigraphic classification based on geomorphological observations and mapping is constructed which accounts for the large-scale patterns of sediment types, ground ice and surface properties in the Lena River Delta. A comparison of the model forcing to in-situ measurements on Samoylov Island in the southern part of the study area yields a satisfactory agreement both for surface temperature, snow depth and timing of the onset and termination of the winter snow cover. The model results are compared to observations of ground temperatures and thaw depths at nine sites in in the Lena River Delta which suggests that thaw depths are in most cases reproduced to within 0.1 m or less and multi-year averages of ground temperatures within 1 to 1.5 °C. The warmest ground temperatures are calculated for grid cells close to the main river channels in the south, as well as areas with sandy sediments and low organic and ice contents in the central delta, where also the largest thaw depths occur. On the other hand, the coldest temperatures are modeled for the eastern part, an area with low surface temperatures and snow depths. The lowest thaw depths are modeled for Yedoma permafrost featuring very high ground ice and soil organic contents in the southern parts of the delta. The comparison to in-situ observations indicates that the satellite-based model scheme is generally capable of estimating the thermal state of permafrost and its time evolution in the Lena River Delta. The approach could hence be a first step towards remote detection of ground thermal conditions and active layer thickness in permafrost areas.

scholarly journals Transient modeling of the ground thermal conditions using satellite data in the Lena River delta, Siberia

2017 ◽  
Vol 11 (3) ◽  
pp. 1441-1463 ◽  
Author(s):  
Sebastian Westermann ◽  
Maria Peter ◽  
Moritz Langer ◽  
Georg Schwamborn ◽  
Lutz Schirrmeister ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Layer Thickness ◽  
Active Layer ◽  
Thermal Conditions ◽  
River Delta ◽  
Active Layer Thickness ◽  
Lena River ◽  
Ground Temperatures ◽  
Lena River Delta

Abstract. Permafrost is a sensitive element of the cryosphere, but operational monitoring of the ground thermal conditions on large spatial scales is still lacking. Here, we demonstrate a remote-sensing-based scheme that is capable of estimating the transient evolution of ground temperatures and active layer thickness by means of the ground thermal model CryoGrid 2. The scheme is applied to an area of approximately 16 000 km2 in the Lena River delta (LRD) in NE Siberia for a period of 14 years. The forcing data sets at 1 km spatial and weekly temporal resolution are synthesized from satellite products and fields of meteorological variables from the ERA-Interim reanalysis. To assign spatially distributed ground thermal properties, a stratigraphic classification based on geomorphological observations and mapping is constructed, which accounts for the large-scale patterns of sediment types, ground ice and surface properties in the Lena River delta. A comparison of the model forcing to in situ measurements on Samoylov Island in the southern part of the study area yields an acceptable agreement for the purpose of ground thermal modeling, for surface temperature, snow depth, and timing of the onset and termination of the winter snow cover. The model results are compared to observations of ground temperatures and thaw depths at nine sites in the Lena River delta, suggesting that thaw depths are in most cases reproduced to within 0.1 m or less and multi-year averages of ground temperatures within 1–2 °C. Comparison of monthly average temperatures at depths of 2–3 m in five boreholes yielded an RMSE of 1.1 °C and a bias of −0.9 °C for the model results. The highest ground temperatures are calculated for grid cells close to the main river channels in the south as well as areas with sandy sediments and low organic and ice contents in the central delta, where also the largest thaw depths occur. On the other hand, the lowest temperatures are modeled for the eastern part, which is an area with low surface temperatures and snow depths. The lowest thaw depths are modeled for Yedoma permafrost featuring very high ground ice and soil organic contents in the southern parts of the delta. The comparison to in situ observations indicates that transient ground temperature modeling forced by remote-sensing data is generally capable of estimating the thermal state of permafrost (TSP) and its time evolution in the Lena River delta. The approach could hence be a first step towards remote detection of ground thermal conditions and active layer thickness in permafrost areas.

The first 20 years (1978-1979 to 1998-1999) of active-layer development, Illisarvik experimental drained lake site, western Arctic coast, Canada1

2002 ◽  
Vol 39 (11) ◽  
pp. 1657-1674 ◽  
Author(s):  
J Ross Mackay ◽  
C R Burn
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Snow Depth ◽  
Weather Conditions ◽  
Active Layer Thickness ◽  
Ground Ice ◽  
Vertical Movements ◽  
Near Surface ◽  
Ground Temperatures ◽  
Lake Bottom

Active-layer thickness, snow depth, minimum soil temperatures, near-surface ground ice, soil heave, and permafrost temperatures have been measured for over 20 years following the 1978 artificial drainage of Lake Illisarvik. Measurements of active-layer thickness and other variables have been made at 25-m intervals along the major and minor axes of the oval-shaped drained-lake bed. Permafrost aggradation commenced in the lake bottom during the first winter following drainage. Before the establishment of vegetation, there was little snow cover, minimum ground temperatures were low, and the active layer was relatively thin. However, both snow depth and minimum ground temperatures have risen where vegetation has grown, the active layer has thickened, and in response, the temperature in permafrost has gradually increased. In the lake bottom, the change in snow depth associated with vegetation growth has been the dominant control on variation in active-layer thickness and not summer weather conditions, which are well correlated with thaw depths along an active-layer course established in the adjacent tundra. Changes in elevation of the surface of the lake bed have been measured with respect to some 40 bench marks anchored in permafrost, and indicate vertical movements of the surface associated with frost heave, thaw subsidence, and the growth of aggradational ice. The ground ice content of near-surface permafrost determined by drilling is in close agreement with the measured uplift of the lake bed. The rate of growth of aggradational ice has been ~0.5 cm a–1 over 20 years.

scholarly journals Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 457 ◽  
Author(s):  
F. Hrbáček ◽  
M. Oliva ◽  
K. Laska ◽  
J. Ruiz-Fernández ◽  
M. A. De Pablo ◽  
...  
Keyword(s):  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Active Layer Thickness ◽  
Mean Annual Temperature ◽  
Climate Trends ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
The Antarctic

Permafrost controls geomorphic processes in ice-free areas of the Antarctic Peninsula (AP) region. Future climate trends will promote significant changes of the active layer regime and permafrost distribution, and therefore a better characterization of present-day state is needed. With this purpose, this research focuses on Ulu Peninsula (James Ross Island) and Byers Peninsula (Livingston Island), located in the area of continuous and discontinuous permafrost in the eastern and western sides of the AP, respectively. Air and ground temperatures in as low as 80 cm below surface of the ground were monitored between January and December 2014. There is a high correlation between air temperatures on both sites (r=0.74). The mean annual temperature in Ulu Peninsula was -7.9 ºC, while in Byers Peninsula was -2.6 ºC. The lower air temperatures in Ulu Peninsula are also reflected in ground temperatures, which were between 4.9 (5 cm) and 5.9 ºC (75/80 cm) lower. The maximum active layer thickness observed during the study period was 52 cm in Ulu Peninsula and 85 cm in Byers Peninsula. Besides climate, soil characteristics, topography and snow cover are the main factors controlling the ground thermal regime in both areas.

scholarly journals Mapping the Main Characteristics of Permafrost on the Basis of a Permafrost-Landscape Map of Yakutia Using GIS

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 462
Author(s):  
Alyona A. Shestakova ◽  
Alexander N. Fedorov ◽  
Yaroslav I. Torgovkin ◽  
Pavel Y. Konstantinov ◽  
Nikolay F. Vasyliev ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Climatic Conditions ◽  
Active Layer Thickness ◽  
Distribution Maps ◽  
Ground Temperatures ◽  
Cryogenic Process ◽  
The Republic ◽  
Ice Content ◽  
Landscape Map

The purpose of this article was to compile four separate digital thematic maps of temperature and ice content of permafrost, the active layer thickness, and cryogenic processes in Yakutia as a basis for assessing changes to modern climate changes and anthropogenic disturbances. In this work, materials on permafrost were used, serving as the basis for compiling a permafrost landscape map of the Republic of Sakha (Yakutia). The maps were compiled using ArcGIS software, which supports attribute table mapping. The ground temperature and active layer thickness maps reflected landscape zonality and regional differences. Peculiarities of genetic types of Quaternary deposits and climatic conditions reflected the ice content of surface sediments and cryogenic process distribution maps. One of the most common is ground temperatures from −2.1 to −4.0 °C, which were found to occupy about 37.4% of the territory of Yakutia. More than half of the region was found to be occupied by permafrost landscapes with a limited thickness of the active layer up to 1.1 m. Ice-rich permafrost (more than 0.4 in ice content) was found to be typical for about 40% of the territory. Thermokarst is the most hazardous process that occurs in half of Yakutia.

Climate warming and active layer thaw in the boreal and tundra environments of the Mackenzie Valley

2007 ◽  
Vol 44 (6) ◽  
pp. 733-743 ◽  
Author(s):  
Ming-ko Woo ◽  
Michael Mollinga ◽  
Sharon L Smith
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Climate Warming ◽  
Probability Distributions ◽  
Organic Layer ◽  
Active Layer Thickness ◽  
Near Surface ◽  
Ground Temperatures ◽  
Thaw Depth ◽  
Mineral Soils

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.

scholarly journals Modelling borehole temperatures in Southern Norway – insights into permafrost dynamics during the 20th and 21st century

2012 ◽  
Vol 6 (3) ◽  
pp. 553-571 ◽  
Author(s):  
T. Hipp ◽  
B. Etzelmüller ◽  
H. Farbrot ◽  
T. V. Schuler ◽  
S. Westermann
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
21St Century ◽  
Little Ice Age ◽  
Ice Age ◽  
Active Layer Thickness ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Mountain Permafrost ◽  
Southern Norway

Abstract. This study aims at quantifying the thermal response of mountain permafrost in southern Norway to changes in climate since 1860 and until 2100. A transient one-dimensional heat flow model was used to simulate ground temperatures and associated active layer thicknesses for nine borehole locations, which are located at different elevations and in substrates with different thermal properties. The model was forced by reconstructed air temperatures starting from 1860, which approximately coincides with the end of the Little Ice Age in the region. The impact of climate warming on mountain permafrost to 2100 is assessed by using downscaled air temperatures from a multi-model ensemble for the A1B scenario. Borehole records over three consecutive years of ground temperatures, air temperatures and snow cover data served for model calibration and validation. With an increase of air temperature of ~1.5 °C over 1860–2010 and an additional warming of ~2.8 °C until 2100, we simulate the evolution of ground temperatures for each borehole location. In 1860 the lower limit of permafrost was estimated to be ca. 200 m lower than observed today. According to the model, since the approximate end of the Little Ice Age, the active-layer thickness has increased by 0.5–5 m and >10 m for the sites Juvvasshøe and Tron, respectively. The most pronounced increases in active layer thickness were modelled for the last two decades since 1990 with increase rates of +2 cm yr−1 to +87 cm yr−1 (20–430%). According to the A1B climate scenario, degradation of mountain permafrost is suggested to occur throughout the 21st century at most of the sites below ca. 1800 m a.s.l. At the highest locations at 1900 m a.s.l., permafrost degradation is likely to occur with a probability of 55–75% by 2100. This implies that mountain permafrost in southern Norway is likely to be confined to the highest peaks in the western part of the country.

scholarly journals Modeling the temperature evolution of Svalbard permafrost during the 20th and 21st century

2011 ◽  
Vol 5 (1) ◽  
pp. 67-79 ◽  
Author(s):  
B. Etzelmüller ◽  
T. V. Schuler ◽  
K. Isaksen ◽  
H. H. Christiansen ◽  
H. Farbrot ◽  
...  
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Surface Air Temperature ◽  
Thermal Conditions ◽  
Global Climate Models ◽  
Ground Temperature ◽  
Active Layer Thickness ◽  
Near Surface ◽  
Ground Temperatures ◽  
Rate Of Increase

Abstract. Variations in ground thermal conditions in Svalbard were studied based on measurements and modelling. Ground temperature data from boreholes were used to calibrate a transient heat flow model describing depth and time variations in temperatures. The model was subsequently forced with historical surface air temperature records and possible future temperatures downscaled from multiple global climate models. We discuss ground temperature development since the early 20th century, and the thermal responses in relation to ground characteristics and snow cover. The modelled ground temperatures show a gradual increase between 1912 and 2010, by about 1.5 °C to 2 °C at 20 m depth. The active layer thickness (ALT) is modelled to have increased slightly, with the rate of increase depending on water content of the near-surface layers. The used scenario runs predict a significant increase in ground temperatures and an increase of ALT depending on soil characteristics.

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