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Andrey Abramov - One of the best experts on this subject based on the ideXlab platform.
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Are Permafrost microorganisms as old as Permafrost
FEMS microbiology ecology, 2021Co-Authors: Andrey Abramov, Tatiana A. Vishnivetskaya, Elizaveta RivkinaAbstract:Permafrost describes the condition of earth material (sand, ground, organic matter, etc.) cemented by ice when its temperature remains at or below 0°C continuously for longer than 2 years. Evidently, Permafrost is as old as the time passed from freezing of the earth material. Permafrost is a unique phenomenon and may preserve life forms it encloses. Therefore, in order to talk confidently about the preservation of paleo-objects in Permafrost, knowledge about the geological age of sediments, i.e. when the sediments were formed, and Permafrost age, when those sediments became permanently frozen, is essential. There are two types of Permafrost-syngenetic and epigenetic. The age of syngenetic Permafrost corresponds to the geological age of its sediments, whereas the age of epigenetic Permafrost is less than the geological age of its sediments. Both of these formations preserve microorganisms and their metabolic products; however, the interpretations of the microbiological and molecular-biological data are inconsistent. This paper reviews the current knowledge of time-temperature history and age of Permafrost in relation to available microbiological and metagenomic data.
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Permafrost is warming at a global scale
Nature communications, 2019Co-Authors: Boris K. Biskaborn, Vladimir E. Romanovsky, Sharon L. Smith, Jeannette Noetzli, Heidrun Matthes, Gonçalo Vieira, Dmitry A. Streletskiy, Philippe Schoeneich, Antoni G. Lewkowicz, Andrey AbramovAbstract:Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of Permafrost temperature change has been compiled. Here we use a global data set of Permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across Permafrost regions for the period since the International Polar Year (2007–2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous Permafrost zone increased by 0.39 ± 0.15 °C. Over the same period, discontinuous Permafrost warmed by 0.20 ± 0.10 °C. Permafrost in mountains warmed by 0.19 ± 0.05 °C and in Antarctica by 0.37 ± 0.10 °C. Globally, Permafrost temperature increased by 0.29 ± 0.12 °C. The observed trend follows the Arctic amplification of air temperature increase in the Northern Hemisphere. In the discontinuous zone, however, ground warming occurred due to increased snow thickness while air temperature remained statistically unchanged.
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thermal state of Permafrost in russia
Permafrost and Periglacial Processes, 2010Co-Authors: V E Romanovsky, Dmitry Drozdov, Naum Oberman, G V Malkova, A L Kholodov, S S Marchenko, Nataliya G Moskalenko, D O Sergeev, N G Ukraintseva, Andrey AbramovAbstract:The results of the International Permafrost Association’s International Polar Year Thermal State of Permafrost (TSP) project are presented based on field measurements from Russia during the IPY years (2007–09) and collected historical data. Most ground temperatures measured in existing and new boreholes show a substantial warming during the last 20 to 30 years. The magnitude of the warming varied with location, but was typically from 0.58 Ct o 28C at the depth of zero annual amplitude. Thawing of Little Ice Age Permafrost is ongoing at many locations. There are some indications that the late Holocene Permafrost has begun to thaw at some undisturbed locations in northeastern Europe and northwest Siberia. Thawing of Permafrost is most noticeable within the discontinuous Permafrost domain. However, Permafrost in Russia is also starting to thaw at some limited locations in the continuous Permafrost zone. As a result, a northward displacement of the boundary between continuous and discontinuous Permafrost zones was observed. This data set will serve as a baseline against which to measure changes of near-surface Permafrost temperatures and Permafrost boundaries, to validate climate model scenarios, and for temperature reanalysis. Copyright # 2010 John Wiley & Sons, Ltd.
Wei Cao - One of the best experts on this subject based on the ideXlab platform.
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Thermal effect of thermokarst lake on the Permafrost under embankment
Advances in Climate Change Research, 2021Co-Authors: Erxing Peng, Yu Sheng, Hu Xiaoying, Wei CaoAbstract:Abstract In Permafrost regions of the Qinghai-Tibet Plateau, road disaster caused by Permafrost degradation cannot be ignored. As a common thermal disaster in Permafrost regions, thermokarst lake has serious thermal erosion on Permafrost and results in Permafrost degradation aggravating. This study focused on two subgrade cross-sections of Gonghe-Yushu Highway in the Qinghai-Tibet Plateau to analyze thermal effect of thermokarst lake on the Permafrost under embankment. The analysis infers that thermokarst lake can transfer heat to Permafrost under the embankment, as a heat resource, and the heat flux decreases with the distance away from thermokarst lake in horizontal and vertical direction. Thermokarst lake can cause average ground temperature of Permafrost under the embankment increasing, and with less distance from the thermokarst lake the temperature increases more severely. Thermokarst lake results in 14 m thickness melting interlayer in soil under lake and change shape of melting area.
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Spatiotemporal changes of Permafrost in the Headwater Area of the Yellow River under a changing climate
Land Degradation & Development, 2019Co-Authors: Yu Sheng, Wei CaoAbstract:This article attempts to predict the spatiotemporal changes of Permafrost in the Headwater Area of the Yellow River (HAYR) on the northeastern Qinghai‐Tibet Plateau, Southwest China by using field monitoring and numerical models. Permafrost in the HAYR is categorized into four types: low‐ and high‐ice‐content high‐plain Permafrost and low‐ and high‐ice‐content alpine Permafrost. According to these Permafrost types, changes in Permafrost temperature were calculated by coupling a geometric model with the soil thermal conduction model. Based on the calculation results, this paper evaluates the changes of Permafrost in the HAYR over the past 50 years and predicts the change trends of Permafrost in the HAYR under the scenarios of RCP2.6, RCP6.0, and RCP8.5 for possible climate change in 2050 and 2010 from the Intergovernmental Panel on Climate Change Fifth Assessment Report. The results show that (a) in the process of Permafrost degradation, the same Permafrost type at different degradation stages results in different modes and rates of increasing temperature. The response of Permafrost to climate change differs in various degradation stages of Permafrost; (b) from 1972 to 2012, the areal extent of Permafrost degradation was 1,056 km², resulting from a sharp air temperature increase after the 1980s. By 2050, the areal extent of Permafrost degradation into seasonal frost is similar under the three scenarios of climate change. The areal extent of Permafrost degradation is 2,224, 2,347, and 2,559 km² or 7.5%, 7.9%, and 8.6% of the total area in the HAYR, respectively. In RCP2.6, the areal extent of Permafrost degradation into seasonal frost by 2100 would be approximately 3,500 km² greater than that by 2050. In RCP6.0, the areal extent of Permafrost degradation by 2100 would be 10,000 km² or 32.9% of the total area in the HAYR. In RCP8.5, the area of Permafrost degradation by 2100 would be 18,492 km² or 62.2% of the total area in the HAYR; (c) the active layer thickness (ALT) in the HAYR would increase significantly. The average of the ALT was 1.51 m by 1972 and 2.01 m by 2012, respectively. Under the RCP2.6, RCP6.0, and RCP8.5 scenarios, the basin‐wide average of ALT would be 2.21, 2.40, and 3.08 m by 2050 and 2.78, 4.07, and 4.39 m by 2100, respectively.
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simulation analysis of the impact of excavation backfill on Permafrost recovery in an opencast coal mining pit
Environmental Earth Sciences, 2016Co-Authors: Wei Cao, Yu Sheng, Yaling ChouAbstract:The article attempts to investigate the status of Permafrost recovery after excavation backfill in an opencast coal mine. To do that, we forecast the Permafrost recovery under certain initial temperatures and different boundary conditions by using the numerical simulation method. The results show that the filling temperature significantly influences Permafrost recovery after backfilling. When the filling temperature decreases from +2.0 to −2.0 °C, the Permafrost recovery rate will greatly accelerate, and the Permafrost thickness will significantly increase. When the surface temperature of the filling is positive, the Permafrost recovery at the bottom of the excavation will be more difficult than when the temperature is negative. The Permafrost recovery rate will be slow, and the Permafrost thickness will be thin. The Permafrost recovery also gradually speeds up the thickening with decreasing natural surface temperature. Thus, backfilling should be conducted in the cold season, and cooling treatment should be applied to the filling before backfilling. The treatment will ensure that the Permafrost recovery is faster and more stable. This measure is also conducive to the recovery of the ecological environment of the mine.
V E Romanovsky - One of the best experts on this subject based on the ideXlab platform.
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thermal state of Permafrost in russia
Permafrost and Periglacial Processes, 2010Co-Authors: V E Romanovsky, Dmitry Drozdov, Naum Oberman, G V Malkova, A L Kholodov, S S Marchenko, Nataliya G Moskalenko, D O Sergeev, N G Ukraintseva, Andrey AbramovAbstract:The results of the International Permafrost Association’s International Polar Year Thermal State of Permafrost (TSP) project are presented based on field measurements from Russia during the IPY years (2007–09) and collected historical data. Most ground temperatures measured in existing and new boreholes show a substantial warming during the last 20 to 30 years. The magnitude of the warming varied with location, but was typically from 0.58 Ct o 28C at the depth of zero annual amplitude. Thawing of Little Ice Age Permafrost is ongoing at many locations. There are some indications that the late Holocene Permafrost has begun to thaw at some undisturbed locations in northeastern Europe and northwest Siberia. Thawing of Permafrost is most noticeable within the discontinuous Permafrost domain. However, Permafrost in Russia is also starting to thaw at some limited locations in the continuous Permafrost zone. As a result, a northward displacement of the boundary between continuous and discontinuous Permafrost zones was observed. This data set will serve as a baseline against which to measure changes of near-surface Permafrost temperatures and Permafrost boundaries, to validate climate model scenarios, and for temperature reanalysis. Copyright # 2010 John Wiley & Sons, Ltd.
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Permafrost thermal state in the polar northern hemisphere during the international polar year 2007 2009 a synthesis
Permafrost and Periglacial Processes, 2010Co-Authors: V E Romanovsky, S L Smith, Hanne H. ChristiansenAbstract:The Permafrost monitoring network in the polar regions of the Northern Hemisphere was enhanced during the International Polar Year (IPY), and new information on Permafrost thermal state was collected for regions where there was little available. This augmented monitoring network is an important legacy of the IPY, as is the updated baseline of current Permafrost conditions against which future changes may be measured. Within the Northern Hemisphere polar region, ground temperatures are currently being measured in about 575 boreholes in North America, the Nordic region and Russia. These show that in the discontinuous Permafrost zone, Permafrost temperatures fall within a narrow range, with the mean annual ground temperature (MAGT) at most sites being higher than −2°C. A greater range in MAGT is present within the continuous Permafrost zone, from above −1°C at some locations to as low as −15°C. The latest results indicate that the Permafrost warming which started two to three decades ago has generally continued into the IPY period. Warming rates are much smaller for Permafrost already at temperatures close to 0°C compared with colder Permafrost, especially for ice-rich Permafrost where latent heat effects dominate the ground thermal regime. Colder Permafrost sites are warming more rapidly. This improved knowledge about the Permafrost thermal state and its dynamics is important for multidisciplinary polar research, but also for many of the 4 million people living in the Arctic. In particular, this knowledge is required for designing effective adaptation strategies for the local communities under warmer climatic conditions. Copyright © 2010 John Wiley & Sons, Ltd.
G S Tipenko - One of the best experts on this subject based on the ideXlab platform.
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offshore Permafrost and gas hydrate stability zone on the shelf of east siberian seas
Geo-marine Letters, 2005Co-Authors: N N Romanovskii, Hanswolfgang Hubberten, A V Gavrilov, A A Eliseeva, G S TipenkoAbstract:Dynamics of the submarine Permafrost regime, including distribution, thickness, and temporal evolution, was modeled for the Laptev and East Siberian Sea shelf zones. This work included simulation of the Permafrost-related gas hydrate stability zone (GHSZ). Simulations were compared with field observations. Model sensitivity runs were performed using different boundary conditions, including a variety of geological conditions as well as two distinct geothermal heat flows (45 and 70 mW/m2). The heat flows used are typical for the coastal lowlands of the Laptev Sea and East Siberian Sea. Use of two different geological deposits, that is, unconsolidated Cainozoic strata and solid bedrock, resulted in the significantly different magnitudes of Permafrost thickness, a result of their different physical and thermal properties. Both parameters, the thickness of the submarine Permafrost on the shelf and the related development of the GHSZ, were simulated for the last four glacial-eustatic cycles (400,000 years). The results show that the most recently formed Permafrost is continuous to the 60-m isobath; at the greater depths of the outer part of the shelf it changes to discontinuous and “patchy” Permafrost. However, model results suggest that the entire Arctic shelf is underlain by relic Permafrost in a state stable enough for gas hydrates. Permafrost, as well as the GHSZ, is currently storing probable significant greenhouse gas sources, especially methane that has formed by the decomposition of gas hydrates at greater depth. During climate cooling and associated marine regression, Permafrost aggradation takes place due to the low temperatures and the direct exposure of the shelf to the atmosphere. Permafrost degradation takes place during climate warming and marine transgression. However, the temperature of transgressing seawater in contact with the former terrestrial Permafrost landscape remains below zero, ranging from −0.5 to −1.8°C, meaning Permafrost degradation does not immediately occur. The submerged Permafrost degrades slowly, undergoing a transformation in form from ice bonded terrestrial Permafrost to ice bearing submarine Permafrost that does not possess a temperature gradient. Finally the thickness of ice bearing Permafrost decreases from its lower boundary due to the geothermal heat flow. The modeling indicated several other features. There exists a time lag between extreme states in climatic forcing and associated extreme states of Permafrost thickness. For example, Permafrost continued to degrade for up to 10,000 years following a temperature decline had begun after a climate optimum. Another result showed that the dynamic of Permafrost thickness and the variation of the GHSZ are similar but not identical. For example, it can be shown that in recent time Permafrost degradation has taken place at the outer part of the shelf whereas the GHSZ is stable or even thickening.
Yu Sheng - One of the best experts on this subject based on the ideXlab platform.
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Thermal effect of thermokarst lake on the Permafrost under embankment
Advances in Climate Change Research, 2021Co-Authors: Erxing Peng, Yu Sheng, Hu Xiaoying, Wei CaoAbstract:Abstract In Permafrost regions of the Qinghai-Tibet Plateau, road disaster caused by Permafrost degradation cannot be ignored. As a common thermal disaster in Permafrost regions, thermokarst lake has serious thermal erosion on Permafrost and results in Permafrost degradation aggravating. This study focused on two subgrade cross-sections of Gonghe-Yushu Highway in the Qinghai-Tibet Plateau to analyze thermal effect of thermokarst lake on the Permafrost under embankment. The analysis infers that thermokarst lake can transfer heat to Permafrost under the embankment, as a heat resource, and the heat flux decreases with the distance away from thermokarst lake in horizontal and vertical direction. Thermokarst lake can cause average ground temperature of Permafrost under the embankment increasing, and with less distance from the thermokarst lake the temperature increases more severely. Thermokarst lake results in 14 m thickness melting interlayer in soil under lake and change shape of melting area.
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Spatiotemporal changes of Permafrost in the Headwater Area of the Yellow River under a changing climate
Land Degradation & Development, 2019Co-Authors: Yu Sheng, Wei CaoAbstract:This article attempts to predict the spatiotemporal changes of Permafrost in the Headwater Area of the Yellow River (HAYR) on the northeastern Qinghai‐Tibet Plateau, Southwest China by using field monitoring and numerical models. Permafrost in the HAYR is categorized into four types: low‐ and high‐ice‐content high‐plain Permafrost and low‐ and high‐ice‐content alpine Permafrost. According to these Permafrost types, changes in Permafrost temperature were calculated by coupling a geometric model with the soil thermal conduction model. Based on the calculation results, this paper evaluates the changes of Permafrost in the HAYR over the past 50 years and predicts the change trends of Permafrost in the HAYR under the scenarios of RCP2.6, RCP6.0, and RCP8.5 for possible climate change in 2050 and 2010 from the Intergovernmental Panel on Climate Change Fifth Assessment Report. The results show that (a) in the process of Permafrost degradation, the same Permafrost type at different degradation stages results in different modes and rates of increasing temperature. The response of Permafrost to climate change differs in various degradation stages of Permafrost; (b) from 1972 to 2012, the areal extent of Permafrost degradation was 1,056 km², resulting from a sharp air temperature increase after the 1980s. By 2050, the areal extent of Permafrost degradation into seasonal frost is similar under the three scenarios of climate change. The areal extent of Permafrost degradation is 2,224, 2,347, and 2,559 km² or 7.5%, 7.9%, and 8.6% of the total area in the HAYR, respectively. In RCP2.6, the areal extent of Permafrost degradation into seasonal frost by 2100 would be approximately 3,500 km² greater than that by 2050. In RCP6.0, the areal extent of Permafrost degradation by 2100 would be 10,000 km² or 32.9% of the total area in the HAYR. In RCP8.5, the area of Permafrost degradation by 2100 would be 18,492 km² or 62.2% of the total area in the HAYR; (c) the active layer thickness (ALT) in the HAYR would increase significantly. The average of the ALT was 1.51 m by 1972 and 2.01 m by 2012, respectively. Under the RCP2.6, RCP6.0, and RCP8.5 scenarios, the basin‐wide average of ALT would be 2.21, 2.40, and 3.08 m by 2050 and 2.78, 4.07, and 4.39 m by 2100, respectively.
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a new map of Permafrost distribution on the tibetan plateau
The Cryosphere, 2016Co-Authors: Defu Zou, Yu Sheng, Changwei Xie, Lin Zhao, Ji Chen, Qiangqiang Pang, Wu Wang, Guangyue Liu, Yanhui Qin, Yongping QiaoAbstract:Abstract. The Tibetan Plateau (TP) has the largest areas of Permafrost terrain in the mid- and low-latitude regions of the world. Some Permafrost distribution maps have been compiled but, due to limited data sources, ambiguous criteria, inadequate validation, and deficiency of high-quality spatial data sets, there is high uncertainty in the mapping of the Permafrost distribution on the TP. We generated a new Permafrost map based on freezing and thawing indices from modified Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperatures (LSTs) and validated this map using various ground-based data sets. The soil thermal properties of five soil types across the TP were estimated according to an empirical equation and soil properties (moisture content and bulk density). The temperature at the top of Permafrost (TTOP) model was applied to simulate the Permafrost distribution. Permafrost, seasonally frozen ground, and unfrozen ground covered areas of 1.06 × 106 km2 (0.97–1.15 × 106 km2, 90 % confidence interval) (40 %), 1.46 × 106 (56 %), and 0.03 × 106 km2 (1 %), respectively, excluding glaciers and lakes. Ground-based observations of the Permafrost distribution across the five investigated regions (IRs, located in the transition zones of the Permafrost and seasonally frozen ground) and three highway transects (across the entire Permafrost regions from north to south) were used to validate the model. Validation results showed that the kappa coefficient varied from 0.38 to 0.78 with a mean of 0.57 for the five IRs and 0.62 to 0.74 with a mean of 0.68 within the three transects. Compared with earlier studies, the TTOP modelling results show greater accuracy. The results provide more detailed information on the Permafrost distribution and basic data for use in future research on the Tibetan Plateau Permafrost.
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simulation analysis of the impact of excavation backfill on Permafrost recovery in an opencast coal mining pit
Environmental Earth Sciences, 2016Co-Authors: Wei Cao, Yu Sheng, Yaling ChouAbstract:The article attempts to investigate the status of Permafrost recovery after excavation backfill in an opencast coal mine. To do that, we forecast the Permafrost recovery under certain initial temperatures and different boundary conditions by using the numerical simulation method. The results show that the filling temperature significantly influences Permafrost recovery after backfilling. When the filling temperature decreases from +2.0 to −2.0 °C, the Permafrost recovery rate will greatly accelerate, and the Permafrost thickness will significantly increase. When the surface temperature of the filling is positive, the Permafrost recovery at the bottom of the excavation will be more difficult than when the temperature is negative. The Permafrost recovery rate will be slow, and the Permafrost thickness will be thin. The Permafrost recovery also gradually speeds up the thickening with decreasing natural surface temperature. Thus, backfilling should be conducted in the cold season, and cooling treatment should be applied to the filling before backfilling. The treatment will ensure that the Permafrost recovery is faster and more stable. This measure is also conducive to the recovery of the ecological environment of the mine.
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Effect of Permafrost degradation on hydrological processes in typical basins with various Permafrost coverage in Western China
Science China Earth Sciences, 2010Co-Authors: Li Niu, Yu ShengAbstract:Monthly discharge of four rivers with various Permafrost coverage and little anthropogenic influence was used to identify effects of Permafrost degradation during the last 50 years, which has occurred because of significant increases in air temperature in the river regions. The basins of the Shule, Heihe, Shiyang and upper Yellow Rivers in northwestern China have 73%, 58%, 33% and 43% Permafrost coverage, respectively. There is snow cover in the basins and no rain to supply rivers during winter. The monthly recession coefficient (RC) in winter reflects groundwater conditions. The RC has increased obviously for the Shule and Heihe rivers with 73% and 58% Permafrost coverage, respectively, but did not increase for the Shiyang River, and decreased insignificantly for the upper Yellow River, which had less Permafrost coverage. There is a distinct positive relationship between RC and annual negative degree-day temperature (NDDT) at the meteorological stations in the basins with high Permafrost coverage. These results imply that Permafrost degradation due to climate warming affects hydrological processes in winter. The effect is obvious in the basins with high Permafrost coverage but negligible in those with low Permafrost coverage. Permafrost degradation increases infiltration, enlarges the groundwater reservoir, and leads to slow discharge recession. The result means that hydrological processes are affected strongly by Permafrost degradation in river basins with high Permafrost coverage, but less in river basins with less Permafrost coverage.
