Shengtao Lan, Bin Cao, Yan Hu, Ziyong Sun, Rui Ma, Xin Li
Talus, as the product of movement and accumulation along the slope after the cracking of cliffs or steep rock walls, is a common landform in the mountain periglacial environment. Significant thermal anomalies within talus have been widely reported to be a result of cooling effects. During the cold season, the increased temperature difference between talus and the ambient environment strengthens the intensity of convection (vertical flows) and transforms into upward advection (lateral flows) and exhausts the internal warm current. During the warm season, heat is concentrated on the surface of the talus, and the internal dominant cold current moves downward along the slope by advection. The principle of the proactive cooling effects of talus has been widely utilized in railway construction within permafrost regions as embankments to alleviate degradation of the underlying permafrost. However, limited model studies have examined the cooling effects of blocky debris in nature, and in situ observations are rare. Therefore, it will be important to increase observations and develop process‐based models that couple heat conduction, convection/advection, water transfer processes, and even the latent heat of phase change. This will help to better understand the extent of the cooling effects and its impact on the thermal regime of permafrost.
{"title":"Talus and its cooling effects on the thermal regime of permafrost: A review","authors":"Shengtao Lan, Bin Cao, Yan Hu, Ziyong Sun, Rui Ma, Xin Li","doi":"10.1002/ppp.2213","DOIUrl":"https://doi.org/10.1002/ppp.2213","url":null,"abstract":"Talus, as the product of movement and accumulation along the slope after the cracking of cliffs or steep rock walls, is a common landform in the mountain periglacial environment. Significant thermal anomalies within talus have been widely reported to be a result of cooling effects. During the cold season, the increased temperature difference between talus and the ambient environment strengthens the intensity of convection (vertical flows) and transforms into upward advection (lateral flows) and exhausts the internal warm current. During the warm season, heat is concentrated on the surface of the talus, and the internal dominant cold current moves downward along the slope by advection. The principle of the proactive cooling effects of talus has been widely utilized in railway construction within permafrost regions as embankments to alleviate degradation of the underlying permafrost. However, limited model studies have examined the cooling effects of blocky debris in nature, and in situ observations are rare. Therefore, it will be important to increase observations and develop process‐based models that couple heat conduction, convection/advection, water transfer processes, and even the latent heat of phase change. This will help to better understand the extent of the cooling effects and its impact on the thermal regime of permafrost.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"126 6","pages":""},"PeriodicalIF":5.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139004432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Magnin, L. Ravanel, Xavier Bodin, P. Deline, Emmanuel Malet, Jean-Michel Krysiecki, P. Schoeneich
This study presents data from the first years of permafrost monitoring in boreholes in the French Alps that started at the end of 2009 in the framework of the PermaFrance network. Nine boreholes are instrumented, among which six monitored permafrost temperature and active layer thickness (ALT) over >10 years. Ice‐poor and cold permafrost in high‐elevation north‐facing rock walls has warmed by up to >1°C at 10 m depth over the reference decade (2011–2020), whereas ice‐rich permafrost (rock glacier) temperatures remained stable. ALT has increased at four of the five boreholes for which decadal data are available. Summer 2015 marks a turning point in ALT regime and greatest ALT values were observed in 2022 (available for six boreholes), but thawing intensity did not show an obvious change. At one site with a layer of coarse blocks about 2 m thick, ALT was stable over 2018–2022 and response to the hottest years was dampened. Linear trends suggest an ALT increase of 2 m per decade for some ice‐poor rock walls, independently of their thermal state. The data reveal a variety of permafrost patterns and evolution with significant intraregional and local differences. Snow modulates the response to air temperature signal in various ways, with an important effect on near‐surface temperature trends and ALT: early snow melting in spring favors an ALT increase in rock walls. Maintaining these monitoring systems and understanding the physical processes controlling heterogeneous responses to climate signals is crucial to better assess permafrost dynamics and to adapt to its consequences.
{"title":"Main results of permafrost monitoring in the French Alps through the PermaFrance network over the period 2010–2022","authors":"F. Magnin, L. Ravanel, Xavier Bodin, P. Deline, Emmanuel Malet, Jean-Michel Krysiecki, P. Schoeneich","doi":"10.1002/ppp.2209","DOIUrl":"https://doi.org/10.1002/ppp.2209","url":null,"abstract":"This study presents data from the first years of permafrost monitoring in boreholes in the French Alps that started at the end of 2009 in the framework of the PermaFrance network. Nine boreholes are instrumented, among which six monitored permafrost temperature and active layer thickness (ALT) over >10 years. Ice‐poor and cold permafrost in high‐elevation north‐facing rock walls has warmed by up to >1°C at 10 m depth over the reference decade (2011–2020), whereas ice‐rich permafrost (rock glacier) temperatures remained stable. ALT has increased at four of the five boreholes for which decadal data are available. Summer 2015 marks a turning point in ALT regime and greatest ALT values were observed in 2022 (available for six boreholes), but thawing intensity did not show an obvious change. At one site with a layer of coarse blocks about 2 m thick, ALT was stable over 2018–2022 and response to the hottest years was dampened. Linear trends suggest an ALT increase of 2 m per decade for some ice‐poor rock walls, independently of their thermal state. The data reveal a variety of permafrost patterns and evolution with significant intraregional and local differences. Snow modulates the response to air temperature signal in various ways, with an important effect on near‐surface temperature trends and ALT: early snow melting in spring favors an ALT increase in rock walls. Maintaining these monitoring systems and understanding the physical processes controlling heterogeneous responses to climate signals is crucial to better assess permafrost dynamics and to adapt to its consequences.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"30 4","pages":""},"PeriodicalIF":5.0,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139251742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. V. Lopes, Fábio Soares de Oliveira, João Santiago Reis, Carlos Ernesto G. R. Schaefer
Soil–parent material is a critical controlling factor of soil properties in the Antarctic region due to a limited degree of soil development. However, the degree to which soil–parent material can be considered the major controlling factor in pedogenesis and subsequent soil physical and chemical properties in Antarctica should be better understood to improve soil mapping and interpretations. The present study aims to analyze the soil properties of different lithological groups on the President Head Peninsula on Snow Island, Maritime Antarctica. Thirty soil profiles across the major lithological groupings on Snow Island (beach deposits, andesites, basalts/andesites, conglomerate, sandstones, siltstones, and mudstones) were described, and the morphological, physical, and chemical properties of samples from sampled genetic horizons were characterized. Beach deposits were most clearly differentiated from other lithological groups, whereas most other groups overlapped strongly in observed properties. Whereas some lithological groups (e.g., sedimentary rock groups) were characterized largely by immature soils with little degree of pedogenesis, other sampled soils exhibited more development. The soil–parent material relationships of Snow Island revealed a unique setting of a complex heterogeneous landscape and show that the area has a great pedological complexity induced by phosphatization, melanization, and cryoturbation processes that preclude placing primary importance on parent material and lithology as the major controlling factor in Antarctic soils.
{"title":"Lithological controls on soil properties, Snow Island, Maritime Antarctica","authors":"D. V. Lopes, Fábio Soares de Oliveira, João Santiago Reis, Carlos Ernesto G. R. Schaefer","doi":"10.1002/ppp.2212","DOIUrl":"https://doi.org/10.1002/ppp.2212","url":null,"abstract":"Soil–parent material is a critical controlling factor of soil properties in the Antarctic region due to a limited degree of soil development. However, the degree to which soil–parent material can be considered the major controlling factor in pedogenesis and subsequent soil physical and chemical properties in Antarctica should be better understood to improve soil mapping and interpretations. The present study aims to analyze the soil properties of different lithological groups on the President Head Peninsula on Snow Island, Maritime Antarctica. Thirty soil profiles across the major lithological groupings on Snow Island (beach deposits, andesites, basalts/andesites, conglomerate, sandstones, siltstones, and mudstones) were described, and the morphological, physical, and chemical properties of samples from sampled genetic horizons were characterized. Beach deposits were most clearly differentiated from other lithological groups, whereas most other groups overlapped strongly in observed properties. Whereas some lithological groups (e.g., sedimentary rock groups) were characterized largely by immature soils with little degree of pedogenesis, other sampled soils exhibited more development. The soil–parent material relationships of Snow Island revealed a unique setting of a complex heterogeneous landscape and show that the area has a great pedological complexity induced by phosphatization, melanization, and cryoturbation processes that preclude placing primary importance on parent material and lithology as the major controlling factor in Antarctic soils.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"38 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139255856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanhui You, Xicai Pan, Wei Fu, Yun Wang, Qihao Yu, Lei Guo, Xinbin Wang
Abstract Investigation of resistivity has been effectively used in assessing the risks of embankmentation and failure. A two‐dimensional (2D) approximation of the surveyed object is commonly assumed for a survey line on the road surface. However, this approximation may not be met when resistivity investigations are conducted over a raised high embankment; under these conditions, regular inversions might yield erroneous results. This study explored the topographical effect of a high embankment on resistivity measurements by forward and inverse modeling of a 3D high embankment model. The results show that a 2D approximation of the survey lines on the road surface significantly increases the apparent resistivity within the depth of the raised embankment. Maximum relative errors reached 21% and 11% for the road shoulder and midline survey lines, respectively. The biased apparent resistivity resulted in an inverted resistivity that was higher than the true values, although resistivity contrasts can still identify interfaces between layers. A geometric factor was used to correct the biased apparent resistivity to eliminate the high embankment topographical effect. Inversion results of the corrected apparent resistivity agreed well with the forward model. The method was then verified by field application. The apparent resistivity of the field data collected on a high embankment in permafrost regions on the Qinghai–Tibet Plateau was corrected before inversion. The permafrost table derived from the inverted resistivity was verified based on borehole temperatures. These findings indicate that the topographical influence of high embankments on resistivity measurements needs to be considered. Correction of the apparent resistivity is indispensable for quantitative interpretation of the inverted resistivity.
{"title":"Topographical effect of high embankments on resistivity investigation of the underlying permafrost table","authors":"Yanhui You, Xicai Pan, Wei Fu, Yun Wang, Qihao Yu, Lei Guo, Xinbin Wang","doi":"10.1002/ppp.2210","DOIUrl":"https://doi.org/10.1002/ppp.2210","url":null,"abstract":"Abstract Investigation of resistivity has been effectively used in assessing the risks of embankmentation and failure. A two‐dimensional (2D) approximation of the surveyed object is commonly assumed for a survey line on the road surface. However, this approximation may not be met when resistivity investigations are conducted over a raised high embankment; under these conditions, regular inversions might yield erroneous results. This study explored the topographical effect of a high embankment on resistivity measurements by forward and inverse modeling of a 3D high embankment model. The results show that a 2D approximation of the survey lines on the road surface significantly increases the apparent resistivity within the depth of the raised embankment. Maximum relative errors reached 21% and 11% for the road shoulder and midline survey lines, respectively. The biased apparent resistivity resulted in an inverted resistivity that was higher than the true values, although resistivity contrasts can still identify interfaces between layers. A geometric factor was used to correct the biased apparent resistivity to eliminate the high embankment topographical effect. Inversion results of the corrected apparent resistivity agreed well with the forward model. The method was then verified by field application. The apparent resistivity of the field data collected on a high embankment in permafrost regions on the Qinghai–Tibet Plateau was corrected before inversion. The permafrost table derived from the inverted resistivity was verified based on borehole temperatures. These findings indicate that the topographical influence of high embankments on resistivity measurements needs to be considered. Correction of the apparent resistivity is indispensable for quantitative interpretation of the inverted resistivity.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135218380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Teddi Herring, Antoni G. Lewkowicz, Christian Hauck, Christin Hilbich, Coline Mollaret, Greg A. Oldenborger, Sebastian Uhlemann, Mohammad Farzamian, Fabrice Calmels, Riccardo Scandroglio
Abstract Electrical resistivity tomography (ERT) is a minimally invasive geophysical method that produces a model of subsurface resistivity from a large number of electrical resistance measurements. Strong resistivity contrasts usually exist between frozen and unfrozen earth materials, making ERT an effective and increasingly utilized tool in permafrost research. In this paper, we review more than 300 scientific publications dating from 2000 to 2022 to identify the capabilities and limitations of ERT for permafrost applications. The annual publication rate has increased by a factor of 10 over this period, but several unique challenges remain, and best practices for acquiring, processing, and interpreting ERT data in permafrost environments have not been clearly established. In this paper, we make recommendations for ERT surveys of permafrost and highlight recent advances in the field, with the objective of maximizing the utility of existing and future surveys.
{"title":"Best practices for using electrical resistivity tomography to investigate permafrost","authors":"Teddi Herring, Antoni G. Lewkowicz, Christian Hauck, Christin Hilbich, Coline Mollaret, Greg A. Oldenborger, Sebastian Uhlemann, Mohammad Farzamian, Fabrice Calmels, Riccardo Scandroglio","doi":"10.1002/ppp.2207","DOIUrl":"https://doi.org/10.1002/ppp.2207","url":null,"abstract":"Abstract Electrical resistivity tomography (ERT) is a minimally invasive geophysical method that produces a model of subsurface resistivity from a large number of electrical resistance measurements. Strong resistivity contrasts usually exist between frozen and unfrozen earth materials, making ERT an effective and increasingly utilized tool in permafrost research. In this paper, we review more than 300 scientific publications dating from 2000 to 2022 to identify the capabilities and limitations of ERT for permafrost applications. The annual publication rate has increased by a factor of 10 over this period, but several unique challenges remain, and best practices for acquiring, processing, and interpreting ERT data in permafrost environments have not been clearly established. In this paper, we make recommendations for ERT surveys of permafrost and highlight recent advances in the field, with the objective of maximizing the utility of existing and future surveys.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135763048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simon Zwieback, Mark McClernan, Mikhail Kanevskiy, Mark T. Jorgenson, Donald A. Walker, Qianyu Chang, Helena Bergstedt, Horacio Toniolo, Vladimir E. Romanovsky, Franz J. Meyer
Abstract The 2015 spring flood of the Sagavanirktok River inundated large swaths of tundra as well as infrastructure near Prudhoe Bay, Alaska. Its lasting impact on permafrost, vegetation, and hydrology is unknown but compels attention in light of changing Arctic flood regimes. We combined InSAR and optical satellite observations to quantify subdecadal permafrost terrain changes and identify their controls. While the flood locally induced quasi‐instantaneous ice‐wedge melt, much larger areas were characterized by subtle, spatially variable post‐flood changes. Surface deformation from 2015 to 2019 estimated from ALOS‐2 and Sentinel‐1 InSAR varied substantially within and across terrain units, with greater subsidence on average in flooded locations. Subsidence exceeding 5 cm was locally observed in inundated ice‐rich units and also in inactive floodplains. Overall, subsidence increased with deposit age and thus ground ice content, but many flooded ice‐rich units remained stable, indicating variable drivers of deformation. On average, subsiding ice‐rich locations showed increases in observed greenness and wetness. Conversely, many ice‐poor floodplains greened without deforming. Ice wedge degradation in flooded locations with elevated subsidence was mostly of limited intensity, and the observed subsidence largely stopped within 2 years. Based on remote sensing and limited field observations, we propose that the disparate subdecadal changes were influenced by spatially variable drivers (e.g., sediment deposition, organic layer), controls (ground ice and its degree of protection), and feedback processes. Remote sensing helps quantify the heterogeneous interactions between permafrost, vegetation, and hydrology across permafrost‐affected fluvial landscapes. Interdisciplinary monitoring is needed to improve predictions of landscape dynamics and to constrain sediment, nutrient, and carbon budgets.
{"title":"Disparate permafrost terrain changes after a large flood observed from space","authors":"Simon Zwieback, Mark McClernan, Mikhail Kanevskiy, Mark T. Jorgenson, Donald A. Walker, Qianyu Chang, Helena Bergstedt, Horacio Toniolo, Vladimir E. Romanovsky, Franz J. Meyer","doi":"10.1002/ppp.2208","DOIUrl":"https://doi.org/10.1002/ppp.2208","url":null,"abstract":"Abstract The 2015 spring flood of the Sagavanirktok River inundated large swaths of tundra as well as infrastructure near Prudhoe Bay, Alaska. Its lasting impact on permafrost, vegetation, and hydrology is unknown but compels attention in light of changing Arctic flood regimes. We combined InSAR and optical satellite observations to quantify subdecadal permafrost terrain changes and identify their controls. While the flood locally induced quasi‐instantaneous ice‐wedge melt, much larger areas were characterized by subtle, spatially variable post‐flood changes. Surface deformation from 2015 to 2019 estimated from ALOS‐2 and Sentinel‐1 InSAR varied substantially within and across terrain units, with greater subsidence on average in flooded locations. Subsidence exceeding 5 cm was locally observed in inundated ice‐rich units and also in inactive floodplains. Overall, subsidence increased with deposit age and thus ground ice content, but many flooded ice‐rich units remained stable, indicating variable drivers of deformation. On average, subsiding ice‐rich locations showed increases in observed greenness and wetness. Conversely, many ice‐poor floodplains greened without deforming. Ice wedge degradation in flooded locations with elevated subsidence was mostly of limited intensity, and the observed subsidence largely stopped within 2 years. Based on remote sensing and limited field observations, we propose that the disparate subdecadal changes were influenced by spatially variable drivers (e.g., sediment deposition, organic layer), controls (ground ice and its degree of protection), and feedback processes. Remote sensing helps quantify the heterogeneous interactions between permafrost, vegetation, and hydrology across permafrost‐affected fluvial landscapes. Interdisciplinary monitoring is needed to improve predictions of landscape dynamics and to constrain sediment, nutrient, and carbon budgets.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135579980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sizhong Yang, Xi Wen, Tonghua Wu, Xiaodong Wu, Xiaoming Wang, Xiaoying Jin, Xiaoying Li, Xue Yang, Ling Yang, Hongwei Wang
Abstract Global climate warming is accelerating permafrost degradation. The large amounts of soil organic matter in permafrost‐affected soils are prone to increased microbial decomposition in a warming climate. Along with permafrost degradation, changes to the soil microbiome play a crucial role in enhancing our understanding and in predicting the feedback of permafrost carbon. In this article, we review the current state of knowledge of carbon‐cycling microbial ecology in permafrost regions. Microbiomes in degrading permafrost exhibit variations across spatial and temporal scales. Among the short‐term, rapid degradation scenarios, thermokarst lakes have distinct biogeochemical conditions promoting emission of greenhouse gases. Additionally, extreme climatic events can trigger drastic changes in microbial consortia and activity. Notably, environmental conditions appear to exert a dominant influence on microbial assembly in permafrost ecosystems. Furthermore, as the global climate is closely connected to various permafrost regions, it will be crucial to extend our understanding beyond local scales, for example by conducting comparative and integrative studies between Arctic permafrost and alpine permafrost on the Qinghai–Tibet Plateau at global and continental scales. These comparative studies will enhance our understanding of microbial functioning in degrading permafrost ecosystems and help inform effective strategies for managing and mitigating the impacts of climate change on permafrost regions.
{"title":"Carbon‐cycling microorganisms in permafrost and their responses to a warming climate: A review","authors":"Sizhong Yang, Xi Wen, Tonghua Wu, Xiaodong Wu, Xiaoming Wang, Xiaoying Jin, Xiaoying Li, Xue Yang, Ling Yang, Hongwei Wang","doi":"10.1002/ppp.2206","DOIUrl":"https://doi.org/10.1002/ppp.2206","url":null,"abstract":"Abstract Global climate warming is accelerating permafrost degradation. The large amounts of soil organic matter in permafrost‐affected soils are prone to increased microbial decomposition in a warming climate. Along with permafrost degradation, changes to the soil microbiome play a crucial role in enhancing our understanding and in predicting the feedback of permafrost carbon. In this article, we review the current state of knowledge of carbon‐cycling microbial ecology in permafrost regions. Microbiomes in degrading permafrost exhibit variations across spatial and temporal scales. Among the short‐term, rapid degradation scenarios, thermokarst lakes have distinct biogeochemical conditions promoting emission of greenhouse gases. Additionally, extreme climatic events can trigger drastic changes in microbial consortia and activity. Notably, environmental conditions appear to exert a dominant influence on microbial assembly in permafrost ecosystems. Furthermore, as the global climate is closely connected to various permafrost regions, it will be crucial to extend our understanding beyond local scales, for example by conducting comparative and integrative studies between Arctic permafrost and alpine permafrost on the Qinghai–Tibet Plateau at global and continental scales. These comparative studies will enhance our understanding of microbial functioning in degrading permafrost ecosystems and help inform effective strategies for managing and mitigating the impacts of climate change on permafrost regions.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135924486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Nakai, T. Hiyama, A. Kotani, Y. Iijima, T. Ohta, T. Maximov
A simple stochastic representation of the spatial variability in thaw depth is proposed. Thaw depth distribution measured in the two larch‐type forests in eastern Siberia, Spasskaya Pad and Elgeeii, showed different spatial, seasonal, and interannual variability, respectively. Year‐to‐year variation in active‐layer thickness was minor in Spasskaya Pad compared to Elgeeii. A gamma distribution adequately represented both sites' thaw depth spatial variability as the cumulative probability. Thus, we developed a simple model using the gamma distribution that illustrates the spatial variability in thaw depth at any thawing stage as a function of a given mean thaw depth. A hierarchy of models was introduced that sequentially considered the constant state, linearity, and nonlinearity in the dependence of the rate parameter of the gamma distribution on the mean thaw depth. Although the requirements of the model levels differed between Spasskaya Pad and Elgeeii, the proposed model successfully represented the spatial variability in thaw depth at both sites during different thaw seasons.
{"title":"Stochastic representation of spatial variability in thaw depth in permafrost boreal forests","authors":"T. Nakai, T. Hiyama, A. Kotani, Y. Iijima, T. Ohta, T. Maximov","doi":"10.1002/ppp.2204","DOIUrl":"https://doi.org/10.1002/ppp.2204","url":null,"abstract":"A simple stochastic representation of the spatial variability in thaw depth is proposed. Thaw depth distribution measured in the two larch‐type forests in eastern Siberia, Spasskaya Pad and Elgeeii, showed different spatial, seasonal, and interannual variability, respectively. Year‐to‐year variation in active‐layer thickness was minor in Spasskaya Pad compared to Elgeeii. A gamma distribution adequately represented both sites' thaw depth spatial variability as the cumulative probability. Thus, we developed a simple model using the gamma distribution that illustrates the spatial variability in thaw depth at any thawing stage as a function of a given mean thaw depth. A hierarchy of models was introduced that sequentially considered the constant state, linearity, and nonlinearity in the dependence of the rate parameter of the gamma distribution on the mean thaw depth. Although the requirements of the model levels differed between Spasskaya Pad and Elgeeii, the proposed model successfully represented the spatial variability in thaw depth at both sites during different thaw seasons.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":" ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2023-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45603814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quantification of freeze–thaw hysteresis of unfrozen water content and electrical resistivity from time lapse measurements in the active layer and permafrost","authors":"Soňa Tomaškovičová, T. Ingeman‐Nielsen","doi":"10.1002/ppp.2201","DOIUrl":"https://doi.org/10.1002/ppp.2201","url":null,"abstract":"","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":" ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45219374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface conditions are known to mediate the impacts of climate warming on permafrost. This calls for a better understanding of the environmental conditions that control the thermal regime and the depth of the active layer, especially within heterogeneous tundra landscapes. This study analyzed the spatial relationships between thaw depths, ground surface temperature (GST), and environmental conditions in a High Arctic tundra environment at Bylot Island, Nunavut, Canada. Measurements were distributed within the two dominant landforms, namely earth hummocks and low‐center polygons, and across a topographic gradient. Our results revealed that GST and thaw depth were highly heterogeneous, varying by up to 3.7°C and by more than 20 cm over short distances (<1 m) within periglacial landforms. This microscale variability sometimes surpassed the variability at the hillslope scale, especially in summer. Late‐winter snowpack thickness was found to be the prime control on the spatial variability in winter soil temperatures due to the highly heterogeneous snow cover induced by blowing snow, and this thermal effect carried over into summer. However, microtopography was the predominant driver of the spatial variability in summer GST, followed by altitude and moss thickness. In contrast, the spatial variability in thaw depth was influenced predominantly by variations in moss thickness. Hence, summer microclimate conditions dominated active layer development, but a thicker snowpack favored soil cooling in the following summer, due to the later disappearance of snow cover. These results enhance our understanding of High Arctic tundra environments and highlight the complexity of considering surface feedback effects in future projections of permafrost states within heterogeneous tundra landscapes.
{"title":"Fine‐scale environment control on ground surface temperature and thaw depth in a High Arctic tundra landscape","authors":"H. Khani, C. Kinnard, S. Gascoin, E. Lévesque","doi":"10.1002/ppp.2203","DOIUrl":"https://doi.org/10.1002/ppp.2203","url":null,"abstract":"Surface conditions are known to mediate the impacts of climate warming on permafrost. This calls for a better understanding of the environmental conditions that control the thermal regime and the depth of the active layer, especially within heterogeneous tundra landscapes. This study analyzed the spatial relationships between thaw depths, ground surface temperature (GST), and environmental conditions in a High Arctic tundra environment at Bylot Island, Nunavut, Canada. Measurements were distributed within the two dominant landforms, namely earth hummocks and low‐center polygons, and across a topographic gradient. Our results revealed that GST and thaw depth were highly heterogeneous, varying by up to 3.7°C and by more than 20 cm over short distances (<1 m) within periglacial landforms. This microscale variability sometimes surpassed the variability at the hillslope scale, especially in summer. Late‐winter snowpack thickness was found to be the prime control on the spatial variability in winter soil temperatures due to the highly heterogeneous snow cover induced by blowing snow, and this thermal effect carried over into summer. However, microtopography was the predominant driver of the spatial variability in summer GST, followed by altitude and moss thickness. In contrast, the spatial variability in thaw depth was influenced predominantly by variations in moss thickness. Hence, summer microclimate conditions dominated active layer development, but a thicker snowpack favored soil cooling in the following summer, due to the later disappearance of snow cover. These results enhance our understanding of High Arctic tundra environments and highlight the complexity of considering surface feedback effects in future projections of permafrost states within heterogeneous tundra landscapes.","PeriodicalId":54629,"journal":{"name":"Permafrost and Periglacial Processes","volume":" ","pages":""},"PeriodicalIF":5.0,"publicationDate":"2023-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44908875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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