The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially...The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially attempts to assess the ground ice volume in permafrost layers on the Qinghai-Tibet Plateau by considering landform types, the corresponding lithological composition, and the measured water content in various regions. An approximation demonstrating the existence of many similarities in lithological composition and water content within a unified landform was established during the calculations. Considerable knowledge of the case study area, here called the Source Area of the Yellow(Huanghe) River(SAYR) in the northeastern Qinghai-Tibet Plateau, has been accumulated related to permafrost and fresh water resources during the past 40 years. Considering the permafrost distribution, extent, spatial distribution of landform types, the ground ice volume at the depths of 3.0–10.0 m below the ground surface was estimated based on the data of 101 boreholes from field observations and geological surveys in different types of landforms in the permafrost region of the SAYR. The total ground ice volume in permafrost layers at the depths of 3.0–10.0 m was approximately(51.68 ± 18.81) km^3, and the ground ice volume per unit volume was(0.31 ± 0.11) m^3/m^3. In the horizontal direction, the ground ice content was higher in the landforms of lacustrine-marshland plains and alluvial-lacustrine plains, and the lower ground ice content was distributed in the erosional platforms and alluvial-proluvial plains. In the vertical direction, the volume of ground ice was relatively high in the top layers(especially near the permafrost table) and at the depths of 7.0–8.0 m. This calculation method will be used in the other areas when the necessary information is available, including landform type, borehole data, and measured water content.展开更多
Large amounts of ground ice are born with permafrost on the Qinghai-Tibet Plateau.Degradation of permafrost resulted from the climate warming will inevitably lead to melting of ground ice.The water released from the m...Large amounts of ground ice are born with permafrost on the Qinghai-Tibet Plateau.Degradation of permafrost resulted from the climate warming will inevitably lead to melting of ground ice.The water released from the melting ground ice enters hydrologic cycles at various levels,and changes regional hydrologic regimes to various degrees.Due to difficulties in monitoring the perma-frost-degradation-release-water process,direct and reliable evidence is few.The accumulative effect of releasing water,however,is remarkable in the macro-scale hydrologic process.On the basis of the monitoring results of water-levels changes in some lakes on the Qinghai-Tibet Plateau,and combined with the previous results of the hydrologic changing trends at the regional scale,the authors preliminarily discussed the possibilities of the degrading permafrost on the Qinghai-Tibet Plateau as a potential water source during climate warming.展开更多
In this paper, stable isotope （δ18O, δD） investigations were completed in ground ice from a deep borehole in the Beiluhe Basin on northern Qinghai-Tibet Plateau to unravel the isotopic variations of ground ice and...In this paper, stable isotope （δ18O, δD） investigations were completed in ground ice from a deep borehole in the Beiluhe Basin on northern Qinghai-Tibet Plateau to unravel the isotopic variations of ground ice and their possible source water. The δ18O and δD of ground ice show distinctive characteristics compared with precipitation and surface water. The near-surface ground ice is highly enriched in heavier isotopes （δ18O and δD）, which were gradually depleted from top to bottom along the profile. It is suggestive of different origin and ice formation process. According to isotopic variations, the ice profile was divided into three sections： the near-surface ground ice at 2.5 m is frozen by the active-layer water which suffered evaporation. It is possible that ground ice between 3 and 4.2 m is recharged by the infiltration of snowmelt. From 5 to 6 m, the ground ice show complex origin and formation processes. Isotopic variations from 6 to 11.1 m and 20.55 m indicate different replenishment water. The calculated slope of freezing line （S=6.4） is larger than the experimental value （5.76）, and is suggestive of complex origin and formation process of ground ice.展开更多
The paper presents the results of a ground penetrating radar （GPR） application for the detection of ground ice. We com- bined a reflection traveltime curves analysis with a frequency spectrogram analysis. We found s...The paper presents the results of a ground penetrating radar （GPR） application for the detection of ground ice. We com- bined a reflection traveltime curves analysis with a frequency spectrogram analysis. We found special anomalies at specific traces in the traveltime curves and ground boundaries analysis, and obtained a ground model for subsurface structure which allows the ground ice layer to be identified and delineated.展开更多
Retrogressive thaw slumps(RTSs),which frequently occur in permafrost regions of the Qinghai-Tibet Plateau(QTP),China,can cause signifcant damage to the local surface,resulting in material losses and posing a threat to...Retrogressive thaw slumps(RTSs),which frequently occur in permafrost regions of the Qinghai-Tibet Plateau(QTP),China,can cause signifcant damage to the local surface,resulting in material losses and posing a threat to infrastructure and ecosystems in the region.However,quantitative assessment of ground ice ablation and hydrological ecosystem response was limited due to a lack of understanding of the complex hydro-thermal process during RTS development.In this study,we developed a three-dimensional hydro-thermal coupled numerical model of a RTS in the permafrost terrain at the Beilu River Basin of the QTP,including ice–water phase transitions,heat exchange,mass transport,and the parameterized exchange of heat between the active layer and air.Based on the calibrated hydro-thermal model and combined with the electrical resistivity tomography survey and sample analysis results,a method for estimating the melting of ground ice was proposed.Simulation results indicate that the model efectively refects the factual hydro-thermal regime of the RTS and can evaluate the ground ice ablation and total suspended sediment variation,represented by turbidity.Between 2011 and 2021,the maximum simulated ground ice ablation was in 2016 within the slump region,amounting to a total of 492 m^(3),and it induced the reciprocal evolution,especially in the headwall of the RTS.High ponding depression water turbidity values of 28 and 49 occurred in the thawing season in 2021.The simulated ground ice ablation and turbidity events were highly correlated with climatic warming and wetting.The results ofer a valuable approach to assessing the efects of RTS on infrastructure and the environment,especially in the context of a changing climate.展开更多
A thermokarst lake is defined as a lake occupying a closed depression formed by ground settlement following thawing of ice-rich permafrost or the melting of massive ice. As it is the most visible morphologic landscape...A thermokarst lake is defined as a lake occupying a closed depression formed by ground settlement following thawing of ice-rich permafrost or the melting of massive ice. As it is the most visible morphologic landscape developed during the process of permafrost degradation, we reviewed recent literature on thermokarst studies, and summarized the main study topics as： development and temporal evolution, carbon release, and ecological and engineering influence of thermokarst lakes. The climate warming, forest fires, surface water pooling, geotectonic fault and anthropogenic activity are the main influencing factors that cause an increase of ground temperatures and melting of ice-rich permafrost, resulting in thermokarst lake formation. Normally a thermokarst lake develops in 3–5 stages from initiation to permafrost recovery. Geo-rectified aerial photographs and remote sensing images show that thermokarst lakes have been mainly experiencing the process of shrinkage or disappearance in most regions of the Arctic, while both lake numbers and areas on the Qinghai-Tibet Plateau have increased. Field studies and modeling indicates that carbon release from thermokarst lakes can feedback significantly to global warming, thus enhancing our understanding of the influences of thermokarst lakes on the ecological environment, and on regional groundwater through drainage. Based on field monitoring and numerical simulations, infrastructure stability can be affected by thermal erosion of nearby thermokarst lakes. This review was undertaken to enhance our understanding of thermokarst lakes, and providing references for future comprehensive studies on thermokarst lakes.展开更多
基金Under the auspices of the Chinese Academy of Sciences(CAS)Key Research Program(No.KZZD-EW-13)National Natural Science Foundation of China(No.91647103)
文摘The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially attempts to assess the ground ice volume in permafrost layers on the Qinghai-Tibet Plateau by considering landform types, the corresponding lithological composition, and the measured water content in various regions. An approximation demonstrating the existence of many similarities in lithological composition and water content within a unified landform was established during the calculations. Considerable knowledge of the case study area, here called the Source Area of the Yellow(Huanghe) River(SAYR) in the northeastern Qinghai-Tibet Plateau, has been accumulated related to permafrost and fresh water resources during the past 40 years. Considering the permafrost distribution, extent, spatial distribution of landform types, the ground ice volume at the depths of 3.0–10.0 m below the ground surface was estimated based on the data of 101 boreholes from field observations and geological surveys in different types of landforms in the permafrost region of the SAYR. The total ground ice volume in permafrost layers at the depths of 3.0–10.0 m was approximately(51.68 ± 18.81) km^3, and the ground ice volume per unit volume was(0.31 ± 0.11) m^3/m^3. In the horizontal direction, the ground ice content was higher in the landforms of lacustrine-marshland plains and alluvial-lacustrine plains, and the lower ground ice content was distributed in the erosional platforms and alluvial-proluvial plains. In the vertical direction, the volume of ground ice was relatively high in the top layers(especially near the permafrost table) and at the depths of 7.0–8.0 m. This calculation method will be used in the other areas when the necessary information is available, including landform type, borehole data, and measured water content.
基金supported by The Outstanding Youth Foundation ProjectNational Natural Science Foundation of China (Grant No.40625004)+1 种基金the grant of the Western Project Program of the Chinese Academy of Sciences (No.KZCX2-XB2-10)the research project of the State Key Laboratory of Frozen Soil Engineering (SKLFSE-ZQ-06)
文摘Large amounts of ground ice are born with permafrost on the Qinghai-Tibet Plateau.Degradation of permafrost resulted from the climate warming will inevitably lead to melting of ground ice.The water released from the melting ground ice enters hydrologic cycles at various levels,and changes regional hydrologic regimes to various degrees.Due to difficulties in monitoring the perma-frost-degradation-release-water process,direct and reliable evidence is few.The accumulative effect of releasing water,however,is remarkable in the macro-scale hydrologic process.On the basis of the monitoring results of water-levels changes in some lakes on the Qinghai-Tibet Plateau,and combined with the previous results of the hydrologic changing trends at the regional scale,the authors preliminarily discussed the possibilities of the degrading permafrost on the Qinghai-Tibet Plateau as a potential water source during climate warming.
基金supported by the National Natural Science Foundation of China(Grant No.41501071)by the State Key Laboratory of Frozen Soils Engineering(Grant No.SKLFSE201511)+1 种基金by the China Postdoctoral Science Foundation(Grant No.2016M590984)by the Chinese Academy of Sciences Key Research Program(Grant No.KZZD-EW-13)
文摘In this paper, stable isotope （δ18O, δD） investigations were completed in ground ice from a deep borehole in the Beiluhe Basin on northern Qinghai-Tibet Plateau to unravel the isotopic variations of ground ice and their possible source water. The δ18O and δD of ground ice show distinctive characteristics compared with precipitation and surface water. The near-surface ground ice is highly enriched in heavier isotopes （δ18O and δD）, which were gradually depleted from top to bottom along the profile. It is suggestive of different origin and ice formation process. According to isotopic variations, the ice profile was divided into three sections： the near-surface ground ice at 2.5 m is frozen by the active-layer water which suffered evaporation. It is possible that ground ice between 3 and 4.2 m is recharged by the infiltration of snowmelt. From 5 to 6 m, the ground ice show complex origin and formation processes. Isotopic variations from 6 to 11.1 m and 20.55 m indicate different replenishment water. The calculated slope of freezing line （S=6.4） is larger than the experimental value （5.76）, and is suggestive of complex origin and formation process of ground ice.
文摘The paper presents the results of a ground penetrating radar （GPR） application for the detection of ground ice. We com- bined a reflection traveltime curves analysis with a frequency spectrogram analysis. We found special anomalies at specific traces in the traveltime curves and ground boundaries analysis, and obtained a ground model for subsurface structure which allows the ground ice layer to be identified and delineated.
基金supported by the Second Tibetan Plateau Scientifc Expedition and Research Program(STEP)(Grant No.2019QZKK0905)the National Science Foundation of China(Grant Nos.42161160328 and 42071097)+2 种基金the Research and Development Project of China National Railway Group Co.,Ltd.(K2022G017)the Guangdong Provincial Key Laboratory of Modern Civil Engineering Technology(2021B1212040003)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2020421).
文摘Retrogressive thaw slumps(RTSs),which frequently occur in permafrost regions of the Qinghai-Tibet Plateau(QTP),China,can cause signifcant damage to the local surface,resulting in material losses and posing a threat to infrastructure and ecosystems in the region.However,quantitative assessment of ground ice ablation and hydrological ecosystem response was limited due to a lack of understanding of the complex hydro-thermal process during RTS development.In this study,we developed a three-dimensional hydro-thermal coupled numerical model of a RTS in the permafrost terrain at the Beilu River Basin of the QTP,including ice–water phase transitions,heat exchange,mass transport,and the parameterized exchange of heat between the active layer and air.Based on the calibrated hydro-thermal model and combined with the electrical resistivity tomography survey and sample analysis results,a method for estimating the melting of ground ice was proposed.Simulation results indicate that the model efectively refects the factual hydro-thermal regime of the RTS and can evaluate the ground ice ablation and total suspended sediment variation,represented by turbidity.Between 2011 and 2021,the maximum simulated ground ice ablation was in 2016 within the slump region,amounting to a total of 492 m^(3),and it induced the reciprocal evolution,especially in the headwall of the RTS.High ponding depression water turbidity values of 28 and 49 occurred in the thawing season in 2021.The simulated ground ice ablation and turbidity events were highly correlated with climatic warming and wetting.The results ofer a valuable approach to assessing the efects of RTS on infrastructure and the environment,especially in the context of a changing climate.
基金support from the State Key Development Program of Basic Research of China(973 Plan,2012CB026101)the Western Project Program of theChinese Academy of Sciences(KZCX2-XB3-19)+1 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(GrantNo.41121061)the National Sci-Tech Support Plan(2014BAG05B05)
文摘A thermokarst lake is defined as a lake occupying a closed depression formed by ground settlement following thawing of ice-rich permafrost or the melting of massive ice. As it is the most visible morphologic landscape developed during the process of permafrost degradation, we reviewed recent literature on thermokarst studies, and summarized the main study topics as： development and temporal evolution, carbon release, and ecological and engineering influence of thermokarst lakes. The climate warming, forest fires, surface water pooling, geotectonic fault and anthropogenic activity are the main influencing factors that cause an increase of ground temperatures and melting of ice-rich permafrost, resulting in thermokarst lake formation. Normally a thermokarst lake develops in 3–5 stages from initiation to permafrost recovery. Geo-rectified aerial photographs and remote sensing images show that thermokarst lakes have been mainly experiencing the process of shrinkage or disappearance in most regions of the Arctic, while both lake numbers and areas on the Qinghai-Tibet Plateau have increased. Field studies and modeling indicates that carbon release from thermokarst lakes can feedback significantly to global warming, thus enhancing our understanding of the influences of thermokarst lakes on the ecological environment, and on regional groundwater through drainage. Based on field monitoring and numerical simulations, infrastructure stability can be affected by thermal erosion of nearby thermokarst lakes. This review was undertaken to enhance our understanding of thermokarst lakes, and providing references for future comprehensive studies on thermokarst lakes.
