Glaciers were solid reservoirs and important water resources in western China,but they were retreating significantly in context of global warming.Laohugou Glacier No.12 was the largest valley glacier in Qilian Mountai...Glaciers were solid reservoirs and important water resources in western China,but they were retreating significantly in context of global warming.Laohugou Glacier No.12 was the largest valley glacier in Qilian Mountains.In this study,realtime kinematic(RTK)data,topographic map and World View-2 satellite imagery were used to measure changes in terminus,extent and volume of Laohugou Glacier No.12.Results showed that Laohugou Glacier No.12 was shrinking significantly since 1957.From1960 to 2015,the terminus reduction of Laohugou Glacier No.12 was 402.96 m(3.99%)in total,and glacier length decreased to 9.7 km from 10.1 km.Reduction of glacier area and volume were the most obvious.From 1957 to 2015,glacier area and volume decreased by 1.54 km^2(7.03%)and 0.1816 km^3,respectively.Reduction trend of terminus and area was slowing in 1950-1980s,even stable for a period in the mid-1980s,and then accelerated.Ice core analysis result and nearly meteorological station data shown an increasing trend of temperature in 1957-2015,it was a main reason of continuous retreating of Laohugou Glacier No.12.展开更多
The Laohugou Glacier No. 12 is the largest valley glacier in Qilian Mountains, which is located in northem Qinghai-Tibet Plateau. Movement is the basic characteristic of glaciers, and is also an important distinction ...The Laohugou Glacier No. 12 is the largest valley glacier in Qilian Mountains, which is located in northem Qinghai-Tibet Plateau. Movement is the basic characteristic of glaciers, and is also an important distinction from other terrestrial natural ice. Glacier changes not only reflect climate change, but also play an important role in humanity society. In the arid regions of western China, glaciers are becoming an important water source. We use the GPS receiver （South-Lingrui $82） as data platform with the aid of RTK measurement technology to observe the surface velocity of Laohugou Glacier No. 12. Surface velocity data shows that the maximum value appears at an altitude of 4,750-4,850 m during the period of 2008-2009. During this period, the west branch surface velocity reached 32.6 m per year at an altitude near 4,830 m, the east branch surface velocity reached 32.4 m per year at the altitude near 4,770 m. Comparing the surface velocity data during 2008-2009 with observation results in 1959, the glacier velocity slowed down about 11%.展开更多
With global warming,glaciers in the high mountains of China are retreating rapidly.However,few data have been reported on whether greenhouse gases from these glaciers are released into the atmosphere or absorbed by gl...With global warming,glaciers in the high mountains of China are retreating rapidly.However,few data have been reported on whether greenhouse gases from these glaciers are released into the atmosphere or absorbed by glacial meltwater.In this study,we collected meltwater and ice samples from Laohugou Glacier No.12 in western China and measured CH_(4)and CO_(2)concentrations.Meltwater from the glacier terminus was continually sampled between 3 and 5 August 2020 to measure CH_(4)and CO_(2)concentrations.The results demonstrated that meltwater is a source of CH_(4)because the average saturations are over 100%.It could be con eluded that CH_(4)in the atmosphere can be released by glacial meltwater.However,the CO_(2)saturations are various,and CO_(2)fluxes exhibit positive(released CO_(2))or negative(absorbed CO_(2))values because the water and atmospheric conditions are variable.More importantly,the CH_(4)and CO_(2)concentrations were higher in meltwater samples from the glacier terminus than in samples from the surface ice(including an ice core)and a surface stream.Although the meltwater effect from the upper part of the glacier cannot be excluded,we speculated that subglacial drainage systems with an anaerobic environment may represent the CH_(4)source,but it needs to be further investigated in the future.However,high mountain glaciers are currently ignored in global carbon budgets,and the increased melting of glaciers with global warming may accelerate the absorption of much more CO_(2)and lead to the release of CH_(4).展开更多
In June 2006,a 20.12 m shallow ice core was recovered from an elevation of 5,040 m in the northern branch firn basin of No.12 Glacier,Great Snow Mountain,in the western part of Qilian Mountain,China.Isotopes(δ 18 O),...In June 2006,a 20.12 m shallow ice core was recovered from an elevation of 5,040 m in the northern branch firn basin of No.12 Glacier,Great Snow Mountain,in the western part of Qilian Mountain,China.Isotopes(δ 18 O),major soluble ions,and radionuclide(β-activity) measurements from the ice core revealed a 46-year record(1960-2006).In this paper,the method of sea-salt ion tracer,correlation analysis and trend analysis were used in this research to confirm the source of the chemical composition.The correlation analysis and HYSPLIT backward trajectory analysis suggests that atmospheric soluble dust species dominate the chemical signature.展开更多
Solid precipitation is not only the main supply for glacier mass,but also exerts an important influence on surface albedo and intensifies glacier melting.However,precipitation type observation is very scarce in the hi...Solid precipitation is not only the main supply for glacier mass,but also exerts an important influence on surface albedo and intensifies glacier melting.However,precipitation type observation is very scarce in the high alpine glaciers,which limits the precise simulation of glacier mass balance.This study assessed three discrimination methods of precipitation types including Ding method,Dai method and Froidurot method based on surface albedo observation data on the Laohugou Glacier No.12(LHG Glacier)in western Qilian Mountains.The results showed that Ding method had a best applicability on the LHG Glacier,the other two need to calibrate parameters when they are used in the high elevation glacier region.Then we fitted the relationship between snowfall probability and fresh snow albedo,and put forward a revised formula to simulate fresh snow albedo based on Ding method,which is expected to reduce the uncertainty in glacier mass and energy balance model.Finally,we found a best air temperature threshold of 4℃for discriminating monthly precipitation types.In order to accurately simulate the glacier melt,it is necessary to obtain the threshold temperature appropriately in different glacier region with different elevation and humidity.展开更多
In June 2006, samples were collected from a 90 cm snow-pit at an elevation of 5 040 m a.s.l, in the northern branch firn basin of the Glacier No. 12, Laohugou Valley, in the western part of Qilian Mountain, China. Oxy...In June 2006, samples were collected from a 90 cm snow-pit at an elevation of 5 040 m a.s.l, in the northern branch firn basin of the Glacier No. 12, Laohugou Valley, in the western part of Qilian Mountain, China. Oxygen isotopes （6180） and major soluble ions were measured. Results showed that Ca2＋ is the dominant cation, and SO42 is the dominant anion. All major ions have close positive correlations with eachother except NO3 and NH4＋. 6180 show positive correlation with air temperature. The method of correlation analysis, sea-salt ion tracer and trend analysis were used to determine the source of the chemical components. The correlation analysis and HYSPLIT backward trajectory analysis suggest that atmospheric soluble dust species dominate the chemical signature.展开更多
基金supported by the National Foundational Scientific and Technological Work Programs of the Ministry of Science and Technology of China (grant No. 2013FY111400)the Project from the State Key Laboratory of Cryospheric Sciences (grant No. SKLCS-ZZ-2017)the National Key Geographic Conditions Monitoring: The Project of Basic National Geographical Conditions Monitoring in 2015
文摘Glaciers were solid reservoirs and important water resources in western China,but they were retreating significantly in context of global warming.Laohugou Glacier No.12 was the largest valley glacier in Qilian Mountains.In this study,realtime kinematic(RTK)data,topographic map and World View-2 satellite imagery were used to measure changes in terminus,extent and volume of Laohugou Glacier No.12.Results showed that Laohugou Glacier No.12 was shrinking significantly since 1957.From1960 to 2015,the terminus reduction of Laohugou Glacier No.12 was 402.96 m(3.99%)in total,and glacier length decreased to 9.7 km from 10.1 km.Reduction of glacier area and volume were the most obvious.From 1957 to 2015,glacier area and volume decreased by 1.54 km^2(7.03%)and 0.1816 km^3,respectively.Reduction trend of terminus and area was slowing in 1950-1980s,even stable for a period in the mid-1980s,and then accelerated.Ice core analysis result and nearly meteorological station data shown an increasing trend of temperature in 1957-2015,it was a main reason of continuous retreating of Laohugou Glacier No.12.
基金supported by the Chinese Key Basic Research Development Project (973) (Grant Number: 2007CB411501)the National Basic Work Program of Chinese Ministry of Science and Technology "Investigation of glacier resources and their variations in China" (Grant number: 2006FY110200)the Self-determination Project of State Key Laboratory of Cryospheric Sciences (Grant number: SKLCS09-04)
文摘The Laohugou Glacier No. 12 is the largest valley glacier in Qilian Mountains, which is located in northem Qinghai-Tibet Plateau. Movement is the basic characteristic of glaciers, and is also an important distinction from other terrestrial natural ice. Glacier changes not only reflect climate change, but also play an important role in humanity society. In the arid regions of western China, glaciers are becoming an important water source. We use the GPS receiver （South-Lingrui $82） as data platform with the aid of RTK measurement technology to observe the surface velocity of Laohugou Glacier No. 12. Surface velocity data shows that the maximum value appears at an altitude of 4,750-4,850 m during the period of 2008-2009. During this period, the west branch surface velocity reached 32.6 m per year at an altitude near 4,830 m, the east branch surface velocity reached 32.4 m per year at the altitude near 4,770 m. Comparing the surface velocity data during 2008-2009 with observation results in 1959, the glacier velocity slowed down about 11%.
基金This research has been supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XAD19070103)the National Key Research and Development Program of China(2020YFA0608501)+2 种基金the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2021)the Youth Innovation Promotion Association,CAS(2020419)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0605).
文摘With global warming,glaciers in the high mountains of China are retreating rapidly.However,few data have been reported on whether greenhouse gases from these glaciers are released into the atmosphere or absorbed by glacial meltwater.In this study,we collected meltwater and ice samples from Laohugou Glacier No.12 in western China and measured CH_(4)and CO_(2)concentrations.Meltwater from the glacier terminus was continually sampled between 3 and 5 August 2020 to measure CH_(4)and CO_(2)concentrations.The results demonstrated that meltwater is a source of CH_(4)because the average saturations are over 100%.It could be con eluded that CH_(4)in the atmosphere can be released by glacial meltwater.However,the CO_(2)saturations are various,and CO_(2)fluxes exhibit positive(released CO_(2))or negative(absorbed CO_(2))values because the water and atmospheric conditions are variable.More importantly,the CH_(4)and CO_(2)concentrations were higher in meltwater samples from the glacier terminus than in samples from the surface ice(including an ice core)and a surface stream.Although the meltwater effect from the upper part of the glacier cannot be excluded,we speculated that subglacial drainage systems with an anaerobic environment may represent the CH_(4)source,but it needs to be further investigated in the future.However,high mountain glaciers are currently ignored in global carbon budgets,and the increased melting of glaciers with global warming may accelerate the absorption of much more CO_(2)and lead to the release of CH_(4).
基金supported by the National Basic Research Program of China (2007CB411501)the National Essential Scientific Program of the Ministry of Scienceand Technology of the People’s Republic of China(2006FY110200)
文摘In June 2006,a 20.12 m shallow ice core was recovered from an elevation of 5,040 m in the northern branch firn basin of No.12 Glacier,Great Snow Mountain,in the western part of Qilian Mountain,China.Isotopes(δ 18 O),major soluble ions,and radionuclide(β-activity) measurements from the ice core revealed a 46-year record(1960-2006).In this paper,the method of sea-salt ion tracer,correlation analysis and trend analysis were used in this research to confirm the source of the chemical composition.The correlation analysis and HYSPLIT backward trajectory analysis suggests that atmospheric soluble dust species dominate the chemical signature.
基金supported by the National key research and development project(2022YFF0711704)the Science Fund for Creative Research Groups of Gansu Province(Grant No.23JRRA567)+2 种基金China Meteorological Administration Climate Change Special Program(CMA-CCSP:QBZ202308)Innovation and Development Project of China Meteorological Administration(CXFZ2022J039)the Gansu Provincial Science and Technology Program(22ZD6FA005)。
文摘Solid precipitation is not only the main supply for glacier mass,but also exerts an important influence on surface albedo and intensifies glacier melting.However,precipitation type observation is very scarce in the high alpine glaciers,which limits the precise simulation of glacier mass balance.This study assessed three discrimination methods of precipitation types including Ding method,Dai method and Froidurot method based on surface albedo observation data on the Laohugou Glacier No.12(LHG Glacier)in western Qilian Mountains.The results showed that Ding method had a best applicability on the LHG Glacier,the other two need to calibrate parameters when they are used in the high elevation glacier region.Then we fitted the relationship between snowfall probability and fresh snow albedo,and put forward a revised formula to simulate fresh snow albedo based on Ding method,which is expected to reduce the uncertainty in glacier mass and energy balance model.Finally,we found a best air temperature threshold of 4℃for discriminating monthly precipitation types.In order to accurately simulate the glacier melt,it is necessary to obtain the threshold temperature appropriately in different glacier region with different elevation and humidity.
文摘本文基于评估和订正后的高亚洲精细再分析数据集(HAR v2),利用COSIMA单点能量−物质平衡模型系统分析了祁连山老虎沟12号冰川消融区4550 m自动气象站处2012年物质和能量交换过程及其对气候变化的响应特征,并在此基础上首次重建了1991—2020年能量和物质平衡序列。研究结果表明:①HAR v2数据集在研究区具有良好的适用性,由此驱动的COSIMA模型显示2012年冰川消融区模拟年累积物质平衡为-2333 mm w.e.。净短波辐射是冰川消融的主要能量来源(90.1%),净长波辐射是能量的主要输出项(58.6%);②该冰川物质平衡对降水变化总体保持线性响应,但对气温变化的响应表现出非对称性和非线性响应特征;③近30 a冰川表面能量收入项中净短波辐射、感热通量多年平均占比分别为89.2%、10.8%,而能量支出项中净长波辐射、消融耗热、潜热通量和地热通量多年平均占比依次为58.6%、26.5%、12.4%和2.5%。该冰川消融区长期处于物质高亏损状态,多年平均消融量为−2392 mm w.e.。在云量以及相对湿度、风速等其它气象因素影响下,净短波辐射的变幅大大超过感热通量、净长波辐射和潜热通量等能量项的变幅是该冰川消融强、弱年形成的主要原因。此外,固态降水也是制约冰川物质平衡的重要因素。
文摘采用HOCK的分布式能量物质平衡模型对老虎沟12号冰川消融期的物质平衡进行了模拟,时间步长为1 h,空间分辨率为30 m.模型结果利用物质平衡观测数据和气象站观测数据验证,模型模拟时期为2012年6月1日-9月30日.模型模拟结果表明,地形因子对太阳辐射影响相当显著;散射辐射在总辐射中的比例较大为39%,模拟期冰川表面物质平衡为-506 mm w.e..在模拟期整个冰川平均上净辐射占能量收入的84%,感热通量占有16%;消融耗热则是能量的主要支出占有62%,潜热通量占有能量支出的38%.
基金supported by the Foundation for Excellent Youth Scholars of CAREERI, CAS (No. 51Y25B01)the National Natural Science Foundation of China (No. 41301064)the National Basic Research Program of China (No. 2007CB411501)
文摘In June 2006, samples were collected from a 90 cm snow-pit at an elevation of 5 040 m a.s.l, in the northern branch firn basin of the Glacier No. 12, Laohugou Valley, in the western part of Qilian Mountain, China. Oxygen isotopes （6180） and major soluble ions were measured. Results showed that Ca2＋ is the dominant cation, and SO42 is the dominant anion. All major ions have close positive correlations with eachother except NO3 and NH4＋. 6180 show positive correlation with air temperature. The method of correlation analysis, sea-salt ion tracer and trend analysis were used to determine the source of the chemical components. The correlation analysis and HYSPLIT backward trajectory analysis suggest that atmospheric soluble dust species dominate the chemical signature.
