The distribution of borehole temperature at four high-altitude alpine glaciers was investigated. The result shows that the temperature ranges from -13.4℃ to -1.84℃, indicating the glaciers are cold throughout the bo...The distribution of borehole temperature at four high-altitude alpine glaciers was investigated. The result shows that the temperature ranges from -13.4℃ to -1.84℃, indicating the glaciers are cold throughout the boreholes. The negative gradient （i.e., the temperature decreasing with the increasing of depth） due to the advection of ice and climate warming, and the negative gradient moving downwards relates to climate warming, are probably responsible for the observed minimum temperature moving to lower depth in boreholes of the Gyabrag glacier and Miaoergou glacier compared to the previously investigated continental ice core borehole temperature in West China. The borehole temperature at 10m depth ranges from -8.0℃ in the Gyabrag glacier in the central Himalayas to -12.9℃ in the Tsabagarav glacier in the Altai range. The borehole temperature at 10 m depth is 3-4 degrees higher than the calculated mean annual air temperature on the surface of the glaciers and the higher 10 m depth temperature is mainly caused by the production of latent heat due to melt-water percolation and refreezing. The basal temperature is far below the melting point, indicating that the glaciers are frozen to bedrock. The very low temperature gradients near the bedrock suggest that the influence of geothermal flux and ice flow on basal temperature is very weak. The low temperature and small velocity of ice flow of glaciers are beneficial for preservation of the chemical and isotopic information in ice cores.展开更多
According to the characteristics of deep engineering surrounding rock main shaft of No.3 mining district in Jinchuan, electron microscope scanning and rock mechanics test were adopted to analyze the damage features of...According to the characteristics of deep engineering surrounding rock main shaft of No.3 mining district in Jinchuan, electron microscope scanning and rock mechanics test were adopted to analyze the damage features of rock. The software of FLAG3D and Burgers body （Kelvin-Maxwell model） were used to research on rheological theory, and rheological model was modified. The results indicate that the damage of rock mass is very serious, and the rheological characteristics also outstanding; rheological behavior of deep surrounding rocks of the shaft can be taken as superposition of transient and stable rheology; and there exist the most dangerous zone on 100 m higher than 1 063 m level, so it is necessity that works of monitor and corresponding reinforcement should strengthen.展开更多
Twenty snow samples were collected from the Qiyi glacier in Qilian Mountains,the Yuzhufeng glacier in eastern Kunlun Mountains,the Xiaodongkemadi glacier in Tanggula Mountains,and the Gurenhekou glacier in Nyainqê...Twenty snow samples were collected from the Qiyi glacier in Qilian Mountains,the Yuzhufeng glacier in eastern Kunlun Mountains,the Xiaodongkemadi glacier in Tanggula Mountains,and the Gurenhekou glacier in Nyainqêntanglha Range over the Tibetan Plateau.The concentration and distribution features of sixteen priority Polycyclic Aromatic Hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS).The sources of these PAHs were explored as well.Our results indicated that the average concentrations of PAHs in snow were in the range of 20.45 60.57 ng/L.Maximum PAHs levels were found in the YZF glacier andminimum in the XDKMD glacier.However,no apparent regional distribution pattern of PAHs was found in the glaciers over the Tibetan Plateau.Moreover,the 2 4 ring low molecular weight PAHs predominated in snow samples and the concentrations of phenanthrene was the highest.Integrated factor analysis and isomer pair ratios suggested that PAHs of glaciers over the Tibetan Plateau were derived from low temperature combustion of coal and biomass,and partially from the exhaust gas of locomotives.Air mass back trajectory indicated that organic compounds detected in snowpit of these four glaciers,in the period of time they represented,mainly came from Central Asia and the arid area of Northwest China by westerly wind circulation.展开更多
基金funded by the National Natural Science Foundation of China (Grant No. 40825017)the Chinese Academy of Sciences(Grant No. KZCX3-SW-344 and 100 Talents Project)
文摘The distribution of borehole temperature at four high-altitude alpine glaciers was investigated. The result shows that the temperature ranges from -13.4℃ to -1.84℃, indicating the glaciers are cold throughout the boreholes. The negative gradient （i.e., the temperature decreasing with the increasing of depth） due to the advection of ice and climate warming, and the negative gradient moving downwards relates to climate warming, are probably responsible for the observed minimum temperature moving to lower depth in boreholes of the Gyabrag glacier and Miaoergou glacier compared to the previously investigated continental ice core borehole temperature in West China. The borehole temperature at 10m depth ranges from -8.0℃ in the Gyabrag glacier in the central Himalayas to -12.9℃ in the Tsabagarav glacier in the Altai range. The borehole temperature at 10 m depth is 3-4 degrees higher than the calculated mean annual air temperature on the surface of the glaciers and the higher 10 m depth temperature is mainly caused by the production of latent heat due to melt-water percolation and refreezing. The basal temperature is far below the melting point, indicating that the glaciers are frozen to bedrock. The very low temperature gradients near the bedrock suggest that the influence of geothermal flux and ice flow on basal temperature is very weak. The low temperature and small velocity of ice flow of glaciers are beneficial for preservation of the chemical and isotopic information in ice cores.
基金Supported by the National Natural Science Foundation of China(50874042)Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-Year Plan Period(2008BAB32B01)
文摘According to the characteristics of deep engineering surrounding rock main shaft of No.3 mining district in Jinchuan, electron microscope scanning and rock mechanics test were adopted to analyze the damage features of rock. The software of FLAG3D and Burgers body （Kelvin-Maxwell model） were used to research on rheological theory, and rheological model was modified. The results indicate that the damage of rock mass is very serious, and the rheological characteristics also outstanding; rheological behavior of deep surrounding rocks of the shaft can be taken as superposition of transient and stable rheology; and there exist the most dangerous zone on 100 m higher than 1 063 m level, so it is necessity that works of monitor and corresponding reinforcement should strengthen.
基金supported by the National Natural Science Foundation of China(Grant Nos.40801023,40930526,40871038)West Light Foundation of the Chinese Academy of Sciences(Grant No.290928601)
文摘Twenty snow samples were collected from the Qiyi glacier in Qilian Mountains,the Yuzhufeng glacier in eastern Kunlun Mountains,the Xiaodongkemadi glacier in Tanggula Mountains,and the Gurenhekou glacier in Nyainqêntanglha Range over the Tibetan Plateau.The concentration and distribution features of sixteen priority Polycyclic Aromatic Hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS).The sources of these PAHs were explored as well.Our results indicated that the average concentrations of PAHs in snow were in the range of 20.45 60.57 ng/L.Maximum PAHs levels were found in the YZF glacier andminimum in the XDKMD glacier.However,no apparent regional distribution pattern of PAHs was found in the glaciers over the Tibetan Plateau.Moreover,the 2 4 ring low molecular weight PAHs predominated in snow samples and the concentrations of phenanthrene was the highest.Integrated factor analysis and isomer pair ratios suggested that PAHs of glaciers over the Tibetan Plateau were derived from low temperature combustion of coal and biomass,and partially from the exhaust gas of locomotives.Air mass back trajectory indicated that organic compounds detected in snowpit of these four glaciers,in the period of time they represented,mainly came from Central Asia and the arid area of Northwest China by westerly wind circulation.
