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
On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage...On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage site by UNESCO in 1992. Data analysis and field survey were conducted on the landslide, collapse, and debris flow gully, to assess the coseismic geological hazards generated by the earthquake using an unmanned aerial vehicle(UAV), remote-sensing imaging, laser range finders, geological radars, and cameras. The results highlighted the occurrence of 13 landslides, 70 collapses, and 25 potential debris flow gullies following the earthquake. The hazards were classified on the basis of their size and the potential property loss attributable to them. Consequently, 14 large-scale hazards, 30 medium-sized hazards, and 64 small hazards accounting for 13%, 28%, and 59% of the total hazards, respectively, were identified. Based on the variation tendency of the geological hazards that ensued in areas affected by the Kanto earthquake(Japan), Chi-chi earthquake(Taiwan China), and Wenchuan earthquake(Sichuan China), the study predicts that, depending on the rain intensity cycle, the duration of geological hazard activities in the Jiuzhaigou Valley may last over ten years and will gradually decrease for the following five to ten yearsbefore returning to pre-earthquake levels. Thus,necessary monitoring and early warning systems must be implemented to ensure the safety of residents,workers and tourists during the construction of engineering projects and reopening of scenic sites to the public.展开更多
Aims Although increases in precipitation variability in arid ecosystems are projected due to climate change,the response of desert shrub communities to precipitation change has not been fully elucidated.Such knowledge...Aims Although increases in precipitation variability in arid ecosystems are projected due to climate change,the response of desert shrub communities to precipitation change has not been fully elucidated.Such knowledge is important since drought-adapted plants exhibit varied mechanisms of survival that may contribute to species coexistence.Methods We tested the responses of eight drought-adapted plants,a mix of graminoids,shrubs and forbs to three summer precipitation scenarios(1.3,2.6 and 3.9 cm per month)in a common garden experiment in the Great Basin(Owens Valley,California).Changes in mineral nutrient uptake(carbon,nitrogen,phosphorus,potassium,calcium,magnesium,manganese,copper,boron,zinc,iron and sodium)and gas exchange parameters(photosynthetic rate and stomatal conductance)were investigated in the studied species.Important Findings Two graminoids(Sporobolus airoides and Leymus triticoides)and one salt tolerant shrub species(Atriplex confertifolia)responded to increased water availability with increases in photosynthetic rate and/or stomatal conductance.There was a significant correlation between water availability and uptake of nutrients for five out of eight species.Artemisia tridentata,with higher rates of photosynthesis,contained greater amounts of potassium,copper and boron,while Juncus arcticus,with higher rates of photosynthesis,contained greater amounts of magnesium and iron,and less sodium.Juncus arcticus and three salt-adapted species(A.confertifolia,Distichlis spicata and S.airoides)exhibited correlations with stomatal conductance and concentrations of nutrients.Results indicate that differential physiological response mechanisms to increased moisture and associated nutrient uptake strategies in drought-adapted species may mediate coexistence under increased summer precipitation.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 National Science Foundation of China (Grant No. 41790432) the International partnership program of CAS (Grant No. 131551KYSB20160002)
文摘On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage site by UNESCO in 1992. Data analysis and field survey were conducted on the landslide, collapse, and debris flow gully, to assess the coseismic geological hazards generated by the earthquake using an unmanned aerial vehicle(UAV), remote-sensing imaging, laser range finders, geological radars, and cameras. The results highlighted the occurrence of 13 landslides, 70 collapses, and 25 potential debris flow gullies following the earthquake. The hazards were classified on the basis of their size and the potential property loss attributable to them. Consequently, 14 large-scale hazards, 30 medium-sized hazards, and 64 small hazards accounting for 13%, 28%, and 59% of the total hazards, respectively, were identified. Based on the variation tendency of the geological hazards that ensued in areas affected by the Kanto earthquake(Japan), Chi-chi earthquake(Taiwan China), and Wenchuan earthquake(Sichuan China), the study predicts that, depending on the rain intensity cycle, the duration of geological hazard activities in the Jiuzhaigou Valley may last over ten years and will gradually decrease for the following five to ten yearsbefore returning to pre-earthquake levels. Thus,necessary monitoring and early warning systems must be implemented to ensure the safety of residents,workers and tourists during the construction of engineering projects and reopening of scenic sites to the public.
文摘Aims Although increases in precipitation variability in arid ecosystems are projected due to climate change,the response of desert shrub communities to precipitation change has not been fully elucidated.Such knowledge is important since drought-adapted plants exhibit varied mechanisms of survival that may contribute to species coexistence.Methods We tested the responses of eight drought-adapted plants,a mix of graminoids,shrubs and forbs to three summer precipitation scenarios(1.3,2.6 and 3.9 cm per month)in a common garden experiment in the Great Basin(Owens Valley,California).Changes in mineral nutrient uptake(carbon,nitrogen,phosphorus,potassium,calcium,magnesium,manganese,copper,boron,zinc,iron and sodium)and gas exchange parameters(photosynthetic rate and stomatal conductance)were investigated in the studied species.Important Findings Two graminoids(Sporobolus airoides and Leymus triticoides)and one salt tolerant shrub species(Atriplex confertifolia)responded to increased water availability with increases in photosynthetic rate and/or stomatal conductance.There was a significant correlation between water availability and uptake of nutrients for five out of eight species.Artemisia tridentata,with higher rates of photosynthesis,contained greater amounts of potassium,copper and boron,while Juncus arcticus,with higher rates of photosynthesis,contained greater amounts of magnesium and iron,and less sodium.Juncus arcticus and three salt-adapted species(A.confertifolia,Distichlis spicata and S.airoides)exhibited correlations with stomatal conductance and concentrations of nutrients.Results indicate that differential physiological response mechanisms to increased moisture and associated nutrient uptake strategies in drought-adapted species may mediate coexistence under increased summer precipitation.
