Ice and snow chemistry of alpine glaciers is crucial for the research of regional atmospheric environment change. Fresh snow samples were weekly collected from Urumqi Glacier No.1 in the Tianshan Mountains, Xin- jiang...Ice and snow chemistry of alpine glaciers is crucial for the research of regional atmospheric environment change. Fresh snow samples were weekly collected from Urumqi Glacier No.1 in the Tianshan Mountains, Xin- jiang, China, and the chemical characteristics and seasonal variations of major ions, mineral dust, δ18O and trace metals were measured. Results show that the concentrations of major ions in the snow are Ca2+ > SO42-> NH4+ > NO3-> Cl-> Na+ > Mg2+ > K+, in which Ca2+ is the dominant cation, and SO42-is the dominant anion. All major ions have close positive correlations with each other except NO3-. δ18O shows positive correlation with air temperature change during the study period. Mineral dust particle and major ionic concentrations in fresh snow have obvious seasonal change, with high concentration in spring but low concentration in summer and autumn, which indicates that the chemical mass input from Asian dust activity to snow is very significant. Temporal changes of trace metals in fresh snow, e.g., Cd, Pb, Zn, Al, Fe, have shown that human-induced pollution of central Asian region also has large contribution to the snow chemistry on alpine glaciers of the Tianshan Mountains.展开更多
Urumqi Glacier No. 1 is a representative glacier in the inland areas of Central Asia and is the only Chinese reference glacier in the World Glacier Monitoring Service. In this study, we explored multi-decadal variatio...Urumqi Glacier No. 1 is a representative glacier in the inland areas of Central Asia and is the only Chinese reference glacier in the World Glacier Monitoring Service. In this study, we explored multi-decadal variations in the flow velocity of the glacier and the influencing factors based on continuous field observations and path coefficient analysis. Results show that the glacier flow velocity decreased from 5.5 m/a in 1980/1981 to 3.3 m/a in 2010/2011. The annual variation in the direction of glacier flow velocity in the western branch and eastern branch was less than 1°–3°, and the change of glacier flow velocity in the western branch was more dramatic than that in the eastern branch. Glacier flow velocity was influenced by glacier morphology(including glacier area, glacier length, and ice thickness), glacier mass balance and local climate conditions(air temperature and precipitation), the glacier morphology being the leading factor. The long-term flow velocity data set of Urumqi Glacier No. 1 contributes to a better understanding of glacier dynamics within the context of climatic warming.展开更多
Topography plays an important role in determining the glacier changes.However,topography has often been oversimplified in the studies of the glacier changes.No systematic studies have been conducted to evaluate the re...Topography plays an important role in determining the glacier changes.However,topography has often been oversimplified in the studies of the glacier changes.No systematic studies have been conducted to evaluate the relationship between the glacier changes and topographic features.The present study provided a detailed insight into the changes in the two branches(east branch and west branch)of Urumqi Glacier No.1 in the Chinese Tianshan Mountains since 1993 and systematically discussed the effect of topography on the glacier parameters.This study analyzed comprehensive recently observed data(from 1992/1993 to 2018/2019),including mass balance,ice thickness,surface elevation,ice velocity,terminus,and area,and then determined the differences in the changes of the two branches and explored the effect of topography on the glacier changes.We also applied a topographic solar radiation model to analyze the influence of topography on the incoming shortwave radiation(SW_(in))across the entire glacier,focusing on the difference in the SW_(in) between the two branches.The glacier mass balance of the east branch was more negative than that of the west branch from 1992/1993 to 2018/2019,and this was mainly attributed to the lower average altitude of the east branch.Compared with the west branch,the decrease rate of the ice velocity was lower in the east branch owing to its relatively increased slope.The narrow shape of the west branch and its southeast aspect in the earlier period resulted in a larger glacier terminus retreat of the west branch.The spatial variability of the SW_(in) across the glacier surface became much larger as altitude increased.The SW_(in) received by the east branch was slightly larger than that received by the west branch,and the northern aspect could receive more SW_(in),leading to glacier melting.In the future,the difference of the glacier changes between the two branches will continue to exist due to their topographic differences.This work is fundamental to understanding how topographic features affect the glacier changes,and provides information for building different types of relationship between the glacier area and ice volume to promote further studies on the basin-scale glacier classification.展开更多
Worldwide examination of glacier change is based on detailed observations from only a small number of glaciers.The ground-based detailed individual glacier monitoring is of strong need and extremely important in both ...Worldwide examination of glacier change is based on detailed observations from only a small number of glaciers.The ground-based detailed individual glacier monitoring is of strong need and extremely important in both regional and global scales.A long-term integrated multi-level monitoring has been carried out on Urumqi Glacier No.1(UG1)at the headwaters of the Urumqi River in the eastern Tianshan Mountains of Central Asia since 1959 by the Tianshan Glaciological Station,Chinese Acamedey of Sciences(CAS),and the glaciological datasets promise to be the best in China.The boundaries of all glacier zones moved up,resulting in a shrunk accumulation area.The stratigraphy features of the snowpack on the glacier were found to be significantly altered by climate warming.Mass balances of UG1 show accelerated mass loss since 1960,which were attributed to three mechanisms.The glacier has been contracting at an accelerated rate since 1962,resulting in a total reduction of 0.37 km2 or 19.3%from 1962 to 2018.Glacier runoff measured at the UG1 hydrometeorological station demonstrates a significant increase from 1959 to 2018 with a large interannual fluctuation,which is inversely correlated with the glacier's mass balance.This study analyzes on the changes in glacier zones,mass balance,area and length,and streamflow in the nival glacial catchment over the past 60 years.It provides critical insight into the processes and mechanisms of glacier recession in response to climate change.The results are not only representative of those glaciers in the Tianshan mountains,but also for the continental-type throughout the world.The direct observation data form an essential basis for evaluating mountain glacier changes and the impact of glacier shrinkage on water resources in the interior drainage rivers within the vast arid and semi-arid land in northwestern China as well as Central Asia.展开更多
As a solid reservoir, a glacier can regulate regional water resources. The annual net mass balance directly reflects the fluctuation of the glacier and climate variability. Based on 51 years of mass balance observatio...As a solid reservoir, a glacier can regulate regional water resources. The annual net mass balance directly reflects the fluctuation of the glacier and climate variability. Based on 51 years of mass balance observation data, the mass balance of Tianshan Mountains Urumqi Glacier No. 1 experienced a nine times positive balance fluctuation and nine times negative balance fluctuation. There were 35 and 16 negative and positive balance years, respectively. From 1996/97 to 2008/09, 12 consecutive negative balance years were observed at Tianshan Mountains Urumqi Glacier No. 1. These results demon- strate that the Urumqi Glacier No. 1 is experiencing a strong negative balance, and the strongest negative balance, -931 mm w.e. (mm water equivalent), during the observation period occurred in 2008. In addition, the cumulative mass balance reached 13,709 mm w.e. in 2008. However, in 2009, the mass balance was positive at 63 mm w.e. The equilibrium-line al- titude changes with the fluctuation in the mass balance, and the effective mass balance gradient is 7.4 mrn/m. In this paper, the headwaters of the Urumqi River were analyzed using meteorological data from 1958 to 2009, including the average seasonal temperature and precipitation. The results showed that the main factor associated with the mass balance variation of Glacier No. 1 is the fluctuation in the summer air temperature, followed by changes in the precipitation.展开更多
Glaciers are crucial water resources for arid inland rivers in Northwest China.In recent decades,glaciers are largely experiencing shrinkage under the climate-warming scenario,thereby exerting tremendous influences on...Glaciers are crucial water resources for arid inland rivers in Northwest China.In recent decades,glaciers are largely experiencing shrinkage under the climate-warming scenario,thereby exerting tremendous influences on regional water resources.The primary role of understudying watershed scale glacier changes under changing climatic conditions is to ensure sustainable utilization of regional water resources,to prevent and mitigate glacier-related disasters.This study maps the current(2020)distribution of glacier boundaries across the Kaidu-Kongque river basin,south slope of Tianshan Mountains,and monitors the spatial evolution of glaciers over five time periods from 2000-2020 through thresholded band ratios approach,using 25 Landsat images at 30 m resolution.In addition,this study attempts to understand the role of climate characteristics for variable response of glacier area.The results show that the total area of glaciers was 398.21 km^(2)in 2020.The glaciers retreated by about 1.17 km^(2)/a(0.26%/a)from 2000 to 2020.The glaciers were reducing at a significantly rapid rate between 2000 and 2005,a slow rate from 2005 to 2015,and an accelerated rate during 2015-2020.The meteorological data shows slight increasing trends of mean annual temperature(0.02℃/a)and annual precipitation(2.07 mm/a).The correlation analysis demonstrates that the role of temperature presents more significant correlation with glacier recession than precipitation.There is a temporal hysteresis in the response of glacier change to climate change.Increasing trend of temperature in summer proves to be the driving force behind the Kaidu-Kongque basin glacier recession during the recent 20 years.展开更多
Glaciers are known as natural ’’solid reservoirs’ ’, and they play a dual role between the composition of water resources and the river runoff regulation in arid and semi-arid areas of China. In this study, we use...Glaciers are known as natural ’’solid reservoirs’ ’, and they play a dual role between the composition of water resources and the river runoff regulation in arid and semi-arid areas of China. In this study, we used in situ observation data from Urumqi Glacier No. 1, Xinjiang Uygur Autonomous Region, in combination with meteorological data from stations and a digital elevation model, to develop a distributed degree-day model for glaciers in the Urumqi River Basin to simulate glacier mass balance processes and quantify their effect on streamflow during 1980–2020. The results indicate that the mass loss and the equilibrium line altitude(ELA) of glaciers in the last 41 years had an increasing trend, with the average mass balance and ELA being-0.85(±0.32) m w.e./a(meter water-equivalent per year) and 4188 m a.s.l., respectively. The glacier mass loss has increased significantly during 1999–2020, mostly due to the increase in temperature and the extension of ablation season. During 1980–2011, the average annual glacier meltwater runoff in the Urumqi River Basin was 0.48×108 m3, accounting for 18.56% of the total streamflow. We found that the annual streamflow in different catchments in the Urumqi River Basin had a strong response to the changes in glacier mass balance, especially from July to August, and the glacier meltwater runoff increased significantly. In summary, it is quite possible that the results of this research can provide a reference for the study of glacier water resources in glacier-recharged basins in arid and semi-arid areas.展开更多
-Rock glaciers are developed at permafrost areas of periglacial environment in Tianshan Mountains [7,17]. Based on field surveying andair-photo interprestation, the paper discusses the shape, characteristics of supply...-Rock glaciers are developed at permafrost areas of periglacial environment in Tianshan Mountains [7,17]. Based on field surveying andair-photo interprestation, the paper discusses the shape, characteristics of supply area, formation conditions and environmental differentiations of rockglaciers at head area of Urmqi River (43°05'-43°08' N, 86°48’-86°53E) inKalawuchen Range and the head areas of Toudao River and Danangou River (43°30’-43°50’N, 85°00-85°30’E) in Yilanhabierga Rangu at ShawanCounty. Formation conditions and morphological characteristics of rockglaciers are studies in terms of topographic conditions, climate, compositionand age.展开更多
Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes.In this study,we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in...Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes.In this study,we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in the period of 1990-2015 in 4 different mountainous sub-regions in Xinjiang Uygur Autonomous Region of Northwest China:the Bogda Peak and Karlik Mountain sub-regions in the Tianshan Mountains;the Yinsugaiti Glacier sub-region in the Karakorum Mountains;and the Youyi Peak sub-region in the Altay Mountains.The standardized snow cover index(NDSI)and correlation analysis were used to reveal the glacier area changes in the 4 sub-regions from 1990 to 2015.Glacial areas in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions in the period of 1990-2015 decreased by 57.7,369.1,369.1,and 170.4 km^(2),respectively.Analysis of glacier area center of gravity showed that quadrant changes of glacier areas in the 4 sub-regions moved towards the origin.Glacier area on the south aspect of the Karlik Mountain sub-region was larger than that on the north aspect,while glacier areas on the north aspect of the other 3 sub-regions were larger than those on the south aspect.Increased precipitation in the Karlik Mountain sub-region inhibited the retreat of glaciers to a certain extent.However,glacier area changes in the Bogda Peak and Youyi Peak sub-regions were not sensitive to the increased precipitation.On a seasonal time scale,glacier area changes in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions were mainly caused by accumulated temperature in the wet season;on an annual time scale,the correlation coefficient between glacier area and annual average temperature was-0.72 and passed the significance test at P<0.05 level in the Karlik Mountain sub-region.The findings of this study can provide a scientific basis for water resources management in the arid and semi-arid regions of Northwest China in the context of global warming.展开更多
As important freshwater resources in alpine basins,glaciers and snow cover tend to decline due to climate warming,thus affecting the amount of water available downstream and even regional economic development.However,...As important freshwater resources in alpine basins,glaciers and snow cover tend to decline due to climate warming,thus affecting the amount of water available downstream and even regional economic development.However,impact assessments of the economic losses caused by reductions in freshwater supply are quite limited.This study aims to project changes in glacier meltwater and snowmelt of the Urumqi River in the Tianshan Mountains under future climate change scenarios(RCP2.6(RCP,Representative Concentration Pathway),RCP4.5,and RCP8.5)by applying a hydrological model and estimate the economic losses from future meltwater reduction for industrial,agricultural,service,and domestic water uses combined with the present value method for the 2030 s,2050 s,2070 s,and 2090 s.The results indicate that total annual glacier meltwater and snowmelt will decrease by 65.6%and 74.5%under the RCP4.5 and RCP8.5 scenarios by the 2090 s relative to the baseline period(1980-2010),respectively.Compared to the RCP2.6 scenario,the projected economic loss values of total water use from reduced glacier meltwater and snowmelt under the RCP8.5 scenario will increase by 435.10×10^(6) and 537.20×10^(6) CNY in the 2050 s and 2090 s,respectively,and the cumulative economic loss value for 2099 is approximately 2124.00×10^(6) CNY.We also find that the industrial and agricultural sectors would likely face the largest and smallest economic losses,respectively.The economic loss value of snowmelt in different sectorial sectors is greater than that of glacier meltwater.These findings highlight the need for climate mitigation actions,industrial transformation,and rational water allocation to be considered in decision-making in the Tianshan Mountains in the future.展开更多
We have developed crustal minimum I-D P- and S-wave velocity models of the collision zone between the northern Tianshan mountain and the Junggar basin (86°E-89°E, 43°N-44.5°N). These two models w...We have developed crustal minimum I-D P- and S-wave velocity models of the collision zone between the northern Tianshan mountain and the Junggar basin (86°E-89°E, 43°N-44.5°N). These two models were created through inversion of 1 370 P- and 1 396 S-wave travel times from 173 well-constrained local earthquakes recorded by the Uriimqi sparse local seismic network and temporary seismic arrays. In contrast to previous models, our results indicate relatively low velocity at both shallow (〈10 km) and deep (30-45 km) depths. The shallow zone is interpreted to be the result of thick surficial sedimentary deposits, whereas the deeper anomaly is interpreted to result from ductile shearing and lower crustal fow. Additionally, we detected several transition layers under the lower crust, which may imply structural complexity of the uppermost mantle in this region. The improved models reduce the RMS residual of earthquake locations by 41.7% from 1.2 to 0.5 seconds. The more accurately located hypocenters appear to correlate with prominent local over-thrusts, which underlie an anticlinal fold belt and several blind faults. Positive station corrections are observed near the Junggar basin, which likely reflects low wave velocity; negative corrections near the Tianshan mountain and Bogda mountain suggest high wave velocity.展开更多
This study analyzes the changes in glacier zones and snow composition of Glacier No.1 in the Tianshan Mountains of China since 1961,and their possible relations with climate.It is found that precipitation dominated th...This study analyzes the changes in glacier zones and snow composition of Glacier No.1 in the Tianshan Mountains of China since 1961,and their possible relations with climate.It is found that precipitation dominated the snow composition and that air temperature and precipitation controlled the distribution of glacier zones,but interannual change in precipitation had a relatively large effect on glacier zones and snow composition during 1963–1981 (P10) and 1963–1989 (P11).However,during 1982–2007 (P20) and 1990–2007 (P21),the air temperature rise (0.57°C/10 a for P20,0.76°C/10 a for P21) was more influential than the precipitation increase (51.3 mm/10 a for P20),and air temperature was principally responsible for the evolution of glacier zones and snow composition most probably resulting from recent climate warming.展开更多
The glacier ELA is one of the important parameters reflecting climate change.Based on observations of the equilibrium line altitude(ELA) of Urumqi Glacier No.1 in the Tianshan Mountains,we established a statistical mo...The glacier ELA is one of the important parameters reflecting climate change.Based on observations of the equilibrium line altitude(ELA) of Urumqi Glacier No.1 in the Tianshan Mountains,we established a statistical model between ELA and its major influencing factors,warm season air temperature(air temperature averages for May,June,July and August) and annual precipitation.Result showed that,warm season air temperature was the leading climatic factor influencing ELA variations.The glacier ELA ascends(descends) 61.7 m when warm season air temperature increases(decreases) by 1°C,and ascends(descends) 13.1 m when cold season precipitation decreases(increases) by 10%.In the period 1959-2008,the glacier ELA showed a general increasing trend,ascending108 m and reaching its highest altitude in 2008 at 4168 m a.s.l.,close to the glacier summit.If future climate is similar to that in the past 50 years,the ELA of Urumqi Glacier No.1 will still ascend with a speed of 2.16 m/a.However,If future climate is similar to that in the period 2000-2008,the ELA will still ascend with a speed of 6.5 m/a before it is stable.As a result of ELA variation,the accumulation area ratio(AAR) of the glacier showed a decreasing trend during the past 50 years.展开更多
On a deglaciated terrain,glacial gravel is the primary component of the natural habitat for vascular plant colonization and succession.Knowledge regarding the role of glacial gravel in vascular plant growth,however,re...On a deglaciated terrain,glacial gravel is the primary component of the natural habitat for vascular plant colonization and succession.Knowledge regarding the role of glacial gravel in vascular plant growth,however,remains limited.In this study,an unmanned aerial vehicle(UAV)was used to investigate plant family composition,species richness,fractional vegetation cover(FVC),and gravel cover(GC)along elevational gradients on the three glacier forelands(Kekesayi,Jiangmanjiaer,and Koxkar Baxi)of the Third Pole(including the eastern Pamir Plateau and western Tianshan Mountains)in China.We then analyzed the spatial characteristics of vascular plants followed by exploring the effect of glacial gravel on vascular plants.Findings indicated that FVC on these glacier forelands generally decreased as the elevation increased or distance from the current glacier terminus decreased.The shady slope(Kekesayi)was more vegetated in comparison to the sunny slope(Jiangmanjiaer)at the glacier basin scale,and the warm and humid deglaciated terrain(Koxkar Baxi)had the highest FVC at the regional scale.Plant family composition and species richness on the glacier forelands decreased with rising elevation,with the exception of those on the Jiangmanjiaer glacier foreland.The relationships between FVC and GC presented negative correlations;particularly,they exhibited variations in power functions on the Kekesayi and Jiangmanjiaer glacier forelands of the eastern Pamir Plateau and a linear function on the Koxkar Baxi glacier foreland of the western Tianshan Mountains.Glacial gravel was found to be conducive to vegetation colonization and development in the early succession stage up until vascular plants adapted to the cold and arid climatic condition,whereas it is unfavorable to the expansion of vascular plants in the later succession stage.These findings suggested that the spatial difference of plant characteristics had close connections with regional climatic and topographic conditions,as well as glacial gravel distribution.In addition,we concluded that aerial photographs can be an asset for studying the functions of micro-environment in vegetation colonization as well as succession on the glacier forelands.展开更多
1-15 Martin F.PRICE,TorARNESEN,Erik GL0ERSEN,Marc J.METZGER,Mapping mountain areas:learning from Global,European and Norwegian perspectives,16-29 Peter NOJAROV,Emil GACHEV,Karsten GRUNEWALD,Recent behavior and possibl...1-15 Martin F.PRICE,TorARNESEN,Erik GL0ERSEN,Marc J.METZGER,Mapping mountain areas:learning from Global,European and Norwegian perspectives,16-29 Peter NOJAROV,Emil GACHEV,Karsten GRUNEWALD,Recent behavior and possible future evolution of the glacieret in the cirque Golemiya Kazan in the Pirin Mountains under conditions of climate warming.展开更多
Hydrological processes were compared, with and without the influence of precipita- tion on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, o...Hydrological processes were compared, with and without the influence of precipita- tion on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, on the northern slope of the eastern Tianshan Mountains, during the melting season (May-September) in 2011. The study was based on hydrological data observed at 10-min intervals, meteorological data observed at 15-min intervals, and glacier melting and snow observations from the Empty Cirque, Zongkong, and Urumqi Glacier No.1 gauging stations. The results indicated that the discharge differed markedly among the three gauging stations. The daily discharge was more than the nightly discharge at the Glacier No.1 gauging station, which contrasted with the patterns observed at the Zongkong and Empty Cirque gauging stations. There was a clear daily variation in the discharge at the three gauging stations, with differences in the magnitude and duration of the peak discharge. When precipitation was not considered, the time-lags between the maximum discharge and the highest temperature were 1-3 h, 10-16 h, and 5-11 h at the Glacier No.l, Empty Cirque, and Zongkong gauging stations, respectively. When precipitation was taken into consideration, the corresponding time-lags were 0-1 h, 13 h, and 6-7 h, respectively. Therefore, the duration from the generation of discharge to confluence was the shortest in the glacierized catchment and the longest in the catchment where was mainly covered by snow. It was also shown that the hydrological process from the generation of discharge to confluence shortened when precipitation was considered. The factors influencing changes in the discharge among the three gauging stations were different. For Glacier No.1 station, the discharge was mainly controlled by heat conditions in the glacierized region, and the discharge displayed an accelerated growth when the temperature exceeded 5℃ in the melt season. It was found that the englacial and subglacial drainage channel of Glacier No.1 had become simpler during the past 20 years. Its weaker retardance and storage of glacier melting water resulted in rapid discharge confluence. It was also shown that the discharge curve and the time-lag between the maximum discharge and the highest temperature could be used to reveal the evolution of the drainage system and the process of glacier and snow melting at different levels of glacier coverage.展开更多
基金Under the auspices of Major State Basic Research Development Program of China(No.2010CB951003)Knowledge Innovation Programs of the Chinese Academy of Sciences(No.KZCXZ-YW-127)National Natural Science Foundation of China(No.40631001,40571033,40701034,40371028,J0630966,40701035)
文摘Ice and snow chemistry of alpine glaciers is crucial for the research of regional atmospheric environment change. Fresh snow samples were weekly collected from Urumqi Glacier No.1 in the Tianshan Mountains, Xin- jiang, China, and the chemical characteristics and seasonal variations of major ions, mineral dust, δ18O and trace metals were measured. Results show that the concentrations of major ions in the snow are Ca2+ > SO42-> NH4+ > NO3-> Cl-> Na+ > Mg2+ > K+, in which Ca2+ is the dominant cation, and SO42-is the dominant anion. All major ions have close positive correlations with each other except NO3-. δ18O shows positive correlation with air temperature change during the study period. Mineral dust particle and major ionic concentrations in fresh snow have obvious seasonal change, with high concentration in spring but low concentration in summer and autumn, which indicates that the chemical mass input from Asian dust activity to snow is very significant. Temporal changes of trace metals in fresh snow, e.g., Cd, Pb, Zn, Al, Fe, have shown that human-induced pollution of central Asian region also has large contribution to the snow chemistry on alpine glaciers of the Tianshan Mountains.
基金funded the National Natural Science Foundation of China (41501010, 41401611)the Funds for Creative Research Groups of China (41121001)the Youth Innovation Promotion Association of Chinese Academy of Sciences
文摘Urumqi Glacier No. 1 is a representative glacier in the inland areas of Central Asia and is the only Chinese reference glacier in the World Glacier Monitoring Service. In this study, we explored multi-decadal variations in the flow velocity of the glacier and the influencing factors based on continuous field observations and path coefficient analysis. Results show that the glacier flow velocity decreased from 5.5 m/a in 1980/1981 to 3.3 m/a in 2010/2011. The annual variation in the direction of glacier flow velocity in the western branch and eastern branch was less than 1°–3°, and the change of glacier flow velocity in the western branch was more dramatic than that in the eastern branch. Glacier flow velocity was influenced by glacier morphology(including glacier area, glacier length, and ice thickness), glacier mass balance and local climate conditions(air temperature and precipitation), the glacier morphology being the leading factor. The long-term flow velocity data set of Urumqi Glacier No. 1 contributes to a better understanding of glacier dynamics within the context of climatic warming.
基金jointly funded by the Third Xinjiang Scientific Expedition Program (2021xjkk0801)the Youth Innovation Promotion Association of Chinese Academy of Sciences (Y2021110)the State Key Laboratory of Cryospheric Science (SKLCS-ZZ-2022)
文摘Topography plays an important role in determining the glacier changes.However,topography has often been oversimplified in the studies of the glacier changes.No systematic studies have been conducted to evaluate the relationship between the glacier changes and topographic features.The present study provided a detailed insight into the changes in the two branches(east branch and west branch)of Urumqi Glacier No.1 in the Chinese Tianshan Mountains since 1993 and systematically discussed the effect of topography on the glacier parameters.This study analyzed comprehensive recently observed data(from 1992/1993 to 2018/2019),including mass balance,ice thickness,surface elevation,ice velocity,terminus,and area,and then determined the differences in the changes of the two branches and explored the effect of topography on the glacier changes.We also applied a topographic solar radiation model to analyze the influence of topography on the incoming shortwave radiation(SW_(in))across the entire glacier,focusing on the difference in the SW_(in) between the two branches.The glacier mass balance of the east branch was more negative than that of the west branch from 1992/1993 to 2018/2019,and this was mainly attributed to the lower average altitude of the east branch.Compared with the west branch,the decrease rate of the ice velocity was lower in the east branch owing to its relatively increased slope.The narrow shape of the west branch and its southeast aspect in the earlier period resulted in a larger glacier terminus retreat of the west branch.The spatial variability of the SW_(in) across the glacier surface became much larger as altitude increased.The SW_(in) received by the east branch was slightly larger than that received by the west branch,and the northern aspect could receive more SW_(in),leading to glacier melting.In the future,the difference of the glacier changes between the two branches will continue to exist due to their topographic differences.This work is fundamental to understanding how topographic features affect the glacier changes,and provides information for building different types of relationship between the glacier area and ice volume to promote further studies on the basin-scale glacier classification.
基金This research was funded by the National Natural Science Foundation of China(Grant No.41761134093)the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0201)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Class A)(Grant Nos.XDA20060201 and XDA20020102)and the State Key Laboratory of Cryospheric Sciences Open Research Fund(Grant No.SKLCS-ZZ-2020).
文摘Worldwide examination of glacier change is based on detailed observations from only a small number of glaciers.The ground-based detailed individual glacier monitoring is of strong need and extremely important in both regional and global scales.A long-term integrated multi-level monitoring has been carried out on Urumqi Glacier No.1(UG1)at the headwaters of the Urumqi River in the eastern Tianshan Mountains of Central Asia since 1959 by the Tianshan Glaciological Station,Chinese Acamedey of Sciences(CAS),and the glaciological datasets promise to be the best in China.The boundaries of all glacier zones moved up,resulting in a shrunk accumulation area.The stratigraphy features of the snowpack on the glacier were found to be significantly altered by climate warming.Mass balances of UG1 show accelerated mass loss since 1960,which were attributed to three mechanisms.The glacier has been contracting at an accelerated rate since 1962,resulting in a total reduction of 0.37 km2 or 19.3%from 1962 to 2018.Glacier runoff measured at the UG1 hydrometeorological station demonstrates a significant increase from 1959 to 2018 with a large interannual fluctuation,which is inversely correlated with the glacier's mass balance.This study analyzes on the changes in glacier zones,mass balance,area and length,and streamflow in the nival glacial catchment over the past 60 years.It provides critical insight into the processes and mechanisms of glacier recession in response to climate change.The results are not only representative of those glaciers in the Tianshan mountains,but also for the continental-type throughout the world.The direct observation data form an essential basis for evaluating mountain glacier changes and the impact of glacier shrinkage on water resources in the interior drainage rivers within the vast arid and semi-arid land in northwestern China as well as Central Asia.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41001040 and J0630966)the Foundation for Excellent Youth Scholars of CAREERI (No. 51Y084911)+1 种基金the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-EW-311)the National Basic Research Program of China (2010CB951003)
文摘As a solid reservoir, a glacier can regulate regional water resources. The annual net mass balance directly reflects the fluctuation of the glacier and climate variability. Based on 51 years of mass balance observation data, the mass balance of Tianshan Mountains Urumqi Glacier No. 1 experienced a nine times positive balance fluctuation and nine times negative balance fluctuation. There were 35 and 16 negative and positive balance years, respectively. From 1996/97 to 2008/09, 12 consecutive negative balance years were observed at Tianshan Mountains Urumqi Glacier No. 1. These results demon- strate that the Urumqi Glacier No. 1 is experiencing a strong negative balance, and the strongest negative balance, -931 mm w.e. (mm water equivalent), during the observation period occurred in 2008. In addition, the cumulative mass balance reached 13,709 mm w.e. in 2008. However, in 2009, the mass balance was positive at 63 mm w.e. The equilibrium-line al- titude changes with the fluctuation in the mass balance, and the effective mass balance gradient is 7.4 mrn/m. In this paper, the headwaters of the Urumqi River were analyzed using meteorological data from 1958 to 2009, including the average seasonal temperature and precipitation. The results showed that the main factor associated with the mass balance variation of Glacier No. 1 is the fluctuation in the summer air temperature, followed by changes in the precipitation.
基金This work was supported by the project of China Geology Survey(DD20190315)Innovation Capability Support Program of Shaanxi(2019TD-040)+1 种基金“Integration of Groundwater Resources Assessment Results in Key Areas of Northwest China”programKey Laboratory of Groundwater and Ecology in Arid and Semi-arid Areas of China Geological Survey.
文摘Glaciers are crucial water resources for arid inland rivers in Northwest China.In recent decades,glaciers are largely experiencing shrinkage under the climate-warming scenario,thereby exerting tremendous influences on regional water resources.The primary role of understudying watershed scale glacier changes under changing climatic conditions is to ensure sustainable utilization of regional water resources,to prevent and mitigate glacier-related disasters.This study maps the current(2020)distribution of glacier boundaries across the Kaidu-Kongque river basin,south slope of Tianshan Mountains,and monitors the spatial evolution of glaciers over five time periods from 2000-2020 through thresholded band ratios approach,using 25 Landsat images at 30 m resolution.In addition,this study attempts to understand the role of climate characteristics for variable response of glacier area.The results show that the total area of glaciers was 398.21 km^(2)in 2020.The glaciers retreated by about 1.17 km^(2)/a(0.26%/a)from 2000 to 2020.The glaciers were reducing at a significantly rapid rate between 2000 and 2005,a slow rate from 2005 to 2015,and an accelerated rate during 2015-2020.The meteorological data shows slight increasing trends of mean annual temperature(0.02℃/a)and annual precipitation(2.07 mm/a).The correlation analysis demonstrates that the role of temperature presents more significant correlation with glacier recession than precipitation.There is a temporal hysteresis in the response of glacier change to climate change.Increasing trend of temperature in summer proves to be the driving force behind the Kaidu-Kongque basin glacier recession during the recent 20 years.
基金funded by the Third Xinjiang Scientific Expedition Program(2021xjkk0801)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0201)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20060201,XDA20020102)the National Natural Science Foundation of China(41761134093,31760151)。
文摘Glaciers are known as natural ’’solid reservoirs’ ’, and they play a dual role between the composition of water resources and the river runoff regulation in arid and semi-arid areas of China. In this study, we used in situ observation data from Urumqi Glacier No. 1, Xinjiang Uygur Autonomous Region, in combination with meteorological data from stations and a digital elevation model, to develop a distributed degree-day model for glaciers in the Urumqi River Basin to simulate glacier mass balance processes and quantify their effect on streamflow during 1980–2020. The results indicate that the mass loss and the equilibrium line altitude(ELA) of glaciers in the last 41 years had an increasing trend, with the average mass balance and ELA being-0.85(±0.32) m w.e./a(meter water-equivalent per year) and 4188 m a.s.l., respectively. The glacier mass loss has increased significantly during 1999–2020, mostly due to the increase in temperature and the extension of ablation season. During 1980–2011, the average annual glacier meltwater runoff in the Urumqi River Basin was 0.48×108 m3, accounting for 18.56% of the total streamflow. We found that the annual streamflow in different catchments in the Urumqi River Basin had a strong response to the changes in glacier mass balance, especially from July to August, and the glacier meltwater runoff increased significantly. In summary, it is quite possible that the results of this research can provide a reference for the study of glacier water resources in glacier-recharged basins in arid and semi-arid areas.
文摘-Rock glaciers are developed at permafrost areas of periglacial environment in Tianshan Mountains [7,17]. Based on field surveying andair-photo interprestation, the paper discusses the shape, characteristics of supply area, formation conditions and environmental differentiations of rockglaciers at head area of Urmqi River (43°05'-43°08' N, 86°48’-86°53E) inKalawuchen Range and the head areas of Toudao River and Danangou River (43°30’-43°50’N, 85°00-85°30’E) in Yilanhabierga Rangu at ShawanCounty. Formation conditions and morphological characteristics of rockglaciers are studies in terms of topographic conditions, climate, compositionand age.
基金sponsored by the National Key Research&Development Program of China(2017YFB0504204)the K.C.Wong Education Foundation(GJTD-2020-14)+1 种基金the International Collaboration Project of the Chinese Academy of Sciences(131965KYSB20200029)the New Water Resources Strategic Research Project in Southern Xinjiang Uygur Autonomous Region,China(403-1005-YBN-FT6I-8)。
文摘Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes.In this study,we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in the period of 1990-2015 in 4 different mountainous sub-regions in Xinjiang Uygur Autonomous Region of Northwest China:the Bogda Peak and Karlik Mountain sub-regions in the Tianshan Mountains;the Yinsugaiti Glacier sub-region in the Karakorum Mountains;and the Youyi Peak sub-region in the Altay Mountains.The standardized snow cover index(NDSI)and correlation analysis were used to reveal the glacier area changes in the 4 sub-regions from 1990 to 2015.Glacial areas in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions in the period of 1990-2015 decreased by 57.7,369.1,369.1,and 170.4 km^(2),respectively.Analysis of glacier area center of gravity showed that quadrant changes of glacier areas in the 4 sub-regions moved towards the origin.Glacier area on the south aspect of the Karlik Mountain sub-region was larger than that on the north aspect,while glacier areas on the north aspect of the other 3 sub-regions were larger than those on the south aspect.Increased precipitation in the Karlik Mountain sub-region inhibited the retreat of glaciers to a certain extent.However,glacier area changes in the Bogda Peak and Youyi Peak sub-regions were not sensitive to the increased precipitation.On a seasonal time scale,glacier area changes in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions were mainly caused by accumulated temperature in the wet season;on an annual time scale,the correlation coefficient between glacier area and annual average temperature was-0.72 and passed the significance test at P<0.05 level in the Karlik Mountain sub-region.The findings of this study can provide a scientific basis for water resources management in the arid and semi-arid regions of Northwest China in the context of global warming.
基金financially supported by the National Natural Science Foundation of China(41690141)the National Key Research and Development Program of China(2019YFC1510500)。
文摘As important freshwater resources in alpine basins,glaciers and snow cover tend to decline due to climate warming,thus affecting the amount of water available downstream and even regional economic development.However,impact assessments of the economic losses caused by reductions in freshwater supply are quite limited.This study aims to project changes in glacier meltwater and snowmelt of the Urumqi River in the Tianshan Mountains under future climate change scenarios(RCP2.6(RCP,Representative Concentration Pathway),RCP4.5,and RCP8.5)by applying a hydrological model and estimate the economic losses from future meltwater reduction for industrial,agricultural,service,and domestic water uses combined with the present value method for the 2030 s,2050 s,2070 s,and 2090 s.The results indicate that total annual glacier meltwater and snowmelt will decrease by 65.6%and 74.5%under the RCP4.5 and RCP8.5 scenarios by the 2090 s relative to the baseline period(1980-2010),respectively.Compared to the RCP2.6 scenario,the projected economic loss values of total water use from reduced glacier meltwater and snowmelt under the RCP8.5 scenario will increase by 435.10×10^(6) and 537.20×10^(6) CNY in the 2050 s and 2090 s,respectively,and the cumulative economic loss value for 2099 is approximately 2124.00×10^(6) CNY.We also find that the industrial and agricultural sectors would likely face the largest and smallest economic losses,respectively.The economic loss value of snowmelt in different sectorial sectors is greater than that of glacier meltwater.These findings highlight the need for climate mitigation actions,industrial transformation,and rational water allocation to be considered in decision-making in the Tianshan Mountains in the future.
基金supported by Basic Research Project of Institute of Earthquake Science, CEA (grant No.2012IES010103)National Natural Science Foundation of China (grant No. 41204037)
文摘We have developed crustal minimum I-D P- and S-wave velocity models of the collision zone between the northern Tianshan mountain and the Junggar basin (86°E-89°E, 43°N-44.5°N). These two models were created through inversion of 1 370 P- and 1 396 S-wave travel times from 173 well-constrained local earthquakes recorded by the Uriimqi sparse local seismic network and temporary seismic arrays. In contrast to previous models, our results indicate relatively low velocity at both shallow (〈10 km) and deep (30-45 km) depths. The shallow zone is interpreted to be the result of thick surficial sedimentary deposits, whereas the deeper anomaly is interpreted to result from ductile shearing and lower crustal fow. Additionally, we detected several transition layers under the lower crust, which may imply structural complexity of the uppermost mantle in this region. The improved models reduce the RMS residual of earthquake locations by 41.7% from 1.2 to 0.5 seconds. The more accurately located hypocenters appear to correlate with prominent local over-thrusts, which underlie an anticlinal fold belt and several blind faults. Positive station corrections are observed near the Junggar basin, which likely reflects low wave velocity; negative corrections near the Tianshan mountain and Bogda mountain suggest high wave velocity.
基金supported by the National Natural Science Foundation of China (40871036)the Open Foundation of the State Key Laboratory of Cryospheric Science,Chinese Academy of Sciences (SKLCS09-04)+1 种基金the China Postdoctoral Science Foundation (20110490062) the National Natural Science Foundation of China (41001006)
文摘This study analyzes the changes in glacier zones and snow composition of Glacier No.1 in the Tianshan Mountains of China since 1961,and their possible relations with climate.It is found that precipitation dominated the snow composition and that air temperature and precipitation controlled the distribution of glacier zones,but interannual change in precipitation had a relatively large effect on glacier zones and snow composition during 1963–1981 (P10) and 1963–1989 (P11).However,during 1982–2007 (P20) and 1990–2007 (P21),the air temperature rise (0.57°C/10 a for P20,0.76°C/10 a for P21) was more influential than the precipitation increase (51.3 mm/10 a for P20),and air temperature was principally responsible for the evolution of glacier zones and snow composition most probably resulting from recent climate warming.
基金supported by the National Natural Science Foundation of China(41121001 and 41171053)the China Postdoctoral Science Foundation(2012M512049)
文摘The glacier ELA is one of the important parameters reflecting climate change.Based on observations of the equilibrium line altitude(ELA) of Urumqi Glacier No.1 in the Tianshan Mountains,we established a statistical model between ELA and its major influencing factors,warm season air temperature(air temperature averages for May,June,July and August) and annual precipitation.Result showed that,warm season air temperature was the leading climatic factor influencing ELA variations.The glacier ELA ascends(descends) 61.7 m when warm season air temperature increases(decreases) by 1°C,and ascends(descends) 13.1 m when cold season precipitation decreases(increases) by 10%.In the period 1959-2008,the glacier ELA showed a general increasing trend,ascending108 m and reaching its highest altitude in 2008 at 4168 m a.s.l.,close to the glacier summit.If future climate is similar to that in the past 50 years,the ELA of Urumqi Glacier No.1 will still ascend with a speed of 2.16 m/a.However,If future climate is similar to that in the period 2000-2008,the ELA will still ascend with a speed of 6.5 m/a before it is stable.As a result of ELA variation,the accumulation area ratio(AAR) of the glacier showed a decreasing trend during the past 50 years.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA19070501)the National Natural Science Foundation of China(41671066)+2 种基金the Ministry of Science and Technology of the People's Republic of China(2018FY100502)the Young Scholars Science Foundation of Lanzhou Jiaotong University(1200061124)the International Partnership Program of Chinese Academy of Sciences(131C11KYSB20160061)。
文摘On a deglaciated terrain,glacial gravel is the primary component of the natural habitat for vascular plant colonization and succession.Knowledge regarding the role of glacial gravel in vascular plant growth,however,remains limited.In this study,an unmanned aerial vehicle(UAV)was used to investigate plant family composition,species richness,fractional vegetation cover(FVC),and gravel cover(GC)along elevational gradients on the three glacier forelands(Kekesayi,Jiangmanjiaer,and Koxkar Baxi)of the Third Pole(including the eastern Pamir Plateau and western Tianshan Mountains)in China.We then analyzed the spatial characteristics of vascular plants followed by exploring the effect of glacial gravel on vascular plants.Findings indicated that FVC on these glacier forelands generally decreased as the elevation increased or distance from the current glacier terminus decreased.The shady slope(Kekesayi)was more vegetated in comparison to the sunny slope(Jiangmanjiaer)at the glacier basin scale,and the warm and humid deglaciated terrain(Koxkar Baxi)had the highest FVC at the regional scale.Plant family composition and species richness on the glacier forelands decreased with rising elevation,with the exception of those on the Jiangmanjiaer glacier foreland.The relationships between FVC and GC presented negative correlations;particularly,they exhibited variations in power functions on the Kekesayi and Jiangmanjiaer glacier forelands of the eastern Pamir Plateau and a linear function on the Koxkar Baxi glacier foreland of the western Tianshan Mountains.Glacial gravel was found to be conducive to vegetation colonization and development in the early succession stage up until vascular plants adapted to the cold and arid climatic condition,whereas it is unfavorable to the expansion of vascular plants in the later succession stage.These findings suggested that the spatial difference of plant characteristics had close connections with regional climatic and topographic conditions,as well as glacial gravel distribution.In addition,we concluded that aerial photographs can be an asset for studying the functions of micro-environment in vegetation colonization as well as succession on the glacier forelands.
文摘1-15 Martin F.PRICE,TorARNESEN,Erik GL0ERSEN,Marc J.METZGER,Mapping mountain areas:learning from Global,European and Norwegian perspectives,16-29 Peter NOJAROV,Emil GACHEV,Karsten GRUNEWALD,Recent behavior and possible future evolution of the glacieret in the cirque Golemiya Kazan in the Pirin Mountains under conditions of climate warming.
基金National Science and Technology Support Plan Projects,No.2012BAC19B07Scientific Research Project of Higher Learning Institution in Gansu Province,No.2013A-018Project of Scientific Ability Promoting of Young Teachers of Northwest Normal University,No.NWNU-LKQN-12-20
文摘Hydrological processes were compared, with and without the influence of precipita- tion on discharge, to identify the differences between glacierized and non-glacierized catchments in the Urumqi River source region, on the northern slope of the eastern Tianshan Mountains, during the melting season (May-September) in 2011. The study was based on hydrological data observed at 10-min intervals, meteorological data observed at 15-min intervals, and glacier melting and snow observations from the Empty Cirque, Zongkong, and Urumqi Glacier No.1 gauging stations. The results indicated that the discharge differed markedly among the three gauging stations. The daily discharge was more than the nightly discharge at the Glacier No.1 gauging station, which contrasted with the patterns observed at the Zongkong and Empty Cirque gauging stations. There was a clear daily variation in the discharge at the three gauging stations, with differences in the magnitude and duration of the peak discharge. When precipitation was not considered, the time-lags between the maximum discharge and the highest temperature were 1-3 h, 10-16 h, and 5-11 h at the Glacier No.l, Empty Cirque, and Zongkong gauging stations, respectively. When precipitation was taken into consideration, the corresponding time-lags were 0-1 h, 13 h, and 6-7 h, respectively. Therefore, the duration from the generation of discharge to confluence was the shortest in the glacierized catchment and the longest in the catchment where was mainly covered by snow. It was also shown that the hydrological process from the generation of discharge to confluence shortened when precipitation was considered. The factors influencing changes in the discharge among the three gauging stations were different. For Glacier No.1 station, the discharge was mainly controlled by heat conditions in the glacierized region, and the discharge displayed an accelerated growth when the temperature exceeded 5℃ in the melt season. It was found that the englacial and subglacial drainage channel of Glacier No.1 had become simpler during the past 20 years. Its weaker retardance and storage of glacier melting water resulted in rapid discharge confluence. It was also shown that the discharge curve and the time-lag between the maximum discharge and the highest temperature could be used to reveal the evolution of the drainage system and the process of glacier and snow melting at different levels of glacier coverage.