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
This paper is based on observed mass balance between East and West Branch of Urumqi Glacier No. l, meteorological data dur- ing 1988-2010, comparative studies the mass balance variations, and analyses the mass balance...This paper is based on observed mass balance between East and West Branch of Urumqi Glacier No. l, meteorological data dur- ing 1988-2010, comparative studies the mass balance variations, and analyses the mass balance sensitivity to climate change. Re- sults show that average mass balance of East and West Branch was -532 mm/a and 435 mm/a, cumulative mass balance was 12,227 mm (ice thinned by 13.6 m) and -10,001 mm (ice thinned by 11.1 m), respectively, and mass loss of East Branch was 97 mm/a larger than West Branch. The East and West Branch ELA (equilibrium line altitude) ascended about 176 m and 154 m, analysis shows the steady-state ELA0 was 3,942 m a.s.1, and 4,011 m a.s.1., and when East and West Branch mass balance de- creased by 100 ram, ELA ascended 20 m and 23 m, respectively. The AAR (accumulation area ratio) of East and West Branch presented an obviously decreasing trend of 34.5% and 23%, equilibrium-state AAR0 was 65% and 66%, when East and West Branch mass balance increased by 100 mm, AAR ascended 4.6% and 4.2%, respectively. Glacier mass balance was sensitive to change of net ablation, net ablation of East and West Branch increased 10x 104 m3, and mass balance decreased 110 mm and 214 mm, respectively. By analyzing mass balance sensitivity to climate change, results suggest that East and West Branch mass bal- ance decreased (increased) 463 mm and 388 mm when ablation period temperature increased (decreased) by 1 ~C, East and West Branch mass balance increased (decreased) 140 mm and 158 mm when annual precipitation increased (decreased) by 100 mm, and sensitivity of East Branch mass balance to climate change was more intense than that of West Branch.展开更多
Similar to most mountain glaciers in the world, Urumqi Glacier No. 1 (UG1), the best observed glacier in China with continued glaciological and climatological monitoring records of longer than 50 years has experienc...Similar to most mountain glaciers in the world, Urumqi Glacier No. 1 (UG1), the best observed glacier in China with continued glaciological and climatological monitoring records of longer than 50 years has experienced an accelerated recession during the past several decades. The purpose of this study is to investigate the acceleration of recession. By taking UG1 as an example, we analyze the generic mechanisms of acceleration of shrinkage of continental mountain glaciers. The results indicate that the acceleration of mass loss of UG1 commenced first in 1985 and second in 1996 and that the lat- ter was more vigorous. The air temperature rises during melting season, the ice temperature augment of the glacier and the albedo reduction on the glacier surface are considered responsible for the accelerated recession. In addition, the simulations of the accelerated shrinkage of UG1 are introduced in this article.展开更多
In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for t...In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for the period 1987/1988-2007/2008 based on temperature and precipitation data from a nearby climate station. The model is calibrated by simulating point measurements of mass bal- ance, mass balance profiles, and mean specific mass balance during 1987/1988-1996/1997. The opti- mized parameters are obtained by using a least square method to make the model fit the measured mass balance through the model calibration. The model validation (1997/1998-2007/2008) indicates that the modeled results are in good agreement with the observations. The static mass balance sensitiv- ity of Urumqi Glacier No. 1 is analyzed by computing the mass balance of the glacier for a temperature increase of 1℃, with and without a 5% precipitation increase, and the values for the east branch are -0.80 and -0.87 m w.e. a-1℃-1, respectively, and for the west branch, the values are -0.68 and -0.74 m w.e. a-1℃-1, respectively. Moreover, the analysis of the parameter stability indicates that the parame- ters in the model determined from the current climate condition can be applied in the prediction of the future mass balance changes for the glacier and provide a reference for extending the model to other small glaciers in western China.展开更多
Chemical records from alpine ice cores provide an invaluable source of paleoclimatic and environ- mental information. Not only the atmospheric chemical composition but also depositional and post-depositional processes...Chemical records from alpine ice cores provide an invaluable source of paleoclimatic and environ- mental information. Not only the atmospheric chemical composition but also depositional and post-depositional processes are recorded within snow/tim strata. To interpret the environmental and climatic significance of ice core records, we studied the variability of glacier snowpack chemistry by investigating homogeneous snowpacks from October 2003 to September 2006 on Urumqi Glacier No. 1 in eastern Tianshan Mountains, Central Asia. Principle Component Analysis of ionic species in dry and wet seasons revealed the impact of meltwater in redistributing ions in the snowpacks. The 1st, 2nd and 3rd principle components for dry seasons differ significantly, reflecting complex associations between depositional or/and post-depositional processes. The variability trend of ionic concentrations during the wet seasons was found to fit a Gauss Function with significant parameters. The elution factor revealed that more than half of ions are leached out during the wet seasons. Differences with respect to ion snowpack mo- bility were found. Of the ions studied SO42- was the most mobile and Mg2+ the least mobile. A threshold relationship between air temperatures and the elution process was investigated over the study period. The results indicate that the strong melt/ablation processes and iconic redistribution occur at a threshold air temperature of 0℃. The study found that surface melt on the snowpacks is the main factor causing the alteration of the snowpack chemistry. Rainfall also has an impact on the chemistry but plays a less significant role than the surface melt.展开更多
To investigate the seasonal variability and potential environmental significance of trace elements in mountain glaciers, the surface snow and snow pit samples were collected at Urumqi Glacier No. 1 (43°06′N, 86...To investigate the seasonal variability and potential environmental significance of trace elements in mountain glaciers, the surface snow and snow pit samples were collected at Urumqi Glacier No. 1 (43°06′N, 86°49′E, 4 130 m a.s.l.), eastern Tianshan (天山), from September 2002 to September 2003, and analyzed for Li, V, Cr, Mn, Co, Cu, and Ba. The samples were acidified (leached) in a manner intended to reasonably approximate the extent to which the natural hydrologic and weathering cycles would liberate elements from mineral grains (dusts) in the ice and snow into the environment. The mean concentrations of Li, V, Cr, Mn, Co, Cu, and Ba are 0.2, 1.1, 0.8, 14.8, 0.1, 0.7, and 3.2 ng/g in surface snow but 1.0, 2.2, 1.8, 92.4, 0.8, 2.9, and 16.2 ng/g in snow pits, respectively. Input varies seasonally: in general, concentrations in the winter are higher than those in the summer. The trace elements are somewhat enriched (relative to expected abundances in material taken di- rectly from the earth's crust) and similar to what is observed in both pre-industrial and modern atmospheric dusts, although some anthropogenic components from nearby industrial cities may be present. Concentration vertical profiles can be redistributed in the post-depositional process, which may cause loss of trace elements in the summer.展开更多
Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007.The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7...Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007.The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7.61 in 2006 and 2007,respectively.In the meltwater,the dominant anions were the bicarbonate and sulphate,and the dominant cation was calcium.The concentration of major cations were varied as c(Ca2+) > c(Mg2+) > c(K+) > c(Na+),while the order for the cations was c(HCO3) > c(SO42) > c(NO3) > c(Cl).The total dissolved solids(TDS) in meltwater had inverse relationships with the diurnal discharge.The major ion composition of meltwater was mainly controlled by rock weathering as inferred from the Gibbs model.Furthermore,the ion ratios and Piper diagram indicated that the main processes controlling the meltwater chemistry were carbonate weathering,pyrite weathering and feldspar weathering in rocks,and Ca2+ and HCO3 were the dominant ions during the carbonate weathering process.Solute flux calculation at Glacier No.1 station suggested that chemical denudation rates were 11.46 and 13.90 ton.km 2.yr 1 in 2006 and 2007,respectively.展开更多
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
This research aimed to identify and characterize individual spherical fly ash particles extracted from surface snow at Urumqi Glacier No.1 (UG1), Eastern Tien Shan, central Asia. Characterization of the spherical part...This research aimed to identify and characterize individual spherical fly ash particles extracted from surface snow at Urumqi Glacier No.1 (UG1), Eastern Tien Shan, central Asia. Characterization of the spherical particles (i.e. morphology, chemical composition and genesis) was obtained by scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDX). This method enabled the characterization of submicroscopic spherical particles, which were present in very small quantities. Spherical particles and agglomerates were identified according to their morphology in five snow samples. Prevalent particle types in all samples were granular spherical particles, hollow spherical particles, irregularly shaped carbonaceous particles and agglomerates. The vast majority of spherical particles in our samples had mostly smooth and glossy surfaces, although these particles varied in diameter and elemental composition. The diameter of fly ash particles ranged from 0.76 to 16.7 m, with an average of 3.79 m (median: 3.21 m). Individual particle analyses of elemental composition showed that particles formed in combustion were mainly composed of carbon, silicon, aluminum and trace elements (e.g. Na, K, Ca, Fe). Some spherical fly ash particles contained toxic heavy metals (e.g. Pb, Cr, As, Zn), and indicated that fly ash particles acted as the main possible carriers of toxic heavy metals deposited in snow and ice of glaciers in high altitudes of central Asia. On the basis of chemical information obtained from EDX, the fly ash particles deposited in the snow could be classified into four types. Namely, Si-dominant particles, with average diameters of 3.24 m were formed by industrial coal combustion via high temperature processes in typical coal-fired heating stations and thermal power plants. Moreover, Fe-dominant particles, with average diameters of 3.82 m, and Ti-dominant spherical particles formed by lower temperature processes in foundry and iron or steel plants. In addition, C-dominant particles, with average diameters of 8.43 m, formed from unburned coal. Fe-dominant particles had larger average diameters than Sidominant particles, indicating that the former were easier to form and developed earlier in the furnace because of their differential melting points of compositional oxide. Backward air mass trajectory analysis suggests that the developed urban regions of central Asia contributed the primary fly ash particles from industrial combustion to the study site through the high-level westerlies jet steam.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
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
Accurate measurements of glacier elevation changes play a crucial role in various glaciological studies related to glacier dynamics and mass balance. In this paper, glacier elevation changes of Urumqi Glacier No.1 bet...Accurate measurements of glacier elevation changes play a crucial role in various glaciological studies related to glacier dynamics and mass balance. In this paper, glacier elevation changes of Urumqi Glacier No.1 between August 2015 and August 2017 were investigated using Sentinel-1 A data and DInSAR technology. Meanwhile, the atmospheric delay error was corrected with the MODIS MOD05L2 products. The weight selection iteration method was applied to calibrate the glacier elevation changes in the mass balance years 2015-2016 and 2016-2017. Finally, the geodetic method was employed to calculate the elevation change values of individual stakes of Urumqi Glacier No.1. Moreover, the elevation change values corrected by the weight selection iteration method were verified. Results showed as follows:(1) the elevation of Urumqi Glacier No.1 glacier affected by atmospheric delay was 1.270 cm from 2015 to 2016. The glacier elevation affected by atmospheric delay from 2016 to 2017 was 1.071 cm.(2) The elevation change value of Urumqi Glacier No.1 was-1.101 m from 2015 to 2016, and the elevation of Urumqi Glacier No.1 decreased by 1.299 m from 2016 to 2017. The overall thickness of Urumqi Glacier No. 1 was thinning.(3) By comparing the elevation change results of individual stakes with corresponding points corrected by the weight selection iteration method, the mean squared errors of difference were 0.343 m and 0.280 m between the two mass balance years, respectively.(4) The accuracy of elevation change in non-glaciated areas was 0.039 m from 2015 to 2016 and 0.034 m from 2016 to 2017. Therefore, it is reliable to use Sentinel-1 A data and the study method proposed in this paper to calculate the elevation change of mountain glaciers with very low horizontal movement.展开更多
For most mountain glaciers,chemical components in snowfall are subject to the elution process under the influences of meltwater before they are preserved in ice,creating difficulties for interpreting ice core records....For most mountain glaciers,chemical components in snowfall are subject to the elution process under the influences of meltwater before they are preserved in ice,creating difficulties for interpreting ice core records.To understand the formation process of ice core records and analyze the influences of meteorological factors on the ice core resolution,we measured ion concentrations of snowpacks from 2003 to 2006 in the PGPI(Program for Glacier Processes Investigation)site of Urumqi Glacier No.1.The ion concentration variation in snowpack exhibits apparent seasonality.In summer,the higher snowmelt rates due to air temperature rise intensify dilution and lead to an exponential decrease in ion concentrations as the accumulated positive temperature increases.In winter,the snow ion concentrations are stable and low as a result of reduced temperature and rare precipitation.Many ions from summer precipitation are leached out by meltwater,and only the precipitation that occurs at the end of the wet season can be preserved.Through tracking the evolution of magnesium ion peaks in the snowpack,it is concluded that the ice core resolution is one year on Urumqi Glacier No.1,albeit 70%of the concentration information is lost.展开更多
Surface snow samples of different altitudes and snow pit samples were collected from Glacier No. 1 at the Urumqi River Head, Tianshan. Denaturing gradient gel electrophoresis (DGGE) was used to examine the diversity...Surface snow samples of different altitudes and snow pit samples were collected from Glacier No. 1 at the Urumqi River Head, Tianshan. Denaturing gradient gel electrophoresis (DGGE) was used to examine the diversity and temporal-spatial characteristics of eukaryotic microorganisms with different altitudes and depths. Results show that the eukaryotic microorganisms belong to four kingdoms--Viridiplantae, Fungi, Amoebozoa, and Alveolata. Among them, algae (especially Chlamydomonadales) were the dominant group. The diversity of eukaryotic microorganisms was negatively correlated with altitude and accumulation time, but positively correlated with 8180 values. These results indicate that temperature is the main factor for the temporal-spatial change of eukaryotic microorganisms, and the diversity of eukaryotic microorganisms could be an index for climate and environmental change.展开更多
Snowpacks samples were colleted from two glaciers: Baishui No.1 glacier and Hailuogou No.1 glacier in June, 2006. The method of sea-salt ions tracer, correlation analysis and trend analysis were used in this research...Snowpacks samples were colleted from two glaciers: Baishui No.1 glacier and Hailuogou No.1 glacier in June, 2006. The method of sea-salt ions tracer, correlation analysis and trend analysis were used in this research in order to confirm the source of main ions, it is indicated that Na^+ is mainly from marine moisture and other ions mainly originate from land dust. The non-marine source percent of Cl^-, NO3^- , SO4^2-, K^+, Ca^2+ and Mg^2+ is 52%, 99%, 100%, 98%, 99.9% and 83%, respectively, in Hailuogou No.1 glacier, while the corresponding value in Baishui No.1 glacier is 68%, 99%, 100%, 98%, 99% and 59%. The non-marine source of ions is from dust of Central Asia arid regions carried by westerly circulation and the plateau borne-areas with Qinghai-Tibet Plateau winter monsoon in two glacial areas. However, the import of local dust in glacial area has made a great contribution to ions concentration in Baishui No.1 glacier, which accounts for the reason why the ions concentration in Baishui No.1 glacier is much higher than that of Hailuogou No.1 glacier. It is obvious that the source of each ion is different between Hailuogou No.1 glacier and Baishui No.1 glacier. There are three reasons which can explain it: firstly, the difference in the internal environment of glacial area, such as lithology, mountain-valley wind system, topographical relief and so on; secondly, the influence exerted by ions elution in snowpacks section, and ions elution in Hailuogou No.1 glacier is very strong; and thirdly, the difference caused due to varying ions transporting styles, deposition modes, chemical characteristics and post-ions-deposition process.展开更多
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supported by the National Natural Science Foundation of China (Grant Nos. 41001040 and J0630966)the Foundation for Excellent Youth Scholars of CAREERI (No. 51Y084911)the National Basic Research Program of China (2010CB951003)
文摘This paper is based on observed mass balance between East and West Branch of Urumqi Glacier No. l, meteorological data dur- ing 1988-2010, comparative studies the mass balance variations, and analyses the mass balance sensitivity to climate change. Re- sults show that average mass balance of East and West Branch was -532 mm/a and 435 mm/a, cumulative mass balance was 12,227 mm (ice thinned by 13.6 m) and -10,001 mm (ice thinned by 11.1 m), respectively, and mass loss of East Branch was 97 mm/a larger than West Branch. The East and West Branch ELA (equilibrium line altitude) ascended about 176 m and 154 m, analysis shows the steady-state ELA0 was 3,942 m a.s.1, and 4,011 m a.s.1., and when East and West Branch mass balance de- creased by 100 ram, ELA ascended 20 m and 23 m, respectively. The AAR (accumulation area ratio) of East and West Branch presented an obviously decreasing trend of 34.5% and 23%, equilibrium-state AAR0 was 65% and 66%, when East and West Branch mass balance increased by 100 mm, AAR ascended 4.6% and 4.2%, respectively. Glacier mass balance was sensitive to change of net ablation, net ablation of East and West Branch increased 10x 104 m3, and mass balance decreased 110 mm and 214 mm, respectively. By analyzing mass balance sensitivity to climate change, results suggest that East and West Branch mass bal- ance decreased (increased) 463 mm and 388 mm when ablation period temperature increased (decreased) by 1 ~C, East and West Branch mass balance increased (decreased) 140 mm and 158 mm when annual precipitation increased (decreased) by 100 mm, and sensitivity of East Branch mass balance to climate change was more intense than that of West Branch.
基金supported by the National Basic Research Program of China (No. 2007CB411501)the Knowledge Innovation Project of the Chinese Academy of Sciences (No. KZCX2-EW-311)the National Natural Science Foundation of China (Nos. 91025012, J0930003/J0109)
文摘Similar to most mountain glaciers in the world, Urumqi Glacier No. 1 (UG1), the best observed glacier in China with continued glaciological and climatological monitoring records of longer than 50 years has experienced an accelerated recession during the past several decades. The purpose of this study is to investigate the acceleration of recession. By taking UG1 as an example, we analyze the generic mechanisms of acceleration of shrinkage of continental mountain glaciers. The results indicate that the acceleration of mass loss of UG1 commenced first in 1985 and second in 1996 and that the lat- ter was more vigorous. The air temperature rises during melting season, the ice temperature augment of the glacier and the albedo reduction on the glacier surface are considered responsible for the accelerated recession. In addition, the simulations of the accelerated shrinkage of UG1 are introduced in this article.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No. KZCX2-EW-311)the National Basic Research Program of China (No. 2007CB411501)the National Natural Science Foundation of China (Nos. 1141001040, J0930003/J0109)
文摘In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for the period 1987/1988-2007/2008 based on temperature and precipitation data from a nearby climate station. The model is calibrated by simulating point measurements of mass bal- ance, mass balance profiles, and mean specific mass balance during 1987/1988-1996/1997. The opti- mized parameters are obtained by using a least square method to make the model fit the measured mass balance through the model calibration. The model validation (1997/1998-2007/2008) indicates that the modeled results are in good agreement with the observations. The static mass balance sensitiv- ity of Urumqi Glacier No. 1 is analyzed by computing the mass balance of the glacier for a temperature increase of 1℃, with and without a 5% precipitation increase, and the values for the east branch are -0.80 and -0.87 m w.e. a-1℃-1, respectively, and for the west branch, the values are -0.68 and -0.74 m w.e. a-1℃-1, respectively. Moreover, the analysis of the parameter stability indicates that the parame- ters in the model determined from the current climate condition can be applied in the prediction of the future mass balance changes for the glacier and provide a reference for extending the model to other small glaciers in western China.
基金supported by the National Natural Science Foundation of China (41261017)
文摘Chemical records from alpine ice cores provide an invaluable source of paleoclimatic and environ- mental information. Not only the atmospheric chemical composition but also depositional and post-depositional processes are recorded within snow/tim strata. To interpret the environmental and climatic significance of ice core records, we studied the variability of glacier snowpack chemistry by investigating homogeneous snowpacks from October 2003 to September 2006 on Urumqi Glacier No. 1 in eastern Tianshan Mountains, Central Asia. Principle Component Analysis of ionic species in dry and wet seasons revealed the impact of meltwater in redistributing ions in the snowpacks. The 1st, 2nd and 3rd principle components for dry seasons differ significantly, reflecting complex associations between depositional or/and post-depositional processes. The variability trend of ionic concentrations during the wet seasons was found to fit a Gauss Function with significant parameters. The elution factor revealed that more than half of ions are leached out during the wet seasons. Differences with respect to ion snowpack mo- bility were found. Of the ions studied SO42- was the most mobile and Mg2+ the least mobile. A threshold relationship between air temperatures and the elution process was investigated over the study period. The results indicate that the strong melt/ablation processes and iconic redistribution occur at a threshold air temperature of 0℃. The study found that surface melt on the snowpacks is the main factor causing the alteration of the snowpack chemistry. Rainfall also has an impact on the chemistry but plays a less significant role than the surface melt.
基金supported by the Knowledge Innovation Project of Chinese Academy of Sciences (No. KZCX2-EW-311)the National Natural Science Foundation of China (Nos. 1141001040 and J0930003/J0109)+1 种基金the State Key Laboratory of Cryospheric Sciences Founding (No. SKLCS-ZZ-2010-04)the Program for New Century Excellent Talents in University from Ministry of Education of China (No. NCET-10-0019)
文摘To investigate the seasonal variability and potential environmental significance of trace elements in mountain glaciers, the surface snow and snow pit samples were collected at Urumqi Glacier No. 1 (43°06′N, 86°49′E, 4 130 m a.s.l.), eastern Tianshan (天山), from September 2002 to September 2003, and analyzed for Li, V, Cr, Mn, Co, Cu, and Ba. The samples were acidified (leached) in a manner intended to reasonably approximate the extent to which the natural hydrologic and weathering cycles would liberate elements from mineral grains (dusts) in the ice and snow into the environment. The mean concentrations of Li, V, Cr, Mn, Co, Cu, and Ba are 0.2, 1.1, 0.8, 14.8, 0.1, 0.7, and 3.2 ng/g in surface snow but 1.0, 2.2, 1.8, 92.4, 0.8, 2.9, and 16.2 ng/g in snow pits, respectively. Input varies seasonally: in general, concentrations in the winter are higher than those in the summer. The trace elements are somewhat enriched (relative to expected abundances in material taken di- rectly from the earth's crust) and similar to what is observed in both pre-industrial and modern atmospheric dusts, although some anthropogenic components from nearby industrial cities may be present. Concentration vertical profiles can be redistributed in the post-depositional process, which may cause loss of trace elements in the summer.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX2-EW-311)the National Natural Science Foundation of China(Nos. 91025012,40701034,J0630966/J0109, 40701035)+1 种基金the SKLCS founding(SKLCS-ZZ-201004,SKLCS-ZZ-2012-01-01)the Foundation for Excellent Youth Scholars of CAREERI,Chinese Academy of Sciences(Y184C81001)
文摘Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007.The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7.61 in 2006 and 2007,respectively.In the meltwater,the dominant anions were the bicarbonate and sulphate,and the dominant cation was calcium.The concentration of major cations were varied as c(Ca2+) > c(Mg2+) > c(K+) > c(Na+),while the order for the cations was c(HCO3) > c(SO42) > c(NO3) > c(Cl).The total dissolved solids(TDS) in meltwater had inverse relationships with the diurnal discharge.The major ion composition of meltwater was mainly controlled by rock weathering as inferred from the Gibbs model.Furthermore,the ion ratios and Piper diagram indicated that the main processes controlling the meltwater chemistry were carbonate weathering,pyrite weathering and feldspar weathering in rocks,and Ca2+ and HCO3 were the dominant ions during the carbonate weathering process.Solute flux calculation at Glacier No.1 station suggested that chemical denudation rates were 11.46 and 13.90 ton.km 2.yr 1 in 2006 and 2007,respectively.
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supported by the National Natural Science Foundation of China (40871046, 40571038 and 4081019001) the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-146)
文摘This research aimed to identify and characterize individual spherical fly ash particles extracted from surface snow at Urumqi Glacier No.1 (UG1), Eastern Tien Shan, central Asia. Characterization of the spherical particles (i.e. morphology, chemical composition and genesis) was obtained by scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDX). This method enabled the characterization of submicroscopic spherical particles, which were present in very small quantities. Spherical particles and agglomerates were identified according to their morphology in five snow samples. Prevalent particle types in all samples were granular spherical particles, hollow spherical particles, irregularly shaped carbonaceous particles and agglomerates. The vast majority of spherical particles in our samples had mostly smooth and glossy surfaces, although these particles varied in diameter and elemental composition. The diameter of fly ash particles ranged from 0.76 to 16.7 m, with an average of 3.79 m (median: 3.21 m). Individual particle analyses of elemental composition showed that particles formed in combustion were mainly composed of carbon, silicon, aluminum and trace elements (e.g. Na, K, Ca, Fe). Some spherical fly ash particles contained toxic heavy metals (e.g. Pb, Cr, As, Zn), and indicated that fly ash particles acted as the main possible carriers of toxic heavy metals deposited in snow and ice of glaciers in high altitudes of central Asia. On the basis of chemical information obtained from EDX, the fly ash particles deposited in the snow could be classified into four types. Namely, Si-dominant particles, with average diameters of 3.24 m were formed by industrial coal combustion via high temperature processes in typical coal-fired heating stations and thermal power plants. Moreover, Fe-dominant particles, with average diameters of 3.82 m, and Ti-dominant spherical particles formed by lower temperature processes in foundry and iron or steel plants. In addition, C-dominant particles, with average diameters of 8.43 m, formed from unburned coal. Fe-dominant particles had larger average diameters than Sidominant particles, indicating that the former were easier to form and developed earlier in the furnace because of their differential melting points of compositional oxide. Backward air mass trajectory analysis suggests that the developed urban regions of central Asia contributed the primary fly ash particles from industrial combustion to the study site through the high-level westerlies jet steam.
基金supported by National Key Project for Basic Research of China,No.2007CB411501National Natural Science Foundation of China,No.4087103+1 种基金International Innovation Partnership Program of the Chinese Academy of Sciences No. CXTD-Z2005-2Knowledge Innovation Project of the Chinese Academy of Sciences No. KZCX2-YW-127
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funded by the Natural Science Foundation of China (Grants No.41761134093)Gansu Provincial Department of Education: ‘Star of Innovation’ Project of Excellent Graduate Students (Grants No.2021CXZX-188)。
文摘Accurate measurements of glacier elevation changes play a crucial role in various glaciological studies related to glacier dynamics and mass balance. In this paper, glacier elevation changes of Urumqi Glacier No.1 between August 2015 and August 2017 were investigated using Sentinel-1 A data and DInSAR technology. Meanwhile, the atmospheric delay error was corrected with the MODIS MOD05L2 products. The weight selection iteration method was applied to calibrate the glacier elevation changes in the mass balance years 2015-2016 and 2016-2017. Finally, the geodetic method was employed to calculate the elevation change values of individual stakes of Urumqi Glacier No.1. Moreover, the elevation change values corrected by the weight selection iteration method were verified. Results showed as follows:(1) the elevation of Urumqi Glacier No.1 glacier affected by atmospheric delay was 1.270 cm from 2015 to 2016. The glacier elevation affected by atmospheric delay from 2016 to 2017 was 1.071 cm.(2) The elevation change value of Urumqi Glacier No.1 was-1.101 m from 2015 to 2016, and the elevation of Urumqi Glacier No.1 decreased by 1.299 m from 2016 to 2017. The overall thickness of Urumqi Glacier No. 1 was thinning.(3) By comparing the elevation change results of individual stakes with corresponding points corrected by the weight selection iteration method, the mean squared errors of difference were 0.343 m and 0.280 m between the two mass balance years, respectively.(4) The accuracy of elevation change in non-glaciated areas was 0.039 m from 2015 to 2016 and 0.034 m from 2016 to 2017. Therefore, it is reliable to use Sentinel-1 A data and the study method proposed in this paper to calculate the elevation change of mountain glaciers with very low horizontal movement.
基金supported by the National Natural Science Foundation of China(41761017,41261017)the Natural Science Foundation of Gansu Province(18JR3RE247)
文摘For most mountain glaciers,chemical components in snowfall are subject to the elution process under the influences of meltwater before they are preserved in ice,creating difficulties for interpreting ice core records.To understand the formation process of ice core records and analyze the influences of meteorological factors on the ice core resolution,we measured ion concentrations of snowpacks from 2003 to 2006 in the PGPI(Program for Glacier Processes Investigation)site of Urumqi Glacier No.1.The ion concentration variation in snowpack exhibits apparent seasonality.In summer,the higher snowmelt rates due to air temperature rise intensify dilution and lead to an exponential decrease in ion concentrations as the accumulated positive temperature increases.In winter,the snow ion concentrations are stable and low as a result of reduced temperature and rare precipitation.Many ions from summer precipitation are leached out by meltwater,and only the precipitation that occurs at the end of the wet season can be preserved.Through tracking the evolution of magnesium ion peaks in the snowpack,it is concluded that the ice core resolution is one year on Urumqi Glacier No.1,albeit 70%of the concentration information is lost.
基金supported by National Natural Science Foundation of China (Grant No.30770329,No.40971034,No.30800154)China Postdoctoral Science Fund (Grant No.20080430794)
文摘Surface snow samples of different altitudes and snow pit samples were collected from Glacier No. 1 at the Urumqi River Head, Tianshan. Denaturing gradient gel electrophoresis (DGGE) was used to examine the diversity and temporal-spatial characteristics of eukaryotic microorganisms with different altitudes and depths. Results show that the eukaryotic microorganisms belong to four kingdoms--Viridiplantae, Fungi, Amoebozoa, and Alveolata. Among them, algae (especially Chlamydomonadales) were the dominant group. The diversity of eukaryotic microorganisms was negatively correlated with altitude and accumulation time, but positively correlated with 8180 values. These results indicate that temperature is the main factor for the temporal-spatial change of eukaryotic microorganisms, and the diversity of eukaryotic microorganisms could be an index for climate and environmental change.
基金National Key Natural Science Foundation of China, No.90511007 National Natural Science Foundation of China, No.40501014+2 种基金 The Project for Important Directionality Foundation, CAS, No.KZCXZ-YW-317 The Project for Outstanding Young Scientists of Natural Science Foundation of China, No.40121101 The Knowledge Innovation Program, CAS, No.CXTD-Z2005-2
文摘Snowpacks samples were colleted from two glaciers: Baishui No.1 glacier and Hailuogou No.1 glacier in June, 2006. The method of sea-salt ions tracer, correlation analysis and trend analysis were used in this research in order to confirm the source of main ions, it is indicated that Na^+ is mainly from marine moisture and other ions mainly originate from land dust. The non-marine source percent of Cl^-, NO3^- , SO4^2-, K^+, Ca^2+ and Mg^2+ is 52%, 99%, 100%, 98%, 99.9% and 83%, respectively, in Hailuogou No.1 glacier, while the corresponding value in Baishui No.1 glacier is 68%, 99%, 100%, 98%, 99% and 59%. The non-marine source of ions is from dust of Central Asia arid regions carried by westerly circulation and the plateau borne-areas with Qinghai-Tibet Plateau winter monsoon in two glacial areas. However, the import of local dust in glacial area has made a great contribution to ions concentration in Baishui No.1 glacier, which accounts for the reason why the ions concentration in Baishui No.1 glacier is much higher than that of Hailuogou No.1 glacier. It is obvious that the source of each ion is different between Hailuogou No.1 glacier and Baishui No.1 glacier. There are three reasons which can explain it: firstly, the difference in the internal environment of glacial area, such as lithology, mountain-valley wind system, topographical relief and so on; secondly, the influence exerted by ions elution in snowpacks section, and ions elution in Hailuogou No.1 glacier is very strong; and thirdly, the difference caused due to varying ions transporting styles, deposition modes, chemical characteristics and post-ions-deposition process.