Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region,located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms,where dist...Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region,located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms,where distribution of plant species is actually limited. It is known to have sufficient endemic floral biodiversity in the Northern Asia. Many plants of Altai Mountain System need effective care and proper conservation measures for their survival and longer-term protection. Important Plant Area identified as the IUCN (the International Union for Conservation of Nature),specified criteria attract global attention for protection of floral biodiversity across the world. The records of 71 plant species from the Chinese Altai Mountains attributed to the criterion A and the dark conifer forests of Chinese Altai Mountains satisfied the criterion C,which may help qualify to fulfill the national obligation of the Convention on Biological Diversity.展开更多
This study presents the long-term temperature monitoring in the Russian Altai Mountains. In contrast to the Mongolian and Chinese parts, the modern temperature regime of the Russian Altai remains unclear. The complexi...This study presents the long-term temperature monitoring in the Russian Altai Mountains. In contrast to the Mongolian and Chinese parts, the modern temperature regime of the Russian Altai remains unclear. The complexity of a comprehensive understanding of permafrost conditions in the Russian Altai is related to the high dissection of the terrain, the paucity of the latest observational data, and the sparse population of permafrost areas. The general objective of this study is to determine the temperature regime on the surface,in the active layer, and in the zero annual amplitude(ZAA) layer, based on the known patterns of permafrost distribution in the region. Using automatic measuring equipment(loggers), we obtained information on the temperature of frozen and thawed ground within the altitudes from 1484 to 2879 m a. s. l. during the period from 2014 to 2020.An array of 15 loggers determined the temperature regime of bare and vegetated areas within watersheds,slopes, and valleys. N-factor parameters and surface temperature are similar to those in the Mongolian Altai, but the mean annual ground temperature at the depth of 1 m has a wide range of fluctuations(more than 32℃) based on research results, and we allocated it into three groups based on altitudinal zonality. Snow cover has a strong influence on the temperature regime, but the determination of the fine-scale variability requires additional study.Ground temperature regime during the observation period remained stable, but continued monitoring allows a more detailed assessment of the response to climatic changes.展开更多
Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-b...Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER) stereo images(2008). The results indicate that a continued and accelerating shrinkage has occurred in the Chinese Altai Mountains during the last 50 years, with mass deficits of 0.43 ± 0.02 and0.54 ± 0.13 m a-1 water equivalent(w.e.) during the periods 1959-1999 and 1999-2008, respectively.Overall, the Chinese Altai Mountains have lost 7.06 ±0.44 km3 in ice volume(equivalent to-0.43 ± 0.03 m a-1 w.e.) from 1959-2008. The spatial heterogeneity in mass loss was potentially affected by comprehensive changes in temperature and precipitation, and had a substantial correlation withglacier size and topographic settings. Comparison shows that in the Chinese Altai Mountains glaciers have experienced a more rapid mass loss than those in the Tianshan and northwestern Tibetan Plateau(TP), and the mass balance of glaciers was slightly less negative relative to those in the Russian Altai, Himalaya, and southern TP.展开更多
With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect o...With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect on runoff is the key to water safety, under climate warming and fast social-economic developing status. In this study, stable isotopic technology was utilized to analyze the snow meltwater effect on regional hydrological processes, and to declare the response of snow hydrology to climate change and snow cover regime, together with longterm meteorological and hydrological observations, in the headwater of Irtysh River, Chinese Altai Mountains during 1961-2015. The average δ^(18) O values of rainfall, snowfall, meltwater, groundwater and river water for 2014–2015 hydrological year were-10.9‰,-22.3‰,-21.7‰,-15.7‰ and-16.0‰, respectively.The results from stable isotopes, snow melting observation and remote sensing indicated that the meltwater effect on hydrological processes in Kayiertesi River Basin mainly occurred during snowmelt supplying period from April to June. The contribution of meltwater to runoff reached 58.1% during this period, but rainfall, meltwater and groundwater supplied 49.1%, 36.9% and 14.0% of water resource to annual runoff, respectively. With rising air temperature and increasing snowfall in cold season, the snow water equivalent(SWE) had an increasing trend but the snow cover duration declined by about one month including 13-day delay of the first day and 17-day advancement of the end day during 1961–2016. Increase in SWE provided more available water resource. However, variations in snow cover timing had resulted in redistribution of surface water resource, represented by an increase of discharge percentage in April and May, and a decline in Juneand July. This trend of snow hydrology will render a deficit of water resource in June and July when the water resource demand is high for agricultural irrigation and industrial manufacture.展开更多
We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in t...We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in the precipitation regime had a positive trend for the warm seasons(April-October),but weakly positive or negative trends for the cold seasons(November-March). It was found that these changes correspond to the decreasing contribution of "Northern meridional and Stationary anticyclone(Nm-Sa)" and "Northern meridional and East zonal(Nm-Ez)" circulation groups and to the increasing contribution of "West zonal and Southern meridional(Wz-Sm)" circulation groups,accordingly to the Dzerdzeevskii classification. In addition,it was found that the variation of precipitation has a step change point in 1980. For the warm seasons,the precipitation change at this point is associated with the reduced influence of "West zonal(Wz)","Northern meridional and Stationary anticyclone(Nm-Sa)" and "Northern meridional and Southern meridional(Nm-Sm)" circulation groups. For the cold seasons,a substantialincrease of "Wz-Sm" and a decrease of "Nm-Sa","Nm-Ez" circulation groups are responsible for the precipitation change in the two time periods(1959-1980 and 1981-2014).展开更多
To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns be...To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat(48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose(δ^(13)C_(cellulose)) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ^(13)C_(cellulose)-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations(AMO). The results show that humification decreased and the δ^(13)C_(celluose)-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant dryingcondition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ^(13)C_(celluose)-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.展开更多
The elemental accumulation and recycling in the metamorphosed Keketale VMS-type Pb-Zn deposit of the Altai Mountains are presented in this study.Based on detailed fieldwork and microscopic observation,the formation of...The elemental accumulation and recycling in the metamorphosed Keketale VMS-type Pb-Zn deposit of the Altai Mountains are presented in this study.Based on detailed fieldwork and microscopic observation,the formation of the deposit involved syngenetic massive sulfide mineralization and epigenetic superim-posed mineralization.Different generations of iron sulfides(i.e.,pyrite and pyrrhotite)with contrasting textural,elemental,and sulfur isotopic features were generated in primary mineralization(including hydrothermal iron sulfides,colloform pyrite)and secondary modification(including annealed iron sul-fides,oriented iron sulfides,and vein-pyrite).It is revealed that the spatial variation in textures and ele-ments of hydrothermal iron sulfides depends on the inhomogeneous fluid compositions and varied environment in VMS hydrothermal system.Both leached sulfur from the footwall volcanic rocks and reduced sulfur by the TSR process are regarded as important sulfur sources.Furthermore,large sulfur iso-topic fractionation and negativeδ^(34)S values were mainly caused by varied oxygen fugacity,and to a lesser extent,temperature fluctuation.The epigenetic polymetallic veins that contain sulfides and sulfosalts(e.g.,jordanite-geocronite,bournonite-seligmannite,boulangerite)were considered as the products of metamorphic fluid scavenged the metal-rich strata.All things considered,it is indicated that two epi-sodes of fluid with distinct origins were essential for the formation of the deposit.The predominant evolved seawater along with subordinate magmatic fluid mobilized metals from volcanic rocks and pre-cipitated massive sulfides near the seafloor are vital for primary mineralization.The metamorphic fluid remobilized metals(i.e.,FMEs:fluid mobile elements,e.g.,Pb,As,Sb)from neighboring volcanic and pyroclastic rocks and destabilized them within the fractured zone are responsible for secondary miner-alization,which enhances the economic value of the deposit.Accordingly,metal-rich Devonian strata had been successively swept by different origins of fluid,leading to progressively elemental enrichment and the formation of a large deposit.Furthermore,the current study enlightens that FME-bearing veins with economic benefits can be discovered near the metamorphosed VMS deposits.展开更多
In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone (3 300 m a.s.I.) of the Kanas Glac...In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone (3 300 m a.s.I.) of the Kanas Glacier in August 2009. A total of 15 samples were analyzed for major ions. Results show that the concentrations of major ions in the snow-firn pack are NH4+〉SO4 2-〉Ca2+〉NO3+〉 Na+〉CI〉K+〉Mg2+. NH4+ is the dominant cation with a medium value of 4.7 ueq-L-1, accounting for 39.8% of the total cations, and SO42- is the dominant anion, with a medium value of 4.0 ueq.L-I, which accounts for 33.9% of the total cations. Compared with Belukha Glacier (Altai), Urumqi Glacier No. 1, and the Inilchek Glacier (Tienshan), there is a lower ion concentrations in the Kanas snow-firn pack. Potential sources of these chemical species are explored using correlation and empirical orthogonal function (EOF) analyses. The analyses indicate that major ion concentrations (except NH4+) originate from crustal dust. Backward trajectory analysis was applied to get the origin of the air mass to Kanas Glacier. The results suggest that air pollutants emitted by forest fires in Siberia could be transported and influence the NH4+, NO3, and SO42 concentrations on the Kanas Glacier.展开更多
Snow properties and their changes are crucial to better understanding of hydrological processes,soil thermal regimes,and surface energy balances.Reliable data and information on snow depth and snow water equivalent(SW...Snow properties and their changes are crucial to better understanding of hydrological processes,soil thermal regimes,and surface energy balances.Reliable data and information on snow depth and snow water equivalent(SWE)are also crucial for water resource assessments and socio-economic development at local and regional scales.However,these data are extremely limited and unreliable in northern Xinjiang,China.This study thus aims to investigate spatial variations of snow depth,SWE,and snow density based on winter snowfield surveys during 2015 through 2017 in the Altai Mountains,northwestern China.The results indicated that snow depth(25-114 cm)and SWE(40-290 mm)were greater in the alpine Kanas-Hemu region,and shallow snow accumulated(9-42 cm for snow depth,26-106 mm for SWE)on the piedmont sloping plain.While there was no remarkable regional difference in the distribution of snow density.Snow property distributions were strongly controlled by topography and vegetation.Elevation and latitude were the most important factors affecting snow depth and SWE,while snow density was strongly affected by longitude across the Altai Mountains in China.The influence of topography on snow property distributions was spatially heterogenous.Mean snow depth increased from 13.7 to 31.2 cm and SWE from 28.5 to 79.9 mm,respectively,with elevation increased from 400 to 1000 m a.s.l.on the piedmont sloping plain.Snow depth decreased to about 15.1 cm and SWE to about 28.5 mm from 1000 to 1800 m a.s.l.,then again increased to about 98.1 cm and 271.7 mm on peaks(-2000 m a.s.l.)in the alpine Kanas-Hemu.Leeward slopes were easier to accumulate snow cover,especially on north-,east-,and southeast-facing slopes.Canopy interception was also the cause of the difference in snow distribution.Snow depth,SWE,and snow density in forests were reduced by 8%-53%,2%-67%and-4%to+48%,respectively,compared with surrounding open areas.Especially when snow depth was less than 40 cm,snow depth and SWE differences in forests were more exaggerated.This study provides a basic data set of spatial distributions and variations of snow depth,SWE and snow density in the Altai Mountains,which can be used as an input parameter in climate or hydrological models.These first-hand observations will help to better understand the relationship between snow,topography and climate in mountainous regions across northern China and other high-mountain Asian regions.展开更多
Over the past 2000 years,a high-resolution pollen record from the Yushenkule Peat(46°45′-46°57′N,90°46′-90°61′E,2374 m a.s.l.)in the south-eastern Altai Mountains of northwestern China has been...Over the past 2000 years,a high-resolution pollen record from the Yushenkule Peat(46°45′-46°57′N,90°46′-90°61′E,2374 m a.s.l.)in the south-eastern Altai Mountains of northwestern China has been used to explore the changes in vegetation and climate.The regional vegetation has been dominated by alpine meadows revealed from pollen diagrams over the past 2000 years.The pollen-based climate was warm and wet during the Roman Warm Period(0-520 AD),cold and wet during the Dark Age Cold Period(520-900 AD),warm and wet during the Medieval Warm Period(900-1300 AD),and cold and dry during the Little Ice Age(1300-1850 AD).Combined with other pollen data from the Altai Mountains,we found that the percentage of arboreal pollen showed a reduced trend along the NW-SE gradient with decreasing moisture and increasing climatic continentality of the Altai Mountains over the past 2000 years;this is consistent with modern distributions of taiga forests.We also found that the taiga(Pinus forest)have spread slightly,while the steppe(Artemisia,Poaceae and Chenopodiaceae)have recovered significantly in the Altai Mountains over the past 2000 years.In addition,the relatively warm-wet climate may promote high grassland productivity and southward expansion of steppe,which favors the formation of Mongol political and military power.展开更多
Melt-albedo feedback on glaciers is recognized as important processes for understanding glacier behavior and its sensitivity to climate change.This study selected the Muz Taw Glacier in the Altai Mountains to investig...Melt-albedo feedback on glaciers is recognized as important processes for understanding glacier behavior and its sensitivity to climate change.This study selected the Muz Taw Glacier in the Altai Mountains to investigate the spatiotemporal variations in albedo and their linkages with mass balance,which will improve our knowledge of the recent acceleration of regional glacier shrinkage.Based on the Landsat-derived albedo,the spatial distribution of ablation-period albedo was characterized by a general increase with elevation,and significant east–west differences at the same elevation.The gap-filling MODIS values captured a nonsignificant negative trend of mean ablation-period albedo since 2000,with a total decrease of approximately 4.2%.From May to September,glacier-wide albedo exhibited pronounced V-shaped seasonal variability.A significant decrease in annual minimum albedo was found from 2000 to 2021,with the rate of approximately−0.30%yr−1 at the 99%confidence level.The bivariate relationship demonstrated that the change of ablation-period albedo explained 82%of the annual mass-balance variability.We applied the albedo method to estimate annual mass balance over the period 2000–2015.Combined with observed values,the average mass balance was−0.82±0.32 m w.e.yr−1 between 2000 and 2020,with accelerated mass loss.展开更多
Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security.In this study,we collected a total of 164 water samples in the wester...Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security.In this study,we collected a total of 164 water samples in the western region of the Altay Mountains,China,in 2021.We used principal component analysis and enrichment factor analysis to examine the chemical properties and spatiotemporal variations of major ions(including F-,Cl-,NO_(3)-,SO_(4)^(2-),Li+,Na+,NH4+,K+,Mg^(2+),and Ca^(2+))present in river water,as well as to identify the factors influencing these variations.Additionally,we assessed the suitability of river water for drinking and irrigation purposes based on the total dissolved solids,soluble sodium percentage,sodium adsorption ratio,and total hardness.Results revealed that river water had an alkaline aquatic environment with a mean pH value of 8.00.The mean ion concentration was ranked as follows:Ca^(2+)>SO_(4)^(2-)>Na+>NO_(3)->Mg^(2+)>K+>Cl->F->NH_(4)+>Li+.Ca^(2+),SO_(4)^(2-),Na+,and NO_(3)-occupied 83%of the total ion concentration.In addition,compared with other seasons,the spatial variation of the ion concentration in spring was obvious.An analysis of the sources of major ions revealed that these ions originated mainly from carbonate dissolution and silicate weathering.The recharge impact of precipitation and snowmelt merely influenced the concentration of Cl-,NO_(3)-,SO_(4)^(2-),Ca^(2+),and Na+.Overall,river water was in pristine condition in terms of quality and was suitable for both irrigation and drinking.This study provides a scientific basis for sustainable management of water quality in rivers of the Altay Mountains.展开更多
Kelan River is a branch of the Ertix River, originating in the Altay Mountains in Xinjiang, northwestern China. The upper streams of the Kelan River are located on the southern slope of the Altay Mountains; they arise...Kelan River is a branch of the Ertix River, originating in the Altay Mountains in Xinjiang, northwestern China. The upper streams of the Kelan River are located on the southern slope of the Altay Mountains; they arise from small glacial lakes at an elevation of more than 2,500 m. The total water-collection area of the studied basin, from 988 to 3,480 m, is about 1,655 km2. Almost 95 percent of the basin area is covered with snow in winter. The westerly air masses deplete nearly all the moisture that comes in the form of snow during the winter months in the upper and middle reaches of the basin. That annual flow from the basin is about 382 mm, about 45 percent of which is contributed by snowmelt. The mean annual precipitation in the basin is about 620 mm, which is primarily concentrated in the upper and middle basin. The Kelan River system could be vulnerable to climate change because of substantial contribution from snowmelt runoff. The hydrological system could be altered significantly because of a warming of the climate. The impact of climate change on the hydrological cycle and events would pose an additional threat to the Altay region. The Kelan River, a typical snow-dominated watershed, has more area at higher elevations and accumulates snow during the winter. The peak flow occurs as a result of snow-melting during the late spring or early summer. Stream flow varies strongly throughout the year because of seasonal cycles of precipitation, snowpack, temperature, and groundwater. Changes in the temperature and precipitation affect the timing and volume of stream-flow. The stream-flow consists of contributions from meltwater of snow and ice and from runoff of rainfall. Therefore, it has low flow in winter, high flow during the spring and early summer as the snowpack melts, and less flows during the late summer. Because of the warming of the current climate change, hydrology processes of the Kelan River have undergone marked changes, as evidenced by the shift of the maximum flood peak discharge from May to June; the largest monthly runoffs also have an increment of about 15 percent related to before 1980; April-June runoff increased from the 60 percent of the annual runoff before 1980 to nearly 70 percent after 1990. The long-term trend shows temperature and precipitation increased mainly in the winter, but the rainfall declined in summer; hydrological process is manifested by the rising runoff in May and decreasing in June. Warming and the increase of winter and spring snowcover would lead to increased snowmelt, increasing the spring-flood hazards and the maximum flood discharge with disastrous consequences. The changed hydrological patterns caused by climate change have already impacted the urban water supply and agricultural and livestock production along the river.展开更多
On the basis of field geological studies of the granotoids in the region, mineralogical, petrological, geochemical(including stable isotope geochemical) and isotopic geochronological investigations were carried out on...On the basis of field geological studies of the granotoids in the region, mineralogical, petrological, geochemical(including stable isotope geochemical) and isotopic geochronological investigations were carried out on selected representative granitic bodies of various types. The authors have concluded that, apart from the bodies of the orogenic granitoid series, there also exist intrusions of the anorogenic granitoid series in the region. The intrusives of the two series were formed not only in different ages and tectonic environments, but also were derived from different sources of materials. Moreover, they are associated with different mineralizations, belonging to different minerologenetic series(Cheng et al., 1983). They show distinctly a series of discriminative criteria. The problems under discussion in the present paper are of important theoretical and practical significance in the studies of granites of the orogenic belt, particularly the studies of the genesis and related metallogeny of the granites of the region.展开更多
Understanding the temporal variations of extreme floods that occur in response to climate change is essential to anticipate the trends in flood magnitude and frequency in the context of global warming. However, long-t...Understanding the temporal variations of extreme floods that occur in response to climate change is essential to anticipate the trends in flood magnitude and frequency in the context of global warming. However, long-term records of paleofloods in arid regions are scarce, thus preventing a thorough understanding of such events. In this study, a reconstruction of paleofloods over the past 300 years was conducted through an analysis of grain sizes from the sediments of Kanas Lake in the Altay Mountains of northwestern China. Results showed that grain parameters and frequency distributions can be used to infer possible abrupt environmental events within the lake sedimentary sequence, and two extreme flood events corresponding to ca. 1736–1765 AD and ca. 1890 AD were further identified based on canonical discriminant analysis(CDA) and coarse percentile versus median grain size(C-M) pattern analysis, both of which occurred during warmer and wetter climate conditions by referring to tree-ring records. These two flood events are also evidenced by lake sedimentary records in the Altay and Tianshan mountains. Furthermore, through a comparison with other records, the flood event from ca. 1736–1765 AD in the study region seems to have occurred in both the arid central Asia and the Alps in Europe, and thus may have been associated with changes in the North Atlantic Oscillation(NAO) index.展开更多
基金supported by the Xinjiang Committee of Science and Technology (200933122)
文摘Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region,located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms,where distribution of plant species is actually limited. It is known to have sufficient endemic floral biodiversity in the Northern Asia. Many plants of Altai Mountain System need effective care and proper conservation measures for their survival and longer-term protection. Important Plant Area identified as the IUCN (the International Union for Conservation of Nature),specified criteria attract global attention for protection of floral biodiversity across the world. The records of 71 plant species from the Chinese Altai Mountains attributed to the criterion A and the dark conifer forests of Chinese Altai Mountains satisfied the criterion C,which may help qualify to fulfill the national obligation of the Convention on Biological Diversity.
基金supported by the Russian Science Fund under basic project No.IX.135.2“Geotemperature field and transformation of the permafrost zone of North Asia and mountainous regions of Central Asia”。
文摘This study presents the long-term temperature monitoring in the Russian Altai Mountains. In contrast to the Mongolian and Chinese parts, the modern temperature regime of the Russian Altai remains unclear. The complexity of a comprehensive understanding of permafrost conditions in the Russian Altai is related to the high dissection of the terrain, the paucity of the latest observational data, and the sparse population of permafrost areas. The general objective of this study is to determine the temperature regime on the surface,in the active layer, and in the zero annual amplitude(ZAA) layer, based on the known patterns of permafrost distribution in the region. Using automatic measuring equipment(loggers), we obtained information on the temperature of frozen and thawed ground within the altitudes from 1484 to 2879 m a. s. l. during the period from 2014 to 2020.An array of 15 loggers determined the temperature regime of bare and vegetated areas within watersheds,slopes, and valleys. N-factor parameters and surface temperature are similar to those in the Mongolian Altai, but the mean annual ground temperature at the depth of 1 m has a wide range of fluctuations(more than 32℃) based on research results, and we allocated it into three groups based on altitudinal zonality. Snow cover has a strong influence on the temperature regime, but the determination of the fine-scale variability requires additional study.Ground temperature regime during the observation period remained stable, but continued monitoring allows a more detailed assessment of the response to climatic changes.
基金supported by the Ministry of Science and Technology of China (MOST) (Grant No. 2013FY111400)the National Natural ScienceFoundation of China (NSFC) (Grant No. 41190084)+4 种基金the Chinese Academy of Sciences (CAS) (Grant No. XDA05090302)the State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute (SKLCS, CAREERI), CAS (Grant No. SKLCS2012-09)the NSFC (Grant No.41471067)provided by "Investigation on glacier resources and their change in China" (Grant No. 2006FY110200)"Glacier change monitoring and its impact assessment research in west China" (Grant No. kzcx2-yw-301)
文摘Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER) stereo images(2008). The results indicate that a continued and accelerating shrinkage has occurred in the Chinese Altai Mountains during the last 50 years, with mass deficits of 0.43 ± 0.02 and0.54 ± 0.13 m a-1 water equivalent(w.e.) during the periods 1959-1999 and 1999-2008, respectively.Overall, the Chinese Altai Mountains have lost 7.06 ±0.44 km3 in ice volume(equivalent to-0.43 ± 0.03 m a-1 w.e.) from 1959-2008. The spatial heterogeneity in mass loss was potentially affected by comprehensive changes in temperature and precipitation, and had a substantial correlation withglacier size and topographic settings. Comparison shows that in the Chinese Altai Mountains glaciers have experienced a more rapid mass loss than those in the Tianshan and northwestern Tibetan Plateau(TP), and the mass balance of glaciers was slightly less negative relative to those in the Russian Altai, Himalaya, and southern TP.
基金funded by the Chinese Academy of Sciences (KJZD-EW-G03-04, QYZDJSSW-DQC039)the National Science Foundation of China (NSFC 41630754, 41690144, 41421061)the Foundation of the State Key Laboratory of Cryospheric Sciences (SKLCS) at Northwest Institute of Eco-Environment and Resources (NIEER), CAS (SKLCS-OP-2017-10, SKLCS-ZZ2016)
文摘With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect on runoff is the key to water safety, under climate warming and fast social-economic developing status. In this study, stable isotopic technology was utilized to analyze the snow meltwater effect on regional hydrological processes, and to declare the response of snow hydrology to climate change and snow cover regime, together with longterm meteorological and hydrological observations, in the headwater of Irtysh River, Chinese Altai Mountains during 1961-2015. The average δ^(18) O values of rainfall, snowfall, meltwater, groundwater and river water for 2014–2015 hydrological year were-10.9‰,-22.3‰,-21.7‰,-15.7‰ and-16.0‰, respectively.The results from stable isotopes, snow melting observation and remote sensing indicated that the meltwater effect on hydrological processes in Kayiertesi River Basin mainly occurred during snowmelt supplying period from April to June. The contribution of meltwater to runoff reached 58.1% during this period, but rainfall, meltwater and groundwater supplied 49.1%, 36.9% and 14.0% of water resource to annual runoff, respectively. With rising air temperature and increasing snowfall in cold season, the snow water equivalent(SWE) had an increasing trend but the snow cover duration declined by about one month including 13-day delay of the first day and 17-day advancement of the end day during 1961–2016. Increase in SWE provided more available water resource. However, variations in snow cover timing had resulted in redistribution of surface water resource, represented by an increase of discharge percentage in April and May, and a decline in Juneand July. This trend of snow hydrology will render a deficit of water resource in June and July when the water resource demand is high for agricultural irrigation and industrial manufacture.
基金supported by RFBR according to the research project No.16-35-00188 mol_aproject“Climatic and ecological changes in Siberia by the data on glacio-chemical,diatomic and sporepollen analysis of ice-cores”(No.0383-2014-0005)
文摘We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in the precipitation regime had a positive trend for the warm seasons(April-October),but weakly positive or negative trends for the cold seasons(November-March). It was found that these changes correspond to the decreasing contribution of "Northern meridional and Stationary anticyclone(Nm-Sa)" and "Northern meridional and East zonal(Nm-Ez)" circulation groups and to the increasing contribution of "West zonal and Southern meridional(Wz-Sm)" circulation groups,accordingly to the Dzerdzeevskii classification. In addition,it was found that the variation of precipitation has a step change point in 1980. For the warm seasons,the precipitation change at this point is associated with the reduced influence of "West zonal(Wz)","Northern meridional and Stationary anticyclone(Nm-Sa)" and "Northern meridional and Southern meridional(Nm-Sm)" circulation groups. For the cold seasons,a substantialincrease of "Wz-Sm" and a decrease of "Nm-Sa","Nm-Ez" circulation groups are responsible for the precipitation change in the two time periods(1959-1980 and 1981-2014).
基金financially supported by Chinese Natural Science International Cooperation Program Foundation Grant (No. 41361140361)Chinese Natural Science Foundation Grant (No. U1203821L08)Chinese Academy Sciences International Cooperation Program (No. GJHZ201315)
文摘To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat(48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose(δ^(13)C_(cellulose)) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ^(13)C_(cellulose)-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations(AMO). The results show that humification decreased and the δ^(13)C_(celluose)-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant dryingcondition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ^(13)C_(celluose)-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.
基金the Innovation Capability Support Program of Shaanxi Province(2022KJXX-91)International Geoscience Program(IGCP-741)+1 种基金National Key Research and Development Program of China(2021YFC2901802,2018YFC0604000)Basic Research Program of natural science in Shaanxi Province(2020JQ-440,2021JQ-327).
文摘The elemental accumulation and recycling in the metamorphosed Keketale VMS-type Pb-Zn deposit of the Altai Mountains are presented in this study.Based on detailed fieldwork and microscopic observation,the formation of the deposit involved syngenetic massive sulfide mineralization and epigenetic superim-posed mineralization.Different generations of iron sulfides(i.e.,pyrite and pyrrhotite)with contrasting textural,elemental,and sulfur isotopic features were generated in primary mineralization(including hydrothermal iron sulfides,colloform pyrite)and secondary modification(including annealed iron sul-fides,oriented iron sulfides,and vein-pyrite).It is revealed that the spatial variation in textures and ele-ments of hydrothermal iron sulfides depends on the inhomogeneous fluid compositions and varied environment in VMS hydrothermal system.Both leached sulfur from the footwall volcanic rocks and reduced sulfur by the TSR process are regarded as important sulfur sources.Furthermore,large sulfur iso-topic fractionation and negativeδ^(34)S values were mainly caused by varied oxygen fugacity,and to a lesser extent,temperature fluctuation.The epigenetic polymetallic veins that contain sulfides and sulfosalts(e.g.,jordanite-geocronite,bournonite-seligmannite,boulangerite)were considered as the products of metamorphic fluid scavenged the metal-rich strata.All things considered,it is indicated that two epi-sodes of fluid with distinct origins were essential for the formation of the deposit.The predominant evolved seawater along with subordinate magmatic fluid mobilized metals from volcanic rocks and pre-cipitated massive sulfides near the seafloor are vital for primary mineralization.The metamorphic fluid remobilized metals(i.e.,FMEs:fluid mobile elements,e.g.,Pb,As,Sb)from neighboring volcanic and pyroclastic rocks and destabilized them within the fractured zone are responsible for secondary miner-alization,which enhances the economic value of the deposit.Accordingly,metal-rich Devonian strata had been successively swept by different origins of fluid,leading to progressively elemental enrichment and the formation of a large deposit.Furthermore,the current study enlightens that FME-bearing veins with economic benefits can be discovered near the metamorphosed VMS deposits.
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. 2010CB951003)+2 种基金the National Natural Science Foundation of China (Nos. 91025012, 111141001, J0930003/J0109)the Program for New Century Excellent Talents in University (No. NCET-10-0019)the SKLCS founding (No. SKLCS-ZZ-2010-04)
文摘In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone (3 300 m a.s.I.) of the Kanas Glacier in August 2009. A total of 15 samples were analyzed for major ions. Results show that the concentrations of major ions in the snow-firn pack are NH4+〉SO4 2-〉Ca2+〉NO3+〉 Na+〉CI〉K+〉Mg2+. NH4+ is the dominant cation with a medium value of 4.7 ueq-L-1, accounting for 39.8% of the total cations, and SO42- is the dominant anion, with a medium value of 4.0 ueq.L-I, which accounts for 33.9% of the total cations. Compared with Belukha Glacier (Altai), Urumqi Glacier No. 1, and the Inilchek Glacier (Tienshan), there is a lower ion concentrations in the Kanas snow-firn pack. Potential sources of these chemical species are explored using correlation and empirical orthogonal function (EOF) analyses. The analyses indicate that major ion concentrations (except NH4+) originate from crustal dust. Backward trajectory analysis was applied to get the origin of the air mass to Kanas Glacier. The results suggest that air pollutants emitted by forest fires in Siberia could be transported and influence the NH4+, NO3, and SO42 concentrations on the Kanas Glacier.
基金funded by the Major Project of China High-resolution Earth Observation System(21-Y20B01-9001-19/22)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20100313)+1 种基金Science&Technology Basic Resources Investigation Program of China(2017FY100503)National Key R&D Program of China(2019YFC1510501).
文摘Snow properties and their changes are crucial to better understanding of hydrological processes,soil thermal regimes,and surface energy balances.Reliable data and information on snow depth and snow water equivalent(SWE)are also crucial for water resource assessments and socio-economic development at local and regional scales.However,these data are extremely limited and unreliable in northern Xinjiang,China.This study thus aims to investigate spatial variations of snow depth,SWE,and snow density based on winter snowfield surveys during 2015 through 2017 in the Altai Mountains,northwestern China.The results indicated that snow depth(25-114 cm)and SWE(40-290 mm)were greater in the alpine Kanas-Hemu region,and shallow snow accumulated(9-42 cm for snow depth,26-106 mm for SWE)on the piedmont sloping plain.While there was no remarkable regional difference in the distribution of snow density.Snow property distributions were strongly controlled by topography and vegetation.Elevation and latitude were the most important factors affecting snow depth and SWE,while snow density was strongly affected by longitude across the Altai Mountains in China.The influence of topography on snow property distributions was spatially heterogenous.Mean snow depth increased from 13.7 to 31.2 cm and SWE from 28.5 to 79.9 mm,respectively,with elevation increased from 400 to 1000 m a.s.l.on the piedmont sloping plain.Snow depth decreased to about 15.1 cm and SWE to about 28.5 mm from 1000 to 1800 m a.s.l.,then again increased to about 98.1 cm and 271.7 mm on peaks(-2000 m a.s.l.)in the alpine Kanas-Hemu.Leeward slopes were easier to accumulate snow cover,especially on north-,east-,and southeast-facing slopes.Canopy interception was also the cause of the difference in snow distribution.Snow depth,SWE,and snow density in forests were reduced by 8%-53%,2%-67%and-4%to+48%,respectively,compared with surrounding open areas.Especially when snow depth was less than 40 cm,snow depth and SWE differences in forests were more exaggerated.This study provides a basic data set of spatial distributions and variations of snow depth,SWE and snow density in the Altai Mountains,which can be used as an input parameter in climate or hydrological models.These first-hand observations will help to better understand the relationship between snow,topography and climate in mountainous regions across northern China and other high-mountain Asian regions.
基金This research was financially supported by Western Young Scholar Program-B of Chinese Academy of Sciences(No.2018-XBQNXZ-B-020)National Natural Science Foundation of China(Grant Nos.41771234 and 41803024)Open Fund of State Key Laboratory of Loess and Quaternary Geology(No.SKLLQG2011).
文摘Over the past 2000 years,a high-resolution pollen record from the Yushenkule Peat(46°45′-46°57′N,90°46′-90°61′E,2374 m a.s.l.)in the south-eastern Altai Mountains of northwestern China has been used to explore the changes in vegetation and climate.The regional vegetation has been dominated by alpine meadows revealed from pollen diagrams over the past 2000 years.The pollen-based climate was warm and wet during the Roman Warm Period(0-520 AD),cold and wet during the Dark Age Cold Period(520-900 AD),warm and wet during the Medieval Warm Period(900-1300 AD),and cold and dry during the Little Ice Age(1300-1850 AD).Combined with other pollen data from the Altai Mountains,we found that the percentage of arboreal pollen showed a reduced trend along the NW-SE gradient with decreasing moisture and increasing climatic continentality of the Altai Mountains over the past 2000 years;this is consistent with modern distributions of taiga forests.We also found that the taiga(Pinus forest)have spread slightly,while the steppe(Artemisia,Poaceae and Chenopodiaceae)have recovered significantly in the Altai Mountains over the past 2000 years.In addition,the relatively warm-wet climate may promote high grassland productivity and southward expansion of steppe,which favors the formation of Mongol political and military power.
基金supported by the National Natural Science Foundation of China[grant number 42001066]the Open-end Foundation for National Cryosphere Desert Data Center[grant number 20D05]+2 种基金the Foundation for Excellent Youth Scholars of NIEER,CAS[grant number FEYS2019003]State Key Laboratory of Cryospheric Science[grant number SKLCS-ZZ-2022]the Third Comprehensive Scientific Expedition of Xinjiang Uyghur Autonomous Region[grant number 2022xjkk0802,2022xjkk0701].
文摘Melt-albedo feedback on glaciers is recognized as important processes for understanding glacier behavior and its sensitivity to climate change.This study selected the Muz Taw Glacier in the Altai Mountains to investigate the spatiotemporal variations in albedo and their linkages with mass balance,which will improve our knowledge of the recent acceleration of regional glacier shrinkage.Based on the Landsat-derived albedo,the spatial distribution of ablation-period albedo was characterized by a general increase with elevation,and significant east–west differences at the same elevation.The gap-filling MODIS values captured a nonsignificant negative trend of mean ablation-period albedo since 2000,with a total decrease of approximately 4.2%.From May to September,glacier-wide albedo exhibited pronounced V-shaped seasonal variability.A significant decrease in annual minimum albedo was found from 2000 to 2021,with the rate of approximately−0.30%yr−1 at the 99%confidence level.The bivariate relationship demonstrated that the change of ablation-period albedo explained 82%of the annual mass-balance variability.We applied the albedo method to estimate annual mass balance over the period 2000–2015.Combined with observed values,the average mass balance was−0.82±0.32 m w.e.yr−1 between 2000 and 2020,with accelerated mass loss.
基金supported by the State Key Laboratory of Cryospheric Science of China(SKLCS-ZZ-2022)the National Key Research and Development Research and Development Program of China(2020YFF0304400)the Third Scientific Expedition in Xinjiang Uygur Autonomous Region of China(2022xjkk0701).
文摘Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security.In this study,we collected a total of 164 water samples in the western region of the Altay Mountains,China,in 2021.We used principal component analysis and enrichment factor analysis to examine the chemical properties and spatiotemporal variations of major ions(including F-,Cl-,NO_(3)-,SO_(4)^(2-),Li+,Na+,NH4+,K+,Mg^(2+),and Ca^(2+))present in river water,as well as to identify the factors influencing these variations.Additionally,we assessed the suitability of river water for drinking and irrigation purposes based on the total dissolved solids,soluble sodium percentage,sodium adsorption ratio,and total hardness.Results revealed that river water had an alkaline aquatic environment with a mean pH value of 8.00.The mean ion concentration was ranked as follows:Ca^(2+)>SO_(4)^(2-)>Na+>NO_(3)->Mg^(2+)>K+>Cl->F->NH_(4)+>Li+.Ca^(2+),SO_(4)^(2-),Na+,and NO_(3)-occupied 83%of the total ion concentration.In addition,compared with other seasons,the spatial variation of the ion concentration in spring was obvious.An analysis of the sources of major ions revealed that these ions originated mainly from carbonate dissolution and silicate weathering.The recharge impact of precipitation and snowmelt merely influenced the concentration of Cl-,NO_(3)-,SO_(4)^(2-),Ca^(2+),and Na+.Overall,river water was in pristine condition in terms of quality and was suitable for both irrigation and drinking.This study provides a scientific basis for sustainable management of water quality in rivers of the Altay Mountains.
基金supported by the State Key Science Research Programme for Global Change Research of China (Grant Nos. 2010CB951402 and 2010CB951404)the State Key Basic Research Development Program of China (973 Pro-gram) (Grant No. 2007 CB411507)the National Natu-ral Science Foundation of China (Grant No. 40771047)
文摘Kelan River is a branch of the Ertix River, originating in the Altay Mountains in Xinjiang, northwestern China. The upper streams of the Kelan River are located on the southern slope of the Altay Mountains; they arise from small glacial lakes at an elevation of more than 2,500 m. The total water-collection area of the studied basin, from 988 to 3,480 m, is about 1,655 km2. Almost 95 percent of the basin area is covered with snow in winter. The westerly air masses deplete nearly all the moisture that comes in the form of snow during the winter months in the upper and middle reaches of the basin. That annual flow from the basin is about 382 mm, about 45 percent of which is contributed by snowmelt. The mean annual precipitation in the basin is about 620 mm, which is primarily concentrated in the upper and middle basin. The Kelan River system could be vulnerable to climate change because of substantial contribution from snowmelt runoff. The hydrological system could be altered significantly because of a warming of the climate. The impact of climate change on the hydrological cycle and events would pose an additional threat to the Altay region. The Kelan River, a typical snow-dominated watershed, has more area at higher elevations and accumulates snow during the winter. The peak flow occurs as a result of snow-melting during the late spring or early summer. Stream flow varies strongly throughout the year because of seasonal cycles of precipitation, snowpack, temperature, and groundwater. Changes in the temperature and precipitation affect the timing and volume of stream-flow. The stream-flow consists of contributions from meltwater of snow and ice and from runoff of rainfall. Therefore, it has low flow in winter, high flow during the spring and early summer as the snowpack melts, and less flows during the late summer. Because of the warming of the current climate change, hydrology processes of the Kelan River have undergone marked changes, as evidenced by the shift of the maximum flood peak discharge from May to June; the largest monthly runoffs also have an increment of about 15 percent related to before 1980; April-June runoff increased from the 60 percent of the annual runoff before 1980 to nearly 70 percent after 1990. The long-term trend shows temperature and precipitation increased mainly in the winter, but the rainfall declined in summer; hydrological process is manifested by the rising runoff in May and decreasing in June. Warming and the increase of winter and spring snowcover would lead to increased snowmelt, increasing the spring-flood hazards and the maximum flood discharge with disastrous consequences. The changed hydrological patterns caused by climate change have already impacted the urban water supply and agricultural and livestock production along the river.
文摘On the basis of field geological studies of the granotoids in the region, mineralogical, petrological, geochemical(including stable isotope geochemical) and isotopic geochronological investigations were carried out on selected representative granitic bodies of various types. The authors have concluded that, apart from the bodies of the orogenic granitoid series, there also exist intrusions of the anorogenic granitoid series in the region. The intrusives of the two series were formed not only in different ages and tectonic environments, but also were derived from different sources of materials. Moreover, they are associated with different mineralizations, belonging to different minerologenetic series(Cheng et al., 1983). They show distinctly a series of discriminative criteria. The problems under discussion in the present paper are of important theoretical and practical significance in the studies of granites of the orogenic belt, particularly the studies of the genesis and related metallogeny of the granites of the region.
基金Under the auspices of National Key Research and Development Program of China(No.2017YFA0603400)National Science Foundation of China(No.41671200,U1603242)
文摘Understanding the temporal variations of extreme floods that occur in response to climate change is essential to anticipate the trends in flood magnitude and frequency in the context of global warming. However, long-term records of paleofloods in arid regions are scarce, thus preventing a thorough understanding of such events. In this study, a reconstruction of paleofloods over the past 300 years was conducted through an analysis of grain sizes from the sediments of Kanas Lake in the Altay Mountains of northwestern China. Results showed that grain parameters and frequency distributions can be used to infer possible abrupt environmental events within the lake sedimentary sequence, and two extreme flood events corresponding to ca. 1736–1765 AD and ca. 1890 AD were further identified based on canonical discriminant analysis(CDA) and coarse percentile versus median grain size(C-M) pattern analysis, both of which occurred during warmer and wetter climate conditions by referring to tree-ring records. These two flood events are also evidenced by lake sedimentary records in the Altay and Tianshan mountains. Furthermore, through a comparison with other records, the flood event from ca. 1736–1765 AD in the study region seems to have occurred in both the arid central Asia and the Alps in Europe, and thus may have been associated with changes in the North Atlantic Oscillation(NAO) index.