Eremurus was described at the beginning of the 19th century.However,due to limited sampling and the small number of gene markers to date,its phylogeny and evolution are largely unknown.In this study,we analyzed plasto...Eremurus was described at the beginning of the 19th century.However,due to limited sampling and the small number of gene markers to date,its phylogeny and evolution are largely unknown.In this study,we analyzed plastomes from 27 species belonging to 2 subgenera and 3 sections of Eremurus,which are found in Central Asia(its center of diversity)and China.We also analyzed nuclear DNA ITS of 33 species,encompassing all subgenera and sections of the genus in Central Asia,southwest Asia and China.Our findings revealed that the genus was monophyletic,although both subgenera Eremurus and Henningia were found to be paraphyletic.Both plastome and nrDNA-based phylogenetic trees had three clades that did not reflect the current taxonomy of the genus.Our biogeographical and time-calibrated trees suggest that Eremurus originated in the ancient Tethyan area in the second half of the Eocene.Diversification of Eremurus occurred from the early Oligocene to the late Miocene.Paratethys Sea retreat and several orogenetic events,such as the progressive uplift of the Qinghai-Tibet Plateau and surrounding mountain belts(Altai,Pamir,Tian Shan),caused serious topographic and climate(aridification)changes in Central Asia that may have triggered a split of clades and speciation.In this transformed Central Asia,speciation proceeded rapidly driven mainly by vicariance caused by numerous mountain chains and specialization to a variety of climatic,topographic and soil conditions that exist in this region.展开更多
Central Asia consists of the former Soviet Republics,Kazakhstan,Kyrgyz Republic,Tajikistan,Turkmenistan,and Uzbekistan.The region’s climate is continental,mostly semi-arid to arid.Agriculture is a significant part of...Central Asia consists of the former Soviet Republics,Kazakhstan,Kyrgyz Republic,Tajikistan,Turkmenistan,and Uzbekistan.The region’s climate is continental,mostly semi-arid to arid.Agriculture is a significant part of the region’s economy.By its nature of intensive water use,agriculture is extremely vulnerable to climate change.Population growth and irrigation development have significantly increased the demand for water in the region.Major climate change issues include melting glaciers and a shrinking snowpack,which are the foundation of the region’s water resources,and a changing precipitation regime.Most glaciers are located in Kyrgyzstan and Tajikistan,leading to transboundary water resource issues.Summer already has extremely high temperatures.Analyses indicate that Central Asia has been warming and precipitation might be increasing.The warming is expected to increase,but its spatial and temporal distribution depends upon specific global scenarios.Projections of future precipitation show significant uncertainties in type,amount,and distribution.Regional Hydroclimate Projects(RHPs)are an approach to studying these issues.Initial steps to develop an RHP began in 2021 with a widely distributed online survey about these climate issues.It was followed up with an online workshop and then,in 2023,an in-person workshop,held in Tashkent,Uzbekistan.Priorities for the Global Energy and Water Exchanges(GEWEX)project for the region include both observations and modeling,as well as development of better and additional precipitation observations,all of which are topics for the next workshop.A well-designed RHP should lead to reductions in critical climate uncertainties in policy-relevant timeframes that can influence decisions on necessary investments in climate adaptation.展开更多
Land use/land cover(LULC)change and climate change are two major factors affecting the provision of ecosystem services which are closely related to human well-being.However,a clear understanding of the relationships b...Land use/land cover(LULC)change and climate change are two major factors affecting the provision of ecosystem services which are closely related to human well-being.However,a clear understanding of the relationships between these two factors and ecosystem services in Central Asia is still lacking.This study aimed to comprehensively assess ecosystem services in Central Asia and analyze how they are impacted by changes in LULC and climate.The spatiotemporal patterns of three ecosystem services during the period of 2000-2015,namely the net primary productivity(NPP),water yield,and soil retention,were quantified and mapped by the Carnegie-Ames-Stanford Approach(CASA)model,Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model,and Revised Universal Soil Loss Equation(RUSLE).Scenarios were used to determine the relative importance and combined effect of LULC change and climate change on ecosystem services.Then,the relationships between climate factors(precipitation and temperature)and ecosystem services,as well as between LULC change and ecosystem services,were further discussed.The results showed that the high values of ecosystem services appeared in the southeast of Central Asia.Among the six biomes(alpine forest region(AFR),alpine meadow region(AMR),typical steppe region(TSR),desert steppe region(DSR),desert region(DR),and lake region(LR)),the values of ecosystem services followed the order of AFR>AMR>TSR>DSR>DR>LR.In addition,the values of ecosystem services fluctuated during the period of 2000-2015,with the most significant decreases observed in the southeast mountainous area and northwest of Central Asia.LULC change had a greater impact on the NPP,while climate change had a stronger influence on the water yield and soil retention.The combined LULC change and climate change exhibited a significant synergistic effect on ecosystem services in most of Central Asia.Moreover,ecosystem services were more strongly and positively correlated with precipitation than with temperature.The greening of desert areas and forest land expansion could improve ecosystem services,but unreasonable development of cropland and urbanization have had an adverse impact on ecosystem services.According to the results,ecological stability in Central Asia can be achieved through the natural vegetation protection,reasonable urbanization,and ecological agriculture development.展开更多
Black carbon(BC)in snow plays an important role to accelerate snow melting.However,current studies mostly focused on BC concentrations,few on their size distributions in snow which affected BC’s effect on albedo chan...Black carbon(BC)in snow plays an important role to accelerate snow melting.However,current studies mostly focused on BC concentrations,few on their size distributions in snow which affected BC’s effect on albedo changes.Here we presented refractory BC(rBC)concentrations and size distributions in snow collected from Chinese Altai Mountains in Central Asia from November 2016 to April 2017.The results revealed that the average rBC concentrations were 5.77 and2.82 ng g-1for the surface snow and sub-surface snow,which were relatively higher in the melting season(April)than that in winter(November-January).The mass median volume-equivalent diameter of rBC size in surface snow was approximately at 120-150 nm,which was typically smaller than that in the atmosphere(about 200 nm for urban atmosphere).However,there existed no specific mass median volume-equivalent diameter of BC size for sub-surface snow in winter.While during the melting season,the median mass size of rBC in sub-surface snow was similar to that in surface snow.Backward trajectories indicated that anthropogenic sourced BC dominated rBC in snow(70%-85%).This study will promote our understanding on BC size distributions in snow,and highlight the possible impact of BC size on climate effect.展开更多
Central Asian States(CAS)have diverse natural resources.This research aims to shed light on the finance–natural resource’s association in the context of CAS namely Kazakhstan,Kyrgyzstan,Tajikistan,Turkmenistan,and U...Central Asian States(CAS)have diverse natural resources.This research aims to shed light on the finance–natural resource’s association in the context of CAS namely Kazakhstan,Kyrgyzstan,Tajikistan,Turkmenistan,and Uzbekistan in 1996–2020 using the cross-sectionally augmented autoregressive distributed lag technique.It seeks to examine the research question,“What is the effect of natural resource wealth on the financial expansion(FE)of Central Asia?”The results demonstrated an inverted U-shaped association between financial growth and natural resource rents.It implies that natural resources are initially a“resource blessing”that later becomes a“resource curse.”Additionally,the effect of institutional quality(INQ)and human development(HD)on financial growth is examined.The results reveal that INQ and HD positively affect FE.Moreover,a bidirectional causal relationship exists between FE and INQ.Finally,all variables contribute to a long term FE.Based on these outcomes,the major policy recommendations are that the CAS authorities diversify their financial services and products and direct the proceeds from natural resource rents to effective invest-ments particularly in HD.In addition,the social and political infrastructures in CAS must be restructured to achieve a high-quality institutional environment,which is necessary to increase the role of the private sector.展开更多
Water resources are one of the key factors restricting the development of arid areas,and cloud water resources is an important part of water resources.The arid region of central Asia is the core region of the current ...Water resources are one of the key factors restricting the development of arid areas,and cloud water resources is an important part of water resources.The arid region of central Asia is the core region of the current national green silk road construction,and is the largest arid region in the world.Based on cloud cover data of ECMWF,the current study analyzed temporal and spatial characteristics of cloud properties in arid regions of Central Asia between 1980 and 2019.Our findings show that:(1)From the point of view of spatial distribution,total cloudiness in arid regions of Central Asia was low in the south and high in the north.The distribution of high cloud frequency and medium cloud frequency was higher in the south and lower in the north,while low cloud frequency distribution was low in the south and high in the north.(2)In terms of time,the variation of cloud cover and cloud type frequency had obvious seasonal characteristics.From winter to spring,cloud cover increased,and the change of cloud type frequency increased.From spring to summer,cloud cover continued to increase and the change of cloud type frequency increased further.Cloud cover began to decrease from summer to autumn,and the change of cloud type frequency also decreased.(3)Generally,average total cloud cover decreased in most of central Asia,and high and medium cloud cover increased while low cloud cover decreased.This study provides a reference for the rational development of cloud resources in the region.展开更多
China is moving to greater economic and political influence in the global scale.One of the Chinese strategy for“go global”is Belt and Road Initiative(BRI)which was announced by President Xi Jinping in 2013.The BRI i...China is moving to greater economic and political influence in the global scale.One of the Chinese strategy for“go global”is Belt and Road Initiative(BRI)which was announced by President Xi Jinping in 2013.The BRI includes a significant number of countries from Asia,Central Asia,the Middle East,Africa,and Europe.In this framework,China relations with Central Asia are an important part of the BRI project.The BRI is not merely an economic project as framed by Beijing,but that it represents a new stage in China’s engagement with the Central Asian republics.The Belt and Road Initiative is highly likely to become China’s most significant contribution to Central Asia economic development.This would affect the China-Central Asia relations economically and politically.展开更多
This paper investigates Central Asia's oil and gas resources, special geopolitics and energy competition, and approaches, challenges and prospects in cooperation between China and Central Asia. The objective is to pr...This paper investigates Central Asia's oil and gas resources, special geopolitics and energy competition, and approaches, challenges and prospects in cooperation between China and Central Asia. The objective is to propose measures for oil and gas cooperation between China and Central Asia. Central Asia is rich in oil and gas resources. Its remaining recoverable reserves of crude oil and natural gas account for 1.9% and 10.6 %, respectively, of the world's total reserves. Moreover, there is great exploration and development potential. As a strategic channel connecting Eurasia, Central Asia has a prominent geopolitical status. Many powerful countries such as the United States, Russia and China, as well as Europe, have an intense energy competition in Central Asia. In the oil and gas cooperation with Central Asia, the China National Petroleum Corporation (CNPC) focuses on establishing a coordination group, promoting overall oil and gas business opportunities and sustainable development, innovating and applying specialty engineering technology and improving project economic benefits. Through its efforts over the last nearly two decades, the China National Petroleum Corporation has completed a 50-million-tonne a year oil and gas production centre in Central Asia and oil and gas pipelines passing through multiple countries, becoming an important channel for securing China's energy imports. If appropriate measures are taken in the 'Thirteenth Five-Year Plan' period or later, the China National Petroleum Corporation will develop a 100-million-tonne p.a. oil and gas production centre in Central Asia and a strategic oil and gas import channel exceeding this amount of production. This cooperation between China and Central Asia is however faced with the following challenges: increasing multinational competition uncertainty, potential risks in the political systems of Central Asian countries, frequently occurring violence and also resource policy tightening in Central Asia. To further oil and gas cooperation with Central Asia, it is recommended that China should develop an energy acquisition strategy, assign a regional energy ambassador, enhance oil and gas supply by mergers and acquisitions, establish regional multinational subsidiaries and improve its risk prevention system.展开更多
Climate warming will cause differences in precipitation distribution and changes in hydrological cycle both at regional and global scales. Arid lands of Central Asia (ALCA), one of the largest arid regions at the mi...Climate warming will cause differences in precipitation distribution and changes in hydrological cycle both at regional and global scales. Arid lands of Central Asia (ALCA), one of the largest arid regions at the middle latitudes in the world, is likely to be strongly influenced by climate warming. Understanding the precipitation varia- tions in the past is an important prerequisite for predicting future precipitation trends and thus managing regional water resources in such an arid region. In this study, we used run theory, displacement, extreme deviation theory, precipitation concentration index (PCI), Mann-Kendall rank correlation and climatic trend coefficient methods to analyze the precipitation in wet and dry years, changes in precipitation over multiple-time scales, variability of precipitation and its rate of change based on the monthly precipitation data during 1950-2000 from 344 meteorological stations in the ALCA. The occurrence probability of a single year with abundant precipitation was higher than that of a single year with less precipitation. The average duration of extreme drought in the entire area was 5 years, with an average annual water deficit of 34.6 mm (accounting for 11.2% of the average annual precipitation over the duration). The occurrence probability of a single wet year was slightly higher than that of a single dry year. The occurrence probability of more than 5 consecutive wet years was 5.8%, while the occurrence probability of more than 5 consecutive dry years was 6.2%. In the center of the study area, the distribution of precipitation was stable at an intra-annual timescale, with small changes at an inter-annual timescale. In the western part of the study area, the monthly variation of precipitation was high at an inter-annual timescale. There were clear seasonal changes in precipitation (PC1=12-36) in the ALCA. Precipitation in spring and winter accounted for 37.7% and 24.4% of the annual precipitation, respectively There was a significant inter-annual change in precipitation in the arid Northwest China (PC1=24-34). Annual precipitation increased significantly (P=0.05) in 17.4% of all the meteorological stations over the study period. The probability of an increase in annual precipitation was 75.6%, with this increase being significant (P=-0.05) at 34.0% of all the meteorological stations. The average increasing rate in annual precipitation was 3.9 mm/10a (P=0.01) in the ALCA. There were significant increasing trends (P=0.01) in precipitation in Kazakhstan, Kyrgyzstan and Tajikistan, with rates of 2.6, 3.1 and 3.7 mm/10a, respectively.展开更多
Accurate inversion of land surface evapotranspiration (ET) in arid areas is of great significance for understanding global eco-hydrological process and exploring the spatio-temporal variation and ecological response...Accurate inversion of land surface evapotranspiration (ET) in arid areas is of great significance for understanding global eco-hydrological process and exploring the spatio-temporal variation and ecological response of water resources. It is also important in the functional evaluation of regional water cycle and water balance, as well as the rational allocation and management of water resources. This study, based on model validation analysis at varied scales in fiwe Central Asian countries and China's Xinjiang, developed an appropriate approach for ET inversion in arid lands. The actual ET during growing seasons of the study area was defined, and the changes in water participating in evaporation in regional water cycle were then educed. The results show the simulation error of SEBS (Surface Energy Balance System) model under cloud amount consideration was 1.34% at 30-m spatial scale, 2.75% at 1-km spatial scale and 6,37% at 4-kin spatial scale. ET inversion for 1980-2007 applying SEBS model in the study area indicates: (1) the evaporation depth (May-September) by land types descends in the order of waters (660.24 ram) 〉 cultivated land (464.66 mm) 〉 woodland (388.44 mm) 〉 urbanized land (168.16 mm) 〉 grassland (160.48 mm) 〉 unused land (83.08 mm); and (2) ET during the 2005 growing season in Xinjiang and Central Asia was 2,168.68x108 m3 (with an evaporation/precipitation ratio of 1.05) and 9,741.03x108 m3 (with an evaporation/precipitation ratio of 1.4), respectively. The results unveiled the spatio-temporal variation rules of ET process in arid areas, providing a reference for further research on the water cycle and water balance in similar arid regions.展开更多
Monitoring glacier mass balance is crucial to managing water resources and also to understanding climate change for the arid and semi-arid regions of Central Asia. This study extracted the inter-annual oscillations of...Monitoring glacier mass balance is crucial to managing water resources and also to understanding climate change for the arid and semi-arid regions of Central Asia. This study extracted the inter-annual oscillations of glacier mass over Central Asia from the first ten principal components(S-PCs) of filtered variability via multichannel singular spectral analysis(MSSA), based on gridded data of glacier mass inferred from Gravity Recovery and Climate Experiment(GRACE) data obtained from July 2002 to March 2015. Two significant cycles of glacier mass balance oscillations were identified. The first cycle with a period of 6.1-year accounted for 54.5% of the total variance and the second with a period of 2.3-year accounted for 4.3%. The 6.1-year oscillation exhibited a stronger variability compared with the 2.3-year oscillation. For the 6.1-year oscillation, the results from lagged cross-correlation function suggested that there were significant correlations between glacier mass balances and precipitation variations with the precipitation variations leading the response of glacier mass balances by 9–16 months.展开更多
Snow cover plays an important role in the fields of climatology and cryospheric science. Remotely-sensed data have been proven to be effective in monitoring snow covers. Improved methods to process the 8-day snow-cove...Snow cover plays an important role in the fields of climatology and cryospheric science. Remotely-sensed data have been proven to be effective in monitoring snow covers. Improved methods to process the 8-day snow-cover products derived from MODIS Terra/Aqua data can dramatically increase the data quality and reduce noise. A five-step algorithm for removing cloud effects was designed to improve the quality of MODIS snow products, and the overall accuracy of the MODIS snow data without cloud(defined as cloud-free snow-cover dataset) was enhanced by more than 90% based on direct and indirect validation methods. The snow-cover frequency(SCF) and snow-cover rate(SCR) of Central Asia were analyzed from 2000 to 2015 using trend analysis and empirical orthogonal functions(EOFs). Over the plain regions, the SCF displayed a significant north-south declining trend with a rate of 0.03 per degree of latitude, and the SCR showed a similar north-south gradient. In the mountainous areas, the SCF significantly increased with altitude by 0.12 per kilometer. Within the study area, the SCF in 65% of the study area experienced an increasing trend, but only 4.3% of the SCF-increasing pixels passed a significance test. The remaining 35% of the area underwent a decreasing trend of SCF, but only 5.2% of the SCF-decreasing pixels passed a significance test. For the entire Central Asia, the inter-annual variations of snow-cover presented a slight and insignificant increase trend from 2000 to 2015. However, the change trends of snow cover are different between the plain and mountainous regions. That is, the annual mean SCR in the plain areas displayed an increasing trend, but a decreasing trend was found in the mountainous areas.展开更多
Using rain-gauge-observation daily precipitation data from the Global Historical Climatology Network(V3.25)and the Chinese Surface Daily Climate Dataset(V3.0),this study investigates the fidelity of the AHPRODITE data...Using rain-gauge-observation daily precipitation data from the Global Historical Climatology Network(V3.25)and the Chinese Surface Daily Climate Dataset(V3.0),this study investigates the fidelity of the AHPRODITE dataset in representing extreme precipitation,in terms of the extreme precipitation threshold value,occurrence number,probability of detection,and extremal dependence index during the cool(October to April)and warm(May to September)seasons in Central Asia during 1961–90.The distribution of extreme precipitation is characterized by large extreme precipitation threshold values and high occurrence numbers over the mountainous areas.The APHRODITE dataset is highly correlated with the gauge-observation precipitation data and can reproduce the spatial distributions of the extreme precipitation threshold value and total occurrence number.However,APHRODITE generally underestimates the extreme precipitation threshold values,while it overestimates the total numbers of extreme precipitation events,particularly over the mountainous areas.These biases can be attributed to the overestimation of light rainfall and the underestimation of heavy rainfall induced by the rainfall distribution–based interpolation.Such deficits are more evident for the warm season than the cool season,and thus the biases are more pronounced in the warm season than in the cool season.The probability of detection and extremal dependence index reveal that APHRODITE has a good capability of detecting extreme precipitation,particularly in the cool season.展开更多
Relatively little is known about fire regimes in grassland and cropland in Central Asia.In this study,eleven variables of fire regimes were measured from 2001 to 2019 by utilizing the burned area and active fire produ...Relatively little is known about fire regimes in grassland and cropland in Central Asia.In this study,eleven variables of fire regimes were measured from 2001 to 2019 by utilizing the burned area and active fire product,which was obtained and processed from the GEE(Google Earth Engine)platform,to describe the incidence,inter-annual variability,peak month and size of fire in four land cover types(forest,grassland,cropland and bare land).Then all variables were clustered to define clusters of fire regimes with unique fire attributes using the K-means algorithm.Results showed that Kazakhstan(KAZ)was the most affected by fire in Central Asia.Fire regimes in cropland in KAZ had the frequent,large and intense characters,which covered large burned areas and had a long duration.Fires in grassland mainly occurred in central KAZ and had the small scale and high-intensity characters with different quarterly frequencies.Fires in forest were mainly distributed in northern KAZ and eastern KAZ.Although fires in grassland underwent a shift from more to less frequent from 2001 to 2019 in Central Asia,vigilance is needed because most fires in grassland occur suddenly and cause harm to humans and livestock.展开更多
The current work examines the impact of the snow cover extent(SCE)of the Tibetan Plateau(TP)on the interannual variation in the summer(June−July−August)surface air temperature(SAT)over Central Asia(CA)(SAT_CA)during t...The current work examines the impact of the snow cover extent(SCE)of the Tibetan Plateau(TP)on the interannual variation in the summer(June−July−August)surface air temperature(SAT)over Central Asia(CA)(SAT_CA)during the 1979−2019 period.The leading mode of the summer SAT_CA features a same-sign temperature anomalies in CA and explains 62%of the total variance in SAT_CA.The atmospheric circulation associated with a warming SAT_CA is characterized by a pronounced high-pressure system dominating CA.The high-pressure system is accompanied by warm advection as well as descending motion over CA,favoring the warming of the SAT_CA.Analysis shows that the interannual variation in the summer SAT_CA is significantly positively correlated with the April SCE over the central-eastern TP.In April,higher than normal SCE over the central-eastern TP has a pronounced cooling effect on the column of the atmosphere above the TP and can persist until the following early summer.Negative and positive height anomalies appear above and to the west of the TP.In the following months,the perturbation forcing generated by the TP SCE anomalies lies near the western center of the Asian subtropical westerly jet(SWJ),which promotes atmospheric waves in the zonal direction guided by the Asian SWJ.Associated with this atmospheric wave,in the following summer,a significant high-pressure system dominates CA,which is a favorable condition for a warm summer SAT_CA.展开更多
In this study, the climate changes over Arid Central Asia(ACA) during the mid-Holocene(approximately 6,000 calendar years ago, MH) and the Last Glacial Maximum(approximately 21,000 calendar years ago, LGM) were invest...In this study, the climate changes over Arid Central Asia(ACA) during the mid-Holocene(approximately 6,000 calendar years ago, MH) and the Last Glacial Maximum(approximately 21,000 calendar years ago, LGM) were investigated using multimodel simulations derived from the Paleoclimate Modelling Intercomparison Project Phase 3(PMIP3). During the MH, the multimodel median(MMM) shows that in the core region of ACA, the regionally averaged annual surface air temperature(SAT) decreases by 0.13°C and annual precipitation decreases by 3.45%, compared with the preindustrial(PI) climate. The MMM of the SAT increases by 1.67/0.13°C in summer/autumn, whereas it decreases by 1.23/1.11°C in spring/winter. The amplitude of the seasonal cycles of the SAT increases over ACA due to different MH orbital parameters. For precipitation, the regionally averaged MMM decreases by 5.77%/5.69%/0.39%/5.24% in spring/summer/autumn/winter, respectively. Based on the analysis of the aridity index(AI), compared with the PI, a drier climate appears in southern Central Asia and western Xinjiang due to decreasing precipitation. During the LGM, the MMM shows that the regionally averaged SAT decreases by 5.04/4.36/4.70/5.12/5.88°C and precipitation decreases by 27.78%/28.16%/31.56%/27.74%/23.29% annually and in the spring, summer, autumn, and winter, respectively. Robust drying occurs throughout almost the whole core area. Decreasing precipitation plays a dominant role in shaping the drier conditions, whereas strong cooling plays a secondary but opposite role. In response to the LGM external forcings, over Central Asia and Xinjiang, the seasonal cycle of precipitation has a smaller amplitude compared with that under the PI climate. In the model-data comparison, the simulated MH moisture changes over ACA are to some extent consistent with the reconstructions, further confirming that drier conditions occurred during that period than during the PI.展开更多
Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this ...Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this study,we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles(MMEs)from the Coupled Model Intercomparison Project Phase 6(CMIP6)under four Shared Socioeconomic Pathway and Representative Concentration Pathway(SSP-RCP)scenarios(SSP126(SSP1-RCP2.6),SSP245(SSP2-RCP4.5),SSP460(SSP4-RCP6.0),and SSP585(SSP5-RCP8.5))during 2015-2100.The bias correction and spatial disaggregation,water-thermal product index,and sensitivity analysis were used in this study.The results showed that the hydrothermal condition is mismatched in the central and southern deserts,whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition.Compared with the historical period,the matched degree of hydrothermal condition improves during 2046-2075,but degenerates during 2015-2044 and 2076-2100.The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions.The result suggests that the optimal scenario in Central Asia is SSP126 scenario,while SSP585 scenario brings further hydrothermal contradictions.This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.展开更多
Holoceneδ^18O records from various archives(ice cores,cave stalagmites,and peat sediments)from the Xinjiang region of northwestern China,in arid central Asia(ACA),are all derived ultimately from local precipitationδ...Holoceneδ^18O records from various archives(ice cores,cave stalagmites,and peat sediments)from the Xinjiang region of northwestern China,in arid central Asia(ACA),are all derived ultimately from local precipitationδ^18O(δ^18Op).Nevertheless,they have been proposed as indicators of different climatic parameters,such as wetness and temperature changes.This article summarizes previously reported records of moisture sources for the Xinjiang region and the results of modern observations conducted at an ice core site and a peat site in the Altai Mountains.The findings are used to propose that the overall positive trends in Holoceneδ^18O records from the various archives from the Xinjiang region primarily reflect the Holocene's long-term warming trend.It is concluded that more site-specific modern observations are needed to further elucidate the environmental significance of Holoceneδ^18O records from this region,especially for the separation of different seasonal temperature signals present withinδ^18O records.展开更多
Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construc...Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the展开更多
Objective Climate fluctuations over suborbital or millennial timescale display significant instability during the last glacial period,which are often superimposed upon the orbital periodicity.They triggered some abrup...Objective Climate fluctuations over suborbital or millennial timescale display significant instability during the last glacial period,which are often superimposed upon the orbital periodicity.They triggered some abrupt climate events,展开更多
基金supported by grants from the Key Projects of the Joint Fund of the National Natural Science Foundation of China (U23A20149)the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (2019QZKK0502)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20050203)International Partnership Program of the Chinese Academy of Sciences (151853KYSB20180009)the state research project Taxonomic revision of polymorphic plant families of the flora of Uzbekistan’ (FZ-20200929321)the State Programs for the years 2021-2025 ’Grid mapping of the flora of Uzbekistan’ and the ’Tree of life:monocots of Uzbekistan’ of the Institute of Botany of the Academy of Sciences of the Republic of Uzbekistan
文摘Eremurus was described at the beginning of the 19th century.However,due to limited sampling and the small number of gene markers to date,its phylogeny and evolution are largely unknown.In this study,we analyzed plastomes from 27 species belonging to 2 subgenera and 3 sections of Eremurus,which are found in Central Asia(its center of diversity)and China.We also analyzed nuclear DNA ITS of 33 species,encompassing all subgenera and sections of the genus in Central Asia,southwest Asia and China.Our findings revealed that the genus was monophyletic,although both subgenera Eremurus and Henningia were found to be paraphyletic.Both plastome and nrDNA-based phylogenetic trees had three clades that did not reflect the current taxonomy of the genus.Our biogeographical and time-calibrated trees suggest that Eremurus originated in the ancient Tethyan area in the second half of the Eocene.Diversification of Eremurus occurred from the early Oligocene to the late Miocene.Paratethys Sea retreat and several orogenetic events,such as the progressive uplift of the Qinghai-Tibet Plateau and surrounding mountain belts(Altai,Pamir,Tian Shan),caused serious topographic and climate(aridification)changes in Central Asia that may have triggered a split of clades and speciation.In this transformed Central Asia,speciation proceeded rapidly driven mainly by vicariance caused by numerous mountain chains and specialization to a variety of climatic,topographic and soil conditions that exist in this region.
基金The National Research University Tashkent Institute of Irrigation and Agricultural Mechanization Engineers of Uzbekistan hosted and provided financial support for the in-person workshop in May of 2023
文摘Central Asia consists of the former Soviet Republics,Kazakhstan,Kyrgyz Republic,Tajikistan,Turkmenistan,and Uzbekistan.The region’s climate is continental,mostly semi-arid to arid.Agriculture is a significant part of the region’s economy.By its nature of intensive water use,agriculture is extremely vulnerable to climate change.Population growth and irrigation development have significantly increased the demand for water in the region.Major climate change issues include melting glaciers and a shrinking snowpack,which are the foundation of the region’s water resources,and a changing precipitation regime.Most glaciers are located in Kyrgyzstan and Tajikistan,leading to transboundary water resource issues.Summer already has extremely high temperatures.Analyses indicate that Central Asia has been warming and precipitation might be increasing.The warming is expected to increase,but its spatial and temporal distribution depends upon specific global scenarios.Projections of future precipitation show significant uncertainties in type,amount,and distribution.Regional Hydroclimate Projects(RHPs)are an approach to studying these issues.Initial steps to develop an RHP began in 2021 with a widely distributed online survey about these climate issues.It was followed up with an online workshop and then,in 2023,an in-person workshop,held in Tashkent,Uzbekistan.Priorities for the Global Energy and Water Exchanges(GEWEX)project for the region include both observations and modeling,as well as development of better and additional precipitation observations,all of which are topics for the next workshop.A well-designed RHP should lead to reductions in critical climate uncertainties in policy-relevant timeframes that can influence decisions on necessary investments in climate adaptation.
基金This study was supported by the Strategic Priority Research Program of Chinese Academy of Sciences,the Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)(XDA2004030202).
文摘Land use/land cover(LULC)change and climate change are two major factors affecting the provision of ecosystem services which are closely related to human well-being.However,a clear understanding of the relationships between these two factors and ecosystem services in Central Asia is still lacking.This study aimed to comprehensively assess ecosystem services in Central Asia and analyze how they are impacted by changes in LULC and climate.The spatiotemporal patterns of three ecosystem services during the period of 2000-2015,namely the net primary productivity(NPP),water yield,and soil retention,were quantified and mapped by the Carnegie-Ames-Stanford Approach(CASA)model,Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model,and Revised Universal Soil Loss Equation(RUSLE).Scenarios were used to determine the relative importance and combined effect of LULC change and climate change on ecosystem services.Then,the relationships between climate factors(precipitation and temperature)and ecosystem services,as well as between LULC change and ecosystem services,were further discussed.The results showed that the high values of ecosystem services appeared in the southeast of Central Asia.Among the six biomes(alpine forest region(AFR),alpine meadow region(AMR),typical steppe region(TSR),desert steppe region(DSR),desert region(DR),and lake region(LR)),the values of ecosystem services followed the order of AFR>AMR>TSR>DSR>DR>LR.In addition,the values of ecosystem services fluctuated during the period of 2000-2015,with the most significant decreases observed in the southeast mountainous area and northwest of Central Asia.LULC change had a greater impact on the NPP,while climate change had a stronger influence on the water yield and soil retention.The combined LULC change and climate change exhibited a significant synergistic effect on ecosystem services in most of Central Asia.Moreover,ecosystem services were more strongly and positively correlated with precipitation than with temperature.The greening of desert areas and forest land expansion could improve ecosystem services,but unreasonable development of cropland and urbanization have had an adverse impact on ecosystem services.According to the results,ecological stability in Central Asia can be achieved through the natural vegetation protection,reasonable urbanization,and ecological agriculture development.
基金supported by the second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0605)the National Science Foundation of China(42271132)+1 种基金Longyuan Youth Innovative Program of Gansu Provincethe Fundamental Research Funds for the Central Universities(lzujbky-2021-74)。
文摘Black carbon(BC)in snow plays an important role to accelerate snow melting.However,current studies mostly focused on BC concentrations,few on their size distributions in snow which affected BC’s effect on albedo changes.Here we presented refractory BC(rBC)concentrations and size distributions in snow collected from Chinese Altai Mountains in Central Asia from November 2016 to April 2017.The results revealed that the average rBC concentrations were 5.77 and2.82 ng g-1for the surface snow and sub-surface snow,which were relatively higher in the melting season(April)than that in winter(November-January).The mass median volume-equivalent diameter of rBC size in surface snow was approximately at 120-150 nm,which was typically smaller than that in the atmosphere(about 200 nm for urban atmosphere).However,there existed no specific mass median volume-equivalent diameter of BC size for sub-surface snow in winter.While during the melting season,the median mass size of rBC in sub-surface snow was similar to that in surface snow.Backward trajectories indicated that anthropogenic sourced BC dominated rBC in snow(70%-85%).This study will promote our understanding on BC size distributions in snow,and highlight the possible impact of BC size on climate effect.
文摘Central Asian States(CAS)have diverse natural resources.This research aims to shed light on the finance–natural resource’s association in the context of CAS namely Kazakhstan,Kyrgyzstan,Tajikistan,Turkmenistan,and Uzbekistan in 1996–2020 using the cross-sectionally augmented autoregressive distributed lag technique.It seeks to examine the research question,“What is the effect of natural resource wealth on the financial expansion(FE)of Central Asia?”The results demonstrated an inverted U-shaped association between financial growth and natural resource rents.It implies that natural resources are initially a“resource blessing”that later becomes a“resource curse.”Additionally,the effect of institutional quality(INQ)and human development(HD)on financial growth is examined.The results reveal that INQ and HD positively affect FE.Moreover,a bidirectional causal relationship exists between FE and INQ.Finally,all variables contribute to a long term FE.Based on these outcomes,the major policy recommendations are that the CAS authorities diversify their financial services and products and direct the proceeds from natural resource rents to effective invest-ments particularly in HD.In addition,the social and political infrastructures in CAS must be restructured to achieve a high-quality institutional environment,which is necessary to increase the role of the private sector.
基金financially supported by the National Natural Science Foundation of China (41867030, 41971036)the National Natural Science Foundation innovation research group science foundation of China (41421061)
文摘Water resources are one of the key factors restricting the development of arid areas,and cloud water resources is an important part of water resources.The arid region of central Asia is the core region of the current national green silk road construction,and is the largest arid region in the world.Based on cloud cover data of ECMWF,the current study analyzed temporal and spatial characteristics of cloud properties in arid regions of Central Asia between 1980 and 2019.Our findings show that:(1)From the point of view of spatial distribution,total cloudiness in arid regions of Central Asia was low in the south and high in the north.The distribution of high cloud frequency and medium cloud frequency was higher in the south and lower in the north,while low cloud frequency distribution was low in the south and high in the north.(2)In terms of time,the variation of cloud cover and cloud type frequency had obvious seasonal characteristics.From winter to spring,cloud cover increased,and the change of cloud type frequency increased.From spring to summer,cloud cover continued to increase and the change of cloud type frequency increased further.Cloud cover began to decrease from summer to autumn,and the change of cloud type frequency also decreased.(3)Generally,average total cloud cover decreased in most of central Asia,and high and medium cloud cover increased while low cloud cover decreased.This study provides a reference for the rational development of cloud resources in the region.
文摘China is moving to greater economic and political influence in the global scale.One of the Chinese strategy for“go global”is Belt and Road Initiative(BRI)which was announced by President Xi Jinping in 2013.The BRI includes a significant number of countries from Asia,Central Asia,the Middle East,Africa,and Europe.In this framework,China relations with Central Asia are an important part of the BRI project.The BRI is not merely an economic project as framed by Beijing,but that it represents a new stage in China’s engagement with the Central Asian republics.The Belt and Road Initiative is highly likely to become China’s most significant contribution to Central Asia economic development.This would affect the China-Central Asia relations economically and politically.
文摘This paper investigates Central Asia's oil and gas resources, special geopolitics and energy competition, and approaches, challenges and prospects in cooperation between China and Central Asia. The objective is to propose measures for oil and gas cooperation between China and Central Asia. Central Asia is rich in oil and gas resources. Its remaining recoverable reserves of crude oil and natural gas account for 1.9% and 10.6 %, respectively, of the world's total reserves. Moreover, there is great exploration and development potential. As a strategic channel connecting Eurasia, Central Asia has a prominent geopolitical status. Many powerful countries such as the United States, Russia and China, as well as Europe, have an intense energy competition in Central Asia. In the oil and gas cooperation with Central Asia, the China National Petroleum Corporation (CNPC) focuses on establishing a coordination group, promoting overall oil and gas business opportunities and sustainable development, innovating and applying specialty engineering technology and improving project economic benefits. Through its efforts over the last nearly two decades, the China National Petroleum Corporation has completed a 50-million-tonne a year oil and gas production centre in Central Asia and oil and gas pipelines passing through multiple countries, becoming an important channel for securing China's energy imports. If appropriate measures are taken in the 'Thirteenth Five-Year Plan' period or later, the China National Petroleum Corporation will develop a 100-million-tonne p.a. oil and gas production centre in Central Asia and a strategic oil and gas import channel exceeding this amount of production. This cooperation between China and Central Asia is however faced with the following challenges: increasing multinational competition uncertainty, potential risks in the political systems of Central Asian countries, frequently occurring violence and also resource policy tightening in Central Asia. To further oil and gas cooperation with Central Asia, it is recommended that China should develop an energy acquisition strategy, assign a regional energy ambassador, enhance oil and gas supply by mergers and acquisitions, establish regional multinational subsidiaries and improve its risk prevention system.
基金financially supported by International Science & Technology Cooperation Program of China (2010DFA92720)the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-YW-T09)the Post-doctoral Fund Program of China (2013M542416)
文摘Climate warming will cause differences in precipitation distribution and changes in hydrological cycle both at regional and global scales. Arid lands of Central Asia (ALCA), one of the largest arid regions at the middle latitudes in the world, is likely to be strongly influenced by climate warming. Understanding the precipitation varia- tions in the past is an important prerequisite for predicting future precipitation trends and thus managing regional water resources in such an arid region. In this study, we used run theory, displacement, extreme deviation theory, precipitation concentration index (PCI), Mann-Kendall rank correlation and climatic trend coefficient methods to analyze the precipitation in wet and dry years, changes in precipitation over multiple-time scales, variability of precipitation and its rate of change based on the monthly precipitation data during 1950-2000 from 344 meteorological stations in the ALCA. The occurrence probability of a single year with abundant precipitation was higher than that of a single year with less precipitation. The average duration of extreme drought in the entire area was 5 years, with an average annual water deficit of 34.6 mm (accounting for 11.2% of the average annual precipitation over the duration). The occurrence probability of a single wet year was slightly higher than that of a single dry year. The occurrence probability of more than 5 consecutive wet years was 5.8%, while the occurrence probability of more than 5 consecutive dry years was 6.2%. In the center of the study area, the distribution of precipitation was stable at an intra-annual timescale, with small changes at an inter-annual timescale. In the western part of the study area, the monthly variation of precipitation was high at an inter-annual timescale. There were clear seasonal changes in precipitation (PC1=12-36) in the ALCA. Precipitation in spring and winter accounted for 37.7% and 24.4% of the annual precipitation, respectively There was a significant inter-annual change in precipitation in the arid Northwest China (PC1=24-34). Annual precipitation increased significantly (P=0.05) in 17.4% of all the meteorological stations over the study period. The probability of an increase in annual precipitation was 75.6%, with this increase being significant (P=-0.05) at 34.0% of all the meteorological stations. The average increasing rate in annual precipitation was 3.9 mm/10a (P=0.01) in the ALCA. There were significant increasing trends (P=0.01) in precipitation in Kazakhstan, Kyrgyzstan and Tajikistan, with rates of 2.6, 3.1 and 3.7 mm/10a, respectively.
基金supported by the National Natural Science Foundation of China (40730633 and 40571030)
文摘Accurate inversion of land surface evapotranspiration (ET) in arid areas is of great significance for understanding global eco-hydrological process and exploring the spatio-temporal variation and ecological response of water resources. It is also important in the functional evaluation of regional water cycle and water balance, as well as the rational allocation and management of water resources. This study, based on model validation analysis at varied scales in fiwe Central Asian countries and China's Xinjiang, developed an appropriate approach for ET inversion in arid lands. The actual ET during growing seasons of the study area was defined, and the changes in water participating in evaporation in regional water cycle were then educed. The results show the simulation error of SEBS (Surface Energy Balance System) model under cloud amount consideration was 1.34% at 30-m spatial scale, 2.75% at 1-km spatial scale and 6,37% at 4-kin spatial scale. ET inversion for 1980-2007 applying SEBS model in the study area indicates: (1) the evaporation depth (May-September) by land types descends in the order of waters (660.24 ram) 〉 cultivated land (464.66 mm) 〉 woodland (388.44 mm) 〉 urbanized land (168.16 mm) 〉 grassland (160.48 mm) 〉 unused land (83.08 mm); and (2) ET during the 2005 growing season in Xinjiang and Central Asia was 2,168.68x108 m3 (with an evaporation/precipitation ratio of 1.05) and 9,741.03x108 m3 (with an evaporation/precipitation ratio of 1.4), respectively. The results unveiled the spatio-temporal variation rules of ET process in arid areas, providing a reference for further research on the water cycle and water balance in similar arid regions.
基金funded by the National Basic Research Program of China (2012CB957703, 2013CB733301)the National Natural Science Foundation of China (41274025, 41174064)
文摘Monitoring glacier mass balance is crucial to managing water resources and also to understanding climate change for the arid and semi-arid regions of Central Asia. This study extracted the inter-annual oscillations of glacier mass over Central Asia from the first ten principal components(S-PCs) of filtered variability via multichannel singular spectral analysis(MSSA), based on gridded data of glacier mass inferred from Gravity Recovery and Climate Experiment(GRACE) data obtained from July 2002 to March 2015. Two significant cycles of glacier mass balance oscillations were identified. The first cycle with a period of 6.1-year accounted for 54.5% of the total variance and the second with a period of 2.3-year accounted for 4.3%. The 6.1-year oscillation exhibited a stronger variability compared with the 2.3-year oscillation. For the 6.1-year oscillation, the results from lagged cross-correlation function suggested that there were significant correlations between glacier mass balances and precipitation variations with the precipitation variations leading the response of glacier mass balances by 9–16 months.
基金funded by the National Key Research and Development Program of China (2016YFA0602302,2016YFB0502502)
文摘Snow cover plays an important role in the fields of climatology and cryospheric science. Remotely-sensed data have been proven to be effective in monitoring snow covers. Improved methods to process the 8-day snow-cover products derived from MODIS Terra/Aqua data can dramatically increase the data quality and reduce noise. A five-step algorithm for removing cloud effects was designed to improve the quality of MODIS snow products, and the overall accuracy of the MODIS snow data without cloud(defined as cloud-free snow-cover dataset) was enhanced by more than 90% based on direct and indirect validation methods. The snow-cover frequency(SCF) and snow-cover rate(SCR) of Central Asia were analyzed from 2000 to 2015 using trend analysis and empirical orthogonal functions(EOFs). Over the plain regions, the SCF displayed a significant north-south declining trend with a rate of 0.03 per degree of latitude, and the SCR showed a similar north-south gradient. In the mountainous areas, the SCF significantly increased with altitude by 0.12 per kilometer. Within the study area, the SCF in 65% of the study area experienced an increasing trend, but only 4.3% of the SCF-increasing pixels passed a significance test. The remaining 35% of the area underwent a decreasing trend of SCF, but only 5.2% of the SCF-decreasing pixels passed a significance test. For the entire Central Asia, the inter-annual variations of snow-cover presented a slight and insignificant increase trend from 2000 to 2015. However, the change trends of snow cover are different between the plain and mountainous regions. That is, the annual mean SCR in the plain areas displayed an increasing trend, but a decreasing trend was found in the mountainous areas.
基金the two anonymous reviewers for their valuable comments and suggestions.This research was funded by the National Key Research and Development Program of China(Grant No.2018YFC1507101)the National Natural Science Foundation of China(Grant Nos.41861144014,41875078 and 41630424)+3 种基金the National Key Research and Development Program of China(Grant No.2016YFA0601501)We acknowledge Hirosaki University for providing the APHRODITE precipitation data(http://aphrodite.st.hirosaki-u.ac.jp/download/)We thank the China Meteorological Data Service Center for providing the Chinese Surface Daily Climate Dataset(V3.0)(https://data.cma.cn/en/?r=data/detail&data-Code=SURF_CLI_CHN_MUL_DAY_CES_V3.0)the National Oceanic and Atmospheric Administration,National Centers for Environmental Information,for providing the GHCN-D dataset(V3.25)(Menne et al.,2012).We convey our gratitude to the contributors of the SciPy ecosystem(Virtanen et al.,2020),which was used for data analysis and visualization.
文摘Using rain-gauge-observation daily precipitation data from the Global Historical Climatology Network(V3.25)and the Chinese Surface Daily Climate Dataset(V3.0),this study investigates the fidelity of the AHPRODITE dataset in representing extreme precipitation,in terms of the extreme precipitation threshold value,occurrence number,probability of detection,and extremal dependence index during the cool(October to April)and warm(May to September)seasons in Central Asia during 1961–90.The distribution of extreme precipitation is characterized by large extreme precipitation threshold values and high occurrence numbers over the mountainous areas.The APHRODITE dataset is highly correlated with the gauge-observation precipitation data and can reproduce the spatial distributions of the extreme precipitation threshold value and total occurrence number.However,APHRODITE generally underestimates the extreme precipitation threshold values,while it overestimates the total numbers of extreme precipitation events,particularly over the mountainous areas.These biases can be attributed to the overestimation of light rainfall and the underestimation of heavy rainfall induced by the rainfall distribution–based interpolation.Such deficits are more evident for the warm season than the cool season,and thus the biases are more pronounced in the warm season than in the cool season.The probability of detection and extremal dependence index reveal that APHRODITE has a good capability of detecting extreme precipitation,particularly in the cool season.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA19030301)。
文摘Relatively little is known about fire regimes in grassland and cropland in Central Asia.In this study,eleven variables of fire regimes were measured from 2001 to 2019 by utilizing the burned area and active fire product,which was obtained and processed from the GEE(Google Earth Engine)platform,to describe the incidence,inter-annual variability,peak month and size of fire in four land cover types(forest,grassland,cropland and bare land).Then all variables were clustered to define clusters of fire regimes with unique fire attributes using the K-means algorithm.Results showed that Kazakhstan(KAZ)was the most affected by fire in Central Asia.Fire regimes in cropland in KAZ had the frequent,large and intense characters,which covered large burned areas and had a long duration.Fires in grassland mainly occurred in central KAZ and had the small scale and high-intensity characters with different quarterly frequencies.Fires in forest were mainly distributed in northern KAZ and eastern KAZ.Although fires in grassland underwent a shift from more to less frequent from 2001 to 2019 in Central Asia,vigilance is needed because most fires in grassland occur suddenly and cause harm to humans and livestock.
基金the National Natural Science Foundation of China(Grant No.42075050).
文摘The current work examines the impact of the snow cover extent(SCE)of the Tibetan Plateau(TP)on the interannual variation in the summer(June−July−August)surface air temperature(SAT)over Central Asia(CA)(SAT_CA)during the 1979−2019 period.The leading mode of the summer SAT_CA features a same-sign temperature anomalies in CA and explains 62%of the total variance in SAT_CA.The atmospheric circulation associated with a warming SAT_CA is characterized by a pronounced high-pressure system dominating CA.The high-pressure system is accompanied by warm advection as well as descending motion over CA,favoring the warming of the SAT_CA.Analysis shows that the interannual variation in the summer SAT_CA is significantly positively correlated with the April SCE over the central-eastern TP.In April,higher than normal SCE over the central-eastern TP has a pronounced cooling effect on the column of the atmosphere above the TP and can persist until the following early summer.Negative and positive height anomalies appear above and to the west of the TP.In the following months,the perturbation forcing generated by the TP SCE anomalies lies near the western center of the Asian subtropical westerly jet(SWJ),which promotes atmospheric waves in the zonal direction guided by the Asian SWJ.Associated with this atmospheric wave,in the following summer,a significant high-pressure system dominates CA,which is a favorable condition for a warm summer SAT_CA.
基金This research was supported by the National Key R&D Program of China (Grant No. 2018YFA0606403)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA20070103)+1 种基金the National Natural Science Foundation of China (Grants 41822502)the CAS–PKU Joint Research Program
文摘In this study, the climate changes over Arid Central Asia(ACA) during the mid-Holocene(approximately 6,000 calendar years ago, MH) and the Last Glacial Maximum(approximately 21,000 calendar years ago, LGM) were investigated using multimodel simulations derived from the Paleoclimate Modelling Intercomparison Project Phase 3(PMIP3). During the MH, the multimodel median(MMM) shows that in the core region of ACA, the regionally averaged annual surface air temperature(SAT) decreases by 0.13°C and annual precipitation decreases by 3.45%, compared with the preindustrial(PI) climate. The MMM of the SAT increases by 1.67/0.13°C in summer/autumn, whereas it decreases by 1.23/1.11°C in spring/winter. The amplitude of the seasonal cycles of the SAT increases over ACA due to different MH orbital parameters. For precipitation, the regionally averaged MMM decreases by 5.77%/5.69%/0.39%/5.24% in spring/summer/autumn/winter, respectively. Based on the analysis of the aridity index(AI), compared with the PI, a drier climate appears in southern Central Asia and western Xinjiang due to decreasing precipitation. During the LGM, the MMM shows that the regionally averaged SAT decreases by 5.04/4.36/4.70/5.12/5.88°C and precipitation decreases by 27.78%/28.16%/31.56%/27.74%/23.29% annually and in the spring, summer, autumn, and winter, respectively. Robust drying occurs throughout almost the whole core area. Decreasing precipitation plays a dominant role in shaping the drier conditions, whereas strong cooling plays a secondary but opposite role. In response to the LGM external forcings, over Central Asia and Xinjiang, the seasonal cycle of precipitation has a smaller amplitude compared with that under the PI climate. In the model-data comparison, the simulated MH moisture changes over ACA are to some extent consistent with the reconstructions, further confirming that drier conditions occurred during that period than during the PI.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)of China(XDA2004030202)Shanghai Cooperation and the Organization Science and Technology Partnership of China(2021E01019)。
文摘Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this study,we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles(MMEs)from the Coupled Model Intercomparison Project Phase 6(CMIP6)under four Shared Socioeconomic Pathway and Representative Concentration Pathway(SSP-RCP)scenarios(SSP126(SSP1-RCP2.6),SSP245(SSP2-RCP4.5),SSP460(SSP4-RCP6.0),and SSP585(SSP5-RCP8.5))during 2015-2100.The bias correction and spatial disaggregation,water-thermal product index,and sensitivity analysis were used in this study.The results showed that the hydrothermal condition is mismatched in the central and southern deserts,whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition.Compared with the historical period,the matched degree of hydrothermal condition improves during 2046-2075,but degenerates during 2015-2044 and 2076-2100.The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions.The result suggests that the optimal scenario in Central Asia is SSP126 scenario,while SSP585 scenario brings further hydrothermal contradictions.This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.
基金We dedicate this paper to the memory of Prof.ZiChu Xie,who passed away in early 2020.Prof.ZiChu Xie was an inspirational mentor and friend.This work was supported by the National Science Foundation of China(41772373,41372181)the Hunan Provincial Natural Science foundation of China(2018JJ1017)+1 种基金the National Key R&D Program of China(2018YFA0606404)and the Construction Program for First-Class Disciplines(Geography)of Hunan Province,China(5010002).We thank Dr.Jan Bloemendal for improving the English language.
文摘Holoceneδ^18O records from various archives(ice cores,cave stalagmites,and peat sediments)from the Xinjiang region of northwestern China,in arid central Asia(ACA),are all derived ultimately from local precipitationδ^18O(δ^18Op).Nevertheless,they have been proposed as indicators of different climatic parameters,such as wetness and temperature changes.This article summarizes previously reported records of moisture sources for the Xinjiang region and the results of modern observations conducted at an ice core site and a peat site in the Altai Mountains.The findings are used to propose that the overall positive trends in Holoceneδ^18O records from the various archives from the Xinjiang region primarily reflect the Holocene's long-term warming trend.It is concluded that more site-specific modern observations are needed to further elucidate the environmental significance of Holoceneδ^18O records from this region,especially for the separation of different seasonal temperature signals present withinδ^18O records.
基金co-supported by National Natural Science Foundation of China (Project number 41502201)"Western Light" project of Chinese Academy of Sciences (XBBS201301)
文摘Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the
基金co-supported by the National Natural Science Foundation of China(Grants Nos:41572162.41290253)International Partnership Program of the Chinese Academy of Sciences(No:132B61KYS20160002)
文摘Objective Climate fluctuations over suborbital or millennial timescale display significant instability during the last glacial period,which are often superimposed upon the orbital periodicity.They triggered some abrupt climate events,