The Qinghai-Xizang Plateau(QXP)serves as a crucial ecological barrier in China and Asia,exerting profound influences on global climate and biodiversity conservation.Gannan Tibetan Autonomous Prefecture(hereinafter ref...The Qinghai-Xizang Plateau(QXP)serves as a crucial ecological barrier in China and Asia,exerting profound influences on global climate and biodiversity conservation.Gannan Tibetan Autonomous Prefecture(hereinafter referred as Gannan Prefecture),located on the northeastern edge of the QXP,represents a fragile alpine ecosystem in which land use change significantly impacts ecosystem services(ESs).This study established a comprehensive framework,utilizing the Patch-generating Land-Use Simulation(PLUS)model coupled with the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to predict land use patterns under the natural development scenario,cultivated land protection scenario,and ecological protection scenario for Gannan Prefecture by 2030 and evaluated four critical ESs:habitat quality(HQ),water yield(WY),soil retention(SR),and carbon storage(CS).The primary aim is to elucidate the impacts of dynamic land use change on ESs.The results revealed that,from 2000 to 2020,HQ exhibited minimal variation,whereas CS experienced a slight decline.Conversely,WY and SR showed significant improvements.Under the natural development scenario,construction land was projected to increase by 4247.74 hm^(2),primarily at the expense of forest land.The cultivated land protection scenario anticipated an increase in farmland by 2634.36 hm^(2),which was crucial for maintaining food security.The ecological protection scenario predicted a notable expansion of forest land,accompanied by a restrained development rate of construction land.The ecological protection scenario also showed an increase in the ecosystem service index(ESI),encompassing 26.07%of the region.Forest land and grassland emerged as the primary contributors to ESs,while construction land substantially impacted WY.Water bodies exhibited minimal contribution to ESs.This study enhanced the understanding of land use change impacts on ESs in fragile and high-altitude ecosystems,offering essential theoretical frameworks and practical direction for forthcoming ecological policy and regional planning endeavors.展开更多
Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomi...Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomic development.In this study,the desertification sensitivity index(DSI)model was established by integrating the spatial distance model and environmentally sensitive area index evaluation method,and then the model was used to quantitatively analyze the spatial and temporal characteristics of desertification sensitivity of the Qinghai-Xizang Plateau from 1990 to 2020.The results revealed that:(1)a general increasing tendency from southeast to northwest was identified in the spatial distribution of desertification sensitivity.The low-sensitivity areas were mostly concentrated in the Hengduan and Nyaingqêntanglha mountains and surrounding forest and meadow areas.The high-sensitivity areas were located mainly in the Kunlun and Altun mountains and surrounding decertified areas.The center of gravity of all types of desertification-sensitive areas moved to the northwest,and the desertification sensitivity showed a decreasing trend as a whole;(2)the area of highly sensitive desertification areas decreased by 8.37%,with extreme sensitivity being the largest change among the sensitivity types.The desertification sensitivity transfer was characterized by a greater shift to lower sensitivity levels(24.56%)than to higher levels(2.03%),which demonstrated a declining trend;(3)since 1990,the change in desertification sensitivity has been dominated by the stabilizing type Ⅰ(29.30%),with the area of continuously increasing desertification sensitivity accounting for only 1.10%,indicating that the management of desertification has achieved positive results in recent years;and(4)natural factors have had a more significant impact on desertification sensitivity on the Xizang Plateau,whereas socioeconomic factors affected only localized areas.The main factors influencing desertification sensitivity were vegetation drought tolerance and aridity index.Studying spatiotemporal variations in desertification sensitivity and its influencing factors can provide a scientific foundation for developing strategies to control desertification on the Qinghai-Xizang Plateau.Dividing different desertification-sensitive areas on the basis of these patterns of change can facilitate the formulation of more targeted management and protection measures,contributing to ecological construction and sustainable economic development in the area.展开更多
The net primary productivity(NPP) is an important indicator for assessing the carbon sequestration capacities of different ecosystems and plays a crucial role in the global biosphere carbon cycle. However, in the cont...The net primary productivity(NPP) is an important indicator for assessing the carbon sequestration capacities of different ecosystems and plays a crucial role in the global biosphere carbon cycle. However, in the context of the increasing frequency, intensity, and duration of global extreme climate events, the impacts of extreme climate and vegetation phenology on NPP are still unclear, especially on the Qinghai-Xizang Plateau(QXP), China. In this study, we used a new data fusion method based on the MOD13A2 normalized difference vegetation index(NDVI) and the Global Inventory Modeling and Mapping Studies(GIMMS) NDVI_(3g) datasets to obtain a NDVI dataset(1982–2020) on the QXP. Then, we developed a NPP dataset across the QXP using the Carnegie-Ames-Stanford Approach(CASA) model and validated its applicability based on gauged NPP data. Subsequently, we calculated 18 extreme climate indices based on the CN05.1 dataset, and extracted the length of vegetation growing season using the threshold method and double logistic model based on the annual NDVI time series. Finally, we explored the spatiotemporal patterns of NPP on the QXP and the impact mechanisms of extreme climate and the length of vegetation growing season on NPP. The results indicated that the estimated NPP exhibited good applicability. Specifically, the correlation coefficient, relative bias, mean error, and root mean square error between the estimated NPP and gauged NPP were 0.76, 0.17, 52.89 g C/(m^(2)·a), and 217.52 g C/(m^(2)·a), respectively. The NPP of alpine meadow, alpine steppe, forest, and main ecosystem on the QXP mainly exhibited an increasing trend during 1982–2020, with rates of 0.35, 0.38, 1.40, and 0.48 g C/(m^(2)·a), respectively. Spatially, the NPP gradually decreased from southeast to northwest across the QXP. Extreme climate had greater impact on NPP than the length of vegetation growing season on the QXP. Specifically, the increase in extremely-wet-day precipitation(R99p), simple daily intensity index(SDII), and hottest day(TXx) increased the NPP in different ecosystems across the QXP, while the increases in the cold spell duration index(CSDI) and warm spell duration index(WSDI) decreased the NPP in these ecosystems. The results of this study provide a scientific basis for relevant departments to formulate future policies addressing the impact of extreme climate on vegetation in different ecosystems on the QXP.展开更多
Formal credit is critical in agricultural production,allowing more expenditure and productive input,thereby improving farmers'welfare.In pastoral China,formal financial institutions are gradually increasing.Howeve...Formal credit is critical in agricultural production,allowing more expenditure and productive input,thereby improving farmers'welfare.In pastoral China,formal financial institutions are gradually increasing.However,a limited understanding remains of how formal credit affects herders'household expenses.Based on a survey of 544 herders from the Qinghai-Xizang Plateau of China,this study adopted the propensity score matching approach to identify the effect of formal credit on herders'total household expenses,daily expenses,and productive expenses.The results found that average age,grassland mortgage,and other variables significantly affected herders'participation in formal credit.Formal credit could significantly improve household expenses,especially productive expenses.A heterogeneity analysis showed that formal credit had a greater impact on the household total expense for those at higher levels of wealth;however,it significantly affected the productive expense of herders at lower wealth levels.Moreover,the mediating effect indicated that formal credit could affect herders'household income,thus influencing their household expenses.Finally,this study suggests that policies should improve herders'accessibility to formal credit.展开更多
Characteristics of root pullout resistance determine the capacity to withstand uprooting and the slope protection ability of plants.However,mechanism underlying the uprooting of taproot-type shrub species in the loess...Characteristics of root pullout resistance determine the capacity to withstand uprooting and the slope protection ability of plants.However,mechanism underlying the uprooting of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau,China remains unclear.In this study,a common taproot-type shrub,Caragana korshinskii Kom.,in northeastern Qinghai-Xizang Plateau was selected as the research material.Mechanism of root-soil interaction of vertical root of C.korshinskii was investigated via a combination of a single-root pullout test and numerical simulation analysis.The results indicated that,when pulling vertically,axial force of the roots decreased with an increase in buried depth,whereas shear stress at root-soil interface initially increased and then decreased as burial depths increased.At the same buried depth,both axial force and shear stress of the roots increased with the increase in pullout force.Shear stress and plastic zone of the soil surrounding the root were symmetrically distributed along the root system.Plastic zone was located close to the surface and was caused primarily by tensile failure.In nonvertical pulling,symmetry of shear stress and plastic zone of the soil surrounding the root was disrupted.We observed larger shear stress and plastic zones on the side facing the direction of root deflection.Plastic zone included both shear and tensile failure.Axial force of the root system near the surface decreased as deflection angle of the pullout force increased.When different rainfall infiltration depths had the same vertical pulling force,root axial force decreased with the increase of rainfall infiltration depth and total root displacement increased.During rainfall infiltration,shear stress and plastic zone of the soil surrounding the root were prone to propagating deeper into the soil.These findings provide a foundation for further investigation of soil reinforcement and slope protection mechanisms of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau and similar areas.展开更多
Due to the great influences of both climate warming and human activities,permafrost on the Qinghai-Xizang Plateau(QXP) has been undergoing considerable degradation.Continuous degradation of plateau permafrost dramatic...Due to the great influences of both climate warming and human activities,permafrost on the Qinghai-Xizang Plateau(QXP) has been undergoing considerable degradation.Continuous degradation of plateau permafrost dramatically modifies the regional water cycle and hydrological processes,affecting the hydrogeological conditions,and ground hydrothermal status in cold regions.Permafrost thawing impacts the ecological environment,engineering facilities,and carbon storage functions,releasing some major greenhouse gases and exacerbating climate change.Despite the utilization of advanced research methodologies to investigate the changing hydrological processes and the corresponding influencing factors in permafrost regions,there still exist knowledge gaps in multivariate data,quantitative analysis of permafrost degradation's impact on various water bodies,and systematic hydrological modeling on the QXP.This review summarizes the main research methods in permafrost hydrology and elaborates on the impacts of permafrost degradation on regional precipitation distribution patterns,changes in surface runoff,expansion of thermokarst lakes/ponds,and groundwater dynamics on the QXP.Then,we discuss the current inadequacies and future research priorities,including multiple methods,observation data,and spatial and temporal scales,to provide a reference for a comprehensive analysis of the hydrological and environmental effects of permafrost degradation on the QXP under a warming climate.展开更多
Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a j...Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.展开更多
Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid ex...Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid expansion of glacial lakes in both regions.Despite being typically considered harsh environments,these lakes serve as vital reservoirs for microbial biodiversity and carbon metabolism.In the face of climate change,glacial lake ecosystems over the QXP and the Arctic are undergoing unprecedentedtransformations.Thisopinioneditorial highlights the significance of conducting research and establishing long-term monitoring programs focused on microbial carbon metabolism in these glacial lakes.展开更多
Comprehensive studies on the basis of pollen records from lake cores at 30 sites in the Qinghai-Xizang Plateau have been used to reconstruct temporal-spatial distributions of Holocene vegetations. Before the, Holocene...Comprehensive studies on the basis of pollen records from lake cores at 30 sites in the Qinghai-Xizang Plateau have been used to reconstruct temporal-spatial distributions of Holocene vegetations. Before the, Holocene (prior to 12.0 ka BP) desert steppe vegetation was developed from the, east to the west in the most parts of the Plateau, with a few exceptions in the extreme southeastern appeared. During the early Holocene ( 12.0 - 9.0 ka BP) deciduous broad-leaved forest/conifer and broad-leaved deciduous mixed forest were distributed in the east of Plateau (104degrees - 98degrees E). Meadows or shrub, meadow appeared in the middle of tire Plateau (98degrees - 92degrees E). Farther west to about 80degrees E, a steppe landscape was present. During the middle Holocene (9.0 - 3.2 ka BP), the palaeovegetations were sequentially conifer and broad-leaved deciduous mixed forest and sclerophyllous broad-leaved forest (104degrees - 98degrees E) - conifer and broad-leaved deciduous mixed forest (98degrees - 94degrees E) - shrub meadow (94degrees - 92degrees E) - steppe (92degrees - 80degrees E). During the late Holocene (after 3.2 ka BP), the palaeovegetations were sequentially sclerophyllous broad-leaved forest - conifer and broad-leaved deciduous mixed forest - meadow - steppe - desert from east to west of the Plateau.展开更多
Global warming has led to the frequent occurrence of extreme climatic events(ECEs)in the ecologically frag ile Qinghai-Xizang Plateau.Rural households face strong barriers in adaption,and food production is seriously ...Global warming has led to the frequent occurrence of extreme climatic events(ECEs)in the ecologically frag ile Qinghai-Xizang Plateau.Rural households face strong barriers in adaption,and food production is seriously threatened.Current methods for increasing household adaptability take a holistic point of view,but do not ac curately identify groups experiencing different adaptive barriers.To better identify different barriers,this paper examines natural,economic,cognitive,and technical barriers.A total of 17 indicators were selected to com prehensively evaluate the degree of barriers to crops adaptation in response to ECEs.Key factors were further analyzed to identify paths to break down the barriers.The results showed the following.(1)Natural barriers were present at the highest degree,economic barriers appear to be smallest,and the overall barriers were bi ased towards the lower quartile.10.82%of the households with the highest barriers.(2)67.38%of households report taking adaptive measures in crops production.The increase of the barriers leads to an increase and then a decrease in the possibility of adaptive behavior.(3)Addressing technical barriers is key to rapidly increasing household adaptive behavior in response to ECEs.The study provides recommendations for local governments to improve household adaptation behavior from two perspectives:short-term and long-term optimization path ways.This study can help governments quickly locate households with different classes of barriers,and propose more targeted adaptation policies.The ultimate goal is to ensure the sustainability of crops production and the well-being of households in northeastern part of the Qinghai-Xizang Plateau.展开更多
With the implementation of significant national strategies and rapid socioeconomic development,many ultra-long deep tunnels are being constructed in the Qinghai–Xizang Plateau region.However,the extreme complexity an...With the implementation of significant national strategies and rapid socioeconomic development,many ultra-long deep tunnels are being constructed in the Qinghai–Xizang Plateau region.However,the extreme complexity and variability of the environment in this region pose significant challenges to the safe construction and long-term operation of the planned or under-construction ultra-long deep tunnels.To address these complex technical challenges,this paper provides a detailed analysis of the complex climate and geology features of the Qinghai–Xizang Plateau during tunnel construction.The climate characteristics of the Qinghai–Xizang Plateau include severe coldness,low oxygen,and unpredictable weather changes.The geological characteristics include complex stress distributions caused by the intense internal and external dynamic coupling of tectonic plates,widespread active tectonic structures,frequent high-intensity earthquakes,fractured rock masses,and numerous active fault zones.Based on the analysis,this paper elaborates on potential sources of major disasters resulting from the characteristics of ultra-long deep tunnel projects in the Qinghai–Xizang Plateau region.These potential disaster sources include the crossing of active fault zones,high geostress rockbursts,large deformation disasters,high-pressure water surges,geothermal hazards,inadequate long-distance ventilation and oxygen supply,and multi-hazard couplings.In response to these challenges,this paper systematically summarizes the latest research progress and technological achievements in the domestic and international literature,and proposes innovative ideas and future development prospects for disaster monitoring and early warning,mechanized intelligent construction,long-term safety services,and emergency security and rescue.These innovative measures are intended to address the challenges of tunnel disaster prevention and control in the complex environment of the Qinghai–Xizang Plateau,contributing to the safe construction and long-term operation of ultra-long deep tunnels in this region.展开更多
Although the monsoon circulation of the Qinghai-Xizang (Tibetan) Plateau, in response to the seasonal variation of the atmospheric heat contrast between the plateau and the surrounding free atmosphere, is important in...Although the monsoon circulation of the Qinghai-Xizang (Tibetan) Plateau, in response to the seasonal variation of the atmospheric heat contrast between the plateau and the surrounding free atmosphere, is important in influencing the atmospheric circulation of the Northern Hemisphere, there are only a few continuous paleoclimatic records available, and these are limited to the plateau’s margin. Here we present a 12,000-a climatic record from Siling Lake in the central Qinghai-Xizang Plateau, constructed from the geochemical and stable isotopic studies on the sediment core CH8803, which shows that展开更多
Based on monthly mean temperature and precipitation, the changing processes and tendencies of temperature and precipitation in Qinghai-Xizang Plateau from 1950s to the early 1990s are analysed. The change of temperatu...Based on monthly mean temperature and precipitation, the changing processes and tendencies of temperature and precipitation in Qinghai-Xizang Plateau from 1950s to the early 1990s are analysed. The change of temperature in the past 40 a is almost unanimous on the spatial scale. The first area becoming warmer is the southeastern Tibet. The plateau is divided into 5 parts according to the change of temperature, and 9 parts according to the change of precipitation. For the past 40a some area has been warmer and drier, others warmer and wetter.展开更多
Areview of the effects of theTibetan Platean on circulation features over the plateau and its surrounding areas has been made, with a special emphasis upon the monsoon circulations in South Asin and East Asia. This in...Areview of the effects of theTibetan Platean on circulation features over the plateau and its surrounding areas has been made, with a special emphasis upon the monsoon circulations in South Asin and East Asia. This includes estimates of heat sources, dynamic and thermal effects of the plateau, adn effects of the plateau on summer and winter monsoons. Major progresses made in this aspect by Chinese meteorologists have been specifically described and are compared with the achievements made by the meteorologists of other countries.展开更多
Guliya ice core records, high lake-level records in the Qinghai-Xizang Plateau and at its north side as well as vegetation succession records indicated that during the period of 30-40 kaBP, namely the later age of the...Guliya ice core records, high lake-level records in the Qinghai-Xizang Plateau and at its north side as well as vegetation succession records indicated that during the period of 30-40 kaBP, namely the later age of the megainterstadial of last glacial period, or the marine oxygen isotope stage 3, the climate of the Qinghai-Xizang Plateau was exceptionally warm and humid, the temperature was 2-4℃ higher than today and the precipitation was 40% to over 100%展开更多
Based on the 1961-1995 atmospheric apparent heat source/sink and the 1961-1990 snow-cover days and depth over the Qinghai-Xizang Plateau (QXP) and the 1961-1995 reanalysis data of NCEP/NCAR and the 1975-1994 OLR data,...Based on the 1961-1995 atmospheric apparent heat source/sink and the 1961-1990 snow-cover days and depth over the Qinghai-Xizang Plateau (QXP) and the 1961-1995 reanalysis data of NCEP/NCAR and the 1975-1994 OLR data, this paper discusses the interannual variability of the heat regime and its relation to atmospheric circulation It is shown that the interannual variability is pronounced, with maximal variability in spring and autumn, and the variability is heterogeneous horizontally. In the years with the weak (or strong) winter cold source, the deep trough over East Asia is to the east (or west) of its normal, which corresponds to strong (or weak) winter monsoon in East Asia. In the years with the strong (or weak) sum mer heat source, there exists an anomalous cyclone (or anticyclone) in the middle and lower troposphere over the QXP and ifs neighborhood and anomalous southwest (or northeast) winds over the Yangtze River valley of China, corresponding to strong (or weak) summer monsoon in East Asia. The summer heat source of the QXP is related to the intensity and position of the South Asia high. The QXP snow cover condition of April has a close relation to the heating intensity of summer. There is a remarkable negative correlation between the summer heat source of the QXP and the convection over the southeastern QXP, the Bay of Bengal, the Indo-China Peninsula, the southeastern Asia, the southwest part of China and the lower reaches of the Yangtze River and in the area from the Yellow Sea of China to the Sea of Japan.展开更多
A preliminary study of the Malan loess on the eastern margin of the Qinghai-Xizang(Tibetan)Plateau and its adjacent area shows that along the boundary of Kunlun Mts.-Buqing Mts.-A’nymaqnMts.-South Qinling(Motianling)...A preliminary study of the Malan loess on the eastern margin of the Qinghai-Xizang(Tibetan)Plateau and its adjacent area shows that along the boundary of Kunlun Mts.-Buqing Mts.-A’nymaqnMts.-South Qinling(Motianling),the Malun loess falls roughly into two main depositional regions:to itsnorth,a hot loess region in which dusts come mainly from the Asian inland arid area;to its south,a coldloess region in which dusts come chiefly from the Qinghai-Xizang Plateau.The possible causative fac-tors and processes for the loess difference are the uplift of the Plateau and the effects of its resultant particuolar landform,the interactions of its induced Asian monsoon,by-flowing westlies and plateau monsoon,and thedifference of sediments of source areas.展开更多
The relations between δ18O and temperature on the different time scales were analysed,according to the data from Tuotuohe (34°13’N, 96°25’E; 4533 m a. s. l. ), Delingha (37°22’N,97°22’E; 2981 ...The relations between δ18O and temperature on the different time scales were analysed,according to the data from Tuotuohe (34°13’N, 96°25’E; 4533 m a. s. l. ), Delingha (37°22’N,97°22’E; 2981 m a. s. l. ) and Xining (36°37’N, 101°46’E; 2261 m a. s. l. ) in the Qnghai-Xizang Plateau. The results show that the significance of d δ18O/dT on different time scales are different.The d δ18O/dT on the synoptic scale reflects the interdependent relation between δ18O and temperature in the short-term synoptic scale process; the d δ18O/d T on the seasonal scale reflects the relation between them whithin a year; and the d δ18O/d T on the climatic scale reflects the relation between them in the long-term climatic change. The calculated d δ18O/dT on climatic scale is very close to the theoretical values on the condition of advection transport for Tuotuohe Station. However, there are great differences between the calculated and the theoretical values for Delingha and Xining stations.展开更多
A comprehensive study in this paper for the lithosphere velocity structure, conductivity structure, density and magnetism structure at the Qinghai-Xizang(Tibetan) Plateau has been completed based on the data of gravit...A comprehensive study in this paper for the lithosphere velocity structure, conductivity structure, density and magnetism structure at the Qinghai-Xizang(Tibetan) Plateau has been completed based on the data of gravity, geomagnetism, and magneto-telluric sounding (MTS), explosion seismology acquired on the comprehensive geophysical profile along Gyirong-Sange-展开更多
Interannual and decadal variations of winter snow cover over the Qinghai-Xizang Plateau (QXP) are analyzed by using monthly mean snow depth data set of 60 stations over QXP for the period of 1958 through 1992. It is f...Interannual and decadal variations of winter snow cover over the Qinghai-Xizang Plateau (QXP) are analyzed by using monthly mean snow depth data set of 60 stations over QXP for the period of 1958 through 1992. It is found that the winter snow cover over QXP bears a pronounced quasi-biennial oscillation, and it underwent an obvious decadal transition from a poor snow cover period to a rich snow cover period in the late 1970’s during the last 40 years. It is shown that the summer rainfall in the eastern China is closely associated with the winter snow cov-er over QXP not only in the interannual variation but also in the decadal variation. A clear relationship ex-ists in the quasi-biennial oscillation between the summer rainfall in the northern part of North China and the southern China and the winter snow cover over QXP. Furthermore, the summer rainfall in the four cli-mate divisions of Qinling-Daba Mountains, the Yangtze-Huaihe River Plain, the upper and lower reaches of the Yangtze River showed a remarkable transition from drought period to rainy period in the end of 1970’s, in good correspondence with the decadal transition of the winter snow cover over QXP. Key words Snow cover over Qinghai-Xizang Plateau - Summer monsoon rainfall in China - Interannual and decadal variations This study was supported by the National Key Programme for Developing Basic Sciences (G 1998040900 Part I).展开更多
基金funded by the National Natural Science Foundation of China(42101276)the Major Project of Key Research Bases for Humanities and Social Sciences Funded by the Ministry of Education of China(22JJD790015)the Science and Technology Project of Gansu Province,China(20JR5RA529).
文摘The Qinghai-Xizang Plateau(QXP)serves as a crucial ecological barrier in China and Asia,exerting profound influences on global climate and biodiversity conservation.Gannan Tibetan Autonomous Prefecture(hereinafter referred as Gannan Prefecture),located on the northeastern edge of the QXP,represents a fragile alpine ecosystem in which land use change significantly impacts ecosystem services(ESs).This study established a comprehensive framework,utilizing the Patch-generating Land-Use Simulation(PLUS)model coupled with the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to predict land use patterns under the natural development scenario,cultivated land protection scenario,and ecological protection scenario for Gannan Prefecture by 2030 and evaluated four critical ESs:habitat quality(HQ),water yield(WY),soil retention(SR),and carbon storage(CS).The primary aim is to elucidate the impacts of dynamic land use change on ESs.The results revealed that,from 2000 to 2020,HQ exhibited minimal variation,whereas CS experienced a slight decline.Conversely,WY and SR showed significant improvements.Under the natural development scenario,construction land was projected to increase by 4247.74 hm^(2),primarily at the expense of forest land.The cultivated land protection scenario anticipated an increase in farmland by 2634.36 hm^(2),which was crucial for maintaining food security.The ecological protection scenario predicted a notable expansion of forest land,accompanied by a restrained development rate of construction land.The ecological protection scenario also showed an increase in the ecosystem service index(ESI),encompassing 26.07%of the region.Forest land and grassland emerged as the primary contributors to ESs,while construction land substantially impacted WY.Water bodies exhibited minimal contribution to ESs.This study enhanced the understanding of land use change impacts on ESs in fragile and high-altitude ecosystems,offering essential theoretical frameworks and practical direction for forthcoming ecological policy and regional planning endeavors.
基金funded by the National Natural Science Foundation of China(42371219)the Key Natural Science Foundation of Gansu Province(24JRRA135)the Oasis Scientific Research Achievements Breakthrough Action Plan Project of Northwest Normal University(NWNU-LZKX-202302).
文摘Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomic development.In this study,the desertification sensitivity index(DSI)model was established by integrating the spatial distance model and environmentally sensitive area index evaluation method,and then the model was used to quantitatively analyze the spatial and temporal characteristics of desertification sensitivity of the Qinghai-Xizang Plateau from 1990 to 2020.The results revealed that:(1)a general increasing tendency from southeast to northwest was identified in the spatial distribution of desertification sensitivity.The low-sensitivity areas were mostly concentrated in the Hengduan and Nyaingqêntanglha mountains and surrounding forest and meadow areas.The high-sensitivity areas were located mainly in the Kunlun and Altun mountains and surrounding decertified areas.The center of gravity of all types of desertification-sensitive areas moved to the northwest,and the desertification sensitivity showed a decreasing trend as a whole;(2)the area of highly sensitive desertification areas decreased by 8.37%,with extreme sensitivity being the largest change among the sensitivity types.The desertification sensitivity transfer was characterized by a greater shift to lower sensitivity levels(24.56%)than to higher levels(2.03%),which demonstrated a declining trend;(3)since 1990,the change in desertification sensitivity has been dominated by the stabilizing type Ⅰ(29.30%),with the area of continuously increasing desertification sensitivity accounting for only 1.10%,indicating that the management of desertification has achieved positive results in recent years;and(4)natural factors have had a more significant impact on desertification sensitivity on the Xizang Plateau,whereas socioeconomic factors affected only localized areas.The main factors influencing desertification sensitivity were vegetation drought tolerance and aridity index.Studying spatiotemporal variations in desertification sensitivity and its influencing factors can provide a scientific foundation for developing strategies to control desertification on the Qinghai-Xizang Plateau.Dividing different desertification-sensitive areas on the basis of these patterns of change can facilitate the formulation of more targeted management and protection measures,contributing to ecological construction and sustainable economic development in the area.
基金supported by the National Natural Science Foundation of China (U2243227)。
文摘The net primary productivity(NPP) is an important indicator for assessing the carbon sequestration capacities of different ecosystems and plays a crucial role in the global biosphere carbon cycle. However, in the context of the increasing frequency, intensity, and duration of global extreme climate events, the impacts of extreme climate and vegetation phenology on NPP are still unclear, especially on the Qinghai-Xizang Plateau(QXP), China. In this study, we used a new data fusion method based on the MOD13A2 normalized difference vegetation index(NDVI) and the Global Inventory Modeling and Mapping Studies(GIMMS) NDVI_(3g) datasets to obtain a NDVI dataset(1982–2020) on the QXP. Then, we developed a NPP dataset across the QXP using the Carnegie-Ames-Stanford Approach(CASA) model and validated its applicability based on gauged NPP data. Subsequently, we calculated 18 extreme climate indices based on the CN05.1 dataset, and extracted the length of vegetation growing season using the threshold method and double logistic model based on the annual NDVI time series. Finally, we explored the spatiotemporal patterns of NPP on the QXP and the impact mechanisms of extreme climate and the length of vegetation growing season on NPP. The results indicated that the estimated NPP exhibited good applicability. Specifically, the correlation coefficient, relative bias, mean error, and root mean square error between the estimated NPP and gauged NPP were 0.76, 0.17, 52.89 g C/(m^(2)·a), and 217.52 g C/(m^(2)·a), respectively. The NPP of alpine meadow, alpine steppe, forest, and main ecosystem on the QXP mainly exhibited an increasing trend during 1982–2020, with rates of 0.35, 0.38, 1.40, and 0.48 g C/(m^(2)·a), respectively. Spatially, the NPP gradually decreased from southeast to northwest across the QXP. Extreme climate had greater impact on NPP than the length of vegetation growing season on the QXP. Specifically, the increase in extremely-wet-day precipitation(R99p), simple daily intensity index(SDII), and hottest day(TXx) increased the NPP in different ecosystems across the QXP, while the increases in the cold spell duration index(CSDI) and warm spell duration index(WSDI) decreased the NPP in these ecosystems. The results of this study provide a scientific basis for relevant departments to formulate future policies addressing the impact of extreme climate on vegetation in different ecosystems on the QXP.
基金funding from the National Natural Science Foundation of China (72303086)the Leading Scientist Project of Qinghai Province, China (2023-NK-147)+1 种基金the Consulting Project of Chinese Academy of Engineering (2023-XY-28,2022-XY-139)the Fundamental Research Funds for the Central Universities, China (lzujbky-2022-sp13)
文摘Formal credit is critical in agricultural production,allowing more expenditure and productive input,thereby improving farmers'welfare.In pastoral China,formal financial institutions are gradually increasing.However,a limited understanding remains of how formal credit affects herders'household expenses.Based on a survey of 544 herders from the Qinghai-Xizang Plateau of China,this study adopted the propensity score matching approach to identify the effect of formal credit on herders'total household expenses,daily expenses,and productive expenses.The results found that average age,grassland mortgage,and other variables significantly affected herders'participation in formal credit.Formal credit could significantly improve household expenses,especially productive expenses.A heterogeneity analysis showed that formal credit had a greater impact on the household total expense for those at higher levels of wealth;however,it significantly affected the productive expense of herders at lower wealth levels.Moreover,the mediating effect indicated that formal credit could affect herders'household income,thus influencing their household expenses.Finally,this study suggests that policies should improve herders'accessibility to formal credit.
基金funded by the National Natural Science Foundation of China (42002283)
文摘Characteristics of root pullout resistance determine the capacity to withstand uprooting and the slope protection ability of plants.However,mechanism underlying the uprooting of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau,China remains unclear.In this study,a common taproot-type shrub,Caragana korshinskii Kom.,in northeastern Qinghai-Xizang Plateau was selected as the research material.Mechanism of root-soil interaction of vertical root of C.korshinskii was investigated via a combination of a single-root pullout test and numerical simulation analysis.The results indicated that,when pulling vertically,axial force of the roots decreased with an increase in buried depth,whereas shear stress at root-soil interface initially increased and then decreased as burial depths increased.At the same buried depth,both axial force and shear stress of the roots increased with the increase in pullout force.Shear stress and plastic zone of the soil surrounding the root were symmetrically distributed along the root system.Plastic zone was located close to the surface and was caused primarily by tensile failure.In nonvertical pulling,symmetry of shear stress and plastic zone of the soil surrounding the root was disrupted.We observed larger shear stress and plastic zones on the side facing the direction of root deflection.Plastic zone included both shear and tensile failure.Axial force of the root system near the surface decreased as deflection angle of the pullout force increased.When different rainfall infiltration depths had the same vertical pulling force,root axial force decreased with the increase of rainfall infiltration depth and total root displacement increased.During rainfall infiltration,shear stress and plastic zone of the soil surrounding the root were prone to propagating deeper into the soil.These findings provide a foundation for further investigation of soil reinforcement and slope protection mechanisms of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau and similar areas.
基金supported by the Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-DQC026).
文摘Due to the great influences of both climate warming and human activities,permafrost on the Qinghai-Xizang Plateau(QXP) has been undergoing considerable degradation.Continuous degradation of plateau permafrost dramatically modifies the regional water cycle and hydrological processes,affecting the hydrogeological conditions,and ground hydrothermal status in cold regions.Permafrost thawing impacts the ecological environment,engineering facilities,and carbon storage functions,releasing some major greenhouse gases and exacerbating climate change.Despite the utilization of advanced research methodologies to investigate the changing hydrological processes and the corresponding influencing factors in permafrost regions,there still exist knowledge gaps in multivariate data,quantitative analysis of permafrost degradation's impact on various water bodies,and systematic hydrological modeling on the QXP.This review summarizes the main research methods in permafrost hydrology and elaborates on the impacts of permafrost degradation on regional precipitation distribution patterns,changes in surface runoff,expansion of thermokarst lakes/ponds,and groundwater dynamics on the QXP.Then,we discuss the current inadequacies and future research priorities,including multiple methods,observation data,and spatial and temporal scales,to provide a reference for a comprehensive analysis of the hydrological and environmental effects of permafrost degradation on the QXP under a warming climate.
基金supported by the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0306)the Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB21B32)the National Natural Science Foundation of China(No.42174069).
文摘Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.
基金supported by Key Collaborative Research Program of the Alliance of International Science Organizations(Grant no.ANSO-CR-KP-2021-04)the Key Program of National Natural Science Foundation of China(Grant no.42330410)。
文摘Glacial lakes,intimately linked to glacier termini,are crucial landscape features of the Qinghai-Xizang Plateau(QXP,Qinghai-Tibet Plateau)and the Arctic.Climate warming has accelerated glacier retreat and the rapid expansion of glacial lakes in both regions.Despite being typically considered harsh environments,these lakes serve as vital reservoirs for microbial biodiversity and carbon metabolism.In the face of climate change,glacial lake ecosystems over the QXP and the Arctic are undergoing unprecedentedtransformations.Thisopinioneditorial highlights the significance of conducting research and establishing long-term monitoring programs focused on microbial carbon metabolism in these glacial lakes.
文摘Comprehensive studies on the basis of pollen records from lake cores at 30 sites in the Qinghai-Xizang Plateau have been used to reconstruct temporal-spatial distributions of Holocene vegetations. Before the, Holocene (prior to 12.0 ka BP) desert steppe vegetation was developed from the, east to the west in the most parts of the Plateau, with a few exceptions in the extreme southeastern appeared. During the early Holocene ( 12.0 - 9.0 ka BP) deciduous broad-leaved forest/conifer and broad-leaved deciduous mixed forest were distributed in the east of Plateau (104degrees - 98degrees E). Meadows or shrub, meadow appeared in the middle of tire Plateau (98degrees - 92degrees E). Farther west to about 80degrees E, a steppe landscape was present. During the middle Holocene (9.0 - 3.2 ka BP), the palaeovegetations were sequentially conifer and broad-leaved deciduous mixed forest and sclerophyllous broad-leaved forest (104degrees - 98degrees E) - conifer and broad-leaved deciduous mixed forest (98degrees - 94degrees E) - shrub meadow (94degrees - 92degrees E) - steppe (92degrees - 80degrees E). During the late Holocene (after 3.2 ka BP), the palaeovegetations were sequentially sclerophyllous broad-leaved forest - conifer and broad-leaved deciduous mixed forest - meadow - steppe - desert from east to west of the Plateau.
基金supported by the Second Scientific Expedition to the Qinghai‒Xizang Plateau(Grant No.2019QZKK0405-05)method-ological support from the State Key Program of the National Natural Science Foundation of China(Grant No.72033005)is also appreciated greatly.
文摘Global warming has led to the frequent occurrence of extreme climatic events(ECEs)in the ecologically frag ile Qinghai-Xizang Plateau.Rural households face strong barriers in adaption,and food production is seriously threatened.Current methods for increasing household adaptability take a holistic point of view,but do not ac curately identify groups experiencing different adaptive barriers.To better identify different barriers,this paper examines natural,economic,cognitive,and technical barriers.A total of 17 indicators were selected to com prehensively evaluate the degree of barriers to crops adaptation in response to ECEs.Key factors were further analyzed to identify paths to break down the barriers.The results showed the following.(1)Natural barriers were present at the highest degree,economic barriers appear to be smallest,and the overall barriers were bi ased towards the lower quartile.10.82%of the households with the highest barriers.(2)67.38%of households report taking adaptive measures in crops production.The increase of the barriers leads to an increase and then a decrease in the possibility of adaptive behavior.(3)Addressing technical barriers is key to rapidly increasing household adaptive behavior in response to ECEs.The study provides recommendations for local governments to improve household adaptation behavior from two perspectives:short-term and long-term optimization path ways.This study can help governments quickly locate households with different classes of barriers,and propose more targeted adaptation policies.The ultimate goal is to ensure the sustainability of crops production and the well-being of households in northeastern part of the Qinghai-Xizang Plateau.
文摘With the implementation of significant national strategies and rapid socioeconomic development,many ultra-long deep tunnels are being constructed in the Qinghai–Xizang Plateau region.However,the extreme complexity and variability of the environment in this region pose significant challenges to the safe construction and long-term operation of the planned or under-construction ultra-long deep tunnels.To address these complex technical challenges,this paper provides a detailed analysis of the complex climate and geology features of the Qinghai–Xizang Plateau during tunnel construction.The climate characteristics of the Qinghai–Xizang Plateau include severe coldness,low oxygen,and unpredictable weather changes.The geological characteristics include complex stress distributions caused by the intense internal and external dynamic coupling of tectonic plates,widespread active tectonic structures,frequent high-intensity earthquakes,fractured rock masses,and numerous active fault zones.Based on the analysis,this paper elaborates on potential sources of major disasters resulting from the characteristics of ultra-long deep tunnel projects in the Qinghai–Xizang Plateau region.These potential disaster sources include the crossing of active fault zones,high geostress rockbursts,large deformation disasters,high-pressure water surges,geothermal hazards,inadequate long-distance ventilation and oxygen supply,and multi-hazard couplings.In response to these challenges,this paper systematically summarizes the latest research progress and technological achievements in the domestic and international literature,and proposes innovative ideas and future development prospects for disaster monitoring and early warning,mechanized intelligent construction,long-term safety services,and emergency security and rescue.These innovative measures are intended to address the challenges of tunnel disaster prevention and control in the complex environment of the Qinghai–Xizang Plateau,contributing to the safe construction and long-term operation of ultra-long deep tunnels in this region.
基金Project supported by the National Natural Science Foundation of China
文摘Although the monsoon circulation of the Qinghai-Xizang (Tibetan) Plateau, in response to the seasonal variation of the atmospheric heat contrast between the plateau and the surrounding free atmosphere, is important in influencing the atmospheric circulation of the Northern Hemisphere, there are only a few continuous paleoclimatic records available, and these are limited to the plateau’s margin. Here we present a 12,000-a climatic record from Siling Lake in the central Qinghai-Xizang Plateau, constructed from the geochemical and stable isotopic studies on the sediment core CH8803, which shows that
基金Project supported by the China Climbing Project "Formation, Evolution, and Environmental Change and Ecosystem of the Qinghai-Xizang Plateau".
文摘Based on monthly mean temperature and precipitation, the changing processes and tendencies of temperature and precipitation in Qinghai-Xizang Plateau from 1950s to the early 1990s are analysed. The change of temperature in the past 40 a is almost unanimous on the spatial scale. The first area becoming warmer is the southeastern Tibet. The plateau is divided into 5 parts according to the change of temperature, and 9 parts according to the change of precipitation. For the past 40a some area has been warmer and drier, others warmer and wetter.
文摘Areview of the effects of theTibetan Platean on circulation features over the plateau and its surrounding areas has been made, with a special emphasis upon the monsoon circulations in South Asin and East Asia. This includes estimates of heat sources, dynamic and thermal effects of the plateau, adn effects of the plateau on summer and winter monsoons. Major progresses made in this aspect by Chinese meteorologists have been specifically described and are compared with the achievements made by the meteorologists of other countries.
文摘Guliya ice core records, high lake-level records in the Qinghai-Xizang Plateau and at its north side as well as vegetation succession records indicated that during the period of 30-40 kaBP, namely the later age of the megainterstadial of last glacial period, or the marine oxygen isotope stage 3, the climate of the Qinghai-Xizang Plateau was exceptionally warm and humid, the temperature was 2-4℃ higher than today and the precipitation was 40% to over 100%
基金the auspices of the National!(G1998040800)CAS's Key Project for Basic Research on the Tibetan Plateau! (KZ951-A1-204, KZ95T-
文摘Based on the 1961-1995 atmospheric apparent heat source/sink and the 1961-1990 snow-cover days and depth over the Qinghai-Xizang Plateau (QXP) and the 1961-1995 reanalysis data of NCEP/NCAR and the 1975-1994 OLR data, this paper discusses the interannual variability of the heat regime and its relation to atmospheric circulation It is shown that the interannual variability is pronounced, with maximal variability in spring and autumn, and the variability is heterogeneous horizontally. In the years with the weak (or strong) winter cold source, the deep trough over East Asia is to the east (or west) of its normal, which corresponds to strong (or weak) winter monsoon in East Asia. In the years with the strong (or weak) sum mer heat source, there exists an anomalous cyclone (or anticyclone) in the middle and lower troposphere over the QXP and ifs neighborhood and anomalous southwest (or northeast) winds over the Yangtze River valley of China, corresponding to strong (or weak) summer monsoon in East Asia. The summer heat source of the QXP is related to the intensity and position of the South Asia high. The QXP snow cover condition of April has a close relation to the heating intensity of summer. There is a remarkable negative correlation between the summer heat source of the QXP and the convection over the southeastern QXP, the Bay of Bengal, the Indo-China Peninsula, the southeastern Asia, the southwest part of China and the lower reaches of the Yangtze River and in the area from the Yellow Sea of China to the Sea of Japan.
基金the National Natural Science Foundation of Chinathe Fund for Returned Overseas Scholars' Starting Work
文摘A preliminary study of the Malan loess on the eastern margin of the Qinghai-Xizang(Tibetan)Plateau and its adjacent area shows that along the boundary of Kunlun Mts.-Buqing Mts.-A’nymaqnMts.-South Qinling(Motianling),the Malun loess falls roughly into two main depositional regions:to itsnorth,a hot loess region in which dusts come mainly from the Asian inland arid area;to its south,a coldloess region in which dusts come chiefly from the Qinghai-Xizang Plateau.The possible causative fac-tors and processes for the loess difference are the uplift of the Plateau and the effects of its resultant particuolar landform,the interactions of its induced Asian monsoon,by-flowing westlies and plateau monsoon,and thedifference of sediments of source areas.
文摘The relations between δ18O and temperature on the different time scales were analysed,according to the data from Tuotuohe (34°13’N, 96°25’E; 4533 m a. s. l. ), Delingha (37°22’N,97°22’E; 2981 m a. s. l. ) and Xining (36°37’N, 101°46’E; 2261 m a. s. l. ) in the Qnghai-Xizang Plateau. The results show that the significance of d δ18O/dT on different time scales are different.The d δ18O/dT on the synoptic scale reflects the interdependent relation between δ18O and temperature in the short-term synoptic scale process; the d δ18O/d T on the seasonal scale reflects the relation between them whithin a year; and the d δ18O/d T on the climatic scale reflects the relation between them in the long-term climatic change. The calculated d δ18O/dT on climatic scale is very close to the theoretical values on the condition of advection transport for Tuotuohe Station. However, there are great differences between the calculated and the theoretical values for Delingha and Xining stations.
文摘A comprehensive study in this paper for the lithosphere velocity structure, conductivity structure, density and magnetism structure at the Qinghai-Xizang(Tibetan) Plateau has been completed based on the data of gravity, geomagnetism, and magneto-telluric sounding (MTS), explosion seismology acquired on the comprehensive geophysical profile along Gyirong-Sange-
文摘Interannual and decadal variations of winter snow cover over the Qinghai-Xizang Plateau (QXP) are analyzed by using monthly mean snow depth data set of 60 stations over QXP for the period of 1958 through 1992. It is found that the winter snow cover over QXP bears a pronounced quasi-biennial oscillation, and it underwent an obvious decadal transition from a poor snow cover period to a rich snow cover period in the late 1970’s during the last 40 years. It is shown that the summer rainfall in the eastern China is closely associated with the winter snow cov-er over QXP not only in the interannual variation but also in the decadal variation. A clear relationship ex-ists in the quasi-biennial oscillation between the summer rainfall in the northern part of North China and the southern China and the winter snow cover over QXP. Furthermore, the summer rainfall in the four cli-mate divisions of Qinling-Daba Mountains, the Yangtze-Huaihe River Plain, the upper and lower reaches of the Yangtze River showed a remarkable transition from drought period to rainy period in the end of 1970’s, in good correspondence with the decadal transition of the winter snow cover over QXP. Key words Snow cover over Qinghai-Xizang Plateau - Summer monsoon rainfall in China - Interannual and decadal variations This study was supported by the National Key Programme for Developing Basic Sciences (G 1998040900 Part I).
