The western alpine region is an important freshwater supply and water conservation area for China and its surrounding areas.As ecological civilization construction progresses,the ecohydrology of the western alpine reg...The western alpine region is an important freshwater supply and water conservation area for China and its surrounding areas.As ecological civilization construction progresses,the ecohydrology of the western alpine region in China,which is a crucial ecological barrier,has undergone significant changes.In this study,we collected 1077 sampling points and presented a comprehensive overview of research results pertaining to the hydrochemistry of river water,meltwater,groundwater,and precipitation in the western alpine region of China using piper diagram,end-member diagram,and hydrological process indication.Water resources in the western alpine region of China were found to be weakly alkaline and have low total dissolved solids(TDS).The mean pH values for river water,meltwater,groundwater,and precipitation are 7.92,7.58,7.72,and 7.32,respectively.The mean TDS values for river water,meltwater,groundwater,and precipitation are 280.99,72.48,544.41,and 67.68 mg/L.The hydrochemical characteristics of the water resources in this region exhibit significant spatial and temporal variability.These characteristics include higher ion concentrations during the freezing period and higher ion concentrations in inland river basins,such as the Shule River Basin and Tarim River Basin.The principal hydrochemical type of river water and meltwater is HCO^(3-)•SO_(4)^(2-)-Ca^(2+),whereas the principal cations in groundwater are Mg^(2+)and Ca^(2+),and the principal anions are HCO^(3-)and SO_(4)^(2-).In terms of precipitation,the principal hydrochemical type is SO_(4)^(2-)-Ca^(2+).The chemical ions in river water and groundwater are primarily influenced by rock weathering and evaporation-crystallization,whereas the chemical ions in meltwater are mainly affected by rock weathering and atmospheric precipitation,and the chemical ions in precipitation are derived primarily from terrestrial sources.The main forms of water input in the western alpine region of China are precipitation and meltwater,and mutual recharge occurs between river water and groundwater.Hydrochemical characteristics can reflect the impact of human activities on water resources.By synthesizing the regional hydrochemical studies,our findings provide insights for water resources management and ecological security construction in the western alpine region in China.展开更多
Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation sy...Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.展开更多
Satellite technologies provide valuable areal precipitation datasets in alpine mountains.However,coarse resolution still limits the use of satellite precipitation datasets in hydrological and meteorological research.W...Satellite technologies provide valuable areal precipitation datasets in alpine mountains.However,coarse resolution still limits the use of satellite precipitation datasets in hydrological and meteorological research.We evaluated different time scales and precipitation magnitudes of Tropical Rainfall Measurement Mission 3B43 V7(TRMM)and Global Precipitation Measurement(GPM)products for alpine regions using ground precipitation datasets from January 2015 to June 2019 obtained from 25 national meteorological stations and 11 sets of T-200B weighing precipitation gauges in the Qilian Mountains.The results indicated that GPM outperformed TRMM at all temporal scales at an elevation<3500 m with a higher probability of detection(POD),false alarm ratio(FAR),and frequency bias index(FBI)and performed best at 3000 m;TRMM performed better than GPM at an elevation>3500 m,with the best performance at 4000 m.GPM and TRMM had the best estimation accuracy in areas with monthly precipitation of 30 mm and 40 mm,respectively.Both TRMM and GPM products underestimated mid to large daily precipitation and overestimated light daily precipitation averaging<2 mm/d.This research not only emphasizes the superiority of GPM/TRMM in different regions but also indicates the limitations of precipitation algorithms.展开更多
Alpine regions face severe flood management challenges due to complex terrain,climate extremes,and sparse data.This commentary critiques limitations in current hydrological practices supporting China's Four-pre st...Alpine regions face severe flood management challenges due to complex terrain,climate extremes,and sparse data.This commentary critiques limitations in current hydrological practices supporting China's Four-pre strategy.Key barriers include poor data quality,model limitations,and fragmented systems.Thus,we recommend optimizing observation networks,using physicsinformed neural networks,and establishing unified data platforms.This integrated approach will enhance flood modeling reliability in data-scarce regions,providing actionable insights for adaptive flood governance in high-risk mountainous regions.展开更多
Since 1950, 700 plots were established in the alpine and canyon region of western Sichuan. The distribution charac-teristics and the relationships between forest succession and environmental gradients were studied. Th...Since 1950, 700 plots were established in the alpine and canyon region of western Sichuan. The distribution charac-teristics and the relationships between forest succession and environmental gradients were studied. The results showed that the main tree species were Picea and Abies in this region, and there were more than 90 forest types. Abies forests mainly dis-tributed in the middle and upper reaches of rivers and their branches, and Picea forests mainly distributed in wide valleys and on half-shaded and half-sunny slopes. The natural regeneration was poor under primitive spruce and fir forest canopy, but was good in the spruce and fire forest gap. The relationship between forest succession and vertical gradient was closely related to the relationship between forest succession procession and plant synusia under primary forests. Human activities could promote and postpone succession process. The results of expanding regeneration were often influenced by topography, vegetation and wind direction.展开更多
The effects of climatic warming on phyllosphere microbial communities remain uncertain.In this study,the effects of long-term(>10 years)experimental warming on phyllosphere epiphytic bacterial and fungal communitie...The effects of climatic warming on phyllosphere microbial communities remain uncertain.In this study,the effects of long-term(>10 years)experimental warming on phyllosphere epiphytic bacterial and fungal communities of Carex alrofusca,Kobresia pygmaea,Potentilla bifurca and Stipa capillacea were examined in the northern Xizang.Overall,warming increased bacterialα-diversity,but reduced fungalα-diversity across the four host plants.Warming altered the bacterial and fungal community compositions mainly by increasing Actinobacteria,Firmicutes and pathotrophsaprotroph fungi,and reducing Basidiomycota and symbiotroph fungi across the four host plants.Warming increased the relative effect of the‘drift&others’process in the bacterial community,but reduced the relative effect of the‘dispersal limitation’process in the bacterial community and the relative effect of the‘homogeneous selection’process in the fungal community across the four host plants.The overall warming effects on the bacterial and fungal communities may be due to overall warming effects on temperature,leaf morphology structure and physicochemical properties,ecological processes of community assembly and topological parameters of species co-occurrence networks of bacteria and fungi.Warming altered the bacterial species co-occurrence network mainly by increasing the vertex,clustering coefficient and heterogeneity,while reducing the average path length and network diameter across host species.Warming altered the fungal species co-occurrence network mainly by increasing the network diameter and reducing the vertex across host species.Warming effects on bacterial and fungal communities varied among host plants,which may be due to the diverse responses to warming of plant height,leaf malondialdehyde,ecological processes of community assembly and topological parameters of species co-occurrence network.Therefore,warming can alter phyllosphere epiphytic bacterial and fungal communities of alpine plants.Such changes varied among host plants and may cause adverse effects on the host plants.展开更多
Soil respiration(Rs)is important for transport-ing or fixing carbon dioxide from the atmosphere,and even diminutive variations can profoundly influence the carbon cycle.However,the R_(s)dynamics in a loess alpine hill...Soil respiration(Rs)is important for transport-ing or fixing carbon dioxide from the atmosphere,and even diminutive variations can profoundly influence the carbon cycle.However,the R_(s)dynamics in a loess alpine hilly region with representative sensitivity to climate change and fragile ecology remains poorly understood.This study investigated the correlation and degree of control between R_(s)and its photosynthetic and environmental factors in five subalpine forest cover types.We examined the correlations between R_(s)and variables temperature(T_(10))and soil moisture content at 10 cm depth(W_(10)),net photosynthetic rate(P_(n))and soil properties to establish multiple models,and the variables were measured for diurnal and monthly vari-ations from September 2018 to August 2019.The results showed that soil physical factors are not the main drivers of R_(s)dynamics at the diel scale;however,the trend in the monthly variation in R_(s)was consistent with that of T_(10)and P_(n).Further,R_(s)was significantly affected by pH,providing further evidence that coniferous forest leaves contribute to soil acidification,thus reducing R_(s).Significant exponential and linear correlations were established between R_(s)and T_(10)and W_(10),respectively,and R_(s)was positively correlated with P_(n).Accordingly,we established a two-factor model and a three-factor model,and the correlation coefficients(R_(2))was improved to different degrees compared with models based only on T_(10)and W_(10).Moreover,temperature sensitivity(Q_(10))was the highest in the secondary forest and lowest in the Larix principis-rupprechtii forest.Our findings suggest that the control of R_(s)by the environment(moisture and tempera-ture)and photosynthesis,which are interactive or comple-mentary effects,may influence spatial and temporal homeo-stasis in the region and showed that the models appropriately described the dynamic variation in R_(s)and the carbon cycle in different forest covers.In addition,total phosphorus(TP)and total potassium(TK)significantly affected the dynamic changes in R_(s).In summary,interannual and seasonal variations in forest R_(s)at multiple scales and the response forces of related ecophysiological factors,especially the interactive driving effects of soil temperature,soil moisture and photo-synthesis,were clarified,thus representing an important step in predicting the impact of climate change and formulating forest carbon management policies.展开更多
Carex brunnescens（Pers.）, a typical clonal species, is considered to be the only herb found to date that can develop on sand dunes in Maqu alpine region of northwestern China. However, the characteristics that C. br...Carex brunnescens（Pers.）, a typical clonal species, is considered to be the only herb found to date that can develop on sand dunes in Maqu alpine region of northwestern China. However, the characteristics that C. brunnescens resists to harsh alpine environment have not been documented. In this study, we conducted a field investigation to determine the morphological, reproductive, and sand-fixing characteristics of C. brunnescens. Concomitantly, we transplanted the belowground rhizomes of C. brunnescens to sand dunes and compared the abilities to restore degraded alpine meadows among sand dunes that had no further treatment（SD＋N）, sand dunes that had straw checkerboard technique but no transplanted rhizomes of C. brunnescens（SD＋SCT）, and sand dunes that had both SCT and transplanted rhizomes of C. brunnescens（SD＋SCT＋P）. We found that belowground vertical rhizomes and horizontal rhizomes（including branching rhizomes and main rhizomes） of C. brunnescens were highly developed and that population reproduction was dominated by horizontal rhizomes. C. brunnescens exhibited a significant sand-fixation effect under following conditions： population density was 145–156 ramets/m^2, vegetation cover was 31.2%–39.3%, total length of belowground rhizomes was 11,223 cm/m^2, total length of belowground first-order roots was 9161–10,524 cm/m^2, fresh weight of aboveground part was 198.5–212.6 g/m^2, and fresh weight of belowground part was 578.8–612.4 g/m^2. It should be particularly noted that SD＋SCT＋P treatment（sand dunes that had both straw checkerboard technique and transplanted rhizomes of C. brunnescens） was the best and SD＋N（sand dunes that had no further treatment） was the worst in terms of following biotic indicators： total number of reproductive ramets, total number of belowground rhizomes, and fresh weight of aboveground and belowground parts of C. brunnescens, contents of soil organic carbon, available nitrogen, microbial biomass carbon, and microbial biomass nitrogen. It implies that applying SCT in sand dunes and transplanting belowground rhizomes to sand dunes with SCT could improve both soil fertility and growth of C. brunnescens. These results suggest that the SCT-promoted high reproductive abilities of belowground rhizomes of C. brunnescens can successfully facilitate the establishment of ramets and can thus be an effective strategy to restore degraded vegetation in Maqu alpine region of northwestern China.展开更多
Monitoring deformation in high undulating mountainous environments is critical for surface process research and disaster prevention studies. Although observations based on interferometric Synthetic Aperture Radar(InSA...Monitoring deformation in high undulating mountainous environments is critical for surface process research and disaster prevention studies. Although observations based on interferometric Synthetic Aperture Radar(InSAR) are an excellent tool for monitoring deformation, the shadow phenomena can limit its application. Based on a series of geomorphic parameters and limited InSAR observation data, surface deformations were reconstructed in areas with missing observations by constructing a random forest model to compensate for the shadow phenomenon at the grid-scale. The findings suggest that this method can be used to rebuild landscape variation characteristics in places where observation data is lacking. The dominant slope direction in the observation area corresponded to a more significant correlation between the reconstructed topography deformation characteristics and the observation. In addition, when building this model, consideration was given to the geomorphic parameter selection, elevation variation, hypsometric integral value, slope form, lithology, slope variation,and aspect variation;these parameters can significantly affect the surface deformation, which is closely related to their spatial autocorrelation. These findings are significant for eliminating the shadow phenomenon, which often occurs in In SAR observations taken over alpine canyon regions. The terrain and lithology of the underlying surface should be considered when reconstructing the surface deformation characteristics of the shadow region by using satellite observation data.展开更多
Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in...Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in higher plants of alpine region.Herein, hydrocarbon leaf wax components of Salix oritrepha, which flourish in Nianbaoyeze Mountains in eastern Tibetan Plateau were fully discussed. The n-alkane distribution in leaves ranges from n-C_(21) to nC_(29) with maxima at n-C_(25), which were entirely different with Salix taxa displayed in previous surveys in non-alpine regions. The unusual even carbon nalkenes from n-C_(22:1) to n-C_(30:1), which were thought to appear only in aquatic organisms, were firstly reported in an alpine plant. Additionally, iso-(2-methyl) alkanes, ranging from i-C_(23) to i-C_(29) with maxima at i-C_(25), which have been commonly reported in microorganisms, were also identified in an alpine plant for the first time. Unusual hydrocarbon distribution detected in Salix oritrepha leaf from Nianbaoyeze Mountains is most likely due to the extreme environment in such alpine region.展开更多
High-resolution ice core records covering long time spans enable reconstruction of the past climatic and environmental conditions allowing the investigation of the earth system's evolution.Preprocessing of ice cor...High-resolution ice core records covering long time spans enable reconstruction of the past climatic and environmental conditions allowing the investigation of the earth system's evolution.Preprocessing of ice cores has direct impacts on the data quality control for further analysis since the conventional ice core processing is time-consuming,produces qualitative data,leads to ice mass loss,and leads to risks of potential secondary pollution.However,over the past several decades,preprocessing of ice cores has received less attention than the improvement of ice drilling,the analytical methodology of various indices,and the researches on the climatic and environmental significance of ice core records.Therefore,this papers reviews the development of the processing for ice cores including framework,design as well as materials,analyzes the technical advantages and disadvantages of the different systems.In the past,continuous flowanalysis(CFA)has been successfully applied to process the polar ice cores.However,it is not suitable for ice cores outside polar region because of high level of particles,the memory effect between samples,and the filtration before injection.Ice core processing is a subtle and professional operation due to the fragility of the nonmetallic materials and the random distribution of particles and air bubbles in ice cores,which aggravates uncertainty in the measurements.The future developments of CFA are discussed in preprocessing,memory effect,challenge for brittle ice,coupling with real-time analysis and optimization of CFA in the field.Furthermore,non-polluting cutters with many different configurations could be designed to cut and scrape in multiple directions and to separate inner and outer portions of the core.This system also needs to be coupled with streamlined operation of packaging,coding,and stacking that can be implemented at high resolution and rate,avoiding manual intervention.At the same time,information of the longitudinal sections could be scanned andidentified,and then classified to obtain quantitative data.In addition,irregular ice volume and weight can also be obtained accurately.These improvements are recorded automatically via user-friendly interfaces.These innovations may be applied to other paleomedias with similar features and needs.展开更多
<div style="text-align:justify;">With global warming and increased human activity,more and more ground surface areas have been affected,which leads to the creation of many problems.To understand the ec...<div style="text-align:justify;">With global warming and increased human activity,more and more ground surface areas have been affected,which leads to the creation of many problems.To understand the ecological environment changes in a typical alpine region,information on landcovers changes in the study area from 2000 to 2020 was obtained by combining remote sensing,geographic information system,and traditional statistical analysis for the Sanjiangyuan National Nature Reserve on the Qinghai-Tibet Plateau,China.The results show that the changes of surface cover in Sanjiangyuan National Nature Reserve are relatively concentrated,mainly distributed in the sections of south,northwest,central,and northeast,with the area of the changed regions and the unchanged regions being 31,127.45 km<sup>2</sup>and 271,941.37 km<sup>2</sup>,respectively.The transformation between the various types of ground landcover is mainly characterized by a shift from other types to grassland and from grassland to bare land.And the regions of change are mostly concentrated between 3500-4600 m in elevation.展开更多
The management of the operating benefits of highland barley growers and growers will gradually increase the per capita production economic benefits and labor income of each highland barley grower and grower in the hig...The management of the operating benefits of highland barley growers and growers will gradually increase the per capita production economic benefits and labor income of each highland barley grower and grower in the high and cold plateau region of Tibet in an orderly and efficient manner,and will boost the industrialization and large-scale healthy development of highland barley production and planting in the region,thus effectively driving the sound and healthy economic development of the local farmers.展开更多
Soil organic carbon(SOC)plays a critical role in the carbon cycle of alpine ecosystems;however,little is known about the dynamics of SOC governed by soil types and elevation gradients in these systems.In this study,so...Soil organic carbon(SOC)plays a critical role in the carbon cycle of alpine ecosystems;however,little is known about the dynamics of SOC governed by soil types and elevation gradients in these systems.In this study,soil properties,environmental conditions,and anthropogenic activities were identified along an 835 km east-west transect in the Yarlung Tsangpo River of the Tibetan Plateau region,which has an elevation range of 2800-5200 m.The information was used to investigate the effects of two soil types(dark felty soils and aeolian soils)and elevation gradients on SOC dynamics.The findings revealed that the average SOC content in dark felty soil(15.13±5.78 g/kg)was significantly greater than that in aeolian soil(7.98±2.76 g/kg).The SOC content of dark felty soil continuously increased with elevation,increasing by about 23.4 g/kg for every 1000 m increase in elevation.In contrast,owing to the high sand particle content and loose,porous structure of aeolian soil,the low SOC content did not vary with elevation.We found that mean annual precipitation(MAP),normalized difference vegetation index(NDVI),electrical conductivity(EC),and clay content(clay)were the primary factors influencing SOC accumulation in dark felty soils.As elevation increased,a more humid and cool water-thermal envi-ronment was formed,significantly improving vegetation(NDVI)and optimizing soil physicochemical properties(clay and EC).These factors interacted synergistically to promote significant SOC accumu-lation in dark felty soils.This study emphasized the importance of the effects of dark felty soil and aeolian soil on the SOC content and improved the understanding of the mechanism by which SOC ac-cumulates in the alpine region of high elevation areas.展开更多
The contribution of climatic change and anthropogenic activities to vegetation productivity are not fully understood.In this study,we determined potential climate-driven gross primary production(GPPp)using a process-b...The contribution of climatic change and anthropogenic activities to vegetation productivity are not fully understood.In this study,we determined potential climate-driven gross primary production(GPPp)using a process-based terrestrial ecosystem model,and actual gross primary production(GPPa)using MODIS Approach in alpine grasslands on the Tibetan Plateau from 2000 to 2015.The GPPa was influenced by both climatic change and anthropogenic activities.Gross primary production caused by anthropogenic activities(GPPh)was calculated as the difference between GPPp and GPPa.Approximately 75.63%and 24.37%of the area percentages of GPPa showed increasing and decreasing trends,respectively.Climatic change and anthropogenic activities were dominant factors responsible for approximately 42.90%and 32.72%of the increasing area percentage of GPPa,respectively.In contrast,climatic change and anthropogenic activities were responsible for approximately 16.88%and 7.49%of the decreasing area percentages of GPPa,respectively.The absolute values of the change trends of GPPp and GPPh of meadows were greater than those of steppes.The GPPp change values were greater than those of GPPh at all elevations,whereas both GPPp and GPPh showed decreasing trends when elevations were greater than or equal to 5000 m,4600 m and 4800 m in meadows,steppes and all grasslands,respectively.Climatic change had stronger effects on the GPPa changes when elevations were lower than 5000 m,4600 m and 4800 m in meadows,steppes and all grasslands,respectively.In contrast,anthropogenic activities had stronger effects on the GPPa changes when elevations were greater than or equal to 5000 m,4600 m and 4800 m in meadows,steppes and all grasslands,respectively.Therefore,the causes of actual gross primary production changes varied with elevations,regions and grassland types,and grassland classification management should be considered on the Tibetan Plateau.展开更多
基金supported by the National Science Foundation for Distinguished Young Scholars (42425107)the Top Talent Project of Gansu province, Chinese Academy of Sciences Young Crossover Team Project (JCTD-2022-18)+5 种基金the "Western Light"-Key Laboratory Cooperative Research Cross-Team Project of Chinese Academy of Sciencesthe Ecological Civilization Special Project of Key Research and Development Program in Gansu Province (24YFFA009)the Gansu Science and Technology Program (25RCKA026)the Science and Technology Project of Lanzhou (2022-2-43)the Excellent Doctoral Program in Gansu Province (23JRRA573)the Lanzhou Talent-Driven City Development Initiative.
文摘The western alpine region is an important freshwater supply and water conservation area for China and its surrounding areas.As ecological civilization construction progresses,the ecohydrology of the western alpine region in China,which is a crucial ecological barrier,has undergone significant changes.In this study,we collected 1077 sampling points and presented a comprehensive overview of research results pertaining to the hydrochemistry of river water,meltwater,groundwater,and precipitation in the western alpine region of China using piper diagram,end-member diagram,and hydrological process indication.Water resources in the western alpine region of China were found to be weakly alkaline and have low total dissolved solids(TDS).The mean pH values for river water,meltwater,groundwater,and precipitation are 7.92,7.58,7.72,and 7.32,respectively.The mean TDS values for river water,meltwater,groundwater,and precipitation are 280.99,72.48,544.41,and 67.68 mg/L.The hydrochemical characteristics of the water resources in this region exhibit significant spatial and temporal variability.These characteristics include higher ion concentrations during the freezing period and higher ion concentrations in inland river basins,such as the Shule River Basin and Tarim River Basin.The principal hydrochemical type of river water and meltwater is HCO^(3-)•SO_(4)^(2-)-Ca^(2+),whereas the principal cations in groundwater are Mg^(2+)and Ca^(2+),and the principal anions are HCO^(3-)and SO_(4)^(2-).In terms of precipitation,the principal hydrochemical type is SO_(4)^(2-)-Ca^(2+).The chemical ions in river water and groundwater are primarily influenced by rock weathering and evaporation-crystallization,whereas the chemical ions in meltwater are mainly affected by rock weathering and atmospheric precipitation,and the chemical ions in precipitation are derived primarily from terrestrial sources.The main forms of water input in the western alpine region of China are precipitation and meltwater,and mutual recharge occurs between river water and groundwater.Hydrochemical characteristics can reflect the impact of human activities on water resources.By synthesizing the regional hydrochemical studies,our findings provide insights for water resources management and ecological security construction in the western alpine region in China.
基金Project(2018YFC0808404)supported by National Key Research and Development Program of China。
文摘Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.
基金National Key R&D Program of China No.2019YFC1510500National Natural Science Foundation of China,No.42101120,No.41971041,No.41971073National Natural Science Foundation of Shandong Province,No.ZR2021QD138。
文摘Satellite technologies provide valuable areal precipitation datasets in alpine mountains.However,coarse resolution still limits the use of satellite precipitation datasets in hydrological and meteorological research.We evaluated different time scales and precipitation magnitudes of Tropical Rainfall Measurement Mission 3B43 V7(TRMM)and Global Precipitation Measurement(GPM)products for alpine regions using ground precipitation datasets from January 2015 to June 2019 obtained from 25 national meteorological stations and 11 sets of T-200B weighing precipitation gauges in the Qilian Mountains.The results indicated that GPM outperformed TRMM at all temporal scales at an elevation<3500 m with a higher probability of detection(POD),false alarm ratio(FAR),and frequency bias index(FBI)and performed best at 3000 m;TRMM performed better than GPM at an elevation>3500 m,with the best performance at 4000 m.GPM and TRMM had the best estimation accuracy in areas with monthly precipitation of 30 mm and 40 mm,respectively.Both TRMM and GPM products underestimated mid to large daily precipitation and overestimated light daily precipitation averaging<2 mm/d.This research not only emphasizes the superiority of GPM/TRMM in different regions but also indicates the limitations of precipitation algorithms.
基金the Science and Technology Projects of Xizang Autonomous Region(XZ202501ZY0145)Natural Science Foundation Youth Project of the Science and Technology Department of Sichuan Province(2024NSFSC0984)China Yangtze Power Co.Ltd(Z242302038).
文摘Alpine regions face severe flood management challenges due to complex terrain,climate extremes,and sparse data.This commentary critiques limitations in current hydrological practices supporting China's Four-pre strategy.Key barriers include poor data quality,model limitations,and fragmented systems.Thus,we recommend optimizing observation networks,using physicsinformed neural networks,and establishing unified data platforms.This integrated approach will enhance flood modeling reliability in data-scarce regions,providing actionable insights for adaptive flood governance in high-risk mountainous regions.
基金This article was supported by State Tenth Five-Year Plan Project (2001BA510B0105) and the Project for Pioneering New Knowledge from Chinese Academy of Sciences (KZCX2-SW-319).
文摘Since 1950, 700 plots were established in the alpine and canyon region of western Sichuan. The distribution charac-teristics and the relationships between forest succession and environmental gradients were studied. The results showed that the main tree species were Picea and Abies in this region, and there were more than 90 forest types. Abies forests mainly dis-tributed in the middle and upper reaches of rivers and their branches, and Picea forests mainly distributed in wide valleys and on half-shaded and half-sunny slopes. The natural regeneration was poor under primitive spruce and fir forest canopy, but was good in the spruce and fire forest gap. The relationship between forest succession and vertical gradient was closely related to the relationship between forest succession procession and plant synusia under primary forests. Human activities could promote and postpone succession process. The results of expanding regeneration were often influenced by topography, vegetation and wind direction.
基金funded by the Pilot Project of Chinese Academy of Sciences(XDA26050501)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2020054)+3 种基金the National Natural Science Foundation of China(31600432)the Lhasa Science and Technology Plan Project,China(LSKJ202422)the Tibet Autonomous Region Science and Technology Project,China(XZ202401JD0029)the Construction of Zhongba County Fixed Observation and Experiment Station of First Support System for Agriculture Green Development,China。
文摘The effects of climatic warming on phyllosphere microbial communities remain uncertain.In this study,the effects of long-term(>10 years)experimental warming on phyllosphere epiphytic bacterial and fungal communities of Carex alrofusca,Kobresia pygmaea,Potentilla bifurca and Stipa capillacea were examined in the northern Xizang.Overall,warming increased bacterialα-diversity,but reduced fungalα-diversity across the four host plants.Warming altered the bacterial and fungal community compositions mainly by increasing Actinobacteria,Firmicutes and pathotrophsaprotroph fungi,and reducing Basidiomycota and symbiotroph fungi across the four host plants.Warming increased the relative effect of the‘drift&others’process in the bacterial community,but reduced the relative effect of the‘dispersal limitation’process in the bacterial community and the relative effect of the‘homogeneous selection’process in the fungal community across the four host plants.The overall warming effects on the bacterial and fungal communities may be due to overall warming effects on temperature,leaf morphology structure and physicochemical properties,ecological processes of community assembly and topological parameters of species co-occurrence networks of bacteria and fungi.Warming altered the bacterial species co-occurrence network mainly by increasing the vertex,clustering coefficient and heterogeneity,while reducing the average path length and network diameter across host species.Warming altered the fungal species co-occurrence network mainly by increasing the network diameter and reducing the vertex across host species.Warming effects on bacterial and fungal communities varied among host plants,which may be due to the diverse responses to warming of plant height,leaf malondialdehyde,ecological processes of community assembly and topological parameters of species co-occurrence network.Therefore,warming can alter phyllosphere epiphytic bacterial and fungal communities of alpine plants.Such changes varied among host plants and may cause adverse effects on the host plants.
基金This work was supported financially by the National Key Research and Development Plan Projects of China(2017YFC0504604).
文摘Soil respiration(Rs)is important for transport-ing or fixing carbon dioxide from the atmosphere,and even diminutive variations can profoundly influence the carbon cycle.However,the R_(s)dynamics in a loess alpine hilly region with representative sensitivity to climate change and fragile ecology remains poorly understood.This study investigated the correlation and degree of control between R_(s)and its photosynthetic and environmental factors in five subalpine forest cover types.We examined the correlations between R_(s)and variables temperature(T_(10))and soil moisture content at 10 cm depth(W_(10)),net photosynthetic rate(P_(n))and soil properties to establish multiple models,and the variables were measured for diurnal and monthly vari-ations from September 2018 to August 2019.The results showed that soil physical factors are not the main drivers of R_(s)dynamics at the diel scale;however,the trend in the monthly variation in R_(s)was consistent with that of T_(10)and P_(n).Further,R_(s)was significantly affected by pH,providing further evidence that coniferous forest leaves contribute to soil acidification,thus reducing R_(s).Significant exponential and linear correlations were established between R_(s)and T_(10)and W_(10),respectively,and R_(s)was positively correlated with P_(n).Accordingly,we established a two-factor model and a three-factor model,and the correlation coefficients(R_(2))was improved to different degrees compared with models based only on T_(10)and W_(10).Moreover,temperature sensitivity(Q_(10))was the highest in the secondary forest and lowest in the Larix principis-rupprechtii forest.Our findings suggest that the control of R_(s)by the environment(moisture and tempera-ture)and photosynthesis,which are interactive or comple-mentary effects,may influence spatial and temporal homeo-stasis in the region and showed that the models appropriately described the dynamic variation in R_(s)and the carbon cycle in different forest covers.In addition,total phosphorus(TP)and total potassium(TK)significantly affected the dynamic changes in R_(s).In summary,interannual and seasonal variations in forest R_(s)at multiple scales and the response forces of related ecophysiological factors,especially the interactive driving effects of soil temperature,soil moisture and photo-synthesis,were clarified,thus representing an important step in predicting the impact of climate change and formulating forest carbon management policies.
基金supported by the National Natural Science Foundation of China (31360087, 31360086)
文摘Carex brunnescens（Pers.）, a typical clonal species, is considered to be the only herb found to date that can develop on sand dunes in Maqu alpine region of northwestern China. However, the characteristics that C. brunnescens resists to harsh alpine environment have not been documented. In this study, we conducted a field investigation to determine the morphological, reproductive, and sand-fixing characteristics of C. brunnescens. Concomitantly, we transplanted the belowground rhizomes of C. brunnescens to sand dunes and compared the abilities to restore degraded alpine meadows among sand dunes that had no further treatment（SD＋N）, sand dunes that had straw checkerboard technique but no transplanted rhizomes of C. brunnescens（SD＋SCT）, and sand dunes that had both SCT and transplanted rhizomes of C. brunnescens（SD＋SCT＋P）. We found that belowground vertical rhizomes and horizontal rhizomes（including branching rhizomes and main rhizomes） of C. brunnescens were highly developed and that population reproduction was dominated by horizontal rhizomes. C. brunnescens exhibited a significant sand-fixation effect under following conditions： population density was 145–156 ramets/m^2, vegetation cover was 31.2%–39.3%, total length of belowground rhizomes was 11,223 cm/m^2, total length of belowground first-order roots was 9161–10,524 cm/m^2, fresh weight of aboveground part was 198.5–212.6 g/m^2, and fresh weight of belowground part was 578.8–612.4 g/m^2. It should be particularly noted that SD＋SCT＋P treatment（sand dunes that had both straw checkerboard technique and transplanted rhizomes of C. brunnescens） was the best and SD＋N（sand dunes that had no further treatment） was the worst in terms of following biotic indicators： total number of reproductive ramets, total number of belowground rhizomes, and fresh weight of aboveground and belowground parts of C. brunnescens, contents of soil organic carbon, available nitrogen, microbial biomass carbon, and microbial biomass nitrogen. It implies that applying SCT in sand dunes and transplanting belowground rhizomes to sand dunes with SCT could improve both soil fertility and growth of C. brunnescens. These results suggest that the SCT-promoted high reproductive abilities of belowground rhizomes of C. brunnescens can successfully facilitate the establishment of ramets and can thus be an effective strategy to restore degraded vegetation in Maqu alpine region of northwestern China.
基金financially supported by the National Natural Science Foundation of China (42107218)China Geology Survey Project (DD20221738)+1 种基金China Three Gorges Corporation (YMJ(XLD) (19) 110)the National Key Research and Development Program of China (2018YFC1505002)。
文摘Monitoring deformation in high undulating mountainous environments is critical for surface process research and disaster prevention studies. Although observations based on interferometric Synthetic Aperture Radar(InSAR) are an excellent tool for monitoring deformation, the shadow phenomena can limit its application. Based on a series of geomorphic parameters and limited InSAR observation data, surface deformations were reconstructed in areas with missing observations by constructing a random forest model to compensate for the shadow phenomenon at the grid-scale. The findings suggest that this method can be used to rebuild landscape variation characteristics in places where observation data is lacking. The dominant slope direction in the observation area corresponded to a more significant correlation between the reconstructed topography deformation characteristics and the observation. In addition, when building this model, consideration was given to the geomorphic parameter selection, elevation variation, hypsometric integral value, slope form, lithology, slope variation,and aspect variation;these parameters can significantly affect the surface deformation, which is closely related to their spatial autocorrelation. These findings are significant for eliminating the shadow phenomenon, which often occurs in In SAR observations taken over alpine canyon regions. The terrain and lithology of the underlying surface should be considered when reconstructing the surface deformation characteristics of the shadow region by using satellite observation data.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41301224, 41601195)Jiangsu Overseas Research & Training Program for University Prominent Young & Middle-aged Teachers and Presidents
文摘Plant biomarkers, such as hydrocarbon waxes, are frequently found in various sediments and could be adopted as paleovegetation and paleoclimate indicators. Nevertheless, scarce researches have focused on leaf waxes in higher plants of alpine region.Herein, hydrocarbon leaf wax components of Salix oritrepha, which flourish in Nianbaoyeze Mountains in eastern Tibetan Plateau were fully discussed. The n-alkane distribution in leaves ranges from n-C_(21) to nC_(29) with maxima at n-C_(25), which were entirely different with Salix taxa displayed in previous surveys in non-alpine regions. The unusual even carbon nalkenes from n-C_(22:1) to n-C_(30:1), which were thought to appear only in aquatic organisms, were firstly reported in an alpine plant. Additionally, iso-(2-methyl) alkanes, ranging from i-C_(23) to i-C_(29) with maxima at i-C_(25), which have been commonly reported in microorganisms, were also identified in an alpine plant for the first time. Unusual hydrocarbon distribution detected in Salix oritrepha leaf from Nianbaoyeze Mountains is most likely due to the extreme environment in such alpine region.
基金supported by the National Natural Science Foundation of China(Grant No.41630754)the State Key Laboratory of Cryospheric Science(SKLCS-ZZ-2017)CAS Key Technology Talent Program and Open Foundation of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(2017490711)
文摘High-resolution ice core records covering long time spans enable reconstruction of the past climatic and environmental conditions allowing the investigation of the earth system's evolution.Preprocessing of ice cores has direct impacts on the data quality control for further analysis since the conventional ice core processing is time-consuming,produces qualitative data,leads to ice mass loss,and leads to risks of potential secondary pollution.However,over the past several decades,preprocessing of ice cores has received less attention than the improvement of ice drilling,the analytical methodology of various indices,and the researches on the climatic and environmental significance of ice core records.Therefore,this papers reviews the development of the processing for ice cores including framework,design as well as materials,analyzes the technical advantages and disadvantages of the different systems.In the past,continuous flowanalysis(CFA)has been successfully applied to process the polar ice cores.However,it is not suitable for ice cores outside polar region because of high level of particles,the memory effect between samples,and the filtration before injection.Ice core processing is a subtle and professional operation due to the fragility of the nonmetallic materials and the random distribution of particles and air bubbles in ice cores,which aggravates uncertainty in the measurements.The future developments of CFA are discussed in preprocessing,memory effect,challenge for brittle ice,coupling with real-time analysis and optimization of CFA in the field.Furthermore,non-polluting cutters with many different configurations could be designed to cut and scrape in multiple directions and to separate inner and outer portions of the core.This system also needs to be coupled with streamlined operation of packaging,coding,and stacking that can be implemented at high resolution and rate,avoiding manual intervention.At the same time,information of the longitudinal sections could be scanned andidentified,and then classified to obtain quantitative data.In addition,irregular ice volume and weight can also be obtained accurately.These improvements are recorded automatically via user-friendly interfaces.These innovations may be applied to other paleomedias with similar features and needs.
文摘<div style="text-align:justify;">With global warming and increased human activity,more and more ground surface areas have been affected,which leads to the creation of many problems.To understand the ecological environment changes in a typical alpine region,information on landcovers changes in the study area from 2000 to 2020 was obtained by combining remote sensing,geographic information system,and traditional statistical analysis for the Sanjiangyuan National Nature Reserve on the Qinghai-Tibet Plateau,China.The results show that the changes of surface cover in Sanjiangyuan National Nature Reserve are relatively concentrated,mainly distributed in the sections of south,northwest,central,and northeast,with the area of the changed regions and the unchanged regions being 31,127.45 km<sup>2</sup>and 271,941.37 km<sup>2</sup>,respectively.The transformation between the various types of ground landcover is mainly characterized by a shift from other types to grassland and from grassland to bare land.And the regions of change are mostly concentrated between 3500-4600 m in elevation.
文摘The management of the operating benefits of highland barley growers and growers will gradually increase the per capita production economic benefits and labor income of each highland barley grower and grower in the high and cold plateau region of Tibet in an orderly and efficient manner,and will boost the industrialization and large-scale healthy development of highland barley production and planting in the region,thus effectively driving the sound and healthy economic development of the local farmers.
基金financially supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0608).
文摘Soil organic carbon(SOC)plays a critical role in the carbon cycle of alpine ecosystems;however,little is known about the dynamics of SOC governed by soil types and elevation gradients in these systems.In this study,soil properties,environmental conditions,and anthropogenic activities were identified along an 835 km east-west transect in the Yarlung Tsangpo River of the Tibetan Plateau region,which has an elevation range of 2800-5200 m.The information was used to investigate the effects of two soil types(dark felty soils and aeolian soils)and elevation gradients on SOC dynamics.The findings revealed that the average SOC content in dark felty soil(15.13±5.78 g/kg)was significantly greater than that in aeolian soil(7.98±2.76 g/kg).The SOC content of dark felty soil continuously increased with elevation,increasing by about 23.4 g/kg for every 1000 m increase in elevation.In contrast,owing to the high sand particle content and loose,porous structure of aeolian soil,the low SOC content did not vary with elevation.We found that mean annual precipitation(MAP),normalized difference vegetation index(NDVI),electrical conductivity(EC),and clay content(clay)were the primary factors influencing SOC accumulation in dark felty soils.As elevation increased,a more humid and cool water-thermal envi-ronment was formed,significantly improving vegetation(NDVI)and optimizing soil physicochemical properties(clay and EC).These factors interacted synergistically to promote significant SOC accumu-lation in dark felty soils.This study emphasized the importance of the effects of dark felty soil and aeolian soil on the SOC content and improved the understanding of the mechanism by which SOC ac-cumulates in the alpine region of high elevation areas.
基金National Natural Science Foundation of China(31600432)National Key Research Projects of China(2017YFA0604801,2016YFC0502005)+1 种基金Bingwei Outstanding Young Talents Program of Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences(2018RC202)Tibet Science and Technology Major Projects of the Pratacultural Industry(XZ201901NA03)
文摘The contribution of climatic change and anthropogenic activities to vegetation productivity are not fully understood.In this study,we determined potential climate-driven gross primary production(GPPp)using a process-based terrestrial ecosystem model,and actual gross primary production(GPPa)using MODIS Approach in alpine grasslands on the Tibetan Plateau from 2000 to 2015.The GPPa was influenced by both climatic change and anthropogenic activities.Gross primary production caused by anthropogenic activities(GPPh)was calculated as the difference between GPPp and GPPa.Approximately 75.63%and 24.37%of the area percentages of GPPa showed increasing and decreasing trends,respectively.Climatic change and anthropogenic activities were dominant factors responsible for approximately 42.90%and 32.72%of the increasing area percentage of GPPa,respectively.In contrast,climatic change and anthropogenic activities were responsible for approximately 16.88%and 7.49%of the decreasing area percentages of GPPa,respectively.The absolute values of the change trends of GPPp and GPPh of meadows were greater than those of steppes.The GPPp change values were greater than those of GPPh at all elevations,whereas both GPPp and GPPh showed decreasing trends when elevations were greater than or equal to 5000 m,4600 m and 4800 m in meadows,steppes and all grasslands,respectively.Climatic change had stronger effects on the GPPa changes when elevations were lower than 5000 m,4600 m and 4800 m in meadows,steppes and all grasslands,respectively.In contrast,anthropogenic activities had stronger effects on the GPPa changes when elevations were greater than or equal to 5000 m,4600 m and 4800 m in meadows,steppes and all grasslands,respectively.Therefore,the causes of actual gross primary production changes varied with elevations,regions and grassland types,and grassland classification management should be considered on the Tibetan Plateau.
