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Biomass burning play a key role in the global carbon cycle by altering the atmospheric composition, and affect regional and global climate. Despite its importance, a very few high-resolution records are available worldwide, especially for recent climate change. This study analyzes levoglucosan, a specific tracer of biomass burning emissions, in a 38-year ice core retrieved from the Shulehe Glacier No. 4, northeastern Tibetan Plateau. The levoglucosan concentration in the Shulehe Glacier No. 4 ice core ranged from 0.1 to 55 ng mL−1, with an average concentration of 8 ± 8 ng mL−1. The concentrations showed a decreasing trend from 2002 to 2018. Meanwhile, regional wildfire activities in Central Asian also exhibited a declining trend during the same period, suggesting the potential correspondence between levoglucosan concentration of the Shulehe Glacier No. 4 ice core and the fire activity of Central Asia. Furthermore, a positive correlation also exists between the levoglucosan concentration of the Shulehe Glacier No. 4 ice core and the wildfire counts in Central Asia from 2002 to 2018. While backward air mass trajectory analysis and fire spots data showed a higher distribution of fire counts in South Asia compared to Central Asia, but the dominance of westerly circulation in the northern TP throughout the year. Therefore, the levoglucosan in the Shulehe Glacier No. 4 provides clear evidence of Central Asian wildfire influence on Tibetan Plateau glaciers through westerlies. This highlights a great importance of ice core data for wildfire history reconstruction in the Tibetan Plateau Glacier regions. [Display omitted] • The average concentration of levoglucosan in ice core showed a decreasing trend from 2002 to 2018. • The levoglucosan of ice core may be affected by fire activities of Central Asia. • The levoglucosan concentration in ice core can record past fire activity. [ABSTRACT FROM AUTHOR]

Vegetation carbon sequestration in alpine areas of West China, such as the Qilian Mountains on the northeastern Tibetan Plateau, has been subject to long-term human intervention under a warming climate since the launch of the western development strategy (WDS) in 2000. However, the human impacts on vegetation carbon sequestration capacity during this period remain unclear. In this study, the magnitude and direction of human impacts on vegetation carbon sequestration capacity (defined as net primary production, NPP) were assessed by the deviation of remote-sensing–estimated actual NPP data from the simulated potential NPP. The potential value was derived from natural system coupling under the assumption that human activities ceased during the assessment period. The impacts of natural forces and historic human activities were then effectively exfoliated in our final assessment using a process-based IBISi model. The results indicate that the total actual vegetation carbon sequestration capacity in the Qilian Mountains has reduced compared with its potential value since the WDS launched. This reduction was mainly attributed to grazing in the grasslands. However, deforestation, mineral resource exploitation, and the construction of hydropower facilities have also caused a reduction in vegetation carbon sequestration capacity at the local scales. In contrast, forestry protections and afforestation, and agricultural activities associated with reclamation, cultivation, irrigation, and fertilization, have resulted in local increases in the vegetation carbon sequestration capacity in the corresponding forest lands, shrublands, and croplands. These findings highlight the importance of ecological protections for vegetation carbon sequestration and were expected to provide evidence to verify the improvement of ecological management and the increasing of carbon sinks in West China. [ABSTRACT FROM AUTHOR]

In recent years, the influence of historical geological and climatic events on the evolution of flora and fauna in the Tibetan Plateau has been a hot research topic. The Qilian Mountain region is one of the most important sources of biodiversity on the Qinghai‐Tibet Plateau. Many species existed in the region during the Pleistocene glacial oscillation, and the complex geographical environment provided suitable conditions for the survival of local species. The shrinkage, expansion, and transfer of the distribution range and population size of species have significant effects on genetic diversity and intraspecific differentiation. To reveal the effects of geological uplift and climate oscillation on the evolution of fish populations in the Qilian Mountains, we investigated the genetic structure, phylogenetic relationship, and phylogeographical characteristics of genus Triplophysa species in the Qilian Mountains using the mitochondrial DNA gene (COI), three nuclear genes (RAG1, sRH, and Myh6) and 11 pairs of nuclear microsatellite markers. We collected 11 species of genus Triplophysa living in the Qilian Mountains, among which Triplophysa hsutschouensis and Triplophysa papillosolabiata are widely distributed in the rivers on the northern slope of the Qilian Mountains. There was a high degree of lineage differentiation among species, and the genetic diversity of endemic species was low. The different geographical groups of T. papillosolabiata presented some allogeneic adaptation and differentiation, which was closely related to the changes in the river system. Except for the population expansion event of T. hsutschouensis during the last glacial period of the Qinghai‐Tibet Plateau (0.025 MYA), the population sizes of other plateau loach species remained stable without significant population expansion. Starting from the east and west sides of the Qilian Mountains, T. hsutschouensis, and T. papillosolabiata showed two species colonization routes in opposite directions. The geological events of the uplift of the Qinghai‐Tibet Plateau and the climatic oscillation of the Quaternary glaciation had a great influence on the genetic structure of the plateau loach in the Qilian Mountains, which promoted the genetic differentiation of the plateau loach and formed some unique new species. The results of this study have important guiding significance for fish habitat protection in the Qilian Mountains. [ABSTRACT FROM AUTHOR]

Understanding the spatial–temporal changes in glacier mass balance and associated drivers on the Tibetan Plateau (TP) is important for predicting future water supplies and glacier-related hazards. However, the comparative study of changes in glacier mass balance in different regions of the same glacierized massif on the TP remains scarce. Combining the reconstructed detailed mass balance time-series from 1970 to 2015 for Ningchan No.1 Glacier in the eastern Qilian Mountains and Qiyi Glacier in the western Qilian Mountains using the energy and mass balance model in this work with the published mass balance data from different glaciers, we find that interannual changes in glacier mass balance are broadly similar in different regions of the Qilian Mountains. These interannual changes are primarily driven by variations in ablation-season (June–September) air temperature (Ta), which impact albedo and melt by changing snowfall and incoming longwave radiation (Lin). We link such interannual mass balance variability to the combination of changes in atmospheric circulation over Europe and changes in sea surface temperature (SST) in the Northwest Pacific during the ablation season which can cause the changes in Ta across the Qilian Mountains. In addition, we find a trend of increasingly negative glacier mass balance across the Qilian Mountains from 1970–1994 compared to 1995–2015. This interdecadal trend is driven by higher ablation-season Ta through increasing Lin and through increasing precipitation falling as rain. Lastly, higher glacier mass loss in the east than in the west Qilian Mountains from 1970–1994 and 1995–2015 was mainly caused by lower glacier area-altitude distribution, as well as a reduction in ablation-season precipitation in the eastern Qilian Mountains. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) become ubiquitous in soil and are an environmental and public health concern worldwide. However, the status of MPs in natural and farmland soils in remote areas remains poorly understood. In this study, we investigated the characteristics of MPs in natural and farmland soils along two transects in the Qilian Mountains of the northern Tibetan Plateau. The average abundance of MPs in natural and farmland soils was 29,778 and 56,123 items kg−1, respectively, with a detection size range of 10–1000 μm. MPs in the size range of 10–100 μm accounted for 84.1% of particles detected. Among the 21 polymers detected, polyethylene dominated in both farmland and natural soils. The shape of MPs was dominated by fragments (95.8%), followed by fibers (3.8%) and beads (0.4%). The abundance of MPs was positively correlated with increasing altitude in natural soils. There was no significant correlation between the abundance of MPs and soil physicochemical properties due to the narrow range of values of soil physicochemical properties. With the growing concern regarding MPs pollution, research on the status of MPs in high altitude and remote areas is critical to understanding their global cycle. [ABSTRACT FROM AUTHOR]

• NDVI increase related to extreme temperature rise • Extreme temperature controls the beginning of vegetation growth • The delayed response of vegetation to extreme precipitation occurred late in growth • The effect of extreme temperatures on vegetation depends on moisture condition • Extreme temperatures intensity and NDVI are projected to increase in the future Understanding how extreme climates affect vegetation is of great importance for the protection of ecosystems. However, most of previous studies focused on the impact of average climate change on vegetation, and few on the effects of extreme climate on vegetation change. Such studies are particularly scare in arid and semiarid mountainous areas where vegetation is relatively homogenous and ecosystems are more vulnerable to climate change. In this study, we analyzed the vegetation response to extreme climate change in the Qilian Mountains, northeastern Tibetan Plateau, employing 11 extreme climate indices and the normalized difference vegetation index (NDVI), and further explored possible future trends in NDVI and extreme climate indices using detrended fluctuation analysis (DFA). The results indicated that NDVI in the Qilian Mountains showed an overall increasing trend from 1982 to 2015, with a rate of 0.004 per decade; 38.11% of the region showed a significant increasing trend and only 3.34% showed a significant decreasing trend. The vegetation areas with a significant increasing trend were dominated by grassland, cropland, and forest. The extreme climate indices accounted for approximately 29.8% of the change in NDVI, with the extreme precipitation intensity index (Rx1day) contributing the largest amount (17.1%), followed by the extreme temperature intensity index (TNx; 12.7%). Compared with extreme temperatures, the interannual variation in extreme precipitation has a greater impact on vegetation growth in the Qilian Mountains because moisture is the main climatic factor that limits vegetation growth in this region. There was a significant time-lagged effect of climate factors on vegetation growth in general, with a lag up to three months. The beginning of vegetation growing season was controlled by temperature-related extreme indices, but not directly by precipitation-related indices, and the cumulative effect of extreme precipitation and the time lag of NDVI's response appeared in the later part of the season. The DFA results showed that the extreme temperature intensity, extreme precipitation intensity, and the NDVI are expected to continuously increase in the future. [ABSTRACT FROM AUTHOR]

The geological processes responsible for outward growth of the Tibetan Plateau are debated. The Qilian Mountains on the northeastern margin of the plateau comprise one of the youngest structural components of the plateau whose understanding is key to deciphering the broader geological evolution of the region. Here, based on a reprocessed deep seismic profile which was originally collected during the 1990s across the northeast margin of the western Qilian Mountains and previous geological and geophysical data, we find evidence for decoupled crustal deformation that was partitioned by a decollement, in which lower-crustal deformation featured by local duplexing preceded upper-crustal deformation featured by imbricate thrusts. Furthermore, we propose that the Asian lithospheric mantle is being underthrust beneath the western Qilian Mountains, as inferred from patterns of lower crustal deformation which is marked by the Moho geometry. Integrating these results yields a better understanding of lithospheric deformation of western Qilian Mountains, northeastern margin of the plateau during the Cenozoic. [ABSTRACT FROM AUTHOR]

[Display omitted] • The evolution of desert environments has significantly deteriorated soil health in semi-arid alpine regions. • Rising desertification reduces the ability of plants to maintain stable soil health. • Worsened desertification enhances the role of soil microbes in determining soil health stability. • Soil health stability in semi-arid alpine mountains exhibits a nonlinear response to desertification. Desertification poses a serious threat to ecosystem health, and with global changes, the variability and uncertainty of ecological functions in semi-arid alpine regions are increasing. A pressing issue is quantifying how desertification affects the soil system functions in these areas. However, empirical evidence is still lacking in exploring the interaction between desertification degradation gradients and soil functions under natural conditions by coupling soil physicochemical properties, soil microbiota, and vegetation. For this purpose, we conducted a survey sampling of soil and vegetation at five sites with no, light, moderate, severe and extremely severe desertification in Qinghai Area of Qilian Mountains National Park, China. We introduced a new concept soil health stability (SHS) to represent the actual health status of soil systems in semi-arid alpine regions and assessed the impact of desertification on this stability. We observed that the intensification of desertification has led to a significant decrease in soil organic matter, relative abundance of soil microorganisms, and plant factors. The contributions of plant factors and soil microbiota to SHS showed a negative correlation with the degradation gradient. SHS varied across different degradation gradients, rather than following a single linear relationship, with a relatively rapid decline in the transition from non-desertification to moderate desertification. Our work emphasizes that the coupled contributions of soil physicochemical properties, soil microbiota, and vegetation to SHS. It calls for intensified prevention and treatment of mild and moderate desertification, while providing new methods and deeper scientific understanding for accurately evaluating soil system functions in semi-arid alpine regions. [ABSTRACT FROM AUTHOR]

• The CO 2 fluxes in winter were three times higher than in other seasons. • Glacier meltwater altered the diel pattern of CO 2 fluxes. • The total CO 2 fluxes from the headwaters were 39.57 (30.04–50.21) Gg C yr−1, ignoring the diurnal variation overestimated the CO 2 fluxes. • The CO 2 fluxes from 1st and 2nd order streams accounted for 77% of the headwaters. Rivers are important sources of the carbon dioxide (CO 2) released into the atmosphere; however, research on CO 2 emission from riverine headwater regions is sparse, particularly from rivers in the Tibetan Plateau (TP) region, which has large area of glaciers and permafrost. We conducted a three-year (2020–2022) observational study of CO 2 flux rates from the riverine headwater region of the Qilian Mountains (QLMs) to determine diel and seasonal CO 2 variations and flux rates. Our results revealed that the annual average CO 2 emission was 0.45 (0.03–1.60) kg CO 2 m−2 yr−1, with the highest flux rates observed in winter [0.87 (0.08–2.67) μmol CO 2 m−2 s−1], which was approximately three times higher than flux rates in other seasons. Glacier meltwater altered the diel pattern of riverine CO 2 flux rates by diluting CO 2 and dissolved inorganic carbon. Meanwhile, CO 2 release from rivers in the permafrost region was dictated by stream order, with a linear decrease as stream order increased. Considering diel variations, the total CO 2 fluxes from the headwater regions of the QLMs were approximately 32.70 (25.00–41.28) Gg C/yr, representing 76 % of the pre-calibration total CO 2 fluxes ignoring diel variations. This study provides essential insights into CO 2 release from headwaters, which have substantial implications for understanding CO 2 outgassing. [ABSTRACT FROM AUTHOR]

Mass movements in China typically encompass landslides, rockfalls, and debris flows, and these processes affect almost 70% of all mountain areas of China. An improved understanding of geomorphic process dynamics and their drivers and process histories are important prerequisites for a proper assessment and a sustainable management of mountain hazards. Tree rings have on varied occasions proven to be a reliable tool for the acquisition of data on past mountain hazards. Here we present the first reconstruction of past landslide activity on a slope in the Qilian Mountains, northeast Tibetan Plateau, China. To this end, a total of 543 Qilian juniper (Sabina przewalskii Kom.) samples were selected from 239 trees growing on or next to a complex landslide body, with the aim to reconstruct past landslide histories at the site. The dataset of disturbed trees was complemented with 174 increment cores from 84 reference Qilian juniper trees growing on three adjacent, yet undisturbed sites. Based on the dating of the samples and the interpretation of growth disturbances (GD) in the tree-ring series of affected trees, we provide the first reconstruction of past landslides as retrieved from a dendrogeomorphic record covering more than a millennium (956–2011 CE). Results show that the first detectable GD occurred as early as in 1042 CE, followed by seven major landslide reccurrences in 1703, 1816, 1848, 1863, 1913, 1970, and 1982. Comparison between our landslide record and a dendroclimatic precipitation reconstruction points to the crucial role of major, longer-term wet precipitation anomalies on landslide occurrence. • We present the longest, tree-ring based landslide reconstruction. • Qilian junipers allow centennial-scale reconstruction of complex landslide processes. • Landslides are caused by successive wet years or extreme rainfalls. • Earthquakes do not seem to trigger landslides at the site. [ABSTRACT FROM AUTHOR]

The vast alpine grasslands of the Tibetan Plateau are lined by a belt of oroboreal coniferous forests in the transition zone to the Central Asian semi-deserts and deserts which may play important roles in the hydrology and biogeochemistry of the region. Many of these forests exist under semi-arid climates, are exposed to rapid climate warming and suffer from intensive human impact. We investigated the carbon stocks in biomass and soil in the Picea crassifolia (Qinghai spruce) forests of the Qilian Mountains, north-eastern Tibetan Plateau. In 18 forest plots at 2600–2800 m elevation, we found ecosystem carbon stocks of 348 Mg C ha −1 with carbon densities of 43 Mg C ha −1 in the live and dead aboveground biomass, 12 Mg C ha −1 in roots, 3 Mg C ha −1 in litter and 305 Mg C ha −1 in the soil (SOC; 0–100 cm). The belowground carbon pools exceed averages reported for northern boreal forests and even more clearly for zonal forest vegetation in the temperate zone. The high SOC density in the P. crassifolia forests are probably the result of slow decomposition rates due to low soil temperatures in combination with low soil moisture. The widespread degradation of mountain spruce forests to shrubland reduces the ecosystem carbon stock by >85 Mg C ha −1 , and is partly caused by a 15%-reduction in SOC. We conclude that the remaining mountain forests of spruce and other conifers at the northern fringe of the Tibetan Plateau play an important role in the regional carbon budget and need urgent conservation. [ABSTRACT FROM AUTHOR]

In China, flash floods are one of the main natural disasters causing loss of life and damage to infrastructure. The threat of flash floods is exacerbated with climate change and increased human activities, such that the number of disasters has shown a clear upward trend in recent years. However, due to the scarcity of instrumental data or overly short timeseries, we are still lacking critical data to understand spatio-temporal patterns and driving factors of extreme flash floods. This missing knowledge is however crucial for a proper management of these hazards, especially in remote mountain environments. In forested catchments, dendrogeomorphology allows the reconstruction of past process activity based on growth disturbances (GDs) in trees that have been affected by past flash floods. Therefore, in our study, for the first time, we reconstruct past flash floods in the Qilian Mountains, northeast Tibetan Plateau, over past centuries. To this end, we sampled 99 Qinghai spruce (Picea crassifolia) trees affected by flash floods, with a total of 194 increment cores, and identified 302 GDs induced by past flash floods. These GDs have been caused by at least 21 flash floods that we are able to reconstruct over the last 170 years. The position of GDs within tree rings and the intra-seasonal dating of past events also allowed discussion of the likely synoptic situations that may have led to the triggering of flash floods in the past. Logistic regression analysis confirms that significant correlation exists between cumulative maximum 5-day August–September precipitation and reconstructed flash floods, which is corresponding to the majority of scars and related tangential rows of traumatic resin ducts (TRDs) found in the latewood portion of growth rings. These results support the idea that abundant precipitation occurring at the end of the summer season and early fall is the key factor driving flash floods in our study area. Our research not only fills the gaps regarding historical flash flood histories in the Qilian Mountains, but also provides a scientific basis for the region's response to climate change and flood prevention and reduction. [ABSTRACT FROM AUTHOR]

Investigation of the altitude of maximum precipitation (AMP) and the factors that determine this height supports the understanding of vertical precipitation distribution in mountains. Based on the field precipitation measurement on the northern flank of the Qilian Mountains, the AMP was investigated at vertical profiles from 1,483 to 4,484 m. It found a 2,300 m-AMP in winter and a 4,200 m-AMP in other seasons and on a yearly scale. The AMPs increase from the cold and dry season to the warm and wet season and therefore increase with precipitation. During winter, the interaction of the predominant high-pressure system, the thermal inversion layer below 2,200 m, and the westerly lead to the 2,300-m AMP. In other seasons, the convergent Tibetan Plateau monsoon causes the water vapor move to the Qilian Mountains, and the enhanced uplifting by the mountain produces greater precipitation with altitude, forming the AMP at the higher areas. The front steepest terrain is the primary factor causing the formation of 4,200-m AMP in the study area. The annual AMP may be roughly equal to seven-eighths of the altitude of the mountain top on the north flank of the Qilian Mountains. [ABSTRACT FROM AUTHOR]

Based on glacio-meteorological records, 7 years of in-situ mass balance data, and a temperature-index model, the long-term annual and seasonal mass balances of Shiyi Glacier in the northeast Tibetan Plateau (TP) were reconstructed from 1963/64 to 2016/17. Variations were then linked to local climatic and macroscale circulation changes. The model was calibrated based on in-situ mass balance data and was driven by daily air temperature and precipitation data recorded at nearby alpine meteorological stations. The results show that the reconstructed annual mass balance experienced an overall downward trend over the past 54 years, with a remarkably high mass loss rate during 1990/91–2016/17. Analysis of mass balance sensitivity and local climatic changes shows that the pronounced mass loss since the 1990s can be mainly attributed to cumulative positive temperature increases caused by air temperature increases and prolongation of the ablation season. From the perspective of macroscale circulation, the reconstructed annual mass balance values correlate well with zonal wind speeds (June to September) in the glacierized region. For the positive/negative phase of the annual mass balance, an inverse spatial pattern in relation to geopotential height change (low/high-pressure centres) and corresponding conversion of cyclonic/anti-cyclonic circulation were present in northern hemisphere mid-latitudes. Comparative analysis of existing long-term mass balance series over the TP indicates that asynchronous climatic changes in the different glacierized regions led to inconsistent interannual fluctuations in glacier mass balance. [ABSTRACT FROM AUTHOR]

The long-term changes of summer freezing level heights in the Qilian Mountains, northeast Tibetan Plateau from 1979 to 2012 is analyzed by using radiosonde data and two global analysis datasets including European Centre for Medium-Range Weather Forecasts re-analysis-Interim (ERA) and National Centers for Environmental Prediction/Department of Energy Reanalysis 2 (NCEP). The freezing level heights in the Qilian Mountains generally show an increasing trend from high latitude to low latitude as well as from low altitude to high altitude. The trend magnitude of ERA during 1979–2012 is approximately 54 m per decade ( p < 0.01) which is slightly larger than that derived from radiosonde-based series (51 m per decade, p < 0.01), and NCEP shows a relatively lower trend by 40 m per decade ( p < 0.05). The correlation between free-air freezing level height and surface air temperature is greatly related with the altitude of stations, and the correlation coefficients are generally larger in alpine station than those in plain stations. Glaciers in the Hexi drainage basin at the northern slope have experienced larger increasing trend magnitudes, which may significantly impact the regional hydrological process. [ABSTRACT FROM AUTHOR]

The Qilian Mountains region, located on the northeastern Tibetan Plateau, is a region in western China that is sensitive to climate change and serves as an important ecological security barrier. Previous studies mostly used meteorological stations to study climate change in the Qilian Mountains; however, due to the known distribution limitations (scarcity and inhomogeneity) of meteorological stations in mountainous areas, relevant results remain inconclusive. To address this issue, we used 30 meteorological stations in and around the Qilian Mountains and the China meteorological forcing dataset (CMFD) with a spatial resolution of 0.1° × 0.1° to comprehensively analyse the spatiotemporal distribution of and variation in the air temperature over the Qilian Mountains, with a particular focus on elevation-dependent warming (EDW); then, land surface albedo data from the ERA5-Land and MODIS products were employed to interpret the EDW. The results showed that the annual mean lapse rate in the Qilian Mountains is −0.56 °C/100 m. From 1979 to 2018, the air temperature over the Qilian Mountains experienced a significant upwards trend with an annual mean rate of 0.39 °C/decade, the maximum rate occurring in December–February (DJF, 0.56 °C/decade) and the minimum rate occurring in June–August (JJA, 0.28 °C/decade). Spatially, significant warming was found in most areas of the Qilian Mountains, and a slight cooling trend was found in the north and southeast. Unlike other typical areas, the Qilian Mountains showed reversed EDW during 1979–2018, i.e., the increasing trends in air temperature decreased with elevation, which was mainly caused by the reversal in EDW over the 1999–2008 period and could be largely explained by the change in land surface albedo. • A high-precision assimilation data is used to analyse air temperature changes in the Qilian Mountains. • Evident elevational dependency of air temperature change is reported. • The Qilian Mountains experienced a significant warming, but with seasonal and spatial differences. • The reversed elevation-dependent warming is detected and attributed to surface albedo change. [ABSTRACT FROM AUTHOR]

Based on the meteorological observations at three sites (4180 m, 4550 m and 5040 m a.s.l.) in Laohugou and the surrounding 7 national meteorological stations, the long-term surface air temperature of the glaciated region in the Qilian Mountains, northeastern Tibetan Plateau during 1957–2013 was reconstructed. The in-situ air temperature observed at 4180 m during 1959–1961 was used to verify the reconstructed temperature series. Several approaches of multiple regressions were applied to select the optimal method in estimating the daily air temperature, including the ordinary least square regression (OLSR), stepwise regression (SR), principal component regression (PCR) and partial least squares regression (PLSR), respectively. According to root mean square error, mean bias error, and correlation coefficient, OLSR is selected as the optimal approach in the study region. The reconstructed daily temperature correlates well with the synchronous observations, and correlation coefficients are higher than 0.96 ( p < 0.01) on an annual basis. All the three sites in the study region have experienced a warming trend, and annual mean temperature has increased by 0.31 C°, 0.35 C° and 0.37 C° per decade at 4180 m, 4550 m and 5040 m ( p < 0.01), respectively. The higher elevations usually have larger trend magnitudes, compared with the lower sites. The positive degree day (PDD, the sum of daily mean temperatures above ice point) has significantly increased by 27.8 C°, 12.8 C°, and 3.2 C° per decade at 4180 m, 4550 m and 5040 m, respectively, which also indicates the continuing shrinkage of glaciers for the study region. [ABSTRACT FROM AUTHOR]

Changes in seasonally frozen ground at high elevations under the effects of global warming and their ecohydrological impacts are important for understanding changes in regional water resources and ecosystems. This study estimates the spatio-temporal variability in the maximum thickness of seasonally frozen ground (MTSFG) in the Qilian Mountains in the northeastern Tibetan Plateau from 1960 to 2014 by using a variant of the Stefan solution. The present study analyzes changes in streamflow and vegetation to reveal the ecohydrological impacts of changes in the MTSFG. Results indicate that the MTSFG shows a mean decreasing trend of 7.4 cm/10a in the past 55 years in correspondence to the significantly increasing air temperature (0.34 °C/10a). The greatest decreasing trend of the MTSFG is at elevations of 3400–3800 m. The annual baseflow has increased significantly in most of the sub-basins for which the increasing precipitation is the main factor. The MTSFG is another major factor for the increase in baseflow during the cold season (from November to April) according to the results of gray relational analysis. The leaf area index (LAI) during the growing season has increased by 0.045/10a since 2000, and the start of growing season has advanced by 1.8–2.1 d/10a at elevations of 3000–3800 m, where the vegetation cover is the densest. Furthermore, results of correlation analysis show that the topsoil moisture increases with the MTSFG decreases. Results of gray relational analysis show that the decrease in MTSFG is the main reason for the advancing green-up dates and increasing LAI in the initial period of the growing season. Our results show that the ecohydrological processes are changing along with frozen soil degradation in the northeastern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Consideration of stable isotopes in precipitation is valuable for investigating hydrological processes. Therefore, correcting the measured isotopic composition of precipitation under below-cloud evaporation is necessary. An accurate description of the underlying processes affecting stable isotopic composition of precipitation could help improve our understanding of the water cycle. The transitivity between monsoonal and arid climates was reflected by the evaporation rate of falling raindrops in precipitation in the Qilian Mountains, a typical transition zone between Tibetan Plateau and arid region of China. Considering 1310 precipitation event-scale samples, based on stable isotope analysis method, the mean below-cloud evaporation rate (f) in the study area was measured as 12.00% during the summer half-year (May–October). The evaporation rate on the northern slopes (12.70%) of the Qilian Mountains in China was significantly higher than that on the southern slopes (9.98%). The transition between monsoonal and arid climates was reflected in the evaporation rate of falling raindrops during precipitation in the Qilian Mountains of China. Below-cloud evaporation contributed to a noticeable enrichment of stable isotopes in the precipitation in the study area. The monthly precipitation δ18O enrichment rate in the Qilian Mountains of China from May to October was 29.18%, 23.35%, 25.60%, 22.99%, 31.64%, and 14.72%, respectively. For every 1.00% increase in the evaporation rate of raindrops in Qilian Mountains of China, the changes in the concentration of oxygen isotopes from the bottom of the clouds to the ground increased by 0.92‰; however, with an evaporation rate of < 5.00%, for every 1.00% increase in the evaporation rate of raindrops the changes in the concentration of oxygen isotopes from the bottom of the clouds to the ground increased by 1.00 ‰ could also be observed. Furthermore, altitude was an important factor affecting below-cloud evaporation in the study area. [ABSTRACT FROM AUTHOR]

Glaciers in the Qilian mountains, located in the northeastern part of the Tibetan Plateau, constitute an important freshwater resource for downstream populations and natural systems. To enhance our understanding of the variability of the glaciers, temporally and spatially comprehensive information on them is needed. In this study, the glacier outlines of ~1990, ~2000 and ~2010 for the whole area were delineated in a semi-automated manner using band TM3/TM5 ratio images of Landsat ETM+ or TM scenes with the help of a merged ASTER GDEM/SRTM v4.1 digital elevation model. Combining our own results with those of previously published studies that span the period back to 1956, we found that the glacier area shrank by 30±8% from 1956 to 2010 and the shrinkage accelerated remarkably in the past two decades. The linear trends of annual air temperature and precipitation measured at weather stations within the glacierized areas were 0.03-0.058C a-1 (significant only after 2000) and 0.37-1.58mm a-1 (not significant) respectively from 1961 to 2010. Glaciers shrank mainly due to the increasing temperature. Glaciers in the Qilian mountains are very unlikely to have experienced positive mass balance over the past decade. Moreover, given the trend toward higher temperatures, the glaciers in this region will continue to shrink. [ABSTRACT FROM AUTHOR]

Abstract: Controversies exist on the tectonic models at the northern margin of the Qinghai-Tibetan Plateau. New magnetotelluric (MT) data, with a bandwidth of 0.001–5827.5s, were collected along one profile starting from the Northern Qilian Mountains in the southern end, crossing the Hexi Corridor, the Kuantan Shan-Hei Shan uplift, the Huahai Basin, and coming into the Beishan Block. Two-dimensional (2D) and three-dimensional (3D) resistivity models of the data are derived using magnetotelluric inversion codes. The 2D models, and the electrical structures along the profile extracted from the 3D models, are comparable and complementary in defining reliable scales and shapes of anomalies in electrical resistivity. The crust-upper mantle structures beneath the northern plateau are characterized by two imbricated southward underthrusted blocks of continental crust or lithosphere. The Northern Qilian Fault is interpreted as a gently south-dipping décollement in the upper crust along the top of a high resistivity body below the Northern Qilian Mountains. The two high resistivity bodies below the Kuantan Shan-Hei Shan uplift are disconnected; the upper crustal one may connect with the high resistivity basement below the Northern Qilian Mountains in that the attitudes and deformations of the strata at these areas are coherent; whereas the lower crust-upper mantle one may be the cold lithospheric materials of the block north to the Hexi Corridor and that forms a south-dipping boundary between the Hexi Corridor and its northern neighbors. The observed high electrical resistivity beneath the Beishan Block provides further support for the notion that the Beishan Block should be rigid as a whole; only in this manner could it transfer stress from south to north. The northern boundary of the Qinghai-Tibetan Plateau is below the Kuantan Shan-Hei Shan Fault and underthrusting of continental crust or lithosphere is the main cause for the thickening of the plateau crust in the north. [Copyright &y& Elsevier]

It is generally hypothesized that tree growth at the upper treeline is normally controlled by temperature while that at the lower treeline is precipitation limited. However, uniform patterns of inter-annual ring-width variations along altitudinal gradients are also observed in some situations. How changing elevation influences tree growth in the cold and arid Qilian Mountains, on the northeastern Tibetan Plateau, is of considerable interest because of the sensitivity of the region’s local climate to different atmospheric circulation patterns. Here, a network of four Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies was developed from trees distributed on a typical mountain slope at elevations ranging from 3000 to 3520 m above sea level (a.s.l.). The statistical characteristics of the four tree-ring chronologies show no significant correlation with increasing elevation. All the sampled tree growth was controlled by a common climatic signal (local precipitation) across the investigated altitudinal gradient (520 m). During the common reliable period, covering the past 450 years, the four chronologies have exhibited coherent growth patterns in both the high- and low-frequency domains. These results contradict the notion of contrasting climate growth controls at higher and lower elevations, and specifically the assumption that inter-annual tree-growth variability is controlled by temperature at the upper treeline. It should be stressed that these results relate to the relatively arid conditions at the sampling sites in the Qilian Mountains. [ABSTRACT FROM AUTHOR]

Aim Fossil pollen spectra from lake sediments on the Tibetan Plateau have been used for qualitative climate reconstruction, but no modern pollen–climate calibration set based on lake sediments is available to infer past climate quantitatively. This study aims to develop such a dataset and apply it to fossil data. Location The Tibetan Plateau, between 30 and 40° N and 87 and 103° E. Methods We collected surface sediments from 112 lakes and analysed them palynologically. The lakes span a wide range of mean annual precipitation ( Pann; 31–1022 mm), mean annual temperature ( Tann; −6.5 to 1 °C), and mean July temperature ( TJuly; 2.6–19.7 °C). Redundancy analysis showed that the modern pollen spectra are characteristic of their respective vegetation types and local climate. Transfer functions for Pann, Tann and TJuly were developed with weighted averaging partial least squares. Model performance was assessed by leave-one-out cross-validation. Results The root mean square errors of prediction (RMSEP) were 104 mm ( Pann), 1.18 °C ( Tann) and 1.17 °C ( TJuly). The RMSEPs, when expressed as percentages of the gradient sampled, were 10.6% ( Pann), 15.7% ( Tann) and 11.9% ( TJuly). These low values indicate the good performance of our models. An application of the models to fossil pollen spectra covering the last c. 50 kyr yielded realistic results for Luanhaizi Lake in the Qilian Mountains on the north-eastern Tibetan Plateau (modern Pann 480 mm; Tann−1 °C). Tann and Pann values similar to present ones were reconstructed for late Marine Isotope Stage 3, with minimum values for the Last Glacial Maximum ( c. 300 mm and 2 °C below present), and maximum values for the early Holocene ( c. 70 mm and 0.5 °C greater than present). Main conclusions The modern pollen–climate calibration set will potentially be useful for quantitative climate reconstructions from lake-sediment pollen spectra from the Tibetan Plateau, an area of considerable climatic and biogeographical importance. [ABSTRACT FROM AUTHOR]

Little is known about the spatial variability in tree growth and its responses to climate on the Tibetan Plateau; however, such information is essential for improving predictions of forest ecosystem response to climatic change. A network of 16 ring width chronologies was developed along a latitudinal transect in the Qilian Mountains, northeastern Tibetan Plateau. A principal components analysis revealed that the residual chronologies had a positive loading on the first unrotated principal component (PC1). After rotation, PC1 yielded the highest loadings on the driest sites in the northwest and decreased to the south and to the east. PC2 was negatively correlated with altitude. Moisture availability was a dominant limiting factor for tree growth, and this dominance increased northwards and westwards along the precipitation gradient. Loadings of the first two rotated principal components separated the 16 forest sites into three major groups corresponding to the three regions affected by the East Asian Monsoon, Westerlies, and their interaction. Thus, spatial variability in tree growth is an excellent bioindicator of regional climate. [ABSTRACT FROM AUTHOR]

Presents a study which determined the ages of five major terraces of the Shagou River at the northern side of Qilian Mountains of the Tibetan Plateau in China. Terrace sequence; Age of terraces; Genesis of terrace and the uplift of Qilian Mountains.

Surface runoff is a major component of the hydrological cycle, and it is essential for supporting the ecosystem services provided by grassland and forest ecosystems. It is of practical importance to understand the mechanisms and the dynamic processes of runoff in a river's basin, and in this study, we focused on the restored montane Pailugou Basin in the Qilian Mountains, Gansu Province, China, since its water status is extremely important for the large arid area and local economies therein. Our purpose was to determine the annual variation in the surface runoff in the Pailugou Basin because it is important to understand the influence of climate fluctuations on surface water resources and the economy of the basin. In addition, little is known about the annual variations in precipitation and runoff in this region of the world. Daily atmospheric precipitation, air temperature and runoff data from 2000 to 2019 were analyzed by the calculation of the uneven annual distribution of surface runoff, the calculation of the complete adjustment coefficient, and the vector accumulation expressed by the concentration degree. We also used the cumulative anomaly approach to determine the interannual variation trend of runoff, while the change trend was quantified by the sliding average method. Finally, we used the Mann–Kendall mutation test method and regression analysis to establish the time-series trend for precipitation and runoff and to determine the period of abrupt runoff changes. The results indicated concentrated and positive distributions of surface runoff on an annual basis, with a small degree of dispersion, and an explicit concentration of extreme flows. The relative variation ranges exhibited a decreasing trend, and the distribution of the surface runoff gradually was uniform over the year. The runoff was highest from July to September (85% of the annual total). We also determined that annual surface runoff in the basin fluctuated over the 20-year period but showed an overall increasing trend, increasing by 3.94 × 105 m3, with an average increase rate of 0.42 × 105 m3 every ten years. From 2005 to 2014, the annual runoff and the proportion of runoff in the flood season (July to September) to the annual runoff fluctuated greatly. The correlation between the runoff and precipitation was significant (r = 0.839, p < 0.05), whereas the correlation between air temperature and surface runoff was low (r = 0.421, p < 0.05). [ABSTRACT FROM AUTHOR]

(1) Background: Climate change significantly impacts the phenology and dynamics of radial tree growth in alpine dryland forests. However, there remains a scarcity of reliable information on the physiological processes of tree growth and cambial phenology in response to long-term climate change in cold and semi-arid regions. (2) Methods: We employed the process-based Vaganov–Shashkin (VS) model to simulate the phenology and growth patterns of Chinese pine (Pinus tabuliformis) in the eastern Qilian Mountains, northeastern Tibetan Plateau. The model was informed by observed temperature and precipitation data to elucidate the relationships between climate factors and tree growth. (3) Results: The simulated tree-ring index closely aligned with the observed tree-ring chronology, validating the VS model's effectiveness in capturing the climatic influences on radial growth and cambial phenology of P. tabuliformis. The model outputs revealed that the average growing season spanned from mid-April to mid-October and experienced an extension post-1978 due to ongoing warming trends. However, it is important to note that an increase in the duration of the growing season did not necessarily result in a higher level of radial growth. (4) Conclusions: While the duration of the growing season was primarily determined by temperature, the growth rate was predominantly influenced by water conditions during the growing season, making it the most significant factor contributing to ring formation. Our study provides valuable insights into the potential mechanisms underlying tree growth responses to climate change in cold and semi-arid regions. [ABSTRACT FROM AUTHOR]

As the transition zone between the Tibetan Plateau and the arid region, the Qilian Mountains are important ecological barriers and source regions of inland rivers in northwest China. In recent decades, drastic changes in the cryosphere have had a significant impact on the quantity and formation process of water resources in the Qilian Mountains. In this study, 2164 environmental isotope samples were used to quantify the runoff components of 11 major rivers in the Qilian Mountains and to investigate the influence of cryosphere changes on mountain runoff. The results showed that the mountain runoff mainly comes from the cryosphere belt, which contributes to approximately 82 %、71 %, and 80 %, respectively, in the Hexi inland water system, upper stream of the Yellow River system, and Qinghai inland river system; the remaining amounts are contributed by precipitation in the vegetation belt. The maximum contribution ratio of glacier and snow meltwater to runoff occurred in May, but not in July and August, when the temperature was the highest. The important contribution of supra-permafrost water to runoff gradually increased from May to October and reached approximately 40 % in some rivers in October. Cryosphere degradation in the Qilian Mountains after 90 years has caused a rapid increase in runoff, a change in the peak runoff time, and an increase in runoff in winter. These changes in hydrological processes bring opportunities and challenges to managing inland river water resources, and various adaptive measures to seek advantages and avoid disadvantages have been proposed. The findings from environmental isotope analysis provide insights into realizing harmony of life, agriculture, industry, and ecological water use. [ABSTRACT FROM AUTHOR]

As the transition zone between the Tibetan Plateau and arid region, the Qilian Mountains are important ecological barriers and source regions of inland rivers in northwest China. In recent decades, drastic changes in the cryosphere have had a considerable impact on the formation process of water resources in the Qilian Mountains. In this study, 2164 environmental isotope samples were used to quantify the runoff components of 11 major rivers in the Qilian Mountains and investigate the influence of cryosphere changes on mountain runoff. The results show that the mountain runoff primarily originates in the cryosphere belt, which contributes approximately 82 %, 71 %, and 80 % to the Hexi inland water system, the upper stream of the Yellow River system, and the Qinghai inland river system, respectively. The maximum contribution ratio of glacier and snow meltwater to runoff occurred in May. The contribution of supra-permafrost water to runoff gradually increased from May and reached approximately 40 % in some rivers in October. Cryosphere degradation in the Qilian Mountains after the 1990s has caused a rapid increase in runoff, changes in the peak runoff time, and an increase in winter runoff. These changes in the hydrological processes bring opportunities and challenges to managing inland river water resources, and various adaptive measures to seek advantages and avoid disadvantages have been proposed. The findings from the environmental isotope analysis provide insights into understanding water resources and realizing the nexus of life, agriculture, industry, and ecological water use. [ABSTRACT FROM AUTHOR]

Global warming is causing some regions to experience frequent and severe drought, with important impacts on montane forest vegetation. In this study, the Qilian Mountains is on the northeastern margin of the Tibetan Plateau which was divided into three study areas, the eastern (HaXi), middle (XiShui) and western (QiFeng) parts. This work focused on interannual trend comparison of tree-ring width (TRW) and enhanced vegetation index (EVI), their relationship characterization from 2000 to 2020, and spatial and temporal pattern portrayal of response to climate factors. The results showed that: (1) the overall interannual variation of TRW and EVI showed a stable increasing trend, and the trend of TRW and EVI gradually became consistent with the increase in drought stress (from the eastern region to the western region and from high elevation to low elevation) (p < 0.01); (2) a significant positive relation was observed between TRW and EVI at the same sampling sites, and the synchrony of the positive correlation gradually increased with the increase of drought stress (p < 0.01); and (3) compared to TRW, EVI is significantly more sensitive with climatic variations, and the dominant climate factors affecting both TRW and EVI dynamics are gradually identical with the increase of drought stress. [ABSTRACT FROM AUTHOR]

Gross primary productivity (GPP) is vital for ecosystems and the global carbon cycle, serving as a sensitive indicator of ecosystems' responses to climate change. However, the impact of future climate changes on GPP in the Tibetan Plateau, an ecologically important and climatically sensitive region, remains underexplored. This study aimed to develop a data-driven approach to predict the seasonal and annual variations in GPP in the Tibetan Plateau up to the year 2100 under changing climatic conditions. A convolutional neural network (CNN) was employed to investigate the relationships between GPP and various environmental factors, including climate variables, CO2 concentrations, and terrain attributes. This study analyzed the projected seasonal and annual GPP from the Coupled Model Intercomparison Project Phase 6 (CMIP6) under four future scenarios: SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5. The results suggest that the annual GPP is expected to significantly increase throughout the 21st century under all future climate scenarios. By 2100, the annual GPP is projected to reach 1011.98 Tg C, 1032.67 Tg C, 1044.35 Tg C, and 1055.50 Tg C under the four scenarios, representing changes of 0.36%, 4.02%, 5.55%, and 5.67% relative to 2021. A seasonal analysis indicates that the GPP in spring and autumn shows more pronounced growth under the SSP3–7.0 and SSP5–8.5 scenarios due to the extended growing season. Furthermore, the study identified an elevation band between 3000 and 4500 m that is particularly sensitive to climate change in terms of the GPP response. Significant GPP increases would occur in the east of the Tibetan Plateau, including the Qilian Mountains and the upper reaches of the Yellow and Yangtze Rivers. These findings highlight the pivotal role of climate change in driving future GPP dynamics in this region. These insights not only bridge existing knowledge gaps regarding the impact of future climate change on the GPP of the Tibetan Plateau over the coming decades but also provide valuable guidance for the formulation of climate adaptation strategies aimed at ecological conservation and carbon management. [ABSTRACT FROM AUTHOR]

Introduction: Biological nitrogen fixation (BNF) plays a crucial role in nitrogen utilization in agroecosystems. Functional characteristics of plants (grasses vs. legumes) affect BNF. However, little is still known about how ecological zones and cropping patterns affect legume nitrogen fixation. This study's objective was to assess the effects of different cropping systems on aboveground dry matter, interspecific relationships, nodulation characteristics, root conformation, soil physicochemistry, BNF, and nitrogen transfer in three ecological zones and determine the main factors affecting nitrogen derived from the atmosphere (Ndfa) and nitrogen transferred (Ntransfer). Methods: The 15N labelingmethod was applied. Oats (Avena sativa L.), forage peas (Pisum sativum L.), common vetch (Vicia sativa L.), and fava beans (Vicia faba L.) were grown in monocultures and mixtures (YS: oats and forage peas; YJ: oats and common vetch; YC: oats and fava beans) in three ecological regions (HZ: Huangshui Valley; GN: Sanjiangyuan District; MY: Qilian Mountains Basin) in a split-plot design. Results: The results showed that mixing significantly promoted legume nodulation, optimized the configuration of the root system, increased aboveground dry matter, and enhanced nitrogen fixation in different ecological regions. The percentage of nitrogen derived from the atmosphere (%Ndfa) and percentage of nitrogen transferred (%Ntransfer) of legumes grown with different legume types and in different ecological zones were significantly different, but mixed cropping significantly increased the %Ndfa of the legumes. Factors affecting Ndfa included the cropping pattern, the ecological zone (R), the root nodule number, pH, ammonium-nitrogen, nitrate-nitrogen, microbial nitrogen mass (MBN), plant nitrogen content (N%), and aboveground dry biomass. Factors affecting Ntransfer included R, temperature, altitude, root surface area, nitrogenfixing enzyme activity, organic matter, total soil nitrogen, MBN, and N%. Discussion: We concluded that mixed cropping is beneficial for BNF and that mixed cropping of legumes is a sustainable and effective forage management practice on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

In this study, we conducted field campaigns at two mountain‐top observatories on the Qilian Mountains (QLM) in the northeastern Tibetan Plateau of China, which plays a vital role in sustaining water resources for the downstream arid and semi‐arid regions. The two observatories, Waliguan Baseline Observatory (WLG) and Laohugou station (LHG), are situated on the eastern and western edge of the QLM, respectively. The objectives of this study were to examine the properties of atmospheric aerosols, CCN concentrations (NCCN) at varying supersaturation levels (SS = 0.2%–1.0%), and the hygroscopic nature of aerosols in the QLM, especially during the formation of orographic cloud. Notably, the average aerosol concentration and NCCN was approximately 2–3 factors higher at WLG compared to LHG. The chemical compositions of aerosols were primarily dominated by sulfate and organic aerosol (OA) at these two sites. A very high hygroscopicity parameter of aerosol calculated using chemical composition was observed at these two sites (0.37 ± 0.03 at LHG vs. 0.30 ± 0.04 at WLG). Enhanced aerosol loading episodes impacted by anthropogenic emission were observed at these two sites. Exploration on high‐loading cases at each site, we found that the CCN activity was dominated by aerosol size, but the chemical processes of aerosol during the formation of orographic cloud could also be important in CCN activity, especially for low SS conditions. These findings collectively underscore the significant impact of anthropogenic air plumes on CCN concentrations in the QLM and their potential influence on precipitation patterns. Plain Language Summary: The Qilian Mountains (QLM), situated in the northeastern Tibetan Plateau of China, have been constructed as a national park, dedicated to protecting its fragile ecological environment. Renowned for its "wet island" effect, the mountains serve as a crucial water resource for the downstream residents in northwest China. Orographic clouds, a primary source of precipitation in these mountains, heavily rely on the presence of cloud condensation nuclei (CCN), typically dominated by natural mineral dust due to its arid and semi‐arid regions around. In recent years, rapid urbanization and heavy human activities around has introduced a significant influx of anthropogenic aerosols. However, the impact of anthropogenic aerosol on the orographic cloud is unclear, especially during summer season when natural mineral dust emissions are limited. To unravel this mystery, we conducted campaigns at two mountain‐top observatories to explore the impact of anthropogenic aerosol transport from low elevation regions during summer season to mountain areas. Our findings highlight the substantial impact of anthropogenic aerosols on CCN concentrations, which offer valuable insights into the understanding the interaction of aerosol and cloud, and potential impact on precipitation in this mountain region. Key Points: Two mountain‐top studies were explored to characterize aerosol and CCN on the QLM in the northeastern TP of ChinaAn overall low NCCN values were observed in these mountain areas, but the concentration at the east was 2–3 times higher than the westElevated NCCN occurred at these two sites when anthropogenic pollutants were transported upslope [ABSTRACT FROM AUTHOR]

This research was designed to explore the variation characteristics of soil C:N:P stoichiometry and enzyme activity in the Qilian Mountains different grassland types. Thus, 7 grassland types (Upland meadow: UM, Alpine meadow: AM, Temperate steppe: ST, Alpine steppe: AS, Temperate Desert Steppe: TDS, Temperate Desert: TD, Alpine desert: AD) of Qilian Natural Reserve were selected to analyze the variation characteristics of soil enzyme activities and stoichiometry of different grassland types and its relationship with environmental factors. The study indicated that the C/N, C/P, and N/P of different grasslands ranged from 5.08 to 17.35, 2.50 to 72.29, and 0.53 to 4.02.The ranking of different types grassland for the C/N was TS ≥ AM ≥ UM ≥ AS ≥ TDS > AD > TD, and the changing pattern of C/P and N/P is similar to that of C/N. The ranking of different types grassland for the urease enzyme activity was UM ≈AS > AD ≈TDS ≈TS ≈AM > TD, and TS ≈AM ≈UM ≈AS ≈AD > TDS > TD for alkaline phosphatase enzyme activity, and AS ≈AM ≈TS ≈TDS≥UM ≥TD ≈AD for catalase enzyme activity. Based on N/P ratio and RDA analysis, nitrogen was the main factor limiting the grassland productivity, and pH, TN, SOC, Richness index and Simpson diversity index were the main environmental factors affecting the soil C:N:P stoichiometry and enzyme activities. Cluster analysis showed that 7 grassland types were clustered into three categories. In conclusion, the stoichiometric characteristics and soil enzyme activities of different grasslands vary with grassland types. Nitrogen was the main factor limiting the grasslands productivity, and pH, TN, SOC, Richness index and Simpson diversity index were the main environmental factors affecting the soil C:N:P stoichiometry and enzyme activities, and the grassland Qilian Mountain can be managed in the ecological district according to the clustering results. The results of this study can provide data support and theoretical guidance for the scientific management and ecological protection of grassland in Qilian Mountains Reserve. [ABSTRACT FROM AUTHOR]

To achieve sustainable development goals and to solve environmental problems, land resources in eco-sensitive areas should be used and optimized. Qinghai, which is an important eco-sensitive area in China, represents a typical ecological vulnerable region on the Qinghai–Tibetan Plateau. Using land use/cover data for 2000, 2010 and 2020, this study applied a series of quantitative methods to analyze the spatial pattern and structure of the production–living–ecological space (PLES) in Qinghai. The results indicated that the spatial pattern of the PLES in Qinghai was stable over time, but the spatial distribution was very different. The structure of the PLES in Qinghai was stable, and the proportion of each space from high to low was ecological (81.01%), production (18.13%) and living (0.86%). We found that the proportion of ecological space in both the Qilian Mountains and the Three River Headwaters Region was lower than the rest of the study area, except for the Yellow River–Huangshui River Valley. Our study objectively and credibly presented the characteristics of the PLES in an important eco-sensitive area in China. This study further formulated targeted policy suggestions to provide a basis for regional sustainable development, ecological environment protection, and land and space optimization in Qinghai. [ABSTRACT FROM AUTHOR]

Insect pests pose a significant threat to alpine ecosystems, especially under rapid environmental change conditions. Therefore, it is necessary to explore the effects of environmental factors on insect pest risks and provide methods for pest management in alpine regions. Habitat heterogeneity and topographic variation are the indicators of insect pest risks. However, few studies have explored the effects of habitat heterogeneity and topographic variation on insect pest risks in alpine regions. We used species distribution modeling (i.e., maxent modeling) to project the distributions of insect pests in this alpine region based on occurrence records. Then, we delineated the high-risk areas for insect pests based on the species distributions under a conceptual risk framework using Zonation software for different ecoregional types. We determined the alpine conifer and mixed forests of the Nujiang Langcang Gorge, the conifer forests of the Qilian Mountains, and the shrublands and meadows of Southeast Tibet as the key areas requiring monitoring for insect pests in Qinghai province based on the scoring of insect pest risk rank with >0.7. Habitat heterogeneity and topographic variation could be developed as indicators of risk exposure to insect pests in alpine regions. Our study suggests that the prevention and control of insect pests should be conducted in areas with high habitat heterogeneity and topographic roughness in alpine regions. We provided new insights into the application of species distribution modeling based on habitat heterogeneity and topographic variation. The results of our study indicate that habitat heterogeneity and topographic variation should be considered for improving pest management effectiveness in alpine regions. [ABSTRACT FROM AUTHOR]

Precipitation patterns and their variations over the Tibetan Plateau (TP) are mainly dominated by the Asian summer monsoon, westerlies, and their interactions. The exact extent of the Asian summer monsoon's influence, however, remains undetermined. Referencing the climatological northern boundary index of the East Asian summer monsoon, we demonstrate that the 300 mm precipitation isoline from May to September can be utilized as an indicator of the northern boundary of the Asian summer monsoon over the TP, allowing for an analysis of the spatial distribution characteristics of the climatological and interannual northern boundary. Our results indicate that the climatological northern boundary of the Asian summer monsoon over the TP lies along the eastern Qilian Mountains-Tanggula Mountains-Qiangtang Plateau-Gangdise Mountains-Western Himalayas during 2001–2020. This position corresponds well with the position of the convergence of westerly (westerlies) and southerly wind (monsoon) in the lower troposphere, representing the interface between dry and wet regions in the rainy season over the TP. There is a significant positive correlation between changes in the zonal/meridional water vapor budget and variations in precipitation to the north/south of the climatological northern boundary, respectively. Additionally, a close relationship exists between the interannual fluctuation range of the northern boundary and the distribution of vegetation across the TP. Compared to the northern boundary of the summer monsoon defined by meteorological criteria, which is established based on 5-day (pentad) mean precipitation (exceeding 4 mm day−1), our climatological northern boundary offers a more objective portrayal of the region that experiences persistent influence from the summer monsoon. These indicate that climatological northern boundary has a clear significance for natural geographical distribution such as the westerlies-monsoon circulation, ecology, and climate. Based on the interannual fluctuation range of the northern boundary, we divided the TP into domains of westerlies, monsoon, and westerlies-monsoon transition. This study could serve as a foundation for further investigation into the interactions between westerlies and monsoon, variations in precipitation patterns and hydrological-ecological systems over the TP. [ABSTRACT FROM AUTHOR]

Anisodus tanguticus is a valuable plant for extracting tropane alkaloids. However, the mechanisms by which plant microbiome mediate the accumulation of tropane alkaloids in Anisodus tanguticus are still not well understood. In this study, we collected 55 wild Anisodus tanguticus populations on the Tibetan Plateau and the tropane alkaloids content, and root-related bacteria and fungi diversitywere analyzed using HPLC and 16 s rDNA and ITS sequencing. The results showed that tropane alkaloids content has obvious geographical distribution characteristics. Anisodine content had a significant positive correlation with latitude, while anisodamine and atropine content had a significant negative correlationwith latitude. Variation partition analysis (VPA) showed that root endophytes play a significant role in promoting tropane alkaloid production in Anisodus tanguticus roots. The root endophytes alone explained 14% of the variation, which was the largest contributor. Soil properties variables could independently explain 5% of the variation, and climate variables could explain 1% of the variation.Of these, endophytic fungi alone accounted for 11%, while bacteria explained only 5%. Random forests and Mantel test showed that different regionally enriched endophytic fungi have a greater impact on the accumulation of tropane alkaloids than the whole endophytic fungi. Richness and relative abundance of enriched endophytic fungi in Hengduan-Qilian Mountains (HQ) group has a significant positive correlation with anisodine content, while richness and relative abundance of enriched endophytic fungi in Himalayas-Hengduan Mountains (HH) group has a significant positive correlation with anisodamine and atropine content. And, these enriched endophytic fungi have high network connectivity and distributed in separate network modules. This study further confirmed that endophytes were closely related to tropane alkaloids accumulation in Anisodus tanguticus and contribute to promote sustainable development, cultivation, and precision medicine of Anisodus tanguticus. [ABSTRACT FROM AUTHOR]

Climate change accelerates the global water cycle. However, the relationships between climate change and hydrological processes in the alpine arid regions remain elusive. We sampled surface water and groundwater at high spatial and temporal resolutions to investigate these relationships in the Qaidam Basin, an extremely arid area in the northeastern Tibetan Plateau. Stable H–O isotopes and radioactive 3 H isotopes were combined with atmospheric simulations to examine hydrological processes and their response mechanisms to climate change. Contemporary climate processes and change dominate the spatial and temporal variations of surface water isotopes, specifically the westerlies moisture transport and the local temperature and precipitation regimes. The H–O isotopic compositions in the eastern Kunlun Mountains showed a gradually depleted eastward pattern, while a reverse pattern occurred in the Qilian Mountains water system. Precipitation contributed significantly more to river discharge in the eastern basin (approximately 45 %) than in the middle and western basins (10 %–15 %). Moreover, increasing precipitation and a shrinking cryosphere caused by current climate change have accelerated basin groundwater circulation. In the eastern and southwestern Qaidam Basin, precipitation and meltwater infiltrate along preferential flow paths, such as faults, volcanic channels, and fissures, permitting rapid seasonal groundwater recharge and enhanced terrestrial water storage. However, compensating for water loss due to long-term ice and snow melt will be a challenge under projected increasing precipitation in the southwestern Qaidam Basin, and the total water storage may show a trend of increasing before decreasing. Great uncertainty about water is a potential climate change risk facing the arid Qaidam Basin. [ABSTRACT FROM AUTHOR]

In the context of global warming, increasing frequency of climate extremes poses a great challenge to natural systems and humankind. However, the spatial and temporal characteristics, as well as the mechanisms of extreme climate change, remain insufficiently understood, particularly in arid and semi-arid mountainous regions with high climate sensitivity and ecological fragility. In this study, we analyzed the spatial and temporal characteristics of 27 extreme climate indices (including intensity, duration, and frequency) in the Qilian Mountains, northeastern Tibetan Plateau, from 1961 to 2016 using the CN05.1 meteorological grid dataset, explored the relationship between the extreme climate indices and internal variability of the climate system (e.g., the North Atlantic Multi-decadal Oscillation (AMO), the Pacific Decadal Oscillation (PDO), and the Arctic Oscillation (AO)), and further probed into the mechanisms affecting climate extremes using ERA5 reanalysis dataset. The results showed that extreme temperatures in the Qilian Mountains were significantly enhanced in terms of intensity, frequency, and duration during 1961–2016. The decrease rates of frost days (FD0) and ice days (ID0) were − 4.4 d per decade and − 4.7 d per decade, respectively, and the increase rate of growing season length (GSL) was 2.9 d per decade. Extreme precipitation intensity increased significantly, with the intensity indices R95P and PRCPTOT showing the most significant change trends of 4 mm per decade and 14.9 mm per decade, respectively (p < 0.05). The number of consecutive dry days (CDD) displayed a significant downward trend, with a rate of −6 d per decade, the number of moderate precipitation days (R10) showed an increasing trend of 0.12 d per decade. Correlation analyses revealed significant associations between the increases in extreme climates and the AMO and PDO. Additionally, the enhancement of the AO contributed to the increased extreme precipitation. Enhanced anticyclonic circulation in Eurasia and geopotential height, as well as increased cloud cover in winter, were the main reasons for the increase in extreme temperatures in the Qilian Mountains, whereas the significant increase in water vapor transport entering the east boundary of the Qilian Mountains in summer mainly contributed to the increase in extreme precipitation. This study highlights internal oscillations in the climate system that regulate the extreme climate variability in the Qilian Mountains at various spatial-temporal scales. • Significant increase in climate extremes in the Qilian Mountains. • Increased extreme precipitation frequency stems from the rise in moderate rain days. • The shifts of AMO and PDO phase influence the increase in climate extremes. • Increased summer water vapor transport contributes to more extreme precipitation. [ABSTRACT FROM AUTHOR]

Climate change is altering species distribution and modifying interactions in microbial communities. Understanding microbial community structure and their interactions is crucial to interpreting ecosystem responses to climate change. Here, we examined the assemblages of stream bacteria and fungi, and the associations between the two groups along elevational gradients in two regions with contrasting precipitation and temperature, that is the Galong and Qilian mountains of the Tibetan Plateau. In the wetter and warmer region, the species richness significantly increased and decreased with elevation for bacteria and fungi, respectively, while were nonsignificant in the drier and colder region. Their bipartite network structure was also different by showing significant increases in connectance and nestedness towards higher elevations only in the wetter and warmer region. In addition, these correlation network structure generally exhibited similar positive association with species richness in the wetter and warmer region and the drier and colder region. In the wetter and warmer region, climatic change along elevation was more important in determining connectance and nestedness, whereas microbial species richness exerted a stronger influence on network structure and robustness in the drier and colder region. These findings indicate substantial forthcoming changes in microbial diversity and network structure in warming climates, especially in wetter and warmer regions on Earth, advancing the understanding of microbial bipartite interactions' response to climate change. [ABSTRACT FROM AUTHOR]

Asian dust has significant impacts on atmospheric systems and global biogeochemical cycles. In this study, we applied the U isotopic method to trace sediments based on their comminuting age, analyzing the uranium isotopes of cryoconite samples from various glaciers in western China, including the Tibetan Plateau (TP) and Tianshan Mountains. We aimed to explore the spatial variability of the (234U/238U) activity ratio and residence time, as well as the transport mechanism of the dust cycle in the region. Additionally, we used Nd‐Sr isotopes data from our previous work to jointly determine the provenance. Our results indicate that the average (234U/238U) activity ratios in southern TP glaciers are higher, with mean range of 0.981–0.993, while those in northeastern TP locations are lower, with mean of 0.974. This suggests a decreasing trend from south to north. In the Tianshan region, the (234U/238U) activity ratio is higher in central areas compared to eastern areas, with a mean range of 0.984–0.996, indicating a decreasing trend from west to east. U‐Sr‐Nd isotopes analysis showed that dust provenance is from multiple sources, including long‐range transported and local dust inputs from the glacier basins, mainly originating from the TP surface and central Asian arid regions. Using the end‐member mixing model analysis and meteorological data, we interpret that the cryoconite dust in eastern Tianshan and Qilian Mountains comes from a complex mixture of the southern Gobi, northern TP surface dust, and Taklimakan and Alxa arid deserts. In contrast, the glacial dust in southern TP locations originates mainly from the plateau surface dust. Our findings suggest that the uranium isotopes in high‐altitude glaciers are primarily influenced by the origins of dust, which are affected by related atmospheric circulation. We also developed a conceptual model to illustrate the complete process of U isotopic fragmentation and migration changes during dust production, transport, and deposition in the TP region. Plain Language Summary: In this study, the U isotopic method to trace sediments depending on their production‐transport histories is applied for the first time to dust deposited on glaciers in various locations of Tibetan Plateau (TP) and Tianshan Mountains in western China. The U isotopic variability of dust from glacial sediment is presented and discussed here, providing valuable data for a broader application of uranium isotopes for sedimentology and provenance studies in the future. Results showed that the (234U/238U) activity ratio signature of dust from glaciers is not uniform but exhibits differences depending on the considered geographic sector of the TP and western China. The present study demonstrates the potential of the 234U/238U technique to gather information about the production history of mineral dust deposited on glaciers in complex contexts as the TP and improve the identification of dust sources. Key Points: We measured the (234U/238U) activity ratio of cryoconite dust in large range scale of western China (including the Tibetan Plateau and Tianshan Mountains)The (234U/238U) activity ratio in high‐altitude glaciers is mainly affected by different source regions and transport processA conceptual model shows the complete view of U isotopic fragmentation and migration change during the dust transport and deposition [ABSTRACT FROM AUTHOR]

The current limited approaches to calculating hillslope erosion rate hamper the study of the relationships among the rates of hillslope erosion, river incision, and tectonic uplift and hence the discussion of steady-state landscape evolution. In this paper, we use remote sensing and geochronological methods to calculate the upper and lower bounding hillslope erosion rates in the Qilian Shan range, Tibet. Our analysis focuses on five convex landslide sediment units derived from the weathered hillslopes at Qingyang Mountain on the tectonically active northeastern Tibetan Plateau. These sediment units range in thickness from 5.5 to 12.8 m and in volume from 119 × 103 to 260 × 103 m3. Based on field observations, measurements extracted from high-resolution DEMs, and optical stimulated luminescence (OSL) ages on fluvial terraces, we obtain lower and upper bounding rates of 0.13 ± 0.03 and 0.21 ± 0.04 mm/yr, respectively. Finally, we calculate incision rates, ranging from 0.21 ± 0.02 to 0.39 ± 0.01 mm/yr, from heights of a dated fluvial terrace above the present river and the time of abandonment of the associated bedrock strath estimated from OSL ages. The rates of hillslope erosion and river incision at Qingyang Mountain and the tectonic uplift of the Qilian Mountains are estimated to be within a factor of two over the past 117 ka, suggesting that a state of dynamic equilibrium has likely existed on this timescale. [ABSTRACT FROM AUTHOR]

Accelerating glacier shrinkage is one of the most consequential of global warming. Yet, projections for the region remain ambiguous because of the tremendous spatial heterogeneity, especially in the Qilian Mountains, where glacier melt runoff is a vital water resource for the arid downstream area. To better understand glacier changes in this region, this study took regional representative Qiyi Glacier as an example and applied an enhanced distributed surface mass balance (SMB) model to glimpse the SMB variation and possible impacts on melt runoff under the RCP 4.5 and RCP 8.5 scenarios. Further, we combined a modified volume-scaling method to update the glacier geometry gradually to enhance long-term reliability. When forced with observed daily temperature and precipitation, the reconstructed glacier SMB, from 1957 through 2013, agrees well with the in situ observations. The result indicates an abrupt change for SMB from positive to negative in 1992 and subsequent mass accelerated loss after 2000. The increased summer air temperature and the pattern of large-scale atmospheric circulation shifts might both cause these changes. Using projected climate forcing from as many as 31 coupled GCMs from the CMIP 5 ensemble, the Qiyi Glacier is projected to undergo sustained SMB loss throughout the 21st century for both RCPs. By 2100, the Qiyi Glacier will lose ~25 m water equivalent (w.e.) for RCP 4.5 and ~37 m w.e. for RCP 8.5. Whereas the glacier area will shrink by 43% for RCP 4.5 and 54% for RCP 8.5 relative to 2013 glacier content, corresponding to the volume of the Qiyi Glacier will lose by 54% for RCP 4.5 and by 65% for RCP 8.5, accordingly. Simultaneously, the glacier terminus will experience extreme melts. The terminus elevation of the Qiyi Glacier will retreat from 4310 m a.s.l. in 2013 to 4810 m a.s.l. (RCP 4.5) and 4838 m a.s.l. (RCP 8.5) by the end of 2100, which will exceed the multi-year average ELA (4749 m) from 1957 to 2013. If the warming trends keep and glaciers melt like the Qiyi Glacier with this 'shocking' rate, it will raise the possibility of crippling, long-term water shortages for Hexi corridors. [ABSTRACT FROM AUTHOR]

Oxygen (O2) is the most abundant molecule in the atmosphere after nitrogen. Previous studies have documented that oxygen concentration remains nearly constant (20.946%) at all altitudes. Here we show for the first time that oxygen concentration varies significantly from earlier consensus and shows strong spatial and seasonal differences. Field observations on the Qinghai-Tibetan Plateau (QTP) indicate oxygen concentration of 19.94–20.66% (2018, n = 80), 19.98–20.78% (2019, n = 166) and 19.97–20.73% (2020, n = 176), all statistically different from earlier reports (p < 0.001) and are lower than the nearly constant. The mean oxygen concentration in summer (20.47%) is 0.31% higher than that of winter (20.16%) (n = 53) at identical locations in 2019, sampled in the Qilian Mountains, northwest QTP. We used LMG (The Lindeman, Merenda and Gold) method to estimate the relative contributions of altitude, air temperature and vegetation index (Fractional Vegetation Cover, FVC and Leaf Area Index, LAI) to oxygen concentration, which are 47%, 32% and 3% (FVC, R2 = 82%); 45%, 30% and 7% (LAI, R2 = 82%), respectively. These findings provide a new perspective for in-depth understanding on population risk in high altitude regions in the context of global climate change, to ensure the health and safety of residents and tourists in high altitude regions and promoting the stability, prosperity and sustainable development of high-altitude regions worldwide. [ABSTRACT FROM AUTHOR]

The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds. In summer, water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains; in winter, westerly winds mainly control the climate. This article compares the wet/dry changes in the region during the mid-Holocene (MH) warm period, the medieval climate anomaly (MCA), the current warm period (CWP), and the future warm period from the perspective of paleoclimate. We found that the MH warm period was mainly affected by the orbit-controlled East Asian summer monsoon, and the region showed warm and humid climate characteristics. The MCA was mainly controlled by solar radiation, and there was a warm and dry phenomenon. The CWP and the future warm period are mainly controlled by the rise in temperature caused by the increase in greenhouse gases, and the climate is becoming more arid. The wet/dry patterns in the CWP and the future warm period in the next century on the northern Tibetan Plateau are similar to those in the MCA. Continued warming will lead to the expansion of the westerly belt and a gradually humid climate. The future wet/dry changes will be more similar to the MH warm period. [ABSTRACT FROM AUTHOR]

Understanding elevation changes on the Tibetan Plateau is crucial to comprehend the changes in topography, landscape, climate, environmental conditions, and water resources. However, some of the current products that track elevation changes only cover specific surface types or limited areas, and others have low spatial resolution. We propose an algorithm to extract ICESat-2 crossover points dataset for the Tibetan Plateau, and form a dataset. The crossover points dataset has a density of 2.015 groups/km², and each group of crossover points indicates the amount of change in elevation before and after a period of time over an area of approximately 17 meters in diameter. Comparing ICESat-2 crossover points data with existing studies on glaciers and lakes, we demonstrated the reliability of the derived elevation changes. The ICESat-2 crossover points provide a refined data source for understanding high-spatial-resolution elevation changes on the Tibetan Plateau. This dataset can provide validation data for various studies that require high-precision or high-resolution elevation change data on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

• We report detrital zircon U-Pb geochronology data from the Tengger Desert. • Tengger sediments were sourced from the Qilian Shan, local basements and Gobi Altay sources. • Precipitation is important for middle to late Quaternary desertification in China. Dust plays a critical role in global biogeochemical and carbon cycles. The deserts of northern China have been important East Asian dust sources throughout the Quaternary. The Tengger Desert, one such major arid dust-producing region in northern China, is thought to have started resembling its current form during the middle to late Pleistocene. As such, understanding the nature of the Tengger Desert's formation and the associated import, storage, and export of sediments are consequential for the regional, and potentially global, climate. The U-Pb detrital zircon geochronology data reported here from both present-day and middle to late Pleistocene Tengger Desert sediments support derivation from the Shiyang River system sourced from the Qilian Mountains mixed with sediments eroded from local basement uplifts and Gobi Altay sources. This interpretation is different from the view that sediments of this age were primarily transported to the Tengger Desert from the arid East Asian continental interior upwind. We note that this analysis suggests a common provenance for Quaternary sediments in the Tengger, Badain Jaran, and Mu Us Deserts wherein these deserts received riverine-sourced sediments from the Qilian Mountains and northeastern Tibetan Plateau. This observation highlights the importance of precipitation at elevation along the present-day margin of the East Asian summer monsoon in driving sediment supply during the middle to late Quaternary desertification within the East Asian continental interior. [ABSTRACT FROM AUTHOR]

In order to explore the glaciochemistry of Shiyi glacier in the central Qilian Mountains, a total of 142 samples have been collected for fresh snow, surface snow, snowpit and meltwater from July 2012 to November 2013. The results indicated cations dominated the glaciochemistry, especially the high Ca 2+ concentration. Relatively high Cl − and Na + concentrations were mainly contributed by desert dust aerosols and the atmospheric aerosols from warm water bodies such as the Black, Caspian, and Aral seas. The analysis also confirmed the chemical ions in fresh snow are mainly contributed by atmospheric wet deposition. Surface snow is mainly influenced by dry deposition, and snowpits are influenced by both atmospheric deposition and leaching process, while meltwater is influenced by water–rock interactions. The profile of ionic concentration in the snowpit became more smoothed during ablation period owing to the influence of leaching. The elution sequence of the snowpit in the Shiyi Glacier was: SO 4 2− > K + > Ca 2+ > Mg 2+ > Na + > Cl − > NO 3 − . The chemical concentrations for meltwater are mainly influenced by water dilution and soil thawing. The ions in snow in the central Qilian Mountains showed relatively lower concentrations than in the western Qilian Mountains, Tianshan Mountains and Altai Mountains. It was closer to balance than in glaciers in the central Tibetan Plateau, but was higher than in the southern Tibetan Plateau. Different ionic sources and dissolution process had caused the differences of chemical composition for fresh snow, surface snow, snowpit and meltwater, and these chemical compositions reflected the atmospheric background values in the northern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Life and civilization in arid regions depend on the availability of freshwater. Arid alpine river basins, where hydrological processes are highly sensitive to rapid warming, act as vital water towers for lowland oases. However, scientific understanding of precipitation variability and related cryosphere–hydrology processes is extremely limited because of the scarcity of in situ observations. The upper Danghe River basin (UDB; ∼14,000 km2) is an arid and westerly dominated basin on the northeastern Tibetan Plateau and is the water source for the Dunhuang Oasis in China. We have established a comprehensive cryosphere–hydrometeorology observation network in the basin since 2014. At present, the network consists of 21 automatic rain gauges, 22 soil freeze–thaw monitoring stations, 4 automatic weather stations (AWS), and a 50-m gradient meteorological tower with an eddy covariance system. In particular, the 18 sites, located in remote areas without public networks, are equipped with new-generation BeiDou-3 communication terminals that enable the observations to be easily, safely, and reliably read and quality controlled in near–real time from offices in the city or at home. This integrated observation network over the UDB that facilitates the monitoring of cryosphere–hydrology processes, land–atmosphere interactions, and local weather processes. In addition, the observations are helpful for the objective evaluation, and continual improvement, of hydrological models, satellite-retrieval products, and reanalysis datasets. Finally, the network is expected to promote a better understanding of the status and role of water towers in arid zones and to provide basic data support for the sustainable development of the Dunhuang Oasis and the Belt and Road. [ABSTRACT FROM AUTHOR]