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The reconstruction of paleo‐elevation serves a dual purpose to enhance our comprehension of geodynamic processes affecting terrestrial landforms and to contribute significantly to the interpretation of atmospheric circulation and biodiversity. The oxygen (δ18Ow) and deuterium (δDw) isotopes in atmospheric precipitation are systematically depleted with the increase of altitude, which are typical and widely applicated paleo‐altimeters. The utilization of hydrogen isotope of hydrous silicate minerals within the shear zone system, volcanic glass, and plant leaf wax alkanes offers valuable insights for addressing evaporation and diagenesis. In this paper, we review the principle, application conditions, and influencing factors of the hydrogen isotope paleo‐altimeter. In addition, we discuss the feasibility of utilizing this technique for quantitatively estimating the paleo‐elevation of the southeastern Tibetan Plateau, where multiple shear zones extend over hundred kilometers parallel to the topographic gradient. [ABSTRACT FROM AUTHOR]

Background: Chronic gastritis caused by Helicobacter pylori (Hp) infection is a common gastrointestinal disorder. Despite the high prevalence of Hp infection and chronic gastritis in the Tibetan Plateau, there is a lack of studies elucidating the influence of plateau hypoxia on Hp-induced gastritis. This study aimed to investigate the impact of high-altitude hypoxia on Hp-induced gastritis, particularly focusing on pathological manifestations and inflammatory responses. Methods: This study was conducted from July 2023 to March 2024 at the Department of Gastroenterology, Affiliated Hospital of Qinghai University. Ninety patients diagnosed with chronic gastritis were enrolled in the study and divided into four groups based on their residential altitude and Hp infection status. Data on endoscopic and pathological characteristics were collected, along with serum oxidative stress and inflammatory markers. Results: Patients with Hp gastritis exhibit distinctive features in the gastric mucosa, including diffuse erythema, enlarged folds, and white turbid mucus during endoscopy. Notably, individuals with Hp gastritis at high altitudes show a higher prevalence of diffuse erythema and enlarged folds. Pathological analysis reveals that these patients have elevated gastric mucosal inflammation scores and increased chronic and active inflammation. Furthermore, individuals with Hp gastritis at high altitudes demonstrate elevated levels of serum TNF-α, IL-1β, IL-6, and MDA, as well as reduced serum SOD and GSH-Px activities. Conclusions: High-altitude hypoxia may exacerbate gastric mucosal damage by enhancing oxidative stress and inflammatory response induced by Hp infection. [ABSTRACT FROM AUTHOR]

Greening of Northern China and the Tibetan Plateau (NCTP) has been observed by increases in the remotely sensed leaf area index (LAI), driven primarily by CO2 fertilization effects, anthropogenic warming, and the implementation of ecological restoration programs. Continued growth of LAI throughout the 21st century is also projected by the Coupled Model Intercomparison Project Phase 6 (CMIP6) scenarios. However, the question of whether local water resources can sustain ongoing grassland greening has not been adequately investigated. Here we assessed the sustainability of water resources under grassland greening across NCTP under various climate scenarios using water yield (WY, defined as precipitation minus actual evapotranspiration) as the key metric. Unexpectedly, we observe the coexistence of increases in LAI and WY in most of NCTP. In a warming climate with increasing precipitation and CO2, we find that grasses maintain high water use efficiency to sustain their growth, contributing to continued local water resource availability. Thus, livestock production may also continue to increase under the simultaneous growth of LAI and WY in the future. Plain Language Summary: The greening of Northern China and the Tibetan Plateau (NCTP) has been observed through increases in remotely sensed leaf area index (LAI), driven primarily by ecological restoration programs, climate change, and CO2 fertilization effects. While continued growth of LAI throughout the 21st century is projected by Coupled Model Intercomparison Project Phase 6 (CMIP6) scenarios, there is limited understanding of whether local water resources may sustain the ongoing process of grassland greening in the context of more frequent and severe drought conditions under global warming. Using three schemes considering plant physiological and hydrological feedbacks toward climate change, our study unveils changes in regional water sustainability (i.e., water yield) under grassland greening across NCTP over the past four decades and up to the end of the 21st century. Surprisingly, we observe the coexistence of future grassland greening and enhanced water resource availability in most of NCTP. Moreover, increased precipitation from atmospheric transport and evaporation recycling, coupled with a warming climate and rising CO2 levels, enables grasses to maintain high water use efficiency, sustaining their growth and contributing to the availability of local water resources. Additionally, projections suggest that the area occupied by livestock production across NCTP may continue to grow due to the simultaneous improvement in grassland and water resource availability. Key Points: Grassland greening and enhanced water resource availability may coexist in most of NCTP in a warming climateEffects of plant physiological and hydrological factors along grassland greening on water yield in the future were analyzedThe positive influence of enhanced water resource availability and ongoing grassland greening on future livestock production was quantified [ABSTRACT FROM AUTHOR]

There are controversies about the climate evolution and driving mechanism around the Tibetan Plateau since the late Cenozoic. To better understand this issue, the Ningnan Basin on the north‐eastern margin of the Tibetan Plateau was taken as the research object. The Ningnan Basin was arid at 23–18 Ma under the influence of global climate change. The extensive deformation indicates that the uplift of the Tibetan Plateau and intracontinental pushing has influenced the Ningnan Basin and the paleoclimate began to be affected in 23 Ma. During the period of 17–13 Ma, the Ningnan Basin was warm and humid and was still under the influence of global climate change. During 8.5–8 Ma, the environment suddenly became dry. At the same time, the Tibetan Plateau was intensely uplifted, which strengthened the winter winds and weakened the summer winds, resulting in the aridity of the Ningnan Basin. [ABSTRACT FROM AUTHOR]

The tropopause is important as a diagnostic of the upper troposphere and lower stratosphere structures, with unique atmospheric thermal, dynamic structures. A comprehensive understanding of the evolution of the fine tropopause structures is necessary and primary to further study the complex multi-scale atmospheric physicochemical coupling processes in the upper troposphere and lower stratosphere. Utilizing the bi-Gaussian function, a novel method is capable of identifying the characteristic parameters of tropopause vertical structures, as well as providing the information of double tropopauses (DT) structures. The new method improves the definition of cold point tropopause, and detects one (or two) most significant local coldest point(s) in mathematical statistics by fitting the temperature profiles to the bi-Gaussian function, which is (are) defined as the tropopause height(s). The bi-Gaussian function exhibits remarkable potential for explicating the variation trend of temperature profiles. The recognition results of the bi-Gaussian method and lapse rate tropopause, as defined by World Meteorological Organization, are compared in detail for different cases. Results indicate that the bi-Gaussian method possesses a lower missed detection rate and false detection rate than lapse rate tropopause, because it is not restricted by thresholds, even in the presence of multiple temperature inversion layers at higher elevations. Five-year (from 2012 to 2016) historical radiosondes in China revealed that the occurrence frequency and thickness of DT, as well as the single tropopause height, and the first and second DT height displayed significant meridional monotonic variations. The occurrence frequency (thickness) of DT increased from 2.93 % (2.61 km) to 72.45 % (6.84 km) in the latitude range [16° N, 50° N]. At mid-latitudes [30° N, 40° N], the meridional gradients of tropopause height were relatively large, essentially corresponding to the climatological location of the subtropical jet and Tibetan Plateau. The average DT thickness reported in this study is approximately 1–2 km thicker than that in previous studies, particularly in the mid-high latitudes [45° N, 50° N], which may be related to the different vertical resolution of temperature profiles provided by various data sources. DT structure occurs most frequently and has the largest meridional gradient in the mid-latitudes, formatted by a combination of poleward advection in the low-latitude upper troposphere and equatorward advection in the high-latitude lower stratosphere. In addition, although DT is thick in winter, the DT temperature difference is small, even the case of the first tropopause temperature is lower than the second tropopause temperature happens occasionally. [ABSTRACT FROM AUTHOR]

The Lancang metamorphic complex is a key component of the Three River Tethys Orogen in the SE Tibetan Plateau, with typical rock assemblages and deformation fabrics recording the subduction of the Paleo-Tethys Ocean and subsequent continental collision. In this study, we present new petrographic and structural observations, together with zircon U-Pb and mica 40Ar/39Ar geochronologic data, to reveal the deformation and kinematics of the Lancang metamorphic complex, thus providing insights into the Permian-Triassic evolution of the eastern Paleo-Tethys domain. The subduction of the Paleo-Tethys Ocean and subsequent collision resulted in a range of structural features, including penetrative regional foliations, thrusts, asymmetric folds at various scales, and ductile deformation fabrics such as asymmetric boudins and porphyroclasts. Zircon U-Pb dating of foliated gabbro and 40Ar/39Ar dating of mica schist and mylonite, which preserve shortening fabrics, suggest that the Paleo-Tethys Ocean was subducted during the Late Carboniferous to Permian-Early Triassic, and the collision of the Baoshan and Simao blocks mainly occurred during ca. 237-230 Ma in the SE Tibetan Plateau. Regional deformation likely shifted from shortening to extension ca. 230 Ma, as reflected by post-collision high-K calc-alkaline magmatism. Our results document regional structural patterns and place timing constraints on the evolution of the Paleo-Tethys Ocean. [ABSTRACT FROM AUTHOR]

The quantitative reconstruction of the length of the rainy season and precipitation on the Tibetan Plateau (TP) is crucial for revealing the spatiotemporal evolution of the Westerlies and Asian summer monsoon, as well as its ecological and environmental effects. Accurately determining the start and end times of the rainy season on the Plateau remains challenging. This study determined the start and end times of the rainy season in different locations on the Plateau by identifying precipitation inflection points. We calculated the duration and precipitation amount of the rainy season and established a transfer function between the modern pollen assemblages and them. Then, we reconstructed the rainy season variations in Kusai Lake (northern TP) and Jiang Co (central TP) during the past two millennia. The results showed that, the rainy season precipitation in Kusai Lake recorded five periods of high precipitation: AD 580–680, 1000–1100, 1200–1450, 1550–1780, and 1920–present, corresponding to the stages with long rainy season. The rainy season precipitation sequence in Jiang Co recorded four periods of high precipitation: AD 80–500, 800–950, 1250–1450, and 1780–present, which is consistent with the long rainy season before AD 1000 but unclear afterward. Spatially, rainy season precipitation on the Plateau exhibited four patterns: "wet in both north and south" may be related to abnormally strong summer monsoons; "dry in both north and south" likely associated with weak Westerly wind and weak summer monsoon; "wet in the south and dry in the north" linked to strong summer monsoon and weak Westerly wind; and "dry in the south and wet in the north" connected to weak summer monsoon and strong Westerly wind. This study revealed the spatiotemporal evolution pattern of the rainy season onset and end, duration, and precipitation amount on the Plateau over the past two millennia. It provides natural background support for further understanding the coupling between Westerly wind and Asian summer monsoon. [ABSTRACT FROM AUTHOR]

Soil moisture (SM) and soil freeze–thaw (FT) are two relatively active surface parameters that are significant to the sustainable development of the water–land–air–plant–human nexus. Over time, regional or global SM and FT datasets with different spatial resolutions have been developed. In response to the requirements of multiscale product validation and multisource uncertainty tracking, a soil moisture and soil temperature (ST) monitoring network in the Qinghai Lake Basin (QLB-NET) was established in September 2019. The QLB-NET is characterized by densely distributed in situ sites (82 sites) measuring SM and ST at 5-, 10-, and 30-cm depths, with 60 sites in a large-scale network covering an area of 36 km × 40 km and 22 sites evenly distributed across two small-scale 1 km × 1 km networks. Quantitative analyses of the in situ measurements show that the QLB-NET can provide stable and reliable ground truth for SM and FT over coarse grid scales, e.g., 36 km × 36 km, 25 km × 25 km, and 0.25° × 0.25°. When statistics are correspondingly performed over 50 out of 54, 25 out of 29, and 25 out of 28 sites, the results are described as follows: 1) the standard deviation of the mean SM varies between 0.0127 and 0.0196 m3 m−3, with the corresponding difference between the upper and lower quartiles being less than 0.02 m3 m−3; 2) the ground freeze–thaw state can be correctly identified with high probabilities ranging from 85.3% to 100% on two freeze–thaw transitional dates. The QLB-NET observed datasets are distributed online and will be continuously updated through cooperation with the National Tibetan Plateau Data Center (http://data.tpdc.ac.cn), facilitating product validation and uncertainty tracking, spatiotemporal analysis of SM change and FT transition, optimization of the SM and FT retrieving algorithms and scaling methods, and development of the mountainous microwave radiative transfer model. SIGNIFICANCE STATEMENT: This study aims to introduce the newly constructed QLB-NET in detail, including the site deployment strategy, the installation and maintenance, the sensor calibration, and the characteristics and quality of the in situ SM and ST measurements. Quantitative analyses of the in situ measurements show that the QLB-NET can provide stable and reliable ground truth for SM and FT over coarse grid scales, e.g., the SMAP 36 km × 36 km grid. The high-quality QLB-NET measurements will facilitate research of product validation and uncertainty tracking, spatiotemporal analysis of SM change and FT transition, optimization of the SM and FT retrieving algorithms and scaling methods, and development of the mountainous microwave radiative transfer model. [ABSTRACT FROM AUTHOR]

In alpine meadows, plants and soil microbes typically engage in competition for nitrogen (N) under N-deficient conditions. However, the acquisition and distribution of N among soil microbes and plants under alpine meadow degradation and climate warming induced by global climate change are still uncharacterized. In this study, we isotope labeled inorganic (NH4+-15N, NO3−-15N) and organic (glycine-15N) N in both degraded and non-degraded plots by using open-top chambers (OTC) to mimic increasing air temperatures. After 6 h, the 15N contents in soil microbes and plants were measured to investigate the effects of degradation and rising air temperature on N allocations in the ecosystems studied. Results showed that alpine meadow degradation significantly reduced soil microbial N accumulation by 52% compared to those in non-degraded plots. In non-degraded plots, warming significantly lowered the organic N levels of soil microbes by 49%, whereas in degraded ones, it reduced both NH4+-15N and NO3−-15N recovery by 80% and 45% on average but increased glycine-15N recovery by 653%. Meanwhile, warming decreased the plant recovery of NH4+-15N and NO3−-15N by 75% and 45% but increased the recovery of glycine-15N by 45% in non-degraded plots. Conversely, in degraded plots, warming markedly lowered NH4+-15N recovery by 40% but increased glycine-15N recovery by 114%. Warming mitigates the effects of alpine meadow degradation on nitrogen allocation among soil microbes and plants. In unwarmed plots, degradation significantly elevated the total 15N recovery ratio of soil microbes to plants by 60%. However, in warmed plots, the impact of degradation on this ratio was reduced. The responses of the 15N recovery ratio of soil microbes and plants to rising temperatures were closely related to alpine meadow quality. In non-degraded areas, warming enhanced the recovery ratio for NH4+-15N by 165% but reduced it for glycine-15N by 66%. Conversely, in degraded plots, warming decreased the recovery ratio for NH4+-15N by 66% but increased it for glycine-15N by 232%. This indicates that warming can increase carbon limitation for soil microbes in degraded alpine meadows, and the restoration of degraded alpine meadows should prioritize restoring carbon accumulation. [ABSTRACT FROM AUTHOR]

The extensive snow cover across the Tibetan Plateau (TP) regions has a major influence on the climate and water supply for over one billion downstream inhabitants. However, an adequate evaluation of snow cover fraction (SCF) variability over the TP simulated by global multiple reanalysis datasets has yet to be undertaken. In this study, we examined eight global reanalysis SCF datasets using the Snow Property Inversion from Remote Sensing (SPIReS) product spanning the period 2001–2020. The results reveal that the HMASR generated the best SCF simulations because of its outstanding spatial and temporal accuracy. The GLDAS and CFSR demonstrated acceptable SCF accuracy with respect to spatial variability, but struggled to reproduce the annual trend. Pronounced SCF overestimations were found when using the ERA5, ERA5L, and JRA55, but SCF was underestimated by MERRA2, and CRAL generated poor spatial pattern. Overall biases were related to the combined effect of precipitation forcing, temperature forcing, snow data assimilation, and SCF parameterization methods, with the dominant factor changing across datasets. In ERA5 and ERA5L, temperature and snowfall bias exhibited significant correlations with SCF bias over most TP areas, therefore having a greater impact on the accuracy of SCF in terms of spatial variability and temporal evolution. On the other hand, the impact of snow assimilation was possibly more pronounced in MERRA2 and CRAL. Although parameterization methods can improve SCF simulation accuracy, their influence was weaker than those of other factors, except for JRA55. To further improve the accuracy of SCF simulation, an ensemble average method was developed. The ensemble based on HMASR and GLDAS generated the most accurate SCF spatial distribution, whereas the ensemble containing ERA5L, CFSR, CRAL, GLDAS, ERA5, and MERRA2 proved optimal for capturing the annual trend. [ABSTRACT FROM AUTHOR]

Oxygenated volatile organic compounds (OVOCs) are reactive species and the primary precursors of free radicals; thus, OVOCs play important roles in tropospheric chemistry. @Tibet field campaigns 2021 discovered surprisingly high levels and activity contributions of OVOCs at Lulang, a site with high vegetation cover and strong solar ultraviolet radiation on the southeast of the Tibetan Plateau (TP). The 13 OVOCs detected accounted for 49 % of the total VOCs (TVOCs; average level of 11.7 ± 4.4 ppb), and the levels of these OVOCs exhibited typical diurnal variation, with high values in the daytime and a peak at approximately 12:00. OVOCs contributed 65 % and 63 % to VOC- k OH and the ozone formation potential, respectively, and thus had a strong influence on atmospheric chemical processes. Two independent methods were used to determine the contributions of various sources and revealed consistent conclusions regarding the importance of biological sources there. The source apportionment results obtained through positive matrix factorization indicated that sunlight-impacted and direct plant emission sources both related to plant sources contributed 47 % of the TVOCs and 65 % of the OVOCs. OVOC source fitting through the photochemical age parameterization method also indicated that biogenic sources made the largest contribution (67 %) to OVOCs and revealed a clear peak at noon. In addition, biomass burning sources were found to be closely related to the VOC background because biomass burning is highly prevalent across the whole TP; these sources made the second greatest contribution (33 %) to the TVOCs and contributed more than 23 % of OVOCs. [ABSTRACT FROM AUTHOR]

Microbial pigments play a significant role in glacier albedo reduction, thereby contributing to accelerated glacier retreat. The Tibetan Plateau has experienced rapid glacier retreat in recent decades due to global warming, yet there is limited understanding of microbial pigment distribution in the region. Here, we investigated the pigment concentration and composition in cryoconite from four glaciers. Our results showed that chlorophylls were the dominant pigments in Palong No. 4 (PL) and Jiemayangzong (JMYZ) glaciers located in the south of the Tibetan Plateau, while carotenoids were dominant in Qiangyong (QY) and Tanggula (TGL) glaciers located in the central region. Additionally, the chlorophyll b to chlorophyll a ratio, which is an indicator of the algae‐to‐cyanobacteria ratio, was higher in PL and JMYZ compared to QY and TGL. By using Random Forest Regression and Structural Equation Modelling, we determined that the concentrations of chlorophyll a, chlorophyll b, and carotenoids were associated with autotrophic bacteria relative abundance, climatic factors, and a combination of bacterial and climatic factors, respectively. This study is the first to describe the distribution of microbial pigments in cryoconite from Tibetan glaciers, providing additional support on the influence of algal pigment on glacier retreat. [ABSTRACT FROM AUTHOR]

The submarine fan with a narrow shelf is usually reactive to environmental signal propagation; however, source-to-sink functioning can be further complicated by several allogenic forcings. Here, we document the high-frequency provenance variations and different sediment delivery models recorded in the late Triassic Zhuoni fan developed in the northeastern Paleo-Tethys Ocean, mainly based on process-based sedimentological and provenance study of the Panyuan section in the West Qinling area in the northeastern margin of Tibetan Plateau. High-, low-density turbidites, hybrid event beds and hyperpycnites are distributed in the lobe-dominated submarine fan succession. Field sedimentological evidence from surrounding outcrops suggests that shelf-edge failure was the main cause of most high-and low-density turbidites with the overall absence of submarine slides or slumps, whereas the narrow shelf configuration together with late Triassic humid pulses is favourable for the occurrence of flood-related hyperpycnites in the Zhuoni fan. Detrital zircon grains (N = 6; n=123-272) generally have Palaeozoic-Mesozoic ages (ca. 350-250 Ma and 500-400 Ma) and Neoarchean-Paleoproterozoic ages (ca. 2100-1750 Ma and 2600-2400 Ma), but they can be further categized into three age groups due to different proportions of Precambrian age populations. The results demonstrate that the potential source areas may include the South and North Qinling Orogenic Belt, Qilian Orogenic Belt, different segments of North China Craton and the tectonic junction area between the Qinling and Qilian Orogenic Belts. The temporal changes in provenance signals, which are reflected by both the detrital zircon age spectra and heavy mineral assemblages, indicate different contributions of those sources in response to sea-level fluctuation. It could thus give rise to temporal variations between reactive and buffered source-to-sink sediment delivery models of the Zhuoni fan, despite the overall narrow shelf configuration. The development of the lowstand Zhuoni fan was directly related to extrabasinal hyperpycnal delivery from the river mouth and its high-frequency provenance variability recorded different efficiencies of signal transfer through the onshore catchment with significantly influence of temporal storage, fluvial rejuvenation or even regional climate variability. The highstand submarine fan was thought to be formed by shelf-edge failure with sediment buffering in the shelf region, which was associated with a strong magnitude of provenance mixing. Our work provides a new perspective for deciphering the different origins of deep-water sediment delivery in response to high-frequency sea-level and climate changes. [ABSTRACT FROM AUTHOR]

Climate change has induced substantial shifts in vegetation boundaries such as alpine treelines and shrublines, with widespread ecological and climatic influences. However, spatial and temporal changes in the upper elevational limit of alpine grasslands ("alpine grasslines") are still poorly understood due to lack of field observations and remote sensing estimates. In this study, taking the Tibetan Plateau as an example, we propose a novel method for automatically identifying alpine grasslines from multi‐source remote sensing data and determining their positions at 30‐m spatial resolution. We first identified 2895 mountains potentially having alpine grasslines. On each mountain, we identified a narrow area around the upper elevational limit of alpine grasslands where the alpine grassline was potentially located. Then, we used linear discriminant analysis to adaptively generate from Landsat reflectance features a synthetic feature that maximized the difference between vegetated and unvegetated pixels in each of these areas. After that, we designed a graph‐cut algorithm to integrate the advantages of the Otsu and Canny approaches, which was used to determine the precise position of the alpine grassline from the synthetic feature image. Validation against alpine grasslines visually interpreted from a large number of high‐spatial‐resolution images showed a high level of accuracy (R2,.99 and.98; mean absolute error, 22.6 and 36.2 m, vs. drone and PlanetScope images, respectively). Across the Tibetan Plateau, the alpine grassline elevation ranged from 4038 to 5380 m (5th–95th percentile), lower in the northeast and southeast and higher in the southwest. This study provides a method for remotely sensing alpine grasslines for the first‐time at large scale and lays a foundation for investigating their responses to climate change. [ABSTRACT FROM AUTHOR]

Tethys tectonic system has experienced a long-term evolution history, including multiple Wilson cycles; thus, it is an ideal target for analyzing plate tectonics and geodynamics. Tethyan evolution is typically characterized by a series of continental blocks that separated from the Gondwana in the Southern Hemisphere, drifted northward, and collided and accreted with Laurasia in the Northern Hemisphere. During this process, the successive opening and closing of multistage Tethys oceans (e.g., Proto-Tethys, Paleo-Tethys, and Neo-Tethys) are considered core parts of the Tethyan evolution. Herein, focusing on the life cycle of an oceanic plate, four key geodynamic processes during the Tethyan evolution, namely, continental margin breakup, subduction initiation (SI), Mid-Ocean Ridge (MOR) subduction, and continental collision, were highlighted and dynamically analyzed to gather the following insights. (1) Breakup of the narrow continental margin terranes from the northern Gondwana is probably controlled by plate subduction, particularly the subduction-induced far-field stretching. The breakup of the Indian continent and the subsequent spreading of the Indian Ocean can be attributed to the interactions between multiple mantle plumes and slab drag-induced far-field stretching. (2) Continental margin terrane collision-induced subduction transference/jump is a key factor in progressive Tethyan evolution, which is driven by the combined forces of collision-induced reverse push, far-field ridge push, and mantle flow traction. Moreover, lithospheric weakening plays an important role in the occurrence of SI. (3) MOR subduction is generally accompanied by slab break-off. In case of the considerably reduced or temporary absence of slab pull, mantle flow traction may contribute to the progression of plate subduction. MOR subduction can dynamically influence the overriding and downgoing plates by producing important and diagnostic geological records. (4) The large gravitational potential energy of the Tibetan Plateau indicates that the long-lasting India-Asia continental collision requires other driving forces beyond the far-field ridge push. Further, the mantle flow traction is a good candidate that may considerably contribute to the continuous collision. The possible future SI in the northern Indian Ocean will release the sustained convergent force and cause the collapse of the Tibetan Plateau. Based on the integration of these four geodynamic processes and their driving forces, a "multiengine-driving" model is proposed for the dynamics of Tethyan evolution, indicating that the multiple stages of Tethys oceanic subduction provide the main driving force for the northward drifting of continental margin terranes. However, the subducting slab pull may be considerably reduced or even lost during tectonic transitional processes, such as terrane collision or MOR subduction. In such stages, the far-field ridge push and mantle flow traction will induce the initiation of new subduction zones, driving the continuous northward convergence of the Tethys tectonic system. [ABSTRACT FROM AUTHOR]

Post-collisional potassic magmatic rocks are widely distributed in the northwestern Tibetan Plateau, yet their magmatic processes remain poorly understood. Here, we present a comprehensive analysis of the whole-rock major and trace elements, as well as the mineral textures and chemistry of the Dahongliutan volcanic rocks in the NW Tibetan Plateau, aiming to reveal the magmatic processes prior to eruption and speculate on the triggering mechanism. The results show that the Dahongliutan volcanic rocks are potassic trachyandesites, which undergo polybaric crystallization during magma ascension. The phenocrysts in these potassic rocks exhibit various textural and compositional zoning styles. The green cores of green-core clinopyroxenes show textural (e.g., resorption texture) and chemical (Fe-rich) disequilibrium with the host rock compositions, suggesting that they may be antecrysts and crystallized from early batches of more evolved magmas. Additionally, alkali feldspar phenocrysts also display disequilibrium characteristics (e.g., overgrowth rim and sieve texture), indicating hot mafic magma recharge and mixing in the magma plumbing system. Therefore, we conclude that the disequilibrium textural and compositional features of green-core clinopyroxene and alkali feldspar phenocrysts provide evidence of magma recharge and mixing prior to eruption. Furthermore, it is likely that the eruption of the Dahongliutan volcano was triggered by magma recharge. [ABSTRACT FROM AUTHOR]

In this study, 112 agricultural topsoil samples were collected from the Yarlung Zangbo River Basin (YZRB) and its two tributaries, and the concentrations, spatial distribution, source apportionment, and potential ecological risk of eight heavy metals (Cd, Hg, Pb, Cr, Cu, Zn, Ni and As) were analyzed. The mean concentrations of Cu, Pb, Zn, Cr, Ni, Cd, As, Hg and Pb were 33.91, 28.21, 86.93, 109.04, 73.58, 0.12, 21.49 and 0.05 mg/kg, respectively. Except for Pb, the concentration of heavy metals in soil exceeded the corresponding local background values, but did not exceed the national soil pollution risk screening values. In terms of spatial distribution, it showed that the heavy metals were enriched in the Nianchu River, and followed by Lhasa River and YZRB mainstream. Furthermore, the ecological risks were ordered as Hg > Cd > As > Ni > Cu > Pb > Cr > Zn, and the potential ecological risk index of the YZRB fell in the range of moderate ecological risk. The high-risk areas were in the facility agriculture fields of the Nianchu River, which was mainly related to agricultural activities. In addition, the positive matrix factorization results showed traffic, agricultural activities, natural weathering of the parent minerals, and atmospheric transport sources were the four sources in soils of the YZRB. This work will provide a scientific reference to develop appropriate pollution control measures and facility farmlands management in the YZRB of Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Pinus yunnanensis Franch. is an economically and ecologically important pine endemic to southwest China. A large number of low-quality and low-efficiency individuals have appeared in P. yunnanensis forests due to climate change, environmental stress, and human overexploitation. There is a lack of comprehensive information about the genetic diversity, population structure and a core germplasm collection establishment with individuals taken across its natural range. Understanding the important information will be invaluable for germplasm efficient conservation and utilization. A total of 287 individuals from 10 populations across its range were analyzed using 17 polymorphic microsatellite markers. The research revealed P. yunnanensis was a typical outcrossing plant (Fis = − 0.1), maintaining moderately high genetic diversity (He = 0.540). The continuous distribution and wind-dispersal traits of two-sacs pollen and winged seeds may have promoted gene flow (Nm = 12.71) and lessened genetic differentiation between populations (Fst = 0.023). There was a lack of significant isolation by distance (P = 0.07). Geographical and ecological isolation following the uplift of the southeastern margin of the Tibetan Plateau may have contributed to the formation of three discrete groups (K = 3). A core collection of 72 individuals (25% of the whole collection) was established, of which genetic diversity parameters showed no-significance from the whole collection. In situ conservation of the three populations (XC, CY, and XP) showing distinct genetic diversity was recommended, and ex situ conservation for individuals with private alleles. The core collection was recommended as a possible germplasm resource for tree breeding and improvement. [ABSTRACT FROM AUTHOR]

Lake surface water temperature (LSWT) is a key parameter in lake energy budget and is highly vulnerable to climate change. However, the long‐term trends in LSWT across China and their driving factors remain uncertain. Here, we used a calibrated lake model to simulate LSWT over 1979–2018 for 91 large lakes (>100 km2) across China. Simulations reveal an overall LSWT warming trend (0.040°C yr−1, p < 0.05), but with large spatial variations. The majority of these lakes show significant warming trends (84%, 0.053°C yr−1), while a significant cooling trend is found in the seven lakes in the northwestern Tibetan Plateau (−0.064°C yr−1). LSWT of approximately 42% of the lakes increases more rapidly than the corresponding ambient air temperature. Regionally, the warming trend is highest for lakes in the Eastern Plain (0.049°C yr−1) and the lowest in the Yunnan‐Guizhou Plateau (0.016°C yr−1). The increases in simulated LSWT also vary across seasons, with a higher rate in winter and spring than in summer and autumn. Changes in air temperature, downward longwave radiation, and wind speed are the most important climatic drivers for LSWT changes. Lake surface warming could be more rapid under future global warming, necessitating greater attention to lake‐atmosphere interactions. Plain Language Summary: Lake surface water temperature (LSWT) is an essential factor in regulating heat and water exchange between lake surface and air. Previous studies have relied on satellite or in situ data to study changes in LSWT at various scales. However, the spatiotemporal variations in LSWT at a national scale and their driving factors are still poorly understood for large countries such as China. Here, we used a one‐dimensional lake model (FLake) to simulate the spatiotemporal variability of LSWT for 91 large lakes (>100 km2) across China from 1979 to 2018. Our simulations reveal a significant warming trend for most lakes, although a few lakes in the northwestern Tibetan Plateau show a cooling trend. Interestingly, 42% (38 of 91) of these lakes showed faster warming rates than nearby air temperatures. LSWT increased faster in spring and winter than in summer and autumn. Lake surface warming is mainly explained by locally rising air temperature, increasing downward longwave radiation, and weakened wind speed. Under the projected warmer climate in the future, lake surface warming is expected to continue, with important implications for lake management and climate change mitigation. Key Points: Lake model revealed a significant annual increase of 0.040°C (p < 0.05) in the surface water temperature of large lakes across China from 1979 to 2018The simulated surface water temperature warmed faster than the local surface air temperature in approximately 42% of the studied lakesChanges in air temperature, downward longwave radiation, and wind speed are the primary contributors to the trends in lake surface water temperature [ABSTRACT FROM AUTHOR]

Background: Domestication and introduction of dairy animals facilitated the permanent human occupation of the Tibetan Plateau. Yet the history of dairy pastoralism in the Tibetan Plateau remains poorly understood. Little is known how Tibetans adapted to milk and dairy products. Results: We integrated archeological evidence and genetic analysis to show the picture that the dairy ruminants, together with dogs, were introduced from West Eurasia into the Tibetan Plateau since ~ 3600 years ago. The genetic admixture between the exotic and indigenous dogs enriched the candidate lactase persistence (LP) allele 10974A > G of West Eurasian origin in Tibetan dogs. In vitro experiments demonstrate that − 13838G > A functions as a LP allele in Tibetans. Unlike multiple LP alleles presenting selective signatures in West Eurasians and South Asians, the de novo origin of Tibetan-specific LP allele − 13838G > A with low frequency (~ 6–7%) and absence of selection corresponds − 13910C > T in pastoralists across eastern Eurasia steppe. Conclusions: Results depict a novel scenario of genetic and cultural adaptations to diet and expand current understanding of the establishment of dairy pastoralism in the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Animals living in high‐altitude environments, such as the Tibetan Plateau, must face harsh environmental conditions (e.g., hypoxia, cold, and strong UV radiation). These animals' physiological adaptations (e.g., increased red cell production and turnover rate) might also be associated with the gut microbial response. Bilirubin is a component of red blood cell turnover or destruction and is excreted into the intestine and reduced to urobilinoids and/or urobilinogen by gut bacteria. Here, we found that the feces of macaques living in high‐altitude regions look significantly browner (with a high concentration of stercobilin, a component from urobilinoids) than those living in low‐altitude regions. We also found that gut microbes involved in urobilinogen reduction (e.g., beta‐glucuronidase) were enriched in the high‐altitude mammal population compared to the low‐altitude population. Moreover, the spatial–temporal change in gut microbial function was more profound in the low‐altitude macaques than in the high‐altitude population, which might be attributed to profound changes in food resources in the low‐altitude regions. Therefore, we conclude that a high‐altitude environment's stress influences living animals and their symbiotic microbiota. [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]

Aims: Mountain environments have high biodiversity and face an accelerating plant invasion risk. Given the enormous ecological and economic value of these ecosystems, there is an urgent need to detect and rapidly respond to invasive species risk. Here, the Tibetan Plateau (TP) in China was selected to examine distribution patterns of invasive alien plants (IAPs) and propose management strategies. Location: The Tibetan Plateau in China. Methods: Based on native and non‐native occurrences of 123 IAPs alongside environmental variables, we assembled species distribution models and the MIGCLIM model to simulate suitable growth and dispersal areas under current climatic conditions. All IAPs were classified based on the predicted suitable area size, occurrence number and harm level to propose various management strategies. Results: There was a significant separation between the climate niches of most IAPs and the climatic conditions of the TP, meaning the areas suitable for most IAPs were limited to low latitudes and elevations. These areas also have further dispersal risks and risks for new IAPs being introduced. Among 123 IAPs, 23 species had above‐average occurrences and suitable distribution areas; in the remaining 100 occurrences and distributions, at least one IAP was less than the average. Main Conclusions: Suitable areas for IAPs in the TP are currently limited to low‐elevation regions, which are also at a higher risk of further expansion. Management measures should focus on potential high‐risk areas and diffusion pathways where IAPs can spread further. Efforts should prevent species that have not been established but have large potential suitable areas from being introduced, eradicate established IAPs with limited suitable areas, and control established IAPs. These results can provide a reference for developing more efficient and cost‐effective management strategies. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) has the largest number of high-altitude glaciers on Earth. As a source of major rivers in Asia, this region provides fresh water to more than one billion people. Any terrestrial water storage (TWS) changes there have major societal effects in large parts of the continent. Due to the recent acceleration in global warming, part of the water environment in TP has become drastically unbalanced, with an increased risk of water disasters. We quantified secular and monthly glacier-mass-balance and TWS changes in water basins from April 2002 to December 2021 through the Gravity Recovery and Climate Experiment and its Follow-on satellite mission (GRACE/GRACE-FO). Adequate data postprocessing with destriping filters and gap filling and two regularization methods implemented in the spectral and space domain were applied. The largest glacier-mass losses were found in the Nyainqentanglha Mountains and Eastern Himalayas, with rates of −4.92 ± 1.38 Gt a−1 and −4.34 ± 1.48 Gt a−1, respectively. The Tien Shan region showed strong losses in its eastern and central parts. Furthermore, we found small glacier-mass increases in the Karakoram and West Kunlun. Most of the glacier mass change can be explained by snowfall changes and, in some areas, by summer rainfall created by the Indian monsoon. Major water basins in the north and south of the TP exhibited partly significant negative TWS changes. In turn, the endorheic region and the Qaidam basin in the TP, as well as the near Three Rivers source region, showed distinctly positive TWS signals related to net precipitation increase. However, the Salween River source region and the Yarlung Zangbo River basin showed decreasing trends. We suggest that our new and improved TWS-change results can be used for the maintenance of water resources and the prevention of water disasters not only in the TP, but also in surrounding Asian countries. They may also help in global change studies. [ABSTRACT FROM AUTHOR]

The northeastern margin of the Tibetan Plateau is the youngest part of the Tibetan Plateau where tectonic activity is intense and climate change is complex. In this study, combined with field investigations, we explored accelerator mass spectrometry 14C and optically stimulated luminescence dating and palynological analysis of the sedimentary sequence in the Qingshuihe Basin to explain the origin of soft‐sediment deformation layer. Dating and palynological results from the Sanchahe section in the basin revealed a detailed history of vegetation variation and associated climate change from ∼18 to ∼5 ka BP. The results indicate that the permafrost developed at ∼18–11.7 ka BP, and the soft‐sediment deformation structures formed at ∼11.7–5 ka BP. Together with the characteristics of the deformation (meter‐scale, continuous symmetrical wave) and paleoclimate, we suggest that the soft‐sediment deformation layer in the late Pleistocene was cryoturbated under climatic conditions. The discovery of a series of cryoturbations in the Qingshuihe Basin has further enriched the regional distribution of periglacial phenomena in the west of the Ordos Plateau, expanded the distribution range of periglacial phenomena, and provided evidence for exploring the temporal and spatial changes in permafrost in northern China at the end of the late Pleistocene. [ABSTRACT FROM AUTHOR]

Environmental changes along an altitudinal gradient can facilitate the differentiation of life-history features in ectothermic species, but little attention has been devoted to the reciprocal influence of altitude and alpine slope directionality on life-history variation. According to life-history theory, increased environmental stress causes a change in reproductive allocation from number to quality of offspring, as well as a stronger trade-off between size and number of offspring. To clarify the influence of environmental pressures on the life-history features of the Qinghai toad-headed lizard Phrynocephalus vlangalii along an altitudinal cline, we surveyed late pregnant females from 3 populations of low (2,600 m), middle (3,400 m), and high (3,600 m) elevations in the Dangjin Mountain of Gansu, China from July to October 2019, and compared their inter-population differences in maternal body size, reproductive characteristics, offspring growth, and locomotor performance. Because of lower temperatures, higher humidity, and lower light intensity caused by slope aspect and altitude, the middle-altitude region experienced stronger environmental stress than the high- and low-altitude regions. Our results showed that females were larger at middle- and high-altitude sites and smaller at the low-altitude site, following Bergmann's rule. We also found that females from low-altitude population gave birth earlier than those from the middle and high altitudes. Our results showed a shift in the offspring size-number trade-off of P. vlangalii in response to colder and harsher environments, with lizards from the alpine steppe (i.e. the middle- and high-altitude habitats) producing fewer but larger offspring than those from the warm steppe (i.e. the low-altitude habitat). Low-altitude juveniles grew faster than high-altitude ones, but at the same rates as middle-altitude juveniles. This result demonstrates that the growth of P. vlangalii was associated with temperature and light intensity. Our findings contribute to enhancing our understanding of the altitudinal variation in life-history features of plateau ectotherms and their phenotypic plasticity or local adaptation. [ABSTRACT FROM AUTHOR]

The spring sensible heating (SSH) over the Tibetan Plateau (TP), which can significantly affect the precipitation in China, has experienced three different stages of change, showing significant increasing (1961–1979, Stage I), decreasing (1980–2002, Stage II), and increasing (2003–2014, Stage III) trends. In this study, the impact of these different trends in TP SSH on spring precipitation (SPR) in China and their possible mechanisms are investigated, based on observations and the reanalysis product. In Stage I, the SPR represents a contrasting north-south pattern associated with the increasing TP SSH, showing increasing trends over southern China and decreasing trends over central and northern China. Further, the spatial distribution of SPR trends shows a contrasting east-west pattern in Stage II. That is, persistent weakening TP SSH plays a more crucial role in increasing and decreasing SPR over southwestern and southern China, respectively. However, compared with the significant trend in SPR in Stage III, the regulation of TP SSH on SPR weakens significantly. Dynamically, the increasing TP SSH in Stage I can strengthen the subtropical westerly jet in the upper layer, simultaneously configured with an anomalous cyclone in northeastern China, which deepens the East Asian trough. Thus, anomalous convergence in the upper layer occurs over central and northern China, favoring the downdraft. It then causes more cold and dry air to move southward in the lower troposphere, which then encounters the warm and wet southwest airflows, boosting the updraft over southern China. In Stage II, regression analysis shows that if the TP SSH increases, an anomalous cyclone in the middle and upper troposphere occurs over the western TP, causing the downdraft and less precipitation over southwestern China, while a cyclone in the lower troposphere occurs over the western North Pacific and extends to southern China, promoting the ascending motions and more precipitation in southern China. However, in this stage, TP SSH actually weakens, thus contributing to more precipitation over southwestern China and less precipitation over southern China. [ABSTRACT FROM AUTHOR]

Previous studies have discovered arboreal pollen in non-forested areas on the Tibetan Plateau, which are mostly anemophilous type and regarded as a result of the Asian summer monsoon. However, the relationship between the spatial distribution of wind-pollinated pollen and monsoon has seldom been illustrated quantitatively. Here, we used 676 surface samples (647 compiled, 29 new samples) to examine the characteristics of the spatial distribution patterns of 13 anemophilous pollen taxa on the southeastern Tibetan Plateau, by employing the spatial interpolation technique. Then, we quantified the correlation between the distributions of these taxa and monsoon wind via Mantel test. The results show that the anemophilous pollen represents at least half percentage of the total pollen assemblages in most areas of the study region. Anemophilous tree pollen mainly distributes in the south and southeastern part, while anemophilous non-tree pollen does in the opposite and perpendicular direction. The distributional pattern of non-anemophilous pollen reflects that their corresponding plants most likely constitute the understory components of different forests or the minorities of non-forests communities. Mantel tests indicate that the anemophilous tree pollen has a highest correlation with the Asian summer monsoon. Anemophilous pollen, overall pollen assemblages and anemophilous pollen with air sacs have higher correlations with summer monsoon. Contrarily, non-anemophilous pollen has relatively weak correlation. Furthermore, we found that the relationships between various pollen groups or separate taxa and the Asian summer monsoon are dependent on sample types. The lake sediment surface samples had the strongest signal of the Asian summer monsoon among the different sample types. Our findings provide the strong evidence of the Asian summer monsoon influencing the pollen distribution patterns. More importantly, the quantification of this correlation between anemophilous tree pollen and the Asian summer monsoon offers the fundamentally theoretical basis of reconstructing paleo-monsoon by the proxy of windborne pollen taxa. [ABSTRACT FROM AUTHOR]

The knowledge about the chemical characteristics of organic aerosols in alpines were still limited. Fifty samples were collected in an alpine site in Tibetan Plateau during May 2015 and April 2016 to measure the concentrations of sugar and biogenic secondary organic aerosol (BSOA) compounds. The annual mean concentrations of anhydrosugar, primary sugars, and sugar alcohols in Mt. Gongga were 86.6 ± 43.1, 168 ± 40.0 and 204 ± 62.9 ng/m3, respectively. All of the anhydrosugars displayed the highest concentrations in winter, followed by spring, autumn, and the lowest ones in summer, which was contributed by dense biomass burning (BB) in winter. In contrast, nearly all of the primary sugar and sugar alcohol levels peaked in summer, which might be associated with the higher rates of vegetation growth and microbial metabolic activities during the warming season. The levels of BSOA tracers also suffered from markedly seasonal variations. The sesquiterpene SOA displayed the highest level in winter (27.3 ± 16.8 ng/m3), which might be associated with the biomass burning in the surrounding regions. However, most of the species of isoprene and monoterpene SOA tracers suffered from the higher levels in summer, which was contributed by the higher biogenic volatile organic compounds (BVOC) emission and reaction rates. Based on source apportionment result, BB (26%) was the dominant contributor to sugar and BSOA species in Mt. Gongga, followed by airborne pollen (24%), plant release (19%), soil emission (13%), fungal spore (9%), and isoprene oxidation (8%). The result of this study reveals mixed contributions of BB and vegetation emission promote the formation of biogenic organic aerosols in Tibetan Plateau. Plain Language Summary: Organic aerosols could influence atmospheric radiative forcing and climate change. The seasonal characteristics and major sources of sugars and BSOA tracers have been identified. Both of anhydrosugars and sesquiterpene SOA tracers showed the higher values in winter due to the impact of BB. Some primary sugars and isoprene/monoterpene SOA tracers suffered the higher levels in summer owing to the dense vegetation emission under the condition of high air temperature and solar radiation. Based on the source apportionment, BB was the dominant source. Our study clearly showed that mixed contributions of BB and vegetation emission promoted the formation of biogenic organic aerosols in Tibetan Plateau. Key Points: One‐year observation was performed in Mt. Gongga to reveal the temporal variations and source apportionment of ambient sugars and biogenic secondary organic aerosol (BSOA)Biomass burning was still the major source of atmospheric sugars in Mt. GonggaThe photochemical oxidation of biogenic volatile organic compounds (BVOC) might be major source of isoprene SOA tracers [ABSTRACT FROM AUTHOR]

Here, we analyze the characteristics and the formation mechanisms of low-level jets (LLJs) in the middle reaches of the Yangtze River during the 2010 mei-yu season using Wuhan station radiosonde data and the fifth generation of the European Centre for Medium-Range Weather Forecasts (ERA5) reanalysis dataset. Our results show that the vertical structure of LLJs is characterized by a predominance of boundary layer jets (BLJs) concentrated at heights of 900–1200 m. The BLJs occur most frequently at 2300 LST (LST=UTC+ 8 hours) but are strongest at 0200 LST, with composite wind velocities >14 m s−1. Synoptic-system-related LLJs (SLLJs) occur most frequently at 0800 LST but are strongest at 1100 LST, with composite wind velocities >12 m s−1. Both BLJs and SLLJs are characterized by a southwesterly wind direction, although the wind direction of SLLJs is more westerly, and northeasterly SLLJs occur more frequently than northeasterly BLJs. When Wuhan is south of the mei-yu front, the westward extension of the northwest Pacific subtropical high intensifies, and the low-pressure system in the eastern Tibetan Plateau strengthens, favoring the formation of LLJs, which are closely related to precipitation. The wind speeds on rainstorm days are greater than those on LLJ days. Our analysis of four typical heavy precipitation events shows the presence of LLJs at the center of the precipitation and on its southern side before the onset of heavy precipitation. BLJs were shown to develop earlier than SLLJs. [ABSTRACT FROM AUTHOR]

The summer precipitation over the southeastern Tibetan Plateau (SETP) exhibits significant diurnal variability, with a notable peak before midnight. This study investigates how thermally forced circulations regulate the diurnal precipitation over the SETP, using surface rain‐gauge observations and high‐resolution reanalysis data from June to August during 2015–2019. Water vapor supply and precipitation onset in the afternoon are associated with the upslope winds and upward motions of the mountain–plains solenoid (MPS) between the SETP and nearby lowlands (the Sichuan Basin and Yunnan–Guizhou Plateau). After sunset, the sustained easterly and stronger southerly winds below 500 hPa transport abundant moisture from the rainy lowlands to the SETP. The findings suggest that these winds are mainly due to the larger zonal continental‐scale thermally forced circulation combined with the meridional large‐scale MPS before midnight and the meridional small‐scale MPS after midnight. Plain Language Summary: The summer rainfall over the southeastern Tibetan Plateau (SETP) is crucial to the hydrological cycle of both the SETP and nearby regions. However, it remains unclear why the rainfall over the SETP mostly occurs at night due to limited observations. This study aims to investigate the role of thermally driven winds in diurnal rainfall during summer (June–August) over the SETP, using high‐resolution reanalysis data and surface rain‐gauge observations. The results show that the strong upward motions and low‐level upslope winds of the thermally forced mountain‐valley wind systems (MVWS) between the SETP and the lowlands (Sichuan Basin and Yunnan–Guizhou Plateau) help to trigger the precipitation and transport moisture in the afternoon. After sunset, thermally forced circulations, including the east–west continental‐scale thermal circulation between the Asian continent and its adjacent ocean, the north–south large‐scale MVWS between the Yunnan–Guizhou Plateau and its southern plain, and the north–south small‐scale MVWS between the SETP and its southern slope, help maintain horizontal winds from the rainy lowlands, transporting abundant moisture to facilitate the rainfall over the SETP at night. Key Points: Thermally forced circulations greatly impact the diurnal cycle of summer precipitation over the southeastern Tibetan Plateau (SETP)Daytime rainfall over this region is associated with the upward motions and upslope winds of the mountain–plains solenoidMulti‐scale thermal circulations are responsible for moisture transport of nighttime rainfall over the SETP [ABSTRACT FROM AUTHOR]

Background: Understanding the relationship between human evolution and environmental changes is the key to lifting the veil on human origin. The hypothesis that environmental changes triggered the divergence of humans from apes (ca. 9.3–6.5 million years ago, Ma) has been poorly tested because of limited continuous environmental data from fossil localities. Lufengpithecus (12.5-6.0 Ma) found on the southeastern margin of the Tibetan Plateau (SEMTP) across the ape–human split provides a good chance for testing this hypothesis. Results: Here, we reconstructed the habitats of L. keiyuanensis (12.5–11.6 Ma) with comprehensive vegetation, climate, and potential food web data by palaeobotanical evidence, together with other multidisciplinary data and partly tested the environment-driven hypothesis by revealing the living conditions of Lufengpithecus. Conclusion: A detailed comparison of hominoids on different continents reveals their behaviour and fate divergence across the ape–human split against the background of global climate change, i.e., the stable living conditions of SEMTP not only provided a so-called 'refuge' for arboreal Lufengpithecus but also acted as a 'double-edged sword', preventing their further evolution while vegetation shifts in East Africa probably stimulated the emergence of human bipedalism, and the intense climatic changes in Europe possibly prevented those hominoids from surviving that time interval. Our findings provide interesting insight into the environmental impacts on the behavioural evolution of hominoids. [ABSTRACT FROM AUTHOR]

The Daliang Shan is a tectonic unit that connects the active southeastern Tibetan Plateau with the stable South China block. As a newly generated (formed later than the Xianshuihe–Xiaojiang active fault system) seismotectonic zone induced by the Tibetan tectonics, the detailed constraints of the crustal deformation are central to the understanding of the kinematics and dynamics of the Tibetan expansion. This paper establishes and analyses a high-spatial resolution global positioning system (GPS) velocity field from a dense GPS network in this region. Our modelling results indicate that, in contrast to the equivalent sinistral strike-slip rate of approximately 5 mm yr–1 on the Anninghe–Zemuhe and Daliangshan faults, their inferred interseismic locking depth varies within a large range. The southern segment of the Anninghe Fault and the middle segment of the Daliangshan Fault have deep locking depths of ∼13 km, indicating that the seismic risk is high in these areas. In addition, the detectable counter-clockwise rotation rate of 0.35 ± 0.12° Myr–1 of the Mabian block makes a significant contribution of ∼50 per cent to the strike-slip motion on its boundary faults. This counter-clockwise rotation may be induced by a left-lateral shear gradient with southeastward motion relative to the South China-fixed reference frame, indicating the significance of a simple-shear pattern in exploring the kinematics of the encroachment of the Tibetan tectonics upon a stable block (craton). [ABSTRACT FROM AUTHOR]

Introduction: Fritillaria przewalskii Maxim. is a Chinese endemic species with high medicinal value distributed in the northeastern part of the Tibetan Plateau. F. przewalskii root-associated rhizosphere bacterial communities shaped by soil properties may maintain the stability of soil structure and regulate F. przewalskii growth, but the rhizosphere bacterial community structure of wild F. przewalskii from natural populations is not clear. Methods: In the current study, soil samples from 12 sites within the natural range of wild F. przewalskii were collected to investigate the compositions of bacterial communities via high-throughput sequencing of 16S rRNA genes and multivariate statistical analysis combined with soil properties and plant phenotypic characteristics. Results: Bacterial communities varied between rhizosphere and bulk soil, and also between sites. Co-occurrence networks were more complex in rhizosphere soil (1,169 edges) than in bulk soil (676 edges). There were differences in bacterial communities between regions, including diversity and composition. Proteobacteria (26.47-37.61%), Bacteroidetes (10.53-25.22%), and Acidobacteria (10.45-23.54%) were the dominant bacteria, and all are associated with nutrient cycling. In multivariate statistical analysis, both soil properties and plant phenotypic characteristics were significantly associated with the bacterial community (p < 0.05). Soil physicochemical properties accounted for most community differences, and pH was a key factor (p < 0.01). Interestingly, when the rhizosphere soil environment remained alkaline, the C and N contents were lowest, as was the biomass of the medicinal part bulb. This might relate to the specific distribution of genera, such as Pseudonocardia, Ohtaekwangia, Flavobacterium (relative abundance >0.01), which all have significantly correlated with the biomass of F. przewalskii (p < 0.05). Discussion: F. przewalskii is evidently averse to alkaline soil with high potassium contents, but this requires future verification. The results of the present study may provide theoretical guidance and new insights for the cultivation and domestication of F. przewalskii. [ABSTRACT FROM AUTHOR]

The 2021 Mw 7.4 Maduo (Madoi) earthquake that struck the northern Tibetan Plateau resulted in widespread coseismic deformation features, such as surface ruptures and soil liquefaction. By utilizing the unmanned aerial vehicle (UAV) photogrammetry technology, we accurately recognize and map 39,286 liquefaction sites within a 1.5 km wide zone along the coseismic surface rupture. We then systematically analyze the coseismic liquefaction distribution characteristics and the possible influencing factors. The coseismic liquefaction density remains on a higher level within 250 m from the surface rupture and decreases in a power law with the increasing distance. The amplification of the seismic waves in the vicinity of the rupture zone enhances the liquefaction effects near it. More than 90% of coseismic liquefaction occurs in the peak ground acceleration (PGA) > 0.50 g, and the liquefaction density is significantly higher in the region with seismic intensity > VIII. Combined with the sedimentary distribution along-strike of the surface rupture, the mapped liquefaction sites indicate that the differences in the sedimentary environments could cause more intense liquefaction on the western side of the epicenter, where loose Quaternary deposits are widely spread. The stronger coseismic liquefaction sites correspond to the Eling Lake section, the Yellow River floodplain, and the Heihe River floodplain, where the soil is mostly saturated with loose fine-grained sand and the groundwater level is high. Our results show that the massive liquefaction caused by the strong ground shaking during the Maduo (Madoi) earthquake was distributed as the specific local sedimentary environment and the groundwater level changed. [ABSTRACT FROM AUTHOR]

Lumbriculus variegatus is a typical cold-water worm and is mainly distributed in the Tibetan Plateau and Northeast in China. The current study aimed to explore the genetic diversity and phylogeography of L. variegatus sampled from different geographical regions based on concatenated (COI + 16S rRNA, 879 bp) genes. Among 63 L. variegatus specimens, 29 haplotypes were identified with high haplotype diversity (h = 0.923) and nucleotide diversity (π = 0.062). The Bayesian phylogenetic analysis and Median-joining haplotype network revealed two lineages, or species, of L. variegatus. Taxa belonging to lineage I was mainly distributed in the Tibetan Plateau of China, North America, and Sweden, while lineage II composed taxa from Northeast China, southern China, and Sweden. The analysis of molecular variance indicated that the genetic difference was mainly due to differences between lineages. Neutrality tests showed that the overall L. variegatus have a stable population since the time of origin. Divergence time analysis suggested that L. variegatus originated from the Triassic period of Mesozoic in 235 MYA (95%HPD: 199–252 MYA), and the divergence between different lineages of L. variegatus began from the next 170 million years. [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]

As a crucial variable in hydrological and climate modeling, a lot of efforts have been made to estimate the evaporation (E, including soil evaporation, canopy interception, and plant transpiration) on the Tibetan Plateau (TP). Most studies showed that the evaporation on the TP stops increasing or even decreases in the recent two decades. However, the spatio‐temporal variability of this phenomenon and its underlying mechanism remains uncertain. Here, we utilized a state‐of‐the‐art version of the sigmoid generalized complementary equation to estimate the monthly evaporation over the TP for the period of 1979–2018. The results show that the annual E increases significantly during 1979–1998 with a rate of 1.94 mm yr−1 (based on the total E over the TP), however, it decreases during 1999–2018 with a rate of −1.06 mm yr−1. The most significant decreasing trend of E occurs in the spring. The areas with the most significant decrement of E include the central and western Qiangtang Plateau, the middle reaches of Yarlung Zangbo River, and the Yangtze River basin. By introducing a new aridity index Rwe, we identified that the decrement of E mainly occurs in the water‐limited regions, which contribute to 60% of the total decreasing trend of the whole region; at the same time, the energy‐limited regions also contribute to 40% of the decreasing trend. This study is important for the hydrological researches and decision making because the trend of E can influence the water resources and agriculture. Plain Language Summary: Terrestrial (E) connects the water cycle and energy flow in the earth‐atmospheric system. A lot of studies have tried to estimate E on the Tibetan Plateau (TP). Most studies showed that the evaporation on the TP decreased in the recent two decades, but its underlying mechanism is not clear. In this study, we estimated the monthly evaporation over the TP using the sigmoid generalized complementary equation. We found that the annual E increases during 1979–1998, however, it decreases during 1999–2018. The decrement of E mainly occurs in the water‐limited regions (60%), but also in the energy‐limited regions (40%). The seasonal variation and spatial variation of E were further studied to explain the decrement of E in the recent two decades. Key Points: The high accuracy of the estimated E was validated at the site scale and basin scaleThe mean annual E increases during 1979–1998, however, decreases during 1999–2018The water‐limited regions contribute 60% to the decrement of E during 1999–2018 [ABSTRACT FROM AUTHOR]

A new, seasonal, laminated ice core pollen record spanning the last 13 years (2000--2012) from Zuoqiupu Glacier (5,600 m a.s.l.), located on the southeastern Tibetan Plateau (TP), reveals clear variations in pollen concentration and assemblage. A total of 117 continuous ice core layers were used for pollen analysis. Samples with high concentrations of Pinus and Tsuga could be identified as layers accumulated in spring, samples with high concentrations of Alnus and Artemisia could be identified as layers accumulated in autumn, and samples rich in herbaceous plant pollen could be regarded as layers deposited in summer. Three peaks of Tsuga pollen concentration accompanied by high Pinus content occurred in the spring of 2003, 2007, and 2010, which corresponded to wetter and warmer conditions modulated by the El Niño decaying phase (April--May in 2003, 2007, and 2010). Thus, pollen grains deposited on the Zuoqiupu Glacier can be used to study the impacts of atmospheric circulations on seasonal climate change over the southeastern TP. [ABSTRACT FROM AUTHOR]

Daluo Mountains lie at front of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau, and are the landform boundary zone between the active Tibetan Plateau and the stable North China Craton. Studying of the late Cenozoic uplift evolution of Daluo Mountains is important for understanding the expansion mechanism of the northeastern margin of the Tibetan Plateau and its influence on the western North China Craton. In this study, the late Cenozoic uplift of Daluo Mountains is constructed from the development of the late Cenozoic alluvial fan around Daluo Mountains. The entire sedimentary sequence and framework of the fan was revealed by the newly obtained drilling core data. The cosmogenic nuclide, optically stimulated luminescence, and detrital zircon U‐Pb dating results provide new evidences for discussion about the initial timing of the late Cenozoic uplift of Daluo Mountains and the key stages of uplift during the Pleistocene. The late Cenozoic alluvial fan at front of Daluo Mountains overlies a set of fluvial‐facies strata; therefore, development of the alluvial‐fan marks the start of late Cenozoic uplift of Daluo Mountains. The timing of this event can be constrained to ∼4.64 Ma. Two extensive gravel layers (dated to ca. 0.76–0.6 Ma and ∼0.05 Ma) developed during the Pleistocene, indicating two episodes of considerable uplift. This study provides a new time scale for the uplift and expansion of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Root-zone soil moisture (RZSM) is an important variable in land–atmosphere interactions, notably affecting the global climate system. Contrary to satellite-based acquisition of surface soil moisture, RZSM is generally obtained from model-based simulations. In this study, in situ observations from the Naqu and Pali networks that represent different climatic conditions over the Tibetan Plateau (TP) and a triple collocation (TC) method are used to evaluate model-based RZSM products, including Global Land Evaporation Amsterdam Model (GLEAM) (versions 3.5a and 3.5b), Global Land Data Assimilation System (GLDAS) (versions 2.1 and 2.2), and the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis (ERA5). The evaluation results based on in situ observations indicate that all products tend to overestimate but could generally capture the temporal variation, and ERA5 exhibits the best performance with the highest R (0.875) and the lowest unbiased RMSE (ubRMSE; 0.015 m3 m−3) against in situ observations in the Naqu network. In the TC analysis, similar results are obtained: ERA5 has the best performance with the highest TC-derived R (0.785) over the entire TP, followed by GLEAM v3.5a (0.746) and GLDAS-2.1 (0.682). Meanwhile, GLEAM v3.5a and GLDAS-2.1 outperform GLEAM v3.5b and GLDAS-2.2 over the entire TP, respectively. Besides, possible error causes in evaluating these RZSM products are summarized, and the effectiveness of TC method is also evaluated with two dense networks, finding that TC method is reliable since TC-derived R is close to ground-derived R, with only 6.85% mean relative differences. These results using both in situ observations and TC method may provide a new perspective for the soil moisture product developers to further enhance the accuracy of model-based RZSM over the TP. Significance Statement: The purpose of this study is to better understand the quality and applicability of GLEAM, GLDAS, and ERA5 RZSM products over the TP using both in situ observations and the triple collocation (TC) method, making it better applied to climate and hydrological research. This study provides four standard statistical metrics evaluation based on in situ observations, as well as the reliable metric, that is, correlation coefficient (R) derived from TC method, and highlights that TC-based evaluation could supplement the ground-based validation, especially over the data-scarce TP region. [ABSTRACT FROM AUTHOR]

Precipitation of future climate models is critical for the assessments of future drought but contains large systematic biases over the Tibetan Plateau. Although the common precipitation bias correction method, quantile mapping has achieved remarkable results in terms of temporal bias correction, it does not consider the spatial distribution of bias. Furthermore, the extent to which precipitation bias affects drought estimation remains unclear. In our study, we take the Qinghai–Tibet Plateau (QHTP) as the case study and quantify the impact of corrected precipitation bias for seven Coupled Model Intercomparison Project Phase 6 (CMIP6) models on drought assessment in historical and future scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). To improve the accuracy of drought prediction, potential evapotranspiration (PET) was also corrected. Firstly, the histogram matching-quantile mapping (HQ) algorithm considering spatial correction is established to correct precipitation and PET. Then, we quantified the effects of precipitation and potential evapotranspiration correction on the change of drought intensity, and finally analyzed the spatiotemporal trends of precipitation, PET, and SPEI over the QHTP in the future. The results show that the HQ method can effectively improve the simulation ability of the model, especially the simulation accuracy of the ensemble model. After correction, the average annual total precipitation (TP) declined by 64.262% in 99.952% of QHTP, the average PET increased in 11.902% of the area and decreased in 88.098% of the area, while the intensity of the drought in 81.331% of the area increased by 2.875% and the 18.669% area decreased by 1.139%. Therefore, the uncorrected simulation data overestimated the future increase trend in precipitation and underestimated the future decrease trend in SPEI. The trend of HQ-corrected TP increased by 3.730 mm/10a, 7.190 mm/10a, and 12.790 mm/10a, and the trend of SPEI (TP and PET corrected) decreased by 0.143/100a, 0.397/100a, and 0.675/100a, respectively. Therefore, quantifying the changing relationship between precipitation bias correction and drought assessments is useful for understanding regional climate change. [ABSTRACT FROM AUTHOR]

Black carbon in snow (BCS) has a significant impact on global climate and is an important component of Earth system modeling. Here, we provide a comprehensive evaluation of BCS simulations in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and its radiative forcing on a global scale. Overall, the multi-model mean generally captures the characteristics of BCS spatial patterns, with maximum concentrations in East Asia and the Tibetan Plateau (~120 ng·g−1), and the lowest in Antarctica (~0.05 ng·g−1). The BCS concentrations in all CMIP6 multi-model mean and individual models generally exhibit a temporally increasing trend globally, with particularly large increases after the 1940s. In terms of seasonal cycles, individual models are generally consistent in most regions. Globally, BCS concentrations are highest around January and lowest in September. The albedo reduction in the Tibetan Plateau and East Asia simulated by the CMIP6 multi-model mean reached ~0.06 in 2014 and may influence climate more than expected. [ABSTRACT FROM AUTHOR]

Soil moisture can be an important preceding signal in seasonal precipitation prediction because of its persistence and influence on the energy and water balance between land and atmosphere. The thawing process of frozen ground on the Tibetan Plateau (TP) during spring makes it difficult to accurately simulate soil variables (e.g., soil moisture and temperature) due to defective parameterizations in numerical models during spring. In this study, we investigate the effectiveness of soil moisture correction using an indirect nudging scheme to simulate the coupling between spring soil moisture and the subsequent precipitation with an advanced research version of the weather research and forecasting (WRF) model. The results without assimilation show that extreme cold and dry land surface states during spring cause a large bias in the spatial pattern of summer precipitation over almost the entire TP. However, the experiments with indirect assimilation in spring show that the spatial pattern of summer precipitation improved significantly. This comparison emphasizes the importance of correcting the spring soil moisture during the freeze–thaw period to significantly adjust the heat and water vapour exchange between the land and atmosphere. Additionally, changes in the circulation of the subtropical–tropical jet, vertical ascent, and region‐related moisture recycling can support an active convection environment over the eastern TP, thereby increasing summer precipitation. Furthermore, the pattern shift in water vapour convergence in summer highlights the regional horizontal transportation of water vapour. The differences between experiments with and without deep‐soil temperature nudging illustrate the significance of soil temperature in soil moisture simulation in the freeze–thaw process. More so, the deep‐soil temperature nudging scheme requires in‐depth studies to correct its variation and quantify its degree of impact on soil moisture. [ABSTRACT FROM AUTHOR]

Simple Summary: Yaks are important for the economy and livelihood of local herders in the Tibetan Plateau and are their primary source of income. Traditionally, the production performance of ruminants is generally improved by increasing the proportion of concentrate feed in the diet. To the best of our knowledge, the optimal proportion of concentrate feed is limited in actual production and research of yak. This study fed three diets with different dietary forage-to-concentrate ratios (50:50, 65:35, and 80:20) to 36 male yaks (Bos grunniens). The changes in the distribution of fecal microorganisms were studied by 16S rRNA gene sequencing and liquid chromatography–mass spectrometry. We found that the dietary forage-to-concentrate ratio significantly impacted yak fecal microorganisms. As such, these studies help us understand the fecal microbiota of yaks, further provide more complete information on the requirements of yak diets in terms of concentrate-to-forage ratio and improve yak growth performance, and provide a theoretical basis for accurate housing of yaks. (1) Background: This study aimed to investigate the effects of different dietary concentrate to roughage ratios on growth performance and fecal microbiota composition of yaks by 16S rRNA gene sequencing. (2) Methods: In the present study, three diets with different dietary forage-to-concentrate ratios (50:50, 65:35, and 80:20) were fed to 36 housed male yaks. (3) Results: The result shows that Final BW, TWG, and ADG were higher in the C65 group than in the C50 and C80 groups, but the difference was not significant (p > 0.05). DMI in the C65 group was significantly higher than in the other two groups (p < 0.05). The DMI/ADG of the C65 group was lower than that of the other two groups, but the difference was insignificant (p > 0.05). At the phylum level, Firmicutes were the most abundant in the C65 group, and the relative abundance of Bacteroidetes was lower in the C65 group than in the other two groups. At the genus level, the relative abundances of Ruminococcaceae_UCG_005, Romboutsia, and Christensenellaceae_R-7 were higher in the C56 group than in the C50 and C80 groups. The relative abundance of Lachnospiraceae_NK3A20 and Rikenellaceaewas_RC9_gut is lower in the C65 group, but the difference was insignificant (p > 0.05). At KEGG level 2, the relative abundance of lipid metabolism and energy metabolism were lowest in the C50 group, and both showed higher relative abundance in the C65 group. (4) Conclusions: In conclusion, the structure of fecal microbiota was affected by different concentrate-to-forage ratios. We found that feeding diets with a concentrate-to-forage ratio of 65:35 improved yaks' growth and energy metabolism. [ABSTRACT FROM AUTHOR]

The north‐eastward extrusion of the Tibetan Plateau has always been under debate. The arcuate tectonic belt is located at the north‐east margin of the Tibetan Plateau and bears crucial information about the tectonic and geomorphic evolution of north‐east Tibetan Plateau. Combined with sedimentary sequence, detrital zircon U–Pb geochronology, and heavy mineral combinations, significant provenance transformation can be determined both in the south‐west and north‐east of the arcuate tectonic belt during the Eocene to Miocene. The far‐field effect of north‐eastward extrusion of the Tibetan Plateau first arrived at the south‐west of the arcuate tectonic belt during the Miocene and resulted in the angular unconformity between the Eocene Qingshuiying period and Miocene Zhangenbao Formation. Then the regional exhumation spread from south‐west to north‐east across the arcuate tectonic belt, and sedimentary hiatus developed between the Miocene Zhangenbao period and Pliocene Ganhegou period. Therefore, tectonic uplift and mountain building of the arcuate tectonic belt expanded north‐eastward during the Eogene to Neogene. This research shed new insights on the north‐eastward extrusion of the Tibetan Plateau from the coupling relationship between basin and range. [ABSTRACT FROM AUTHOR]

• Warming does not alter aboveground net primary productivity (ANPP) regardless of grassland degradation, but degradation reduces it. • Warming does not alter net ecosystem carbon change (NEE) regardless of grassland degradation. • There are no interactions between warming and degraded grassland on plant composition, ANPP and NEE. • Warming neither accelerates degradation of alpine grasslands nor promotes restoration of degraded alpine grasslands. It is still debated whether warming induces degradation of alpine grasslands and whether warming accelerates the restoration of degraded alpine grasslands. Here we conducted a warming experiment using open top chambers to explore warming effects on plant composition and diversity, aboveground net primary productivity (ANPP) and net ecosystem carbon exchange (NEE) in alpine grassland at three degradation levels (i.e., no-degradation, moderate degradation and desertification) on the Tibetan Plateau from 2014 to 2016. There were no interactive effects between warming and degradation level on the variables measured in our study, except for plant diversity. Warming enhanced plant species diversity at no-degradation sites but had no significant influence on species diversity at sites of moderate degradation and desertification. Generally, warming alone had no significant effects on ANPP or seasonal average NEE during the experimental period, but its effect on them varied with year. In addition, compared with non-degraded sites, heavy degradation decreased ANPP by 35.8%, 44.2% and 63.8%, and reduced NEE by 71.8%, 63.4% and 70.3% in 2014, 2015 and 2016, respectively. The effects of moderate degradation on ANPP and NEE varied with year, enhancing ANPP by 37.3% and 37.7% in 2015 and 2016, but moderate degradation had no remarkable influence on seasonal average NEE compared with non-degraded sites. These results suggest that warming neither accelerates degradation of alpine grasslands nor promotes restoration of degraded alpine grasslands on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The roles of plateau pika (Ochotona coronae) in the Tibetan Plateau are often controversial, because it is often regarded as a destructive pest or an ecosystem engineer. Here a meta-analysis using 72 paired observations was conducted to examine whether the impacts of plateau pika on environmental quality (i.e., plant and soil properties) depend on population density in the Tibetan Plateau. Pika population density was used as a proxy for disturbance intensity. The pika disturbance intensity was divided into five groups based on the number of burrows, including low disturbance intensity (LD) (9–30 burrows per ha), medium disturbance intensity (MD) (31–100 burrows per ha), high disturbance intensity (HD) (101–170 burrows per ha), extreme disturbance intensity (ED) (171–240 burrows per ha) and uncontrolled (or excessive) disturbance intensity (UD) (>241 burrows per ha). Given that sample sizes in some of the groups are small (especially for the HD), we further pooled the disturbance groups including the LD–MD and HD–UD. Overall, relative to control (i.e., no disturbing), there was a great increase (80.3%) in aboveground biomass under the LD–MD, whereas a decrease of 41.1% occurred under the HD–UD. At the same time, plant coverage, species richness, height, and belowground biomass greatly decreased only in the HD–UD. Furthermore, the effect size of plant coverage, species richness, and aboveground biomass also declined with pika burrow density significantly. With regard to soil properties, there was a significant increase in soil organic carbon, ammonium nitrogen, and soil organic carbon stock under the LD–MD, whereas a decrease under the HD–UD. In addition, soil total nitrogen, total potassium, and nitrate nitrogen increased at the LD–MD and HD–UD. Nevertheless, the effect size of these soil properties (with >20 observations) was not related to pika burrow density. In summary, there is an implication that the low and moderate disturbance of pikas is beneficial to maintain and promote ecosystem functioning in the Tibetan grasslands. In the future pikas' eradication policy should be reconsidered in alpine grassland management. • Low and medium pika disturbance increased aboveground mass and soil organic carbon. • Species richness and aboveground mass reduced if pika disturbance was above medium. • The pika eradication policy should be reconsidered. [ABSTRACT FROM AUTHOR]

Preferential flow (PF) through soil and regolith results in a rapid vertical and lateral water movement within the profile. This study focused on quantifying PF in contrasting forested hillslopes of the Hailuo Valley, located on China's east Tibetan Plateau. Quantifying PF in this region is challenging since the underlying matrix is complex, with shallow soils, thick underlying saprolite, and the combined effect of moraines and weathered residual material. We developed new methods that integrated dye tracing with a high‐frequency soil moisture monitoring network to characterise PF pathways and quantity PF frequency on contrasting forested hillslopes (coniferous and broadleaved). Dye tracing experiments showed that soil‐root interfaces in the upper soil layer (10–50 cm) and soil‐rock interfaces in the deeper soil layer (50–100 cm) were the primary PF pathways and that large rocks strongly influence the percolation depth of water. The high‐frequency soil moisture network revealed that the mean PF frequency was 67.8% and 71.7% in the coniferous and broadleaved forests, respectively. The frequency of PF in the deeper soil layer increased from upslope to the downslope locations on both forested hillslopes, highlighting the tendency for PF to occur downslope. In addition to matrix conditions (e.g., stony saprolite soil), the total amount and maximum intensity of precipitation (as throughfall in this study) were identified as factors that control PF occurrence. In contrast, the initial soil water conditions (at 10, 50 and 100 cm depth) were insignificant in predicting PF occurrence. Results of this field‐based study highlight that PF is a ubiquitous and critical subsurface flow mechanism that regulates rainfall‐runoff relationships in forests of the Tibetan Plateau, underscoring the need to consider PF in hillslope hydrological modelling. Highlights: Combined dye tracing and soil moisture monitoring network were applied to explore PF on forested hillslopes.Root networks and rock fragments constituted the main PF paths.PF frequency increased from upslope to downslope in two forest types.Initial soil moisture conditions showed no controlling effect on PF occurrence. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) has unique atmospheric dynamics and thermal structures that originate from its giant terrain and complex climate. High vertical-resolution thermal radiosondes were launched near the central (Lhasa, 91°06′E, 29°36′N, 3670 m above sea level (ASL)) and marginal (Da Qaidam, 95°21′E, 37°51′N, 3180 m ASL) areas of the TP during the summers of 2018 and 2020, respectively. Atmospheric turbulence parameters were calculated, and the characteristics of the atmospheric turbulent vertical structure at sunset in these two areas were analyzed and compared. Affected by TP thermal forcing and stably controlled by the summer monsoon anticyclone, the atmospheric refractive index structure constant (Cn2) tended to increase and then decrease with increasing height, reaching a maximum at the tropopause (∼18 km ASL) at the Lhasa site. Although Cn2 at the Da Qaidam site also tended to increase at the tropopause, the position of the strong turbulent band (STB) (5–7 km ASL) was below the tropopause height corresponding to the potential temperature lapse rate minimum. The vertical distribution of Cn2 at the two sites, particularly regarding the position of the STB, was highly correlated with the atmospheric stability (Ri) and the thermal mixing scale (LT). The significant correlations among the three parameters (STB, Ri, and LT) indicated that the strong fluctuations in temperature caused by thermal mixing were the dominant factor causing the Ri to be less than its critical value of 0.25. Moreover, the suppression strength involving the upward transport of the heat sources was the main reason for the different turbulent vertical structures and STB positions at the two sites. The zonal mean thermodynamic and dynamical fields derived from the reanalysis data also showed a height difference in the heat sources transported to the troposphere at the two sites. In the marginal TP, the material and energy in the lower troposphere were transported by the turbulent atmosphere upward along the slope of the mountain and converged at the central TP (28°N–35°N) with strong thermal forcing up to the tropopause. In the STB of the Lhasa site, the turbulent dissipation rate and eddy diffusion coefficient increased sharply, indicating that the turbulent atmosphere in this central site was highly diffused, and the small-scale turbulence transported the material and energy upward. [ABSTRACT FROM AUTHOR]