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Inherent biases in numerical simulation models of global climate models (GCMs) reduce the scope for accurately assessing future droughts under multimodel ensemble. The aim of this research is to increase the efficiency of multimodel ensembles. Consequently, this paper introduces a two-way hybrid weighting scheme for ensembling multiple GCMs. The proposed weighting scheme enhances the coherence of the multimodel ensemble of climate model simulations with real observed data and minimizes the impact of non-identical seasonal behavior in climate simulations within the multimodel ensemble. In the application, we consider precipitation data from 18 GCMs of CMIP6 from the Tibet Plateau region. To evaluate the effectiveness of the proposed scheme, we compared the proposed ensemble data with simple model averaged (SMA) ensemble using the Pearson product-moment correlation coefficient (r), root mean squared error (RMSE), and mean absolute error (MAE). Furthermore, we assessed the future characteristics of various drought categories using the steady-state probabilities of a Markov Chain. Small values of errors metircs and high correlation indicate that the proposed hybrid weighting scheme exhibits better performance than the SMA. Under the proposed index, the long term probabilities of various drought classe show variations across different time scales of drought. These results provide perspectives on how the the long term probabilities of various drought categories evolve over time. [ABSTRACT FROM AUTHOR]

Tibetan Buddhism has an inseparable connection with the spatial characteristics, development process, and human-natural environment of the Tibetan Plateau. This paper takes monasteries as carriers of Tibetan Buddhist culture in U-Tsang region which is one of the traditional geographical units of Tibet. Using geospatial analysis methods, this study explores the spatial quantification characteristics of Tibetan Buddhist monasteries and qualitatively and quantitatively analyzes the factors that influence the spatial distribution of monasteries. The results indicate that: (1) Political activities of human society influence the pattern of political power. Under the unique context of Tibetan theocracy system, the scope of political authority has a significant influence and affects the religious spatial pattern in the U-Tsang region throughout history. The distribution of monasteries in the U-Tsang region shows significant spatial differences at three sub-regional scales. (2) The religious spatial pattern in the U-Tsang is the result of the diverse interaction of human-natural factors. The results indirectly endorse that religious space is an inevitable product of the interaction between humans and the environment. (3) The religious spatial distribution patterns in the three major Tibetan regions have distinct characteristics, closely related to the superior conditions of their respective historical and geographical environments. [ABSTRACT FROM AUTHOR]

This paper reports lithium concentrations and isotopic compositions of olivines in the oceanized subcontinental lithospheric mantle (SCLM) peridotites of the Tibetan Yunzhug ophiolite. The results show systematic Li isotope changes with distance from the rim of olivine grains. δ7Li values of olivine in dunites decrease from + 10.46 to + 1.33‰ with increasing distance to olivine rim from 26.15 to 124.71 μm. A negative correlation of δ7Li and Li content in olivine from dunite and harzburgite indicates recent diffusive ingress of Li into the peridotites. The extremely heavy Li isotopic composition requires the seawater or seawater alteration endmember in the mixing model, and reveals Li diffusion from seawater into olivine. As in dunites, olivines in a harzburgite sample show similar variations in δ7Li as a function of distance from the grain rim (e.g., 6.01 to 1.73 in sample 14YZ13). We suggest that the behavior of Li in the oceanized SCLM peridotites may be controlled by Li diffusion from seawater, as Li activity in the liquid state is higher than the solid state in transporting Li through the olivines in the peridotites. This study supports that seawater Li diffusion is one of the important factors for the heterogeneity of mantle Li isotopes in ophiolites. [ABSTRACT FROM AUTHOR]

This paper reports lithium concentrations and isotopic compositions of olivines in the oceanized subcontinental lithospheric mantle (SCLM) peridotites of the Tibetan Yunzhug ophiolite. The results show systematic Li isotope changes with distance from the rim of olivine grains. δ7Li values of olivine in dunites decrease from + 10.46 to + 1.33‰ with increasing distance to olivine rim from 26.15 to 124.71 μm. A negative correlation of δ7Li and Li content in olivine from dunite and harzburgite indicates recent diffusive ingress of Li into the peridotites. The extremely heavy Li isotopic composition requires the seawater or seawater alteration endmember in the mixing model, and reveals Li diffusion from seawater into olivine. As in dunites, olivines in a harzburgite sample show similar variations in δ7Li as a function of distance from the grain rim (e.g., 6.01 to 1.73 in sample 14YZ13). We suggest that the behavior of Li in the oceanized SCLM peridotites may be controlled by Li diffusion from seawater, as Li activity in the liquid state is higher than the solid state in transporting Li through the olivines in the peridotites. This study supports that seawater Li diffusion is one of the important factors for the heterogeneity of mantle Li isotopes in ophiolites. [ABSTRACT FROM AUTHOR]

Changes in patterns of meteorological parameters, like precipitations, temperature, wind, etc., are causing significant increases in various extreme events. And these extreme events, i.e., floods, heatwaves, hurricanes, droughts, etc., lead to a shortage of water resources, crop failures, wildfires, and economic losses. However, Global Circulation Models (GCMs) are considered the most important tools for quantifying climate change. Therefore, we selected 20 different GCMs of precipitation in our research, as the frequency of extreme events, like drought and flood, is highly related to changes in precipitation patterns. However, this research introduced a new weighting scheme — MCFSAWS-Ensemble: Monte Carlo Feature Selection Adaptive Weighting Scheme to Ensemble multiple GCMs, whereas, Monte Carlo Feature Selection (MCFS) is one of the most popular algorithms for discovering important variables. However, the proposed weighting scheme (MCFSAWS-Ensemble) is mainly based on two sources. Initially, it evaluates the prior performance of each GCM model to define their relative importance using MCFS. Then, it computes value by value difference between the observed and simulated model. In addition, the application of this paper is based on the monthly time series data of precipitation in the Tibet Plateau region of China. In addition, we used twenty GCMs from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to analyze the implications of the MCFSAWS-Ensemble. Further, we compared the performance of the MCFSAWS-Ensemble scheme with Simple Model Averaging (SMA) through Mean Average Error (MAE) and correlation statistics. The results of this research indicate that the proposed weighting scheme (MCFSAWS-Ensemble) is more accurate than the SMA approach. Consequently, we recommend the use of advanced machine learning algorithms such as MCFS for making accurate multi-model ensembles. [ABSTRACT FROM AUTHOR]

A systematic understanding of the spatio-temporal changes and driving factors in the Qinghai-Tibet Plateau holds significant scientific reference value for the future of ecological sustainable development. This paper utilizes MODIS normalized difference vegetation index (NDVI) and meteorological data to investigate the spatio-temporal changes and driving factors of vegetation coverage in the Qinghai-Tibet Plateau from 2001 to 2020. Methods employed include the dimidiate pixel model, trend analysis, partial correlation analysis, and residual analysis. The results demonstrate a generally fluctuating upward trend in vegetation coverage across the Tibetan Plateau over the past two decades, with spatial expansion occurring from northwest to southeast. Vegetation coverage exhibits a positive correlation with climate factors. Approximately 60.7% of the area showed a positive correlation between vegetation fractional cover (FVC) and precipitation, with 8.66% of the area demonstrating extremely significant (p < 0.05) and significant (p < 0.01) positive correlation. Human activities, on the whole, have contributed to the enhancement of vegetation cover in the Qinghai-Tibet Plateau. The areas where human activities have positively impacted vegetation cover are primarily situated in north-central Qinghai and north of Ngari, while areas experiencing degradation include certain grassland regions in central-eastern Yushu, Nagqu, and Lhasa. [ABSTRACT FROM AUTHOR]

The Bayan Har Basin is an important part of the Tethys tectonic in the Tibet Plateau. There are various conjectures regarding the basement and tectonic attributes of the Bayan Har Basin. Based on the aeromagnetic anomaly characteristics in the Bayan Har Basin, the structural units and fault system are derived, and the basement composition and structural attributes are discussed in this paper. We draw the following conclusions: (1) The Bayan Har Basin and its adjacent regions can be divided into five magnetic structural units, consisting of the southern Tarim Block, the Qiangtang Block, the western Yangtze Block, the Qinling–Qiliang–Kunlun Orogenic Belt and the Bayan Har Basin. (2) The Muztagh–Kunlun–A'nyêmaqên suture zone and the Xijir Ulan–Yushu–Jinsha River suture zone are the basic frameworks of the north–south division of the basin. (3) The basement in the eastern Bayan Har Basin is composed of Proterozoic metamorphic rocks, and the basement in the western and central basin is composed of Meso–Neoproterozoic metamorphic rocks. (4) The Triassic tectonic attribute of the Bayan Har Basin may be foreland basin. [ABSTRACT FROM AUTHOR]

In this paper, a depth-averaged numerical model is proposed to simulate the propagation of debris flows. To understand the dynamical features of debris flows, the granular-liquid mixture model is employed, where the resistance of liquid constituent consisting of water and fine particles is described by Herschel-Bulkley rheology, and the resistance of granular constituent involving the coarse particles is formulated by the Voellmy model. An Eulerian leapfrog finite difference scheme is employed to numerically solve the governing equations of debris flows. Several idealized dam break problems are numerically implemented to test the accuracy and stability of the numerical scheme, and good agreement with the analytical solutions is found. Furthermore, the experiment carried out by Iverson (2010) is numerically implemented in this study to validate the proposed model, and the results are in good agreement. Then, a typical debris flow in Tianmo gully in Tibet, China, is numerically analyzed based on the proposed model. The results show that several details of the motion of debris flows over a real terrain can be accurately predicted by the proposed model. The comparisons between the basal Coulomb friction model and the Voellmy model show that the mobility of debris flows can be overestimated when only the Coulomb friction model is employed. An analysis based on the unsteady motion of a uniform mass indicates that Voellmy resistance can rescue the issue in regard to the absence of resistance of the granular component due to fully liquefied states. Finally, the influence of the rheology of liquid slurry on the motion of debris flows is analyzed, and the results demonstrate that the basal resistances caused by the liquid slurry were very small relative to the basal resistances caused by granular constituent. [ABSTRACT FROM AUTHOR]

Drought is one of the most complex natural hazards. Therefore, precise drought monitoring and forecasting are the biggest tasks for hydrologists and environmentalists. Under grid data structure, this paper provides a new drought index—the adaptive standardized precipitation index (ASPI), for the evolution of drought, inferring its spatio-temporal patterns and detecting trends. The methodology of the proposed index is based mainly on dynamic time warping clustering algorithm and dynamic principal components. Historical simulated precipitation data from the Australian community climate and earth-system simulator model of coupled model intercomparison project 6 of 727 grid points scattered around the Tibet Plateau has been considered. Results show that as the time scale increases, the severe and extreme drought trends have increased significantly. Further, the significant decreasing magnitude in ASPI reveals the persistence of future drought in the Tibet Plateau region. From a data mining point of view, the outcomes associated with this research recommend the endorsement of ASPI for effective and precise drought monitoring under grid data structure. [ABSTRACT FROM AUTHOR]

Deep underground rock tunnels and caverns in mountainous areas are often subjected to the coupling impacts of high geo-stresses and high-ground temperature that can threaten the stability of rock masses. This paper presents an experimental study of strength, deformation, and failure as well as energy evolution characteristics for rockburst potential evaluation of granite under the influence of coupled high confining pressure and ground temperature using a series of triaxial compression tests with samples drilled from a borehole about 1000 m in the depth of a mountain tunnel in Tibet area. Three representative confining pressures (20, 40, and 60 MPa) and four typical temperatures (30, 60, 90, and 120 ℃) around the engineering range were inspected according to the previous tunnel site investigations. The strength and deformability of the granite samples were analyzed under the influence of coupled high confining pressure and temperature. An energy storage index is introduced to discuss rockburst potential of the granite under thermal–mechanical coupled conditions. It is found that high-ground temperature leads to degradation of mechanical properties of the granite samples, while high pressure increases its strength and deformability. In addition, the high pressure and ground temperature couplings increase both the energy storage capacity and rockburst potential, with 60–90 ℃ being the strengthening range. The findings are beneficial to understanding the behavior of surrounding rock masses, the evaluation of its stability, and rockburst potential for deep underground tunnels in areas with high in-situ stress and ground temperature. Highlights: Mechanical and energy evolution behaviors of granite were reported under thermal-mechanical coupled conditions. Rockburst potential of granite under thermal-mechanical coupled conditions was evaluated by an energy index. Granite strength decreased with increasing temperature with 60–90 ℃ being the strengthening range of rock potential. [ABSTRACT FROM AUTHOR]

Central Tibet constitutes part of the central part of the Qinghai–Tibetan Plateau, which is one of the highest seismically active areas in China. This paper discusses the regularity of seismic activity in this area. Based on a stratified viscoelastic earth model, we calculated the Coulomb stress changes imparted from four strong earthquakes (M ≥ 6.3) along the Bengco–southeastern piedmont of the Nyainqentanglha mountain fault zone in this region. The result shows that the study area may be entering a new active period from 2020. There was a trigger between the strong earthquakes (M ≥ 6.3) on the Bengco fault zone. The post-seismic viscous relaxation effect of a strong earthquake had a significant impact on subsequent earthquakes (M ≥ 6.3). In the next 100 years, the Coulomb stress loading is more than 1.0 MPa in the northwest section of the Bengco fault and the central part of Nimu segment of the southeastern piedmont of the Nyainqentanglha mountain fault. Thence, strong earthquakes may occur along these fault segments. The maximum magnitude of the earthquake could be M6.7 in the next 100 years. [ABSTRACT FROM AUTHOR]

Terminalia chebula Retz. (Fam. Combretaceae), commonly called black or chebulic myrobalan, is a species of Terminalia. In Tibet, T. chebula is called the "King of Medicine". It is well known as 'Haritaki' since it can be used to cure all kinds of diseases and is considered sacred to God Siva (Hara). The whole plant possesses high medicinal value. The aim of this article is to review the available scientific information regarding traditional uses, bioactive chemical constituents, and pharmacological activities of T. chebula based on in vitro and in vivo studies. First, in this paper, the studies published on T. chebula from 1980 to 2022 were reviewed, and the biological activity and mechanisms of action of T. chebula were evaluated based on in vitro and in vivo studies. T. chebula presented anti-diabetic, anti-hyperlipidemic, antioxidant, hepatoprotective, neuroprotective, anti-inflammatory, anti-arthritic, gastroprotective, anti-microbial, antiparasitic, wound healing, and anti-aging activities. Thus, this review suggests potential applications of T. chebula in nutraceuticals, functional foods, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

On June 25, 2020, Jinweng Co in Yiga, Tibet, experienced an outburst flood that resulted in catastrophic damage to farmland and roads. The complex causal factors for glacial lake outburst flooding (GLOF) are not fully understood. This paper provides a systematic analysis of the contributing factors leading to the GLOF disaster in terms of meteorological triggering, glacial activity, lake expansion, landslide, and glacial collapse. The analysis is based on multi-source remote sensing approaches. Pixel offset tracking of Sentinel-1 images shows changes in the glacier flow velocity from 2017 to 2020. Sentinel-2 and Landsat-8 images and inventory data have revealed the expansion of the lake since 1998. The satellite precipitation measurements revealed that the highest daily rainfall in recent years occurred approximately 4 days before the GLOF. Time series synthetic aperture radar (SAR) backscattering images and interferograms suggest that a landslide had occurred from the western lateral moraine into the lake. Additionally, SAR images suggest possible ice collapse from the glacier tongue into the lake. The causal mechanism for the June 2020 GLOF event was likely the dam failure triggered by heavy rainfall and combined with landslides and ice collapses. Our research can provide a reference to identify and mitigate glacial lake outburst disasters in mountainous regions based on satellite optical and radar images. [ABSTRACT FROM AUTHOR]

Monte Carlo simulations have been performed to study the effects of near-earth thunderstorms electric field on the showers with different zenith angle ranges. A vertical and uniform atmospheric electric field model is used in our simulations. The counting rates of ground cosmic rays at YBJ (located at YangBaJing, Tibet, China, 4300 m a. s. l.) are found to be associated with the strength and polarity of the electric field. The variations are also strongly dependent upon the shower's zenith angle and the distance to shower core. During thunderstorms, when the distance to shower core is less than a certain value (4 m in −1000 V/cm and 40 m in +1000 V/cm), the counting rates decrease as the distance to shower core decreases, and the decreased amplitude becomes larger with the increasing zenith angle and electric field strength, especially for that in positive fields (i.e., fields accelerating positive charges downwards). As the distance to shower core increases, an increase of ground cosmic ray intensity occurs, and the enhanced amplitude becomes lager with smaller zenith angles. However, when the distance to shower core is large enough (320 m in −1000 V/cm and 540 m in +1000 V/cm), the enhanced amplitude increases with the increasing zenith angle as well as the rising strength of the electric field. A clear relationship between the intensity variations of the ground cosmic rays from showers with different zenith angle ranges and the distances to shower core in fields is given in this paper. Our simulation results are beneficial to understand the flux variations obtained by ground-based cosmic ray detectors with scaler mode and shower mode, as well as the acceleration mechanisms of secondary charged particles caused by an atmospheric electric field. [ABSTRACT FROM AUTHOR]

The accuracy of passive satellite cloud top height (CTH) retrieval shows regional dependence. This paper assesses the CTH derived from the FY-4A and Himawari-8 satellites through comparison with those from the ground-based millimeter radar at two sites: Yangbajing, Tibet, China (YBJ), and the Institute of Atmospheric Physics (IAP), Beijing, China. The comparison shows that Himawari-8 missed more CTHs at night than FY-4A, especially at YBJ. It is found that the CTH difference (CTHD; radar CTH minus satellite CTH) for FY-4A and Himawari-8 is 0.06 ± 1.90 km and −0.02 ± 2.40 km at YBJ respectively, and that is 0.93 ± 2.24 km and 0.99 ± 2.37 km at IAP respectively. The discrepancy between the satellites and radar at IAP is larger than that at YBJ. Both satellites show better performance for mid-level and low-level clouds than for high-level clouds at the two sites. The retrievals from FY-4A agree well with those from Himawari-8, with a mean difference of 0.08 km at YBJ and 0.06 km at IAP. It is found that the CTHD decreases as the cloud depth increases at both sites. However, the CTHD has no obvious dependence on cloud layers and fractions. Investigations show that aerosol concentration has little impact on the CTHD. For high and thin clouds, the CTHD increases gradually with the increase of the surface temperature, which might be a key factor causing the regional discrepancy between IAP and YBJ. [ABSTRACT FROM AUTHOR]

To evaluate rockbursts in deep-lying long tunnels, a multiple factor analysis and predictions were conducted. It is necessary to establish whether the primary evaluation indexes cover the entire development–occurrence–evolution process for rockbursts and how best to determine the weights of the final selected indexes. We developed an evaluation model with attribute reduction and chose 5 out of 11 primary evaluation indexes to cover the typical characteristics of energy storage, rockburst proneness, and risk of failure. The weights of the primary evaluation indexes and the offset distance were then determined using the entropy weight ideal point method. Combining geostress field inversion and rock mechanic tests, the evaluation model was applied to the case of the Sangzhuling Tunnel along the Sichuan–Tibet railway. Rockburst prediction results achieved 41.2% and 94.1% accuracy when using the Manhattan and Euclidean distance functions, respectively. A more specific classification of the evaluation indexes may optimize the weight assignment and help obtain more accurate results. This paper provides a reliable method for rockburst predictions for hard rock and deep-lying long tunnels, which may have good prospects for engineering applications. [ABSTRACT FROM AUTHOR]

Y-chromosome-specific short tandem repeat loci (Y-STRs) are commonly analysed in forensic science for paternity testing, familial searches, and, in sexual assault cases, to determine male DNA identity from mixed sources with high background female DNA content. The Microreader 40Y ID System is a six-dye multiplex amplification kit that contains 17 Y-STR loci from the Yfiler Plus PCR Amplification Kit and the powerplex Y23 system (DYS19, DYF385a/b, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS549, DYS635(Y GATA C4), DYS643, Y GATA H4, DYS460, DYS481, DYS533, DYF387S1, DYS449, DYS518, DYS570, DYS576, and DYS627), plus six high polymorphic loci (DYS444, DYS447, DYS557, DYS596, DYS527 a/b) as well as 4 additional candidate Y-STR loci (DYS593, DYF404S1, DYS645) and a Y-Indel loci (Rs2032678), thereby providing greater efficiency, compatibility, and accuracy. The Microreader 40Y ID System can directly amplify markers from blood or saliva on filter paper or FTA cards, without template extraction or purification, and can also be used for extracted DNA templates. To verify the efficiency and accuracy of the kit, the Microreader 40Y ID System was validated by investigating sensitivity, amplification conditions, male-male and male-female mixtures, PCR inhibition, species specificity, reproducibility, and efficacy with degraded samples. The Y-STR loci were also tested using 437 male samples from Tibet, Han, and Yi. The Microreader 40Y ID System was able to compensate for some of the shortcomings of Y-STR markers in practical applications, such as cost and profile interpretation, and fully meets the domestic Y chromosome database construction specifications and requirements. [ABSTRACT FROM AUTHOR]

Background and aims: In recent decades, an increasing proportion of alpine shrub meadow has become severely degraded owing to the combined effects of global climate warming and rodent infestation, with significant impacts on soil water retention. The present paper investigates the patterns and controlling factors of soil water retention of alpine shrub meadow under different degrees of degradation, to help inform decisions on the management of degraded alpine shrub meadow. Methods: Four degradation stages were defined: non-degradation (ND); light degradation (LD); moderate degradation (MD) and higher degradation (HD). Pearson correlation and redundancy analysis were used to examine the relationships between soil physical properties and soil hydraulic properties. Results: Sand content increased while clay content decreased with increasing degree of degradation. In HD treatment, the available nitrogen and soil bulk density of surface soil layer was significantly lower than that in the other three stages, whereas the soil organic matter content and soil total porosity of surface soil layer was increased significantly, the soil compaction of 0–10 cm soil depth in HD was reduced significantly. The soil water retention of 0–60 cm soil depth first decreased and then increased with increasing degradation, with the maximum values occurring in HD, and the soil organic matter has an overwhelming effect on soil water retention than soil texture. Conclusions: As the degree of degradation increased, the surface soil structure deteriorated, and available nitrogen reduced while soil organic matter increased sharply in higher degradation, which leads to the highest soil water retention in higher degradation. Our results suggested that the soil water retention in degraded alpine grassland was largely determined by soil organic matter, and the soil organic matter parameters should be incorporated in hydrological models of degraded alpine ecosystem. [ABSTRACT FROM AUTHOR]

This paper explores multi-instrument space-borne observations in order to validate physical concepts of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) in relation to a selection of major seismic events. In this study we apply some validated techniques to observations in order to identify atmospheric and ionospheric precursors associated with some of recent most destructive earthquakes: M8.6 of March 28, 2005 and M8.5 of Sept. 12, 2007 in Sumatra, and M7.9 of May 12, 2008 in Wenchuan, China. New investigations are also presented concerning these three earthquakes and for the M7.2 of March 2008 in the Xinjiang-Xizang border region, China (the Yutian earthquake). It concerns the ionospheric density, the Global Ionospheric Maps (GIM) of the Total Electron Content (TEC), the Thermal Infra-Red (TIR) anomalies, and the Outgoing Longwave Radiation (OLR) data. It is shown that all these anomalies are identified as short-term precursors, which can be explained by the LAIC concept proposed in [S. Pulinets, D. Ouzounov, J. Asian Earth Sci. 41, 371 (2011)]. [ABSTRACT FROM AUTHOR]

Trench basin, as an important sedimentary repository in oceanic subduction zones, documents faithfully the evolution of paleodrainage and paleogeographic information. Because of the frequent intense deformation during and after deposition, the recognition of trench-basin strata in orogenic belts is quite challenging. Several trench-fill deposits have been identified from the Yarlung Zangbo suture in southern Tibet, which can be classified into two types based on major differences in formation timing and tectonic setting. The first type developed during subduction of the Neotethyan oceanic slab in the Cretaceous (e.g., the Jiachala, Rongmawa, and Luogangcuo formations), and the second type developed during the initial stage of the India-Asia collision in the Palaeogene (e.g., the Sangdanlin-Zheya formations). The former was originally deposited on the subducting oceanic crust and then accreted as tectonic slices into the subduction complex; the latter was deposited unconformably on the continental margin of the subducting Indian plate and then involved in the subduction complex during the continental collision. Typical lithologies of trench-basin fills include abyssal chert, siliceous shale, silty to sandy turbidites, debris flows deposits, and slump deposits without carbonate. Detritus feeding these basins were chiefly from the uplifted terrane in the upper plate. This paper summarizes the geological features of trench basins developed in southern Tibet and proposes criteria for recognizing trench-basins in collisional orogens. [ABSTRACT FROM AUTHOR]

Tunneling in complicated geological conditions frequently encounters problems with squeezing ground, large ground deformation, rockbursts, asymmetric deformation, non-linear rheology of surrounding rock, water inrush, and failure of supporting structures. In this paper, the Sichuan–Tibet highway, which is located at the north-west edge of the Sichuan basin and the eastern margin of the Qinghai–Tibet plateau, serves as a case study to investigate potential hazard sources for tunnels constructed in complex and difficult mountainous areas. Consideration first is given to the following 5 sets of conditions: crossing a fault zone, shallow tunnels in soft rock, crossing a landslide deposit, and deep tunnels in hard and soft rock formations. A program of field tests was performed to study the changes in rock pressure and the performance of support structures in different geological conditions. The results confirmed that the squeezing of rock depended upon a combination of the surrounding rock strength and the in situ stress field; fracture zones and water conditions reduced the integrity and mechanical properties of the surrounding rocks; topography and bedding structure can induce asymmetric mechanical behavior of the supporting structures during construction. Meanwhile, time-dependent rock deformation may have greater adverse impacts on the structural safety performance of tunnel during their operation. [ABSTRACT FROM AUTHOR]

Tibet, which is rich in mineral resources, is a treasure trove for geological explorers. However, prospecting work has been slow, especially in the western part, due to the precipitous terrain, changeable climate and low access. Hence, modern advanced field analytical technology and effective data processing methods play significant roles in rapid and efficient exploration in Tibet. In this paper, spectrum-area fractal modeling and portable X-ray fluorescence analysis (pXRFA) were used to identify and verify geochemical anomalies associated with Ag-Pb-Zn mineralization based on a stream-sediment dataset of 39 elements in the Dajiacuo-Xurucuo region of western Tibet. First, staged factor analysis (SFA) was used to obtain the Ag-Pb-Zn-Cd geochemical assemblage. Second, the first-factor pattern obtained using SFA was dissociated by a spectrum-area (S-A) fractal model and a digital elevation model (DEM)-based geochemical model (DGM) was constructed. Finally, the sections of Ag, Cd, Pb, and Zn were obtained using pXRFA. The results show that Ag-Pb-Zn-Cd enrichment zones were mostly located around the contact belt of volcanic rocks and intrusions, or along SE-NW trending faults. Considering the variable terrain and catchment basin, the extension of long axes of Ag-Pb-Zn-Cd anomalies into higher elevation areas that are favorable for Ag-Pb-Zn mineralization should be investigated. Anomaly maps created with the aid of a DGM show promising potential for mineralization in the Dajiacuo-Xurucuo region, and abundant Ag-Pb-Zn mineralization was identified with the assistance of pXRFA in the source areas for the geochemical anomalies in the Dajiacuo. We conclude that SFA and the S-A fractal model constitute a valid tool to identify or verify geochemical anomalies in areas of low-density stream-sediment sampling. The pXRFA can accurately determine the source of geochemical anomalies and improve anomaly verification efficiency. [ABSTRACT FROM AUTHOR]

The paper tries to make an assessment of the borderland regions of China and India with a focus on Xinjiang, Tibet, Kashmir and the Indian Northeast. The paper looks at the conflict in India and China's periphery, how these conflicts have evolved with time and how they have changed their character with the passage of time, from the 1950s until the present day. After looking at some background, the paper primarily focusses on three key issues which impact on all four of the conflicts: the rise of ethnic nationalism, the impact of external forces on the conflict and the human rights situation. After making an assessment of the political situation, the paper looks at the areas of similarity and differences between the four regions. Methodologically, a bottom-up approach was taken and in-depth unstructured interviews were carried out with people from the conflict zones that the paper considers. [ABSTRACT FROM AUTHOR]

In this paper, we present new major and trace element chemical data for the basalts and phonolites of the Nare ocean island fragment (NaOI), as well as zircon U-Pb age data and Hf isotope compositions for the NaOI phonolites in the middle segment of the Bangong-Nujiang Suture Zone, northern Tibet. Our aim is to assess the genesis of these rocks and to reconstruct the Middle Triassic evolution of the Bangong-Nujiang Tethyan Ocean (BNTO). The NaOI retains an ocean island-type double-layered structure comprising a basaltic basement and an oceanic sedimentary cover sequence (conglomerate and limestone, the latter accompanied by layers of erupted phonolite near the top of the sequence). The basalts in the NaOI are enriched in light rare earth elements and high field strength elements (Nb, Ta, Zr, Hf, and Ti), and they exhibit chondrite-normalized REE patterns and primitive mantle-normalized trace element patterns similar to those of ocean island basalts. Taking into consideration their high Dy/Yb, Sm/Yb, and La/Sm ratios, we conclude that the NaOI basalts were derived from the partial melting of garnet peridotite in the mantle. The NaOI phonolites have LREE-enriched chondrite-normalized REE patterns with negative Eu anomalies (Eu/Eu* = 0.41-0.43) and primitive mantle-normalized trace element patterns with enrichments in Nb, Ta, Zr, and Hf, and depletions in Ba, U, Sr, P, and Ti. Given the high contents of Nb (172-256 ppm), Ta (11.8-16.0 ppm), Zr (927-1117 ppm), and Hf (20.8-26.9 ppm), and the very low contents of MgO (0.11-0.25 wt%), the very low Mg# values (5-10), and the near-zero contents of Cr (1.27-7.59 ppm), Ni (0.43-7.19 ppm), and Co (0.11-0.38 ppm), and the small and homogeneously positive εHf(t) values (+ 4.9 to + 9.5), we infer that the NaOI phonolites were formed by the fractional crystallization of an OIB-derived mafic parent magma. The phonolites of the NaOI contain zircons that yielded U-Pb ages of 239 and 242 Ma, indicating that the NaOI formed during the Middle Triassic. These data, combined with data from modern ocean islands (e.g., Canary Islands, Cape Verde, Fernando de Noronha, Tristan da Cunha, and Gough in the Atlantic Ocean, and Society and Austral-Cook in the Pacific Ocean), lead us to infer that the BNTO was open for a long time before the Middle Triassic, and that the ocean had already developed into a mature ocean with a thick oceanic lithosphere by at least the Middle Triassic. [ABSTRACT FROM AUTHOR]

Introduction Despite significant global improvements in maternal health, large disparities persist. In China, rural women and women who live in western regions experience lower rates of maternal healthcare utilization and higher rates of maternal mortality than women elsewhere in the country. This paper examines maternal health care-seeking among nomadic Tibetan women in rural western China, a particularly understudied group. Methods Secondary data analysis was conducted with survey data collected in 2014 in Qinghai Province, China. Participants (rural, nomadic, adult women) provided birth histories and information on care received during antenatal, intrapartum and/or postpartum period(s). Using bivariate and multivariable logistic regression models, these outcomes were explored in relation to maternal characteristics (e.g., educational attainment and parity), use of health insurance, and time. Results Approximately half of all women had ever used antenatal care, institutional delivery, and/or skilled birth attendance. The utilization of these services has increased over time, from 10% of births prior to the year 2000, to approximately 50% since 2000. Utilization increased by year (odds ratios ranging from 1.1 to 1.3) even after controlling for covariates. Women with health insurance coverage were significantly more likely to use these services than women without insurance, although less than 20% of women reported that insurance paid for any antenatal and/or childbirth care. Discussion Utilization of maternal care is improving among this population but rates remain low in comparison to other women in rural, western China. Further targeted interventions may be needed to reach and adequately address the maternal health needs of this unique population. [ABSTRACT FROM AUTHOR]

To cherish the memory of the late Professor Duzheng YE on what would have been his 100th birthday, and to celebrate his great accomplishment in opening a new era of Tibetan Plateau (TP) meteorology, this review paper provides an assessment of the atmospheric heat source (AHS) over the TP from different data resources, including observations from local meteorological stations, satellite remote sensing data, and various reanalysis datasets. The uncertainty and applicability of these heat source data are evaluated. Analysis regarding the formation of the AHS over the TP demonstrates that it is not only the cause of the atmospheric circulation, but is also a result of that circulation. Based on numerical experiments, the review further demonstrates that land-sea thermal contrast is only one part of the monsoon story. The thermal forcing of the Tibetan-Iranian Plateau plays a significant role in generating the Asian summer monsoon (ASM), i.e., in addition to pumping water vapor from sea to land and from the lower to the upper troposphere, it also generates a subtropical monsoon-type meridional circulation subject to the angular momentum conservation, providing an ascending-air large-scale background for the development of the ASM. [ABSTRACT FROM AUTHOR]

Introduction: To estimate the prevalence of Kashin-Beck disease (KBD) among children in 2017 in Changdu of Tibet. Methods: We adopted a four-step recruitment to include children aged 7–12 years from seven identified historically endemic counties in Changdu. Posterior–anterior radiographs of right hand and wrist were taken and were graded at four sites (metaphysis, epiphysis, and bony end of phalanges and metacarpal and carpal bones). Two trained researchers independently read the films. Inter-rater reliability was assessed using weighted Kappa and percentage agreement. We fitted logistic regression model to examine the association of age, sex, and altitude of residential village with prevalence of KBD. We examined association between site involvement and severity of KBD using chi-square test. Results: We recruited 13,573 children (mean age = 9.3 years, 48.40% girls) with a response rate of 95.81%. The overall prevalence of radiographic KBD was 0.26%. Luolong County had the highest prevalence (0.69%), followed by Bianba (0.26%), Basu (0.24%), Mangkang (0.14%), Zuogong (0.14%), Dingqing (0.07%), and Chaya (0.00%). A higher risk of radiographic KBD was associated with older age (P for trend <0.001) and girls (OR=1.86, 95% CI: 0.94, 3.70), but not the altitude of residential village (P for trend=0.957). Metaphysis was involved in all cases of KBD while lesions in epiphysis and bony end of phalanges and metacarpals were only observed in severe cases. Conclusions: The prevalence of radiographic KBD among children aged 7–12 years was low in Changdu compared with previous census data, suggesting the effectiveness of preventative measures. Key Points • In this study, 13,573 Tibetan children were taken X-ray films of their hands and wrists. • The prevalence of radiographic KBD among children aged 7–12 years was low in Changdu of Tibet. • The preventative measures against KBD launched by Chinese government were effective in decreasing new onsets of KBD among Tibetan children. [ABSTRACT FROM AUTHOR]

This paper uses the theory of social construction of reality deriving from the writings of Max Weber, Alfred Schutz, Thomas Luckmann and Peter Berger to explain the origin of national identity and hence the emergence of a nation. It argues that social construction of national reality originates from everyday life experience taken for granted during the process of socialization. Individuals make sense out of the external world. Experiences taken for granted become actor's stock of knowledge. A common scheme of knowledge shared by the community serves to differentiate in-group (nationals) and out-group (foreigners). Collective consciousness thus defines national identity and hence a nation. Unless people (both in-group and out-group) interact with and learn from each other, different stocks of knowledge taken for granted will create political tension. This theory will be applied to understand the tensions in Tibet and along the Taiwan Strait. The paper further argues that Taiwan can hardly separate from mainland China in the future, while strong Tibetan consciousness continues to defy against powerful Chineseness, resulting in endless upheavals in the region. [ABSTRACT FROM AUTHOR]

Objectives Whether in metropoles or remote mountain communities, the availability and adoption of contraceptive technologies prompt serious and wide-ranging biological, social, and political-economic questions. The potential shifts in women's capacities to create spaces between pregnancies or to prevent future pregnancies have profound and often positive biological, demographic, and socioeconomic implications. Less acknowledged, however, are the ambivalences that women experience around contraception use-vacillations between moral frameworks, generational difference, and gendered forms of labor that have implications well beyond the boundaries of an individual's reproductive biology. This paper hones in on contraceptive use of culturally Tibetan women in two regions of highland Nepal whose reproductive lives occurred from 1943 to 2012. Methods We describe the experiences of the 296 women (out of a study of more than 1000 women's reproductive histories) who used contraception, and under what circumstances, examining socioeconomic, geographic, and age differences as well as points of access and patterns of use. We also provide a longitudinal perspective on fertility. Results Our results relate contraception usage to fertility decline, as well as to differences in access between the two communities of women. Conclusions We argue that despite seemingly similar social ecologies of these two study sites-including stated reasons for the adoption of contraception and expressed ambivalence around its use, some of which are linked to moral and cosmological understandings that emerge from Buddhism-the dynamics of contraception uptake in these two regions are distinct, as are, therefore, patterns of fertility transition. [ABSTRACT FROM AUTHOR]

10Be/7Be is a stratospheric sensitive tracer. In this paper, measurements of 10Be/7Be and surface O3 from October 2005 to May 2006 at Mt. Waliguan (hereafter WLG, 100.898°E, 39.287°N, 3810 m, a.s.l.), China global atmospheric watch (GAW) observatory, are introduced and used to investigate the stratosphere-troposphere transport (STT) and its impact on surface O3 on the Tibetan Plateau. The results show that the magnitude of STT is weak in winter, followed by strengthening from the end of winter to 10 7 10 7 the middle of spring (from mid February to mid April) with large increases in Be, Be, Be/ Be and surface O3. At the end of spring (from the end of April to mid May in this paper), the STT weakened, and the continuous increase of surface O3 at WLG is produced by tropospheric photochemistry reactions. [ABSTRACT FROM AUTHOR]

Fusha structural belt (FSB) is one of the most important tectonic units in front of the Western Kunlun Orogen, northwestern Tibetan Plateau (NW China), in which the Kekeya oil field was discovered in 1971. However, there is no new oil field discovered since then due to the unclarity of the intense and complex Cenozoic deformation in this area. Based on field investigation, seismic interpretation and Continuous Electromagnetic Profile data, we analyze in detail the Cenozoic deformation history, emphasizing on the spatial and temporal variation of the deformation of the FSB in this paper. The result suggests that the FSB was dominated by two deformation events, (1) early (Miocene-early Pliocene) folding event expressed by anticline, with the western segment E-W orienting, while the eastern segment NWW-SEE orienting and (2) later (since late Pliocene) transpressional faulting event that destroyed and divided the earlier anticline into a number of fault blocks. The transpressional faulting caused dextral strike-slip reverse fault, with the dip angles decreasing eastward from ~90° to <45°. The dextral strike-slip reverse fault developed in the core of the anticline in the western part which caused the anticline into several fault blocks, while in the eastern part, the fault developed in the north limb of the anticline with the core of the anticline reserved. Based on the spatial variation of structural characteristics, we propose that the fault block traps and anticline traps in the eastern segment and fault block traps in western segment are favorable for hydrocarbon accumulation. [ABSTRACT FROM AUTHOR]

The Amdo microcontinent is located within the middle of Bangong-Nujiang suture (BNS) zone in the shape of lens. The basic geological research restricts geologists from understanding the histories of tectonic evolution of BNS and regional geology more deeply. This paper systematically studies the geochronology and geochemistry of granitic gneisses from Amdo basement. These data provide constraints on formation age, source characteristics and tectonic setting of their protolith. The SHRIMP zircon U-Pb dating is operated for granitic gneisses. Samples AGS-2 and AGS-3 (granitic gneiss) yield average zircon U-Pb ages of 485±14 and 487±6 Ma, respectively. These ages should represent the formation age of protolith and indicate that they are formed in the Early Ordovician. Granitic gneisses are characterized by high SiO, NaO, KO and AlO, low Fe and Mg, enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), depletion in heavy rare earth elements (HREEs) and high field strength elements (HFSEs), with negative Eu anomaly. The Rittmann index ( σ) is 1.77 to 2.60, less than 3.3. The aluminum saturation index (A/CNK) values range from 0.88 to 1.26. These features suggest that protolith of granitic gneisses from Amdo basement show characteristics of calc-alkaline and S-type granite, and they could be derived from partial melting of metamorphic greywackes in the upper crust of low maturity. The tectonic setting is syn-collision. These all suggest that the formation of protolith of granitic gneisses from Amdo are caused by the Early Paleozoic orogeny, which could be related to proto-Tethyan oceanic subduction along Gondwana continental margins, and does not result from the production of Pan-African orogenesis. [ABSTRACT FROM AUTHOR]

In order to investigate the evolution of Shiquanhe-Yongzhu-Jiali ophiolitic mélange belt, the gabbros from new discovered Zhongcang ophiolitic mélange are studied through petrology, whole-rock geochemistry, zircon U-Pb dating and Lu-Hf isotope. The gabbros investigated in this paper contain cumulate gabbro and gabbro dike, and they have undergone greenschist-amphibolite facies metamorphism. The chondrite normalized rare earth element (REE) patterns of most of these rocks show flat types with slightly light REE (LREE) depletion and the N-MORB normalized incompatible elements diagrams indicate depletion in high field strength elements (HFSE) (Nb, Ta) and enrichment in large ion lithophile elements (LILE). These gabbros have island arc and mid-ocean ridge basalt affinities, suggesting that they were originated in an oceanic back arc basin. Whole rock geochemistry and high positive ɛ( t) values show that these gabbros were derived from ∼30% partial melting of a spinel lherzolite mantle, which was enriched by interaction with slab-derived fluids and melts from sediment. U-Pb analyses of zircons from cumulate gabbro yield a weighted mean age of 114.3±1.4 Ma. Based on our data and previous studies, we propose that an intra-oceanic subduction system and back arc basin operated in the Neo-Tethy Ocean of central Tibet during Middle Jurassic and Early Cretaceous, resembling modern active intra-oceanic subduction systems in the western Pacific. [ABSTRACT FROM AUTHOR]

On the April 9 of 2000, a gigantic rapid rock slide-debris avalanche occurred in Bomi, Tibet. Some 280-300 × 10 m of material travelled 10 km within 10 min and dammed the Yigong River, forming a 2.9 × 10 m³ barrier lake. Wind tunnel testing was undertaken to determine the aerodynamic parameters involved, from the initial rock slide-fall to its point of impact. The paper reports the numerical analyses undertaken and discusses the significance of the air-cushion effect. It is concluded that Yigong rapid rock slide-debris avalanche 'flew' in the air for about 12.9 s from its detachment from the source to its collision with the floor of the Zamunong gully at 3,317 m asl. The velocity of the avalanche mass at the point of detachment was some 81.8 m/s and the collision velocity approximately 117 m/s. [ABSTRACT FROM AUTHOR]

Little is known about the soils that support agriculture in Tibet. The aim of this paper is to investigate the physical and chemical properties of Tibet's agricultural soils, the nutritional status of wheat ( Triticum aestivum L.) and barley ( Hordeum vulgare L.) crops, and the sustainability of current soil management practices. Physical descriptions of Tibet's agricultural soils were based on soil pits dug at three locations across Tibet's agricultural zone. Chemical analyses were conducted on soils from seven sites across the zone. Nutritional constraints to agriculture were identified through leaf tissue tests on wheat and barley crops from 23 fields. These results, combined with published information on farm inputs and yields, provided insight into the sustainability of current nutrient practice. Soils were found to be silty or sandy clay loams with alkaline reaction, low organic content and low K and Zn status. Leaf analysis revealed one third to one half of cereal crops were marginal or deficient for K, Zn and Mg. Most farmers export grain and import only nitrogenous and phosphatic fertilizers leading to a nutrient imbalance. A balanced fertilizer program is required to halt nutrient depletion and increase grain production. Reduced tillage and crop residue retention are needed to improve soil health. [ABSTRACT FROM AUTHOR]

Vertical mobile grazing is typical in undulating mountain landscapes. However, recent social, economic, and political changes in China are impacting these traditional practices. This paper presents findings of a study conducted in the Tibetan communities of southwest China to assess the current status of mountain pastoralism and its future viability. Rangeland environment, livestock variety, and grazing form were found to be significantly related factors, which made it possible to analyze livestock distribution. The yak population-the main mobile grazer in alpine pasture- is currently stagnating while the population of cattle raised around settlements is steadily increasing. This situation is likely closely related to labor shortages in households, which have triggered the imbalanced distribution of livestock. The fact that the key to rangeland sustainability is to stimulate mobile grazing runs counter to current privatization policies. [ABSTRACT FROM AUTHOR]

This paper focuses on assistance that externally-resident daughters provide for their aging parents in rural Tibet, China, to challenge the notion that rapid modernization invariably threatens family-based care systems for the elderly. The authors discuss social and economic changes associated with modernization that have created new opportunities for parents to send daughters out of their natal households in ways that can benefit them in old age. By investing in a daughter's education so she can secure salaried employment, or by helping a daughter establish a small business so she can earn an independent livelihood, the authors demonstrate how some externally-resident daughters represent a novel form of social capital that parents can draw on for social support. Daughters with income and freedom from extended family obligations are now providing elderly parents with (1) leverage against co-resident children who do not treat them well, (2) temporary places of refuge from ill-treatment at home, (3) caretaking services and financial support when they require hospitalization, and (4) financial resources independent of their household which they can use to pursue age-appropriate activities like pilgrimage. The authors conclude that this new form of social capital vested in externallyresident daughters is having a positive impact on the lives of the elderly in rural Tibet. [ABSTRACT FROM AUTHOR]

This paper describes 2007/2008 inter-annual changes in runoff from the Zhadang Glacier located on the northern slope of Nyainqêntanglha Range, Tibet, and analyzes their causes. Precipitation increased by 17.9% in summer months of 2008 compared with the same period in 2007, drainage basin runoff decreased by 33.3%, and glacial meltwater decreased by 53.8%. Change in positive accumulated air temperature explained approximately half of the inter-annual difference in glacial meltwater using a degree-day model. This suggests that the glacier is extremely sensitive to changes in air temperature. Energy balance analysis showed that change in glacier surface albedo, considered to be caused by difference in precipitation form, resulted in the large inter-annual difference in glacial meltwater. It was shown statistically that precipitation form in the summer months of 2007 was mainly rainfall which comprised 71.5% of total precipitation, while during the same period in 2008 rainfall accounted for 30.7%, with the majority of precipitation falling as snow. Precipitation form should be considered an independent factor when analyzing glacier sensitivity to climate change or forecasting the runoff from certain glaciers. [ABSTRACT FROM AUTHOR]

This paper provides information about the distribution, structure, and ecology of the world's largest alpine ecosystem, the Kobresia pygmaea pastures in the southeastern Tibetan plateau. The environmental importance of these Cyperaceae mats derives from the extremely firm turf, which protects large surfaces against erosion, including the headwaters of the Huang He, Yangtze, Mekong, Salween, and Brahmaputra. The emphasis of the present article is on the climate-driven evolution and recent dynamics of these mats under the grazing impact of small mammals and livestock. Considering pedological analyses, radiocarbon datings, and results from exclosure experiments, we hypothesize that the majority of K. pygmaea mats are human-induced and replace forests, scrub, and taller grasslands. At present, the carrying capacity is increasingly exceeded, and reinforced settlement of nomads threatens this ecosystem especially in its drier part, where small mammals become strong competitors with livestock and the removal of the turf is irreversible. Examples of rehabilitation measures are given. [ABSTRACT FROM AUTHOR]

This paper presents a large data set on carbon isotope composition (δ13C) of modern soils which were collected under the main vegetation communities along an altitude of 1250–5500 m above sea level in the Qinghai-Tibetan Plateau. The δ13C values of 198 samples range from -28.6 to -15.1‰ versus PDB and exhibit a clean relation to different vegetation communities from forest (-25.9 ± 1.2‰) to shrub (-24.7 ± 1.4‰), steppe (-23.1 ± 1.3‰), alpine meadow (-23.6 ± 0.7‰), alpine desert steppe (-21.3 ± 1.6‰), and alpine desert (-18.9 ± 2.5‰). We attributed the observed variability in δ13C values to that the mean annual precipitation (MAP) and the mean annual temperature (MAT) are the main factors controlling the distribution of vegetation types in the Tibetan Plateau, which causes the change in carbon isotope composition of modern soils at any given altitude. The result of both linear and nonlinear regression analyses also confirms that MAP and MAT are the major factors affecting the δ13C values of surface soils. In the absence of favorable moisture and temperature conditions, low pCO2 alone is not sufficient to cause the distinct changes in carbon isotope composition of modern soils in the Tibetan Plateau. This study provides some fundamental information on the carbon isotope composition of terrestrial carbon pools and bears some practical significance for the use of carbon isotope data to document vegetation changes and environmental conditions of the high plateau in the past. [ABSTRACT FROM AUTHOR]