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

Cryptosporidium and Giardia are important intestinal zoonotic pathogens that can infect various hosts and cause diarrhoeal diseases. There are few reports of the epidemiological prevalence and molecular characterization of Cryptosporidium and Giardia in wild birds around Qinghai Lake and in the surrounding areas on the Qinghai-Tibetan Plateau, Northwest China. Therefore, the aim of this study was to determine the Cryptosporidium spp. and Giardia duodenalis genotypes and their epidemiological prevalence in wild birds by PCR amplification. To our knowledge, this is the first report of a variety of Cryptosporidium spp. and G. duodenalis infections in wild birds from that area, with overall prevalence rates of 8.98% (61/679) and 3.39% (23/679), respectively. Furthermore, PCR sequencing confirmed the presence of Cryptosporidium baileyi (n = 3), Cryptosporidium parvum (n = 58), and G. duodenalis assemblage B (n = 19) and E (n = 4) in wild birds from the areas around Qinghai Lake. The results of the present study demonstrated the wide distribution of Cryptosporidium and Giardia among wild birds, which has potential public health significance. Moreover, the study findings also provided useful molecular epidemiological data for monitoring and investigating the two parasitic protozoa in wild animals and surrounding environments. [ABSTRACT FROM AUTHOR]

Glacier retreat in the Qinghai-Tibetan Plateau (QTP), the "third pole of the world", has attracted the attention of researchers worldwide. Glacier inventories in the 1970s and the 2000s provide valuable information to infer changes in individual glaciers. However, individual glacier volumes are either missing, incomplete or have large errors in these inventories, and thus, the use of these datasets to investigate changes in glaciers in QTP in the past few decades has become a challenge, particularly in the context of climate change. In this study, individual glacier volume data in the Randolph Glacier Inventory version 4.0 (RGI 4.0, 1970s) and the second Glacier Inventory of China (GIC-Ⅱ, 2000s) are recalculated and consolidated using a slope-dependent algorithm based on elevation datasets for the QTP. The two consolidated inventories (The data are available under https://doi.org/10.11888/Glacio.tpdc.270390 (Liu, 2020). For the time of review, the data will be accessible through the following review link https://data.tpdc.ac.cn/en/data/4b88e394-0eb4-44c4-aa38-32aeb614daff/.) are validated by comparing the observed and estimated glacier data reported in the literature. The two consolidated glacier inventories are then compared for different mountains over the QTP to detect changes in glacier areas, volumes, fragmentation status, etc. during the past 3–4 decades. Based on the results, the slope-dependent algorithm performed well in computing individual glacier volumes and other elements, compared with the widely used volume-area scaling which often leads to overestimation in the interior Plateau and underestimation in other areas of the QTP in both RGI 4.0 and GIC-Ⅱ. The comparison of the two inventories reveals a total area of glaciers in the QTP of approximately 59026.5 km2 in the RGI 4.0 and 44301.2 km2 in the GIC-Ⅱ. The total glacier volume is 4045.9 km3 in the GIC-Ⅱ compared with 4716.7 km3 in the RGI 4.0. The results suggest a significant retreat and melting of glaciers in the QTP. However, variations are observed in different glaciers. The Karakoram Mountains contain the largest number of surged glaciers, while the highest level of retreat is observed in the Gandise Mountains. An increase in the fragmentation index is observed in the northern mountains, particularly the Pamir Plateau, which displays the highest trends of glacier movement and deformation. The glacier volumes decrease mainly on south-westward aspects and increase to various extents on the other aspects of most mountains. The consolidation of the glacier inventories and the findings of the analysis performed in this study provide important databases for future glacier-related studies, particularly for investigating the effects of climate change on glaciers in the past and projecting future effects. [ABSTRACT FROM AUTHOR]

As the largest river basin of the Tibetan Plateau, the upper Brahmaputra River basin (also called "Yarlung Zangbo" in Chinese) has profound impacts on the water security of local and downstream inhabitants. Precipitation in the basin is mainly controlled by the Indian summer monsoon and westerly and is the key to understanding the water resources available in the basin; however, due to sparse observational data constrained by a harsh environment and complex topography, there remains a lack of reliable information on basin-wide precipitation (there are only nine national meteorological stations with continuous observations). To improve the accuracy of basin-wide precipitation data, we integrate various gauge, satellite, and reanalysis precipitation datasets, including GLDAS, ITP-Forcing, MERRA2, TRMM, and CMA datasets, to develop a new precipitation product for the 1981–2016 period over the upper Brahmaputra River basin, at 3 h and 5 km resolution. The new product has been rigorously validated at different temporal scales (e.g., extreme events, daily to monthly variability, and long-term trends) and spatial scales (point and basin scale) with gauge precipitation observations, showing much improved accuracies compared to previous products. An improved hydrological simulation has been achieved (low relative bias: -5.94 %; highest Nash–Sutcliffe coefficient of efficiency (NSE): 0.643) with the new precipitation inputs, showing reliability and potential for multidisciplinary studies. This new precipitation product is openly accessible at 10.5281/zenodo.3711155 (Wang et al., 2020) and additionally at the National Tibetan Plateau Data Center (https://data.tpdc.ac.cn , last access: 10 July 2020, login required). [ABSTRACT FROM AUTHOR]

Cryptosporidium and Giardia are well-known parasitic protozoans responsible for waterborne and foodborne diarrhoeal diseases. However, data are not available on market vegetables contaminated with Cryptosporidium and Giardia in China. In the present study, 642 different vegetable samples were collected from Xining City street vendors in the Qinghai Province to study the Cryptosporidium and Giardia contamination rates via PCR and sequence analyses. Cryptosporidium spp. and Giardia duodenalis were detected in 16 (2.5%) and 73 (11.4%) samples, respectively. Two species of Cryptosporidium, C. parvum (n = 11) and C. andersoni (n = 5), were identified. G. duodenalis assemblage B was identified in almost all positive samples (n = 72), except one sample that contained G. duodenalis assemblage E. We report on the rate of Cryptosporidium and Giardia contamination in vegetables for the first time from the Qinghai Tibetan Plateau Area (QTPA) in China. [ABSTRACT FROM AUTHOR]

River discharge, as one of the most essential climate variables, plays a vital role in the water cycle. Small-scale headwater catchments including high-mountain regions of Tibetan Plateau (TP) Rivers are mostly ungauged. Satellite technology shows its potential to fill this gap with a high correlation of satellite-derived effective river width and corresponding in-situ gauged discharge. This study is innovative in estimating daily river discharge using modified Manning equation (Model 1), Bjerklie equation (Model 2), and Rating curve approach (Model 3) by combining river surface hydraulic variables directly derived from remote-sensing datasets with other variables indirectly derived from empirical equations, which greatly contributes to the improvement of river flow measurement information especially over small rivers of TP. We extracted the effective width from Landsat image and flow depth via hydraulic geometry approach. All the input parameters directly or indirectly derived from remote sensing were combined and substituted into the fundamental flow equations/models to estimate discharges of Lhasa River. The validation of all three models' results against the in-situ discharge measurements shows a strong correlation (the Nash–Sutcliffe efficiency coefficient (NSE) and the coefficient of determination (R2) values ≥0.993), indicating the potentiality of the models in accurately estimating daily river discharges. Trends of an overestimation of discharge by Model 1 and underestimation by Model 2 are observed. The discharge estimation by using Model 3 outperforms Model 1 and Model 2 due to the uncertainties associated with the estimation of input parameters in the other two models. Generally, our discharge estimation methodology performs well and shows a superior result as compared with previously developed multivariate empirical equations and its application for other places globally can be the focus of upcoming studies. [ABSTRACT FROM AUTHOR]

Reliable information about river discharge plays a key role in sustainably managing water resources and better understanding of hydrological systems. Therefore, river discharge estimation using remote sensing techniques is an ongoing research goal, especially in small, headwater catchments which are mostly ungauged due to environmental or financial limitations. Here, a novel method for river discharge estimation based entirely on remote sensing-derived parameters is presented. The model inputs include average river width, estimated from Landsat imagery by using the modified normalized difference water index (MNDWI) approach; average depth and velocity, based on empirical equations with inputs from remote sensing; channel slope from a high resolution shuttle radar topography mission digital elevation model (SRTM DEM); and channel roughness coefficient via further analysis and classification of Landsat images with support of previously published values. The discharge of the Lhasa River was then estimated based on these derived parameters and by using either the Manning equation (Model 1) or Bjerklie equation (Model 2). In general, both of the two models tend to overestimate discharge at moderate and high flows, and underestimate discharge at low flows. The overall performances of both models at the Lhasa gauge were satisfactory: comparisons with the observations yielded Nash–Sutcliffe efficiency coefficient (NSE) and R2 values ≥ 0.886. Both models also performed well at the upper gauge (Tanggya) of the Lhasa River (NSE ≥ 0.950) indicating the transferability of the methodology to river cross-sections with different morphologies, thus demonstrating the potential to quantify streamflow entirely from remote sensing data in poorly-gauged or ungauged rivers on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibetan Plateau Area (QTPA) is a plateau with the highest average altitude, located in Northwestern China. There is a risk for interspecies disease transmission, such as spotted fever rickettsioses. However, information on the molecular characteristics of the spotted fever group (SFG) Rickettsia spp. in the area is limited. This study performed screenings, and detected the DNA of human pathogen, SFG Rickettsia spp., with 11.3% (25/222) infection rates in yaks (Bosgrunniens). BLASTn analysis revealed that the Rickettsia sequences obtained shared 94.3–100% identity with isolates of Rickettsia spp. from ticks in China. One Rickettsia sequence (MN536161) had 100% nucleotide identity to two R. raoultii isolates from Chinese Homo sapiens, and one isolate from Qinghai Dermacentorsilvarum. Meanwhile, another Rickettsia sequence (MN536157) shared 99.1–99.5% identity to one isolate from Dermacentor spp. in China. Furthermore, the phylogenetic analysis of SFG Rickettsia spp. ompA gene revealed that these two sequences obtained from yaks in the present study grouped with the R. slovaca and R. raoultii clades with isolates identified from Dermacentor spp. and Homo sapiens. Our findings showed the first evidence of human pathogen DNA, SFG Rickettsia spp., from animals, in the QTPA. [ABSTRACT FROM AUTHOR]

The authors of this article would like to state that C. environmental is not a species, but rather a group of un-identified Cryptosporidium isolates from the environment. It is referred to in the literature as Cryptosporidium environmental sequence and not as a species. [ABSTRACT FROM AUTHOR]

Vegetation dynamics are sensitive to climate change and human activities, as vegetation interacts with the hydrosphere, atmosphere, and biosphere. The Yarlung Zangbo River (YZR) basin, with the vulnerable ecological environment, has experienced a series of natural disasters since the new millennium. Therefore, in this study, the vegetation dynamic variations and their associated responses to environmental changes in the YZR basin were investigated based on Normalized Difference Vegetation Index (NDVI) and Global Land Data Assimilation System (GLDAS) data from 2000 to 2016. Results showed that (1) the YZR basin showed an obvious vegetation greening process with a significant increase of the growing season NDVI (Zc = 2.31, p < 0.05), which was mainly attributed to the wide greening tendency of the downstream region that accounted for over 50% area of the YZR basin. (2) Regions with significant greening accounted for 25.4% of the basin and were mainly concentrated in the Nyang River and Parlung Tsangpo River sub-basins. On the contrary, the browning regions accounted for <25% of the basin and were mostly distributed in the urbanized cities of the midstream, implying a significant influence of human activities on vegetation greening. (3) The elevation dependency of the vegetation in the YZR basin was significant, showing that the vegetation of the low-altitude regions was better than that of the high-altitude regions. The greening rate exhibited a significantly more complicated relationship with the elevation, which increased with elevated altitude (above 3500 m) and decreased with elevated altitude (below 3500 m). (4) Significantly positive correlations between the growing season NDVI and surface air temperature were detected, which were mainly distributed in the snow-dominated sub-basins, indicating that glaciers and snow melting processes induced by global warming play an important role in vegetation growth. Although basin-wide non-significant negative correlations were found between precipitation and growing season NDVI, positive influences of precipitation on vegetation greening occurred in the arid and semi-arid upstream region. These findings could provide important information for ecological environment protection in the YZR basin and other high mountain regions. [ABSTRACT FROM AUTHOR]