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The Tibetan Plateau (TP) has a significant influence on local, regional, and even global weather and climate systems. Precipitation on the TP plays a critical role in the energy and water cycle and terrestrial ecosystem. This study reviewed recent research progress in precipitation changes in recent decades and explored their mechanisms involved based on observations (meteorological station data and satellite remote sensing data) and simulations [global climate models (GCMs) and downscaling modelling]. Our review suggested that the TP precipitation decreases progressively from southeast to northwest, mainly occurs in summer (June–August), accounting for ∼60–70% of annual total, and marginally occurs in winter (December–February), accounting for less than 10%. Diurnal variation of precipitation and convective activity are obvious on the TP. The TP has experienced an overall surface air wetting trend since the 1960s, but with apparent regional and seasonal differences. Projected precipitation on the TP from GCMs and statistical downscaling methods (SDMs) generally increases, while from dynamic downscaling methods (DDMs) slightly increases or even decreases as greenhouse gas emissions continue in the future. Influencing factors such as the TP' and Asian land heating, large-scale atmospheric circulations, climate warming, aerosols, and land surface conditions all exert prominent but complicated effects on precipitation changes on the TP. More efforts should be made to improve the reliabilities and accuracies of precipitation observational data sets, GCMs, and downscaling modelling. Finally, directions for future research are discussed based on the various means covering high-quality precipitation observations and more skilful simulations, which are synthetically used to investigate the TP precipitation and its driving mechanisms. It is expected that this review and its results will be beneficial for hydrological and precipitation studies over the TP.

The Tibetan Plateau (TP) is a vast elevated plateau in central Asia, and profoundly impacts regional weather and climate, and even global atmospheric circulation. Here, two frequently used ERA-Interim reanalyses with a spatial resolution of 1.5° × 1.5° (EIN15) and 0.75° × 0.75° (EIN75) are evaluated using a gridded observation dataset at 0.25° spatial resolution from the National Climate Center in China across the TP that covers the period 1979–2012. Climatological characteristics, mean monthly changes, and spatial–temporal trends are examined, with a focus on air temperature and precipitation. Topographic corrections for temperature in ERA-Interim are first conducted based on a vertical temperature lapse rate. The results show that EIN15 and EIN75 with topographic correction closely reproduce the spatial distribution and mean monthly change of temperature on the TP, notwithstanding some cold biases not seen in the observations. The two reanalysis datasets exhibit significant temperature increases over most of the TP, which is similar to the observations. However, the trends exhibit different spatial patterns for all seasons aside from summer, and have lower magnitudes than the observations. EIN15 and EIN75 also reproduce the broad spatial distribution of precipitation, but overestimate precipitation amounts, especially on the southern TP. They also capture some of the observed spatial patterns in the precipitation trend for the period 1979–2012, particularly in winter. Overall, the mean monthly change, mean annual, winter, and summer climatology, and their temporal trends of temperature reproduced by the ERA-Interim data are much better than those of precipitation. As a result of its higher resolution and more accurate topography, EIN75 generates a closer fit to the observed temperatures on the TP than EIN15, but there are no significant differences in precipitation between the two reanalysis datasets. Evaluation of these datasets would be very informative for further climate research and simulations on the TP.

Pollutants that are usually transported from southern Asia to the Tibetan Plateau deposit on the Plateau surface, change snow albedo and thereby surface radiative flux. This results numerous climatic implications like as erratic monsoon, perturbation in hydrological cycle, etc. However, the accurate estimation of these climatic implications is not well understood, because the atmospheric pollution is a heterogeneous mixture of various particle types. Therefore, this part of climate research requires a detailed investigation of physical and chemical properties of atmospheric pollutants. This study aimed to examine the physical and chemical properties of atmospheric pollutants across the Himalayan regions along two transboundary south-north transects. The information of individual-particles was obtained using microscopy-based techniques that comprises transmission electron microscope (TEM) and Energy-dispersive X-ray spectrometer (EDX). Study capture the signatures of various types of atmospheric species such as black carbon (BC), mineral dust, fly ash, organic matter, sulfate, nitrite, ammonium, and NaCl. Microscopy-based techniques confirm that these particles were generally in mixing state, for example salt-coated particles accounting for 25–56% of the total particles in sampled locations. Our analysis shows that urban and rural locations are characterized with atmospheric particles which sourced from anthropogenic activities, whereas remote locations with those released from natural crustal. However, the relative contributions of anthropogenic particles were higher than that of particles released from natural crustal. The presence of such particles over remote locations of Himalayan region provides an evidence of prevailing atmospheric transport processes, which further need to be well understood. It is expected that this work would be helpful in understanding the regional atmospheric conditions and the transboundary transport process of haze particles. As these informations are of great importance in modeling studies, which further lead to improve understanding of haze particles climate effects.

Brassica juncea L. is an attractive species in PTMs contaminated soil remediation ascribing to its high tolerance under stress and great accumulation capacity of metals. To identify the potential Cd/Zn accumulators from numerous different Chinese mustard cultivars for practical phytoremediation is a promising strategy in China. In present work, a pot experiment involving elevated Cd/Zn concentrations was performed among 21 cultivars. Regarding physiological and biochemical indicators under Cd/Zn stress, principal component analysis and cluster analysis were used for cultivar tolerance evaluation and classification. Results showed that BJ (Bao Jie, var. involutus) cultivar was distinguished as a potential phytoremediation candidate comparing with other cultivars. Moreover, BJ accumulated the maximum Cd content of 63.85 and 77.29 mg kg−1 DW in shoots and roots, respectively, and the maximum Zn uptake by BJ were 6693 and 4777 mg kg−1 DW in shoots and roots, respectively. Accordingly, BJ had the highest Cd/Zn tolerance, remarkable accumulation and translocation capacity (accumulation factor (AF) > 1 for Cd and Zn; translocation factor (TF) > 0.8 for Cd and TF > 1 for Zn). In addition, the superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities of the mustard increased initially under low Cd/Zn stress as compared to the control and then declined dramatically with the increasing metals exposure concentration. Therefore, the antioxidant enzymes may play a protective role against reactive oxygen species (ROS) under low Cd/Zn stress, whereas the defense system might be collapsed under relatively high Cd/Zn stress. Furthermore, the enhanced Cd/Zn exposure led to an increase in malondialdehyde (MDA) content in the mustard cultivars, indicating that Cd/Zn had induced more severe oxidative stress and higher degree of lipid peroxidation had occurred. The present investigation results indicated that BJ (Bao Jie, var. involutus), as a native cultivar, can be further applied in the field trials of phytoremediation practices in contaminated soil.

Climate change has greatly affected regional hydrological processes at temporal and spatial scales, and much attention has been focused on how runoff changed under the background of global warming in recent years. In northwest China, Taohe River provides major water resource to several semi-arid regions. To quantificationally estimate water resource, the influence of precipitation and temperature on runoff needs to be further studied. In this paper, hydro-meteorological data from 1956 to 2014 were used to analyze the changes of temperature, precipitation and runoff based on Mann–Kendall test and double cumulative curve method. The main findings were that the temperature had a significant increasing trend (0.26 °C/10a), while precipitation showed an insignificant increasing trend (0.9 mm/10a). Runoff exhibited a significant decreasing trend (− 2.7 × 108 m3/10a) and break point of the runoff occurred in 1987. Thus, compared with benchmark value during the period 1956–1987, runoff after 1987 was reduced to 70.7% of the previous level on average, from 37.5 × 108 m3 in 1956–1987 to 26.5 × 108 m3 in 1988–2014, with a decreasing rate of 29.3%; and runoff changes in each month were all decreased after 1987, particularly in September by 41.29%. Double cumulative curve and correlation results revealed that precipitation was the dominant factor controlling changes in runoff and their correlation coefficient reached up to 0.73. The magnitude of precipitation dominated runoff from April to October, accounting for more than 95% of the total annual runoff. However, runoff decreased more dramatically than precipitation after 1987, which indicated that there were some non-precipitation factors, like the increase of evaporation caused by temperature rise and human activities, responsible for the decline of runoff from 1988 to 2014. Some large-scale climate factors had a good tele-connective relation with variability of runoff. Overall, this study exhibited a scientific fact of runoff decreasing in the upper Taohe River basin and aimed to provide a basic direction for reasonable allocation of water resources by the Taohe River Diversion Project sustainably.

Understanding the current regional climate is of great importance for better estimating future climate change and assessing its influence on water resources and ecosystems. The Yellow River provides important water resources for industrial and domestic activities. However, climate simulations over the Yellow River Basin (YRB) have rarely been attempted. In this study, downscaled mean climate over the upper and middle reaches of the YRB using the REgional MOdel (REMO) at 0.22° spatial resolution under the Coordinated Regional Downscaling Experiment (CORDEX), driven by ERA-Interim reanalysis, was evaluated by comparison against one gridded observational dataset (CN05.1) for the period 1982–2016. Two reanalysis datasets (ERA5 and ERA-Interim) were used to reveal possible causes for the differences between the simulations and observations. REMO reproduced the spatial patterns of mean temperature satisfactorily despite some evident deviations. REMO had a predominantly mixed bias (a cold bias for the upper reach and a warm bias for the rest) in all four seasons. Due to the effects of differential snow cover, temperature biases were elevation-dependent, especially in winter months. REMO broadly reproduced the spatial variability of precipitation with a wet bias, which could be largely attributed to anomalous moisture flux transport. In terms of interannual variability, the observational data showed significant warming across all four seasons, while REMO simulated weaker warming trends. Precipitation trends were positive in all seasons except in summer, but REMO failed to capture the trends in winter and spring. The observed elevation-dependent warming (EDW) was reproduced by REMO, except in spring. The EDW was likely to be explained by the snow-albedo feedback, owing to the apparent decrease in snow cover at high elevations.

Graphitic porous carbons with high electronic conductivity and abundant pores show great potential in many fields due to their unique physical and chemical properties. The traditional technique for the acquirement of artificial graphite is always conducted under high temperature above 2700 °C, leading to serious energy loss and high costs. In this study, antibiotic bacteria residues (ABRs), a kind of solid waste generated upon the production of antibiotics, are recycled into hollow-tunneled graphitic carbon derived from ABRs with N-doping (N-GC) using Na2CO3 as catalyst at 900 °C. Compared with graphitic carbon (G-AC) derived from ABRs at 2800 °C, the obtained N-GC shows a decent graphitization degree (69.8% vs. 57.0% of G-AC), high electronic conductivity (36.90 S cm−1 vs. 17.06 S cm−1 of G-AC at 20 MPa), well-developed porous structure as well as a high N containing amount (1.26% vs. 0.50% of G-AC). When used as anode material for Li-ion batteries (LIBs), the N-GC sample shows excellent electrochemical properties including good cyclability, long durability and good rate performance.

Calcination temperature plays a key role in determining the phase purity, composition and microstructures for the zeolitic imidazolate frameworks (ZIFs) derived transition metal oxides materials, the investigation on the influences of the calcination temperature during ZIFs derivative process is helpful to dissect the reaction mechanism and the transformation process. The present work is aimed at constructing ZnWO4 nanocrystals derived from ZIF-8 via a facile strategy, and systematical study on the influences of calcination temperature during ZIFs derivative process on the microstructure, phase purity and composition of the final product. More importantly, the probable evolution mechanisms for the microstructure and the composition of the as-obtained final products are proposed. It is found that the crystallinity, composition, microstructure and electrochemical performances of the ZnWO4 samples strongly depend on the calcination temperature. When the calcination temperature is lower than 700 °C (500 and 600 °C), the ZnWO4/C composite nanocrystals can be obtained. Whereas the as-synthesized products are pure ZnWO4 nanocrystals featuring single crystalline under the higher calcination temperatures (700–900 °C). Due to the single crystalline structure and the optimal microstructures, the ZnWO4 sample obtained at 800 °C exhibits the superior electrochemical performances when applied as anode material for lithium-ion batteries such as excellent cyclic stability, higher capacity and better rate capability. The present work may provide the deep insight into the Zn-based materials derived from the ZIF-8, and paves a facile and general strategy for the precise control the microstructures and composition of the other transition metal oxides derived from ZIFs.

Purpose To explore the possibility of using amide proton transfer-weighted imaging (APTWI) for the identification and diagnosis of cervical squamous carcinoma (CSC), cervical adenocarcinoma (CA) and different levels of CSC. Materials and methods Seventy-six patients with newly diagnosed uterine cervical cancer (UCC) were studied prior to treatment, including 20 with poorly differentiated (Grade 3) CSC, 23 with moderately differentiated (Grade 2) CSC, 17 with well-differentiated (Grade 1) CSC, and 16 with CA (13 with poorly differentiated (Grade 3) CA and 3 with moderately differentiated (Grade 2) CA). Differences in the magnetization transfer ratio at 3.5 ppm (MTRasym (3.5 ppm)) were identified between CSC and CA and between high-level (Grade 3) CSC and low-level (Grade 2 and Grade 1) CSC, as well as among all three grades of CSC differentiation. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic thresholds and performance of the parameters. Spearman correlation analysis was used to examine the correlation between the MTRasym (3.5 ppm) and histological grade. Results The MTRasym (3.5 ppm) in CA was higher than that in CSC (P = 0.001). The MTRasym (3.5 ppm) in high-level CSC was higher than that in low-level CSC (P = 0.001). The MTRasym (3.5 ppm) was positively correlated with the grade of CSC differentiation (r = 0.498, P = 0.001). The MTRasym (3.5 ppm) in Grade 3 CSC was higher than that in Grade 2 and Grade 1 CSC (P = 0.02/0.01). No significant difference in the MTRasym (3.5 ppm) was found between Grade 2 CSC and Grade 1 CSC (P = 0.173). The area under the ROC curve (AUC) for the MTRasym (3.5 ppm) in distinguishing CSC and CA was 0.779, with a cut-off, sensitivity, and specificity of 2.97%, 60.0% and 82.5%, respectively. The AUC for distinguishing high-/low-level CSC was 0.756, with a cut-off, sensitivity, and specificity of 3.29%, 68.8% and 83.3%, respectively. Conclusion APTWI may be a useful technique for the identification and diagnosis of CSC, CA and different levels of CSC, which may have an important impact on clinical strategies for treating patients with UCC.

To investigate the effects of land-surface schemes in 2 regional climate models (RegCM3 and RegCM4.3.4) on the Tibetan Plateau (TP) climate simulation, 3 groups of 10 yr (1992-2001) simulation experiments were performed based on 2 land-surface schemes (BATS and CLM3.5). The simulations (RegCM3_BATS, RegCM4_BATS, and RegCM4_CLM) were compared with observed data by setting the same domain and initial and lateral atmospheric boundary conditions and using 30 km spatial resolution. The results showed that, compared to observed data, regional average annual mean temperature was underestimated by 1.22, 2.11, and 1.32 degrees C, and regional average annual precipitation was overestimated by 43.2, 49.8, and 18.4% in RegCM3_BATS, RegCM4_BATS, and RegCM4_CLM respectively. There were significant differences in simulated energy and water budget components among the 3 models resulting from the influence of the 2 different land-surface parameterization schemes, which impacted the simulated precipitation and temperature results through interaction between the land surface and the atmosphere. Therefore, climate simulation over the TP is very sensitive to the use of different land-surface schemes in regional climate models. Overall, use of RegCM4_CLM instead of RegCM_BATS resulted in a warmer and drier land surface and a better simulation of annual average spatial patterns of temperature and precipitation.

Regional climate models are widely used because of their high resolution. They are especially useful for regions with complex topography and with sparse observations such as the Qinghai-Xizang (Tibetan) Plateau (QTP). We examined the effectiveness of a regional model for simulating climate along the route of the Qinghai-Xizang (Tibetan) Railway (QTR) for use as a practical tool to guide maintenance and long-term management of the railway. We present a 20 yr (1982-2001) climate simulation using a regional climate model (RegCM3) over the QTP with 45 km spatial resolution, and compare the simulated results with the CRU TS3.1 climate data set and with meteorological station data. We investigated the distribution and variation of temperature and precipitation over the QTP and along the QTR. The results show that RegCM3 is able to reproduce the broad characteristics and spatial distribution of temperature over the QTP, including significant regional differences and interannual variability, compared with the CRU dataset. The annual cycle of simulated temperature is close to the observed, although simulated temperatures are slightly higher than observed in winter. RegCM3 also reproduces the broad spatial distribution of summer precipitation (when most precipitation occurs on the QTP) and in more spatial detail than the limited observational data. More precipitation is simulated than observed in the southern QTP, and less in the northern QTP. Although RegCM3 does reproduce annual variations of precipitation at the QTR stations reasonably well, there are some flaws. The simulated inter annual variations of precipitation are not as good as those for temperature. Further improvements to the land-surface parameterization scheme for local conditions are required in future work on the QTP.

On the basis of meteorological station records during 1961-2010, we investigate the variations of temperature and precipitation in the Qaidam Basin. Results show that climate warming is significant in the region of Qaidam Basin over the past 50years, with an average warming rate of 0.53 degrees C10a(-1). The largest and smallest warming rate happened at Mangya station (0.89 degrees C10a(-1)) and Lenghu station (0.24 degrees C10a(-1)), respectively. Seasonal warming was greatest in winter at eight meteorological stations, ranging from 0.43 degrees C10a(-1) (Lenghu station) to 1.01 degrees C10a(-1) (Delingha station). Since 1961, the annual precipitation has increased with a rate of 7.38mm10a(-1). Seasonal precipitation mainly increased in summer (4.02mm10a(-1)). The maximum precipitation increase occurred at Delingha station (25.09mm10a(-1)) and the minimum at Lenghu station (0.10mm10a(-1)). The elevation dependency of warming trends is unremarkable because most of the stations are located at lower altitudes. It is suggested that sunshine duration is related to the tendencies of temperature increase at different stations. Pollution emissions from industrial processes (i.e. brown clouds) and urbanization are the main factors contributing to the warming climate. Furthermore, the predominant weakening of zonal wind speed over the Tibetan Plateau resulted from the global warming also contributes to the climate warming in the Qaidam Basin. Consequently, the warming rate in the Qaidam Basin is much higher than in other regions over the Tibetan Plateau. The Qaidam Basin is thus considered to be the most susceptible region with the most significant warming in the Tibetan Plateau.

Spatial patterns of annual and seasonal precipitation over the source region of the Yellow River and the corresponding long-term trends for the period 1960–2013 are investigated using the meteorological station data. The spatial precipitation variability analysis shows an increasing gradient of precipitation from northeast to southwest in the study area. Annual, spring, summer, and winter precipitation present increasing trend, but autumn precipitation shows a decreasing trend in the last 50 years. It is also noted that the distribution of the intra-annual precipitation is very uneven, precipitation in rainy season (May–October) accounts for about 90 % of the total annual rain. Meanwhile, this research analyzes the spatial precipitation characteristic of the rainy season in 2013 (mainly from June to September). Based on the observed precipitation data and the meteorological station data, the rainy season precipitation that varies according to different topographic conditions is analyzed, and the regression model between recorded precipitation and geographical factors is built up too. The spatial distribution graph of the rainy season precipitation is generated on GIS platform by regression model and graphical features. This distribution shows a general northeast–southwest gradient of increasing rainy season precipitation in the study area and has detailed spatial precipitation characteristic along with altitude.

The temporal and spatial variation in soil temperature play a significant role in energy and water cycle between land surface and atmosphere on the Tibetan Plateau. Based on the observed soil temperature data (hourly data from 1 January 2001 to 31 December 2005) obtained by GAME-Tibet, the diurnal, seasonal and interannual variations in soil temperature at BJ site (31.37° N, 91.90° E; 4509 a.s.l.) near Naqu in the central Tibetan Plateau were analyzed. Results showed that the average diurnal variation in soil temperature at 4 and 20 cm depth can be described as sinusoidal curve, which is consistent with the variation of solar radiation. However, the average diurnal variation in soil temperature under 60 cm was very weak. The average diurnal amplitude in soil temperature decreased by the exponential decay function with the increase of soil depth (R2=0.92, p

The effects of different RegCM4 land-surface schemes on Tibetan Plateau (TP) precipitation simulations were investigated. Two groups of ten-year (1992–2001) simulation experiments (hereafter referred to as BATS and CLM) were performed based on two land-surface schemes (BATS and CLM3.5, resp.) and were compared with observed data using the same domain, initial, and lateral boundary conditions, cumulus convective scheme, and spatial resolution. The results showed that the CLM monthly precipitation more closely matched the observed data compared with BATS. BATS and CLM both overestimated summer precipitation in the northern TP but underestimated summer precipitation in the southern TP. However, CLM, because of its detailed land-surface process descriptions, reduced the overestimated precipitation areas and magnitudes of BATS. Compared to CN05, the regional average summer precipitation in BATS and CLM was overestimated by 34.7% and underestimated by 24.7%, respectively. Higher soil moisture, evapotranspiration, and heating effects in the BATS experiment triggered changes in atmospheric circulation patterns over the TP. Moreover, BATS simulated the lower atmosphere as warmer and more humid and the upper atmosphere (~150 hPa) as colder than the CLM simulations; these characteristics likely increased the instability for moist convection and produced more summer precipitation.