Understanding the Asian water tower requires a redesigned precipitation observation strategy.

The Asian water tower (AWT) serves as the source of 10 major Asian river systems and supports the lives of ~2 billion people. Obtaining reliable precipitation data over the AWT is a prerequisite for understanding the water cycle within this pivotal region. Here, we quantitatively reveal that the "observed" precipitation over the AWT is considerably underestimated in view of observational evidence from three water cycle components, namely, evapotranspiration, runoff, and accumulated snow. We found that three paradoxes appear if the so-called observed precipitation is corrected, namely, actual evapotranspiration exceeding precipitation, unrealistically high runoff coefficients, and accumulated snow water equivalent exceeding contemporaneous precipitation. We then explain the cause of precipitation underestimation from instrumental error caused by wind-induced gauge undercatch and the representativeness error caused by sparse-uneven gauge density and the complexity of local surface conditions. These findings require us to rethink previous results concerning the water cycle, prompting the study to discuss potential solutions.

Developed and developing world responsibilities for historical climate change and CO2 mitigation.

At the United Nations Framework Convention on Climate Change Conference in Cancun, in November 2010, the Heads of State reached an agreement on the aim of limiting the global temperature rise to 2 °C relative to preindustrial levels. They recognized that long-term future warming is primarily constrained by cumulative anthropogenic greenhouse gas emissions, that deep cuts in global emissions are required, and that action based on equity must be taken to meet this objective. However, negotiations on emission reduction among countries are increasingly fraught with difficulty, partly because of arguments about the responsibility for the ongoing temperature rise. Simulations with two earth-system models (NCAR/CESM and BNU-ESM) demonstrate that developed countries had contributed about 60-80%, developing countries about 20-40%, to the global temperature rise, upper ocean warming, and sea-ice reduction by 2005. Enacting pledges made at Cancun with continuation to 2100 leads to a reduction in global temperature rise relative to business as usual with a 1/3-2/3 (CESM 33-67%, BNU-ESM 35-65%) contribution from developed and developing countries, respectively. To prevent a temperature rise by 2 °C or more in 2100, it is necessary to fill the gap with more ambitious mitigation efforts.

Variations in global temperature and precipitation for the period of 1948 to 2010.

Climate change has impacts on both natural and human systems. Accurate information regarding variations in precipitation and temperature is essential for identifying and understanding these potential impacts. This research applied Mann-Kendall, rescaled range analysis and wave transform methods to analyze the trends and periodic properties of global and regional surface air temperature (SAT) and precipitation (PR) over the period of 1948 to 2010. The results show that 65.34% of the area studied exhibits significant warming trends (p < 0.05) while only 3.18% of the area exhibits significant cooling trends. The greatest warming trends are observed in Antarctica (0.32 °C per decade) and Middle Africa (0.21 °C per decade). Notably, 62.26% of the area became wetter, while 22.01% of the area shows drying trends. Northern Europe shows the largest precipitation increase, 12.49 mm per decade. Western Africa shows the fastest drying, -21.05 mm per decade. The rescaled range analysis reveals large areas that show persistent warming trends; this behavior in SAT is more obvious than that in PR. Wave transform results show that a 1-year period of SAT variation dominates in all regions, while inconsistent 0.5-year bands are observed in East Asia, Middle Africa, and Southeast Asia. In PR, significant power in the wavelet power spectrum at a 1-year period was observed in 17 regions, i.e., in all regions studied except Western Europe, where precipitation is instead characterized by 0.5-year and 0.25-year periods. Overall, the variations in SAT and PR can be consistent with the combined impacts of natural and anthropogenic factors, such as atmospheric concentrations of greenhouse gases, the internal variability of climate system, and volcanic eruptions.

Evaluation of historical CMIP6 model simulations and future projections of temperature over the Pan-Third Pole region.

The Pan-Third Pole (PTP) region, which encompasses the Eurasian highlands and their surroundings, has experienced unprecedented, accelerated warming during the past decades. This study evaluates the performance of historical simulation runs of the Coupled Model Intercomparison Project (CMIP6) in capturing spatial patterns and temporal variations observed over the PTP region for mean and extreme temperatures. In addition, projected changes in temperatures under four Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) are also reported. Four indices were used to characterize changes in temperature extremes: the annual maximum value of daily maximum temperature (TXx), the annual minimum value of daily minimum temperature (TNn), and indices for the percentage of warm days (TX90p) and warm nights (TN90p). Results indicate that most CMIP6 models generally capture the characteristics of the observed mean and extreme temperatures over the PTP region, but there still are slight cold biases in the Tibetan Plateau. Future changes of mean and extreme temperatures demonstrate that a strong increase will occur for the entire PTP region during the twenty-first century under all four SSP scenarios. Between 2015 and 2099, ensemble area-averaged annual mean temperatures are projected to increase by 1.24 °C/100 year, 3.28 °C/100 year, 5.57 °C/100 year, and 7.40 °C/100 year for the SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5 scenarios, respectively. For TXx and TNn, the most intense warming is projected in Central Asia. The greatest number of projected TX90p and TN90p will occur in the Southeast Asia and Tibetan Plateau, respectively.

High-quality reconstruction of China's natural streamflow.

Reconstruction of natural streamflow is fundamental to the sustainable management of water resources. In China, previous reconstructions from sparse and poor-quality gauge measurements have led to large biases in simulation of the interannual and seasonal variability of natural flows. Here we use a well-trained and tested land surface model coupled to a routing model with flow direction correction to reconstruct the first high-quality gauge-based natural streamflow dataset for China, covering all its 330 catchments during the period from 1961 to 2018. A stronger positive linear relationship holds between upstream routing cells and drainage areas, after flow direction correction to 330 catchments. We also introduce a parameter-uncertainty analysis framework including sensitivity analysis, optimization, and regionalization, which further minimizes biases between modeled and inferred natural streamflow from natural or near-natural gauges. The resulting behavior of the natural hydrological system is represented properly by the model which achieves high skill metric values of the monthly streamflow, with about 83% of the 330 catchments having Nash-Sutcliffe efficiency coefficient (NSE) > 0.7, and about 56% of the 330 catchments having Kling-Gupta efficiency coefficient (KGE) > 0.7. The proposed construction scheme has important implications for similar simulation studies in other regions, and the developed low bias long-term national datasets by statistical postprocessing should be useful in supporting river management activities in China.

Prognosis and predictive value of heat-shock proteins expression in oral cancer: A PRISMA-compliant meta-analysis.

BACKGROUND: Heat-shock proteins (HSP) is a key chaperone protein which maintains intracellular proteostasis and is expressed on the surface of solid and hematological malignancies. Several studies have reported paradoxical evidence of the association between HSP expression and prognosis of oral cancer. To address the discrepancy, we carried out the meta-analysis to assess the role of HSP such as: HSP70, HSP90, HSP27, HSP60, and HSP105 in susceptibility, progression, and prognosis of oral cancer. MATERIALS AND METHODS: We retrieved the PubMed, Embase, Web of science, China National Knowledge Infrastructure (CNKI), and Wanfang databases to acquire the eligible studies which were associated with HSP70, HSP90, HSP27, HSP60, and HSP105 protein expression and oral cancer. We applied hazard ratio (HR) and its 95% confidence interval (95% CI) to assess the value of HSP protein expression in overall survival of oral cancer; odds ratio (OR) and its 95% CI were used to evaluate the association of risk and clinical features of oral cancer. Funnel plot, Begg test, and Egger line regression test were utilized to observe publication bias among studies. All statistical analysis was performed with Stata 14.0 software (Stata Corporation, College Station, TX). RESULTS: A total of 26 studies were included in the present meta-analysis. On based of the results, HSP70 and HSP27 had no significant association with progression of oral cancer. However, the pooled HR and 95% CI revealed a significant well effects of HSP70 and HSP27 expression on survival of oral cancer. Moreover, the susceptibility of oral cancer was significantly associated with HSP70 and HSP60 overexpression. CONCLUSION: HSP70 and HSP27 protein overexpression might be valuable biomarkers for the prognosis of oral cancer. And HSP70 and HSP60 might have potential predictive effects on the risk of oral cancer.

The energy and water cycles under climate change.

Energy and water cycles have been a hot research topic in the global scientific community. The global climate change observed over the last century is having a profound impact on global and regional energy and water cycles, leading to more frequent extreme climatic events and affecting water security, ecosystem and socioeconomic development around the world. The impact is especially obvious over the highland regions such as the Tibetan Plateau. Here we have an interview with one of world's most renowned experts in hydroclimatology, Professor Soroosh Sorooshian from the University of California at Irvine, to share his insights on the subject of energy and water cycles.

Long noncoding RNA UCA1 promotes cell growth, migration, and invasion by targeting miR-143-3p in oral squamous cell carcinoma.

BACKGROUND: The long noncoding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) is dysregulated in many types of tumors; however, its role in oral squamous cell carcinoma (OSCC) remains unclear. This study aims to determine the effect of lncRNA UCA1 on OSCC. METHODS: Fifty-six paired OSCC and adjacent nontumorous tissues were collected and the levels of UCA1, miR-143-3p, and MYO6 in the tissues were evaluated by qRT-PCR. In in vitro experiments, cell viability, migration, and invasion were measured by, respectively, performing CCK-8, wound healing, and transwell assays. The target relationships among UCA1, miR-143-3p, and MYO6 were verified by dual-luciferase assay. Western blot and immunohistochemistry were carried out to determine the protein levels. Xenograft mouse model was established to explore the effects of UCA1 in vivo. RESULTS: Levels of UCA1 and MYO6 were increased significantly in OSCC, while the level of miR-143-3p was decreased compared with the adjacent nontumorous tissues. UCA1 promoted OSCC cell growth, migration, and invasion both in vitro and in vivo, while miR-143-3p reversed the progression. MYO6 was validated as a target for miR-143-3p, and MYO6 overexpression reversed the effects of miR-143-3p mimic on OSCC cells. CONCLUSION: LncRNA UCA1 contributes to the proliferation and metastasis of OSCC cells by targeting miR-143-3p and upregulating its downstream gene MYO6. UCA1 could serve as a promising novel target therapy for treatment of OSCC.

The mutual effects of graphene oxide nanosheets and cadmium on the growth, cadmium uptake and accumulation in rice.

The broad application and unique properties of graphene oxide (GO) nanosheets make them interact with other pollutants and subsequently alter their behaviors and toxicities. However, investigation on the effects of GO nanosheets on plant uptake of co-occurring heavy metals is scarce. We evaluated the mutual effects of cadmium (Cd) at 1 mg/L and different concentrated GO nanosheets (0, 1 and 10 mg/L) on the rice seed germination, further seedling growth, Cd uptake and accumulation in rice roots and shoots in a hydroponic system. The effects of GO were concentration dependent. GO alone at 1 mg/L showed no apparent effects, while GO alone at 10 mg/L accelerated the rice seed germination and root growth due to the improved water uptake. Cd alone showed adverse effects on the rice seed germination, which was alleviated by the presence of GO at 1 or 10 mg/L. GO at 10 mg/L also increased the membrane permeability, thus enhancing Cd uptake by rice roots and shoots. These results indicate that GO can change the effects of Cd on the rice seed germination and Cd uptake as well as accumulation in the roots and shoots of rice seedlings, which is helpful for understanding the fate and ecotoxicological impacts of both GO and Cd.

Simultaneous removal of U(VI) and Re(VII) by highly efficient functionalized ZIF-8 nanosheets adsorbent.

The simultaneously efficient removal of cationic and anionic radionuclides is an important and challenging topic for nuclear waste remediation as well as environmental protection. Herein, monoclinic ZIF-8 nanosheets modified with ethyleneimine polymer (denoted as ZIF-8/PEI) was achieved and used to determine the capture behaviors of both U(VI) oxycations and Re(VII) oxyanions from aqueous solution. ZIF-8/PEI assemblies showed a maximum U(VI) and Re(VII) uptake capacity of 665.3 (pH 5.0) and 358.2 mg/g (pH 3.5), respectively. Experimental, spectroscopic and theoretical calculation results directly unraveled that U(VI) adsorption onto ZIF-8/PEI assemblies was mainly ascribed to the coordination with abundant amino groups and weakly due to the Zn terminal hydroxyl groups, while anion exchange mechanism contributed predominantly to the Re(VII) sequestration. This work not only sheds light on the interaction mechanisms of simultaneous capture of U(VI) and Re(VII) but also highlights the versatile material design of cationic and anionic radionuclide immobilization in radioactive wastewater remediation.

MiR-155-5p promotes oral cancer progression by targeting chromatin remodeling gene ARID2.

BACKGROUND: Dysregulation of miRNAs is associated with aberrant migration and invasion by suppressing relevant target genes in multiple cancers, including oral squamous cell carcinoma (OSCC). Accumulating evidence suggests that microRNA-155-5p is involved in carcinogenesis and tumor progression. However, the exact function and molecular mechanism of miR-155-5p in OSCC remain unclear. This study aimed to investigate the function of miR-155-5p and the molecular mechanisms underlying the influencing progression of OSCC. METHODS: The miR-155-5p expression level in the OSCC tissues and oral cancer cell lines were determined by the qRT-PCR. Gain-of-function and knockdown approach were used to examine the effect of miR-155-5p on cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of OSCC. The luciferase reporter assay was applied to confirm the AT-rich interactive domain 2 (ARID2) as a potential target of miR-155-5p, and the rescue experiment was employed to verify the roles of the miRNA-155-5p-ARID2 axis in OSCC progression. Immunohistochemical staining was used to detect ARID2 expression in another cohort sample tissues from OSCC patients. RESULTS: MiR-155-5p was significantly upregulated in OSCC tissues and cell lines. The miR-155-5p expression level was positively correlated with tumor size, TNM stage, histological grade and lymph node metastasis of OSCC patients. Functional assays demonstrated that miR-155-5p enhanced OSCC cell proliferation, migration and invasion. Mechanistically, ARID2 was identified as a direct target and functional effector of miR-155-5p in OSCC. Furthermore, ARID2 overexpression could rescue the aberrant biological function by overexpressed miR-155-5p in OSCC cells. Notably, we showed that ARID2 could be used as an independent prognosis factor in OSCC. CONCLUSIONS: Our results suggest that miR-155-5p facilitates tumor progression of OSCC by targeting ARID2, and miR-155-5p-ARID2 axis may be a potential therapeutic target of OSCC.

Functional analysis of long-chain non-coding RNA in oral squamous cell carcinoma.

BACKGROUND: This study aimed to investigate the expression profile of long-chain non-coding RNA (lncRNA) in oral squamous cell carcinoma (OSCC) and to explore the biological functions of differentially expressed lncRNA in the cancer tissues as compared with adjacent normal tissues, and the differentially expressed lncRNAs related to OSCC were screened. METHODS: High-throughput lncRNA microarray assay was used to detect the expression of lncRNA and mRNA in the OSCC tissues and adjacent normal tissues from five patients. The expression profiles of the lncRNA and mRNA in the cancer tissues and adjacent normal tissues were analyzed and the differentially expressed lncRNA and mRNAs were identified. The differentially expressed mRNA was analyzed with GO, Pathway and disease annotation enrichment database, and the mRNAs related to the tumor and the lncRNA-mRNA co-expression network were employed to screen the key lncRNA related to the occurrence and development of OSCC. RESULTS: A total of 3,022 differentially expressed lncRNAs and 4,364 differentially expressed mRNAs were identified in the OSCC tissues as compared with adjacent normal tissues. A further analysis revealed 130 major differentially expressed mRNAs related to the tumor. When the correlation was >0.99 or <-0.99 and P value was <0.05, there were 73 differentially expressed mRNA in case of mRNA /lncRNA co-expression. The intersection of two gene symbols resulted in the nine lncRNAs closely related to the OSCC, in which five showed up-regulation and six had down-regulation. Based on the co-expression of the lncRNAs and mRNAs (correlation 40.99 or correlation -0.99 and P value <0.05), there were differentially expressed mRNAs with co-expression with lncRNA. CONCLUSIONS: The differentially expressed lncRNAs identified in this study are related to the occurrence and development of OSCC. This may provide new therapeutic targets and biomarkers for OSCC and is also helpful for further investigation of pathogenesis of OSCC.

Nitrogen-doped porous carbon-based fluorescence sensor for the detection of ZIKV RNA sequences: fluorescence image analysis.

Many studies have demonstrated that metal-organic frameworks (MOFs) are universal fluorescence quenchers for DNA/RNA detection. Nevertheless, the structural stability of many MOFs is relatively weak, which limits their practical applications. Thus, it remains a great interest to develop constitutionally stable nano biosensor suitable for application in the complex environment. Herein, a new angle of nitrogen-doped porous carbon (NPC) obtained from MOFs-based precursors by virtue of a simple method was applied as a nano biosensor for the fluorescence detection of Zika virus (ZIKV) RNA sequences. The fluorescence signal capturing was carried out by using a charge-coupled device (CCD)-based imaging system. The NPC could adsorb TAMRA-tagged ZIKV RNA probe (P-DNA) to form P-DNA@NPC complex accompanied by substantial fluorescence quenching. Upon adding the complementary target RNA (T-RNA), the P-DNA could release from NPC by forming a double-stranded hybrid and induce the fluorescence recovery. The P-DNA@NPC complex was valid and reliable for ZIKV RNA sequences assay with a limit of detection (LoD) at 0.23 nM, which is superior to many of the previously reported fluorescent DNA sensors. Moreover, it could distinguish mismatched RNA and was effective in detecting ZIKV RNA sequences spiked in the human saliva sample. We envision that this study would offer an interesting new angle on the potential integrating application of carbon nanomaterials and CCD-based fluorescence imaging platform in the field of nucleic acid assay.

Mutual effects behind the simultaneous removal of toxic metals and cationic dyes by interlayer-expanded MoS2 nanosheets.

Simultaneous removal of coexisting metals and dyes from industrial wastewaters is challenging, and the mutual effects behind the co-adsorption of these pollutants remain unclear. Herein, interlayer-expanded MoS2 (IE-MoS2) nanosheets prepared by a one-pot simple and scalable method were tested to simultaneously remove toxic metals and cationic dyes. The adsorption capacities of IE-MoS2 nanosheets were 499, 423, 500, 355, and 276 mg/g for Pb(II), Cu(II), methylene blue, malachite green, and rhodamine B, respectively, in a mono-contaminant system. Interestingly, the sequestration amount of Pb(II) was dependent on the concentrations of dyes in the binary Pb(II)-dye systems, while uptake of cationic dyes was almost not influenced by coexisting Pb(II). The simultaneous adsorption mechanism was further confirmed by spectroscopic methods. The IE-MoS2 nanosheets were easily regenerated and reused for six adsorption-desorption cycles without structure destruction, thus avoiding the potential hazards of nanomaterial to the ecosphere. More interestingly, high-efficiency uptake of Pb(II) from intentionally contaminated natural water and model textile effluent was obtained by using a column filled with IE-MoS2 nanosheets. In summary, IE-MoS2 nanosheets with facile and scalable synthesis method, efficient adsorption performance, and excellent reusability showed potential promise for the integrative treatment of complex wastewater bearing both metals and organic pollutants.

Adsorption of 17ß-estradiol from aqueous solutions by a novel hierarchically nitrogen-doped porous carbon.

A novel interconnected hierarchically nitrogen-doped porous carbon (IHNPC) derived from metal-organic framework-based composites was obtained via a facile method and applied as a superior material for the capture of 17ß-estradiol (E2) from aqueous solution. The adsorption kinetic and isotherm behaviors were well described by the pseudo-second-order and Langmuir models. Various thermodynamic parameters uncovered that E2 adsorption onto IHNPC was spontaneous and exothermic. Moreover, the adsorption rate of E2 by IHNPC didn't decrease with increasing water salinity in the presence of electrolyte ions and humic acids. Naturally occurring aquatic particles can enhance (i.e., Al2O3), decrease (i.e., kaolin and SiO2) or have no obvious effects (i.e., montmorillonite) on the adsorption rate of E2 by IHNPC. The high adsorption capacity and remarkable adsorption selectivity of IHNPC highlighted the application of IHNPC for the capture of E2 and provided understanding of the fate and transport of E2 in natural aquatic environments.

Global heat stress on health, wildfires, and agricultural crops under different levels of climate warming.

The effects of heat stress are spatially heterogeneous owing to local variations in climate response, population density, and social conditions. Using global climate and impact models from the Inter-Sectoral Impact Model Intercomparison Project, our analysis shows that the frequency and intensity of heat events increase, especially in tropical regions (geographic perspective) and developing countries (national perspective), even with global warming held to the 1.5 °C target. An additional 0.5 °C increase to the 2 °C warming target leads to >15% of global land area becoming exposed to levels of heat stress that affect human health; almost all countries in Europe will be subject to increased fire danger, with the duration of the fire season lasting 3.3 days longer; 106 countries are projected to experience an increase in the wheat production-damage index. Globally, about 38%, 50%, 46%, 36%, and 48% of the increases in exposure to health threats, wildfire, crop heat stress for soybeans, wheat, and maize could be avoided by constraining global warming to 1.5 °C rather than 2 °C. With high emissions, these impacts will continue to intensify over time, extending to almost all countries by the end of the 21st century: >95% of countries will face exposure to health-related heat stress, with India and Brazil ranked highest for integrated heat-stress exposure. The magnitude of the changes in fire season length and wildfire frequency are projected to increase substantially over 74% global land, with particularly strong effects in the United States, Canada, Brazil, China, Australia, and Russia. Our study should help facilitate climate policies that account for international variations in the heat-related threats posed by climate change.

2015-16 floods and droughts in China, and its response to the strong El Niño.

The features of hydro-climate anomalies in China in 2015-2016 were analyzed in great detail, together with possible responses to the super 2015-16 El Niño event. The 2015-16 El Niño is characterized as a "strong" event in terms of the duration, intensity, and coverage of warming sea surface temperature (SST) in the central and east-central equatorial Pacific in comparison to the 1982-83 and 1997-98 events. The floods and droughts frequency were incidence of floods and droughts per year, respectively. The results show several significant anomalies in China: 1) About 9%-173% of precipitation variance in 2015-16 can be attributed to this El Niño; 2) There was significant inconformity between hydro-climate anomalies and the occurrence of floods and droughts; 3) Flood frequency has increased, especially over Southeast China and the Yangtze River in the summer of 2016; 4) Drought frequency has also increased, especially over Northeast China in summer of 2015, Northwest China in spring of 2016, and most parts in winter of 2015. The response of China hydro-climate anomalies to the 2015-16 El Niño was significant via El Niño and warm Indian Ocean induced circulation anomalies, which were characterized by stronger and more westward-extending western Pacific subtropical high and anomalous water vapor transport. Knowledge of the response of hydro-climate extremes to El Niño can provide valuable information to improve flood and drought forecasting in China.

Clinical significance of cytokeratin in the cervical lymph nodes of patients with mandibular gingival squamous cell carcinoma.

The present study aims to analyze the expression of broad spectrum cytokeratin in the cervical lymph nodes of patients with mandibular gingival squamous cell carcinoma and explore the metastasis of mandibular gingival squamous cell carcinoma in cervical lymph nodes. This study included 42 patients with mandibular gingival squamous cell carcinoma, which was staged according to the clinical staging criteria by International Union Against Cancer 2002 (UICC) and the Level staging method of cervical lymph node by American Academy of Otolaryngology-Head and Neck Surgery 1991. Monoclonal mouse anti-human cytokeratin (AE1/AE3) antibody was used in immunohistochemical examination and hematoxylin and eosin (H&E) staining. All positive sections by H&E staining were also positive by immunohistochemistry (IHC). The positive rate of routine H&E staining and serial-section H&E staining was 8.03 and 9.57%, respectively, the positive rate of IHC was 12.82%. The positive rate of IHC was significantly different with that of routine H&E staining (χ2=7.17, P<0.01), yet not significantly different with that of serial-section H&E staining (χ2=3.10, P>0.05). Lymph node metastasis was mainly in Level I, II and III, both serial-section H&E staining and IHC showed lymph node metastasis in Level IV for advanced patients. IHC showed 19 lymph node micrometastasis in 12 patients, while neither serial-section nor routine H&E staining showed micrometastasis. Lymph node dissection of hyoid bone (mainly in Level I, II and III) could be used for early patients, and the dissection could be expanded to Level IV for advanced patients.

An estimate of human and natural contributions to changes in water resources in the upper reaches of the Minjiang River.

Climate change and human activities have changed the spatial-temporal distribution of water resources, especially in a fragile ecological area such as the upper reaches of the Minjiang River (UMR) basin, where they have had a more profound effect. The average of double-mass curve (DMC) and Distributed Time-Variant Gain Hydrological Model (DTVGM) are applied to distinguish between the impacts of climate change and human activities on water resources in this paper. Results indicated that water resources decreased over nearly 50 years in the UMR. At the annual scale, contributions of human activities and climate change to changes in discharge were -77% and 23%, respectively. In general, human activities decreased the availability of water resources, whereas climate change increased the availability of water resources. However, the impacts of human activities and climate change on water resources availability were distinctly different on annual versus seasonal scales, and they showed more inconsistency in summer and autumn. The main causes of decreasing water resources are reservoir regulation, and water use increases due to population growth. The results of this study can provide support for water resource management and sustainable development in the UMR basin.

Detecting the quantitative hydrological response to changes in climate and human activities.

Understanding the relative contributions of climate change and human activities to changes in runoff is important for sustainable management of regional water resources. In this study, we systematically review ten commonly used quantitative methods drawn from three main categories-empirical statistics, elasticity-based methods, and hydrological modeling. We explain the calculation processes for the different methods and summarize their applications and characteristics. Then, using the Yanhe River basin as a case study, we employ all ten methods to separate out the effects of climate change and human activities on changes in runoff. The results show that climate change played a dominant role in the decline in runoff in the Yanhe River basin. Climate change was estimated to account for 46.1%-60.8% (mean 54.1%) of the total decrease in runoff, whereas human activities accounted for 39.1%-53.9% (mean 45.9%). Elasticity-based methods and hydrological modeling produced similar estimates, but the estimates made using empirical statistics were different. Empirical statistics were not a suitable method for the Yanhe River basin. We also discuss the factors that influence the different methods and the applicable conditions for each methodological category.