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Tetracycline (TC) represents a broad-spectrum antibiotic to treat bacterial infections. In this study, a ratiometric fluorescence (FL) probe was developed for the detection of TC in water samples by using waste printing paper extract as a FL indicator. In this ratiometric probe, the emission of printing paper extract at 436 nm gradually decreased and the emission of mixed solution at 538 nm significantly increased with the sequential addition of TC upon being excited at 390 nm, coupled with a remarkable FL color change from bright blue to faint yellow. Thus, a ratiometric F538 /F436 FL probe was created for TC detection by simply mixing the printing paper extraction and TC. Under the optimized conditions, the linear range from 1-100 μM and a detection limit of 0.48 μM (S/N = 3) for TC were obtained. Importantly, the FL probe can be easily prepared with rapid response, high sensitivity, and good selectivity. The application of the waste printing paper extract for the detection of TC in environmental water samples was demonstrated.

Sunshine duration (SD) has recently received a great deal of attention as it relates to climatic research under global climate change. Here, we explored the spatiotemporal variability of SD in the Pearl River Delta (PRD) in mainland China during 1960-2018. A novel equation was proposed to assess the relative influence of 5 climatic variables on variability in SD based on random forest (RF) analysis. The dominant variables, their temporal evolution driving SD, and their spatial distribution are discussed. Results showed that SD in the PRD varied significantly, both at a temporal and spatial scale. At the spatial scale, SD decreased gradually from the southeast to the northwest; in most areas, SD exhibited a downward trend. Temporally, annual SD decreased significantly at a rate of 57.01 h decade-1 during 1960-2018 (p < 0.01), suggesting a continuous dimming; an abrupt change occurred in 1981 with a main oscillation period of 3.0 yr. The annual mean SD showed a positive correlation with wind speed (WS) and a negative correlation with the other 4 climatic variables. Precipitation was determined to be the most influential variable, with a relative influence rate of 34.46%. The relative influence rates of the 5 examined variables changed over time, and their spatial distribution demonstrated significant diversity across different regions. Aerosols were found to be a factor driving SD in the PRD, but could not completely explain the change in SD in recent years. These findings provide a reference for studying the spatiotemporal variability of SD and detecting its influencing factors in highly urbanized areas.

Lithium-ion hybrid capacitors (LIHCs) is a promising electrochemical energy storage devices which combines the advantages of lithium-ion batteries and capacitors. Herein, we developed a facile multistep pyrolysis method, prepared an amorphous structure and a high-level N-doping carbon nanotubes (NCNTs), and by removing the Co catalyst, opening the port of NCNTs, and using NCNTs as anode material. It is shows good performance due to the electrolyte ions enter into the electrode materials and facilitate the charge transfer. Furthermore, we employ the porous carbon material (APDC) as the cathode to couple with anodes of NCNTs, building a LIHCs, it shows a high energy density of 173 Wh/kg at 200 W/kg and still retains 53 Wh/kg at a high power density of 10 kW/kg within the voltage window of 0–4.0 V, as well as outstanding cyclic life keep 80% capacity after 5000 cycles. This work provides an opportunity for the preparation of NCNTs, that is as a promising high-performance anode for LIHCs.

Flooding is a major natural disaster that has brought tremendous losses to mankind throughout the ages. Even so, floods can be controlled by appropriate measures to minimize loss and damage. Flood risk assessment is an essential analytic step in preventing floods and reducing losses. Identifying previous flood risk and predicting future features are conducive to understanding the changing patterns and laws of flood risk. Taking the Dongjiang River basin as a study case, we assessed and regionalized flood risk in 1990, 2000, and 2010 from the past perspective and explored dynamic expansion during 1990-2010. Then, we projected land-use type, population, and gross domestic product in 2030 and 2050 and finally assessed and regionalized the risk from a future perspective. Results show that areas with very high risk accounted for 14.98-18.08% during 1990-2010; approximately 13.90% areas of the basin transformed from lower-level risk to higher-level risk whereas 9.07% fell from a higher level to a lower level during the period. For the future scenario, areas with very high and high risk in 2030 and 2050 are expected to account for 21.55% and 24.84%, respectively. Generally, our study can better identify changes in flood risk at a spatial scale and reveal the dynamic evolution rule, which provides a synthetical means of flood prevention and reduction, flood insurance, urban planning, and water resource management in the future under global climate change, especially for developing or high-speed urbanization regions.

With the release of Global Precipitation Measurement Integrated Multi-satellitE Retrievals for GPM products, hydrologists can obtain precipitation data with higher resolution and wider coverage. However, great uncertainties still exist in the accuracy and hydrological utility of these data in alpine and gorge regions with sparse gauge stations. In this study, the Lancang River Basin in China was used as an example, and near real-time products (IMERG-E and IMERG-L) and post-processed products (IMERG-F and TMPA 3B42-V7) were evaluated. Different indexes and methods were applied to evaluate the accuracy of these products. The variable infiltration capacity hydrological model was adopted to evaluate their hydrological utility. The following findings were obtained. (1) Compared with observed precipitation data, the near real-time products tend to underestimate, while the post-processed products tend to overestimate precipitation. The performance of the four products in winter is poor. (2) IMERG products offer improvements in two aspects: first, the near real-time products achieve good accuracy and second, the detectability and the accuracy in gorge areas have been greatly improved. (3) The near real-time products have the potential for hydrological applications. The best simulation result was obtained based on IMERG-F, followed by 3B42-V7, IMERG-E, and IMERG-L. (4) The four products can provide reliable precipitation data for the hydrological application over the Lancang River Basin.

Understanding the trend characteristics of design rainstorm and spatial heterogeneity of extreme precipitation is of great importance to reduce disasters induced by rare extreme precipitation. Using a high-resolution (0.5° × 0.5°) daily gridded data set of precipitation across mainland China from 1961 to 2013, this study investigated the historical changing trend and spatial heterogeneity of design rainstorm using the 30-year moving window method (30YM). Differences in the quantification of the design rainstorm were compared for the use of the 30YM and the 30-year-based increasing window method (30YBI). The results show that a significant increasing intensity but no spatially uniform trend of design rainstorm can be observed across mainland China based on the 30YM analysis. The south, east, and northeast China mainly showed an increasing trend, but the southwest and north China presented a decreasing trend. The spatial heterogeneity of the design rainstorm was greatly enhanced if the nonstationarity assumption was adopted on the national scale. The heterogeneity showed an increasing trend mainly in southeast, north, northeast, and northwest China, and a decreasing trend in southwest and west China, indicating significant regional variation in spatial heterogeneity. For most areas of mainland China, especially for southeastern, northeastern, and western China, use of the most recent precipitation sub-series to quantify the design rainstorm may weaken the potential nonstationarity and guarantee the safety of infrastructure in these areas where design rainfall increases.

This study mainly evaluated and compared satellite-based quantitative precipitation estimate products (QPEs) for the drought monitoring of mainland China. Two long-term (more than 30 a) satellite-based QPEs, i.e. the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR) and the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS), and a short-term (18a) QPE, i.e. the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) 3B42V7 are considered. Two widely used drought indices, the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI), are chosen to evaluate the drought monitoring utility. The 3B42V7 was only evaluated with PDSI due to the short data records. The results show that all the three QPEs perform satisfactorily in the eastern part of China when using both SPI and PDSI. However, their performances for west China could not be clearly determined due to the sparse gauge networks. 3B42V7 features best performance among the three QPEs in the evaluation using PDSI. To further spatiotemporally evaluate the drought utility of the QPEs, four typical drought-affected regions, i.e. northeast China (NEC), Huang-Huai-Hai plain (3HP), southwest China (SWC), and Loess plateau (LP) were extracted from mainland China for specific case studies. Temporally, all three QPEs are able to detect the typical drought of the four regions with both SPI and PDSI, and 3B42V7 presents the least deviation in PDSI estimate. Spatially, both CHIRPS and 3B42V7 accurately catch the spatial centers and extent of the typical drought events, while PERSIANN-CDR could not match the spatial patterns of drought events well. Generally, the long-term PERSIANN-CDR and CHIRPS perform satisfactorily in drought detection and are suitable for drought utility; however, caution should be applied when studying the spatial variation of drought using PERSIANN-CDR. CHIRPS could also be suitable for near-real-time drought monitoring for its shorter time latency of data release. The short-term 3B42V7 also performs well in many cases, and has thus considerable potential for drought monitoring.

Understanding the internal microstructure of silkworm cocoons is beneficial for developing biomaterials. In this study, both domesticated (Bombyx mori) and wild silkworm cocoons (Antheraea pernyi and Antheraea mylitta) were studied using the X-ray micro computed tomography (XCT), and their microstructural characteristics were analyzed quantitatively. It is discovered that fiber widths of the cocoons significantly increased from the inner to the outer layer. It is also detected that for the three cocoons in the core regions, unaffected by the surface condition, from the inner to the outer layer, fiber percentages show significant decrease initially, and then no obvious change, and the fibers in different layers are more aligned towards the short diameter of the cocoon, and Antheraea mylitta fibers display the highest fiber orientation. Fractal dimension of the domestic cocoon was significantly reduced, whereas those of the wild cocoons display no obvious change. The two wild cocoons show significantly higher maximum strength, initial modulus and breaking energy than the domesticated cocoons, and Antheraea pernyi performs better maximum strength and breaking energy than Antheraea mylitta. The tensile property is closely related to fiber percentage, fiber intersectional density and fractal dimension.

Availability of precipitation data at high spatial and temporal resolution is crucial for the understanding of precipitation behaviors that are determinant for environmental aspects such as hydrology, ecology, and social aspects like agriculture, food security, or health issues. This study evaluates the performance of 3B42-V7 satellite-based precipitation product on extreme precipitation estimates in China, by using the Fuzzy C-Means algorithm and L-moment-based regional frequency analysis method. The China Gauge-based Daily Precipitation Analysis (CGDPA) product is employed to measure the estimation biases of 3B42-V7. Results show that: (1) for most regions of China, the Generalized Extreme Value and Generalized Normal distributions are preferable for extreme precipitation estimates; (2) the extreme precipitation estimations of 3B42-V7 for different return periods have a high correlation with those of CGDPA, with biases within 25% for a majority of China on extreme precipitation estimates.

Rapid urbanisation and economic growth in developing Asian countries have exacerbated their exposure to flood hazards, particularly evident in low-lying urban cities that are currently facing increasing risks from extreme precipitations, likely made worse by the impending climate change. We present a set of simplified indices representative of the characteristics of rainfall-runoff process for evaluating pluvial flood hazard using the fuzzy comprehensive evaluation method. The highly urbanised Pearl River Delta (PRD) region in southern China is studied as an example of mapping the regional pluvial flood hazard and assessing the socio-economic exposure at risk. The developed hazard map captures the broad patterns of high flood hazard zones when compared with reported surface water flooding hotspots and the PRD riverine flood map from the 2015 Global Assessment Report. Further analysis on the regional socio-economic profiles suggests that most PRD cities are faced with large flood loss potential, with estimates of approximate 23 million people and 2.4 trillion RMB Gross Domestic Product (GDP) exposed to high flood hazard. Mega cities Guangzhou and Shenzhen top the ranking with over 20% to 40% of their dense urban settlements in the high flood hazard zone. This highlights the impact of human activities on the natural surface runoff process, and the need for robust flood hazard assessment for better understanding and design of holistic solutions towards more adequate flood mitigation systems for continuous urbanisation and future climate conditions. Accepted version This work was partially supported by the Sino-Singapore International Joint Research Institute (Project No. 205-A017020) and the National Key R&D Program of China (2018YFC1508200).

Spatial interpolation of precipitation data is an essential input for hydrological modelling. At present, the most frequently used spatial interpolation methods for precipitation are based on the assumption of stationary in spatial autocorrelation and spatial heterogeneity. As climate change is altering the precipitation, stationary in spatial autocorrelation and spatial heterogeneity should be first analysed before spatial interpolation methods are applied. This study aims to propose a framework to understand the spatial patterns of autocorrelation and heterogeneity embedded in precipitation using Moran's I, Getis–Ord test, and semivariogram. Variations in autocorrelation and heterogeneity are analysed by the Mann–Kendall test. The indexes and test methods are applied to the 7-day precipitation series which are corresponding to the annual maximum 7-day flood volume (P-AM7FV) upstream of the Changjiang river basin. The spatial autocorrelation of the P-AM7FV showed a statistically significant increasing trend over the whole study area. Spatial interpolation schemes for precipitation may lead to better estimation and lower error for the spatial distribution of the areal precipitation. However, owing to the changing summer monsoons, random variation in the spatial heterogeneity analysis shows a significant increasing trend, which reduces the reliability of the distributed hydrological model with the input of local or microscales.

To evaluate the accuracy and applicability of the TMPA 3B42-V7 precipitation product for the Lancang River basin, we used different statistical indices to explore the performance of the product in comparison to gauge data. Then, we performed a hydrologic simulation using the Variable Infiltration Capacity (VIC) hydrological model with two scenarios (Scenario I: streamflow simulation using gauge-calibrated parameters; Scenario II: streamflow simulation using 3B42-V7-recalibrated parameters) to verify the applicability of the product. The results of the precipitation analysis show good accuracy of the V7 precipitation data. The accuracy increases with the increase of both space and time scales, while time scale increases cause a stronger effect. The satellite can accurately measure most of the precipitation but tends to misidentify non-precipitation events as light precipitation events (

A rapid increase in the risk of urban flooding in recent years has urged the research community to enrich approaches to deal with urban flooding problems. The state-of-the-art approach consists of coupling one-dimensional (1D) and two-dimensional (2D) hydrodynamic models. However, at present such coupled 1D/2D models are mostly commercial and complex to build and run. The present study has proposed a new simple approach for modeling urban flooding by coupling Storm Water Management Model (SWMM) and LISFLOOD-FP, two widely used freewares with relatively simple components. The coupled model was firstly applied to the Shiqiao Creek District in Dongguan City, South China, and verified against four major historical floods. The testing results demonstrate the capability of the coupled model in predicting urban flooding. The successful coupling of SWMM and LISFLOOD-FP offers another simple, practical approach for urban flooding estimation, which can be readily used by non-expert users or those who do not have access to commercial modules.

Hydrological models have been widely applied in flood forecasting, water resource management and other environmental sciences. Most hydrological models calibrate and validate parameters with available records. However, the first step of hydrological simulation is always to quantitatively and objectively split samples for use in calibration and validation. In this paper, we have proposed a framework to address this issue through a combination of a hierarchical scheme through trial and error method, for systematic testing of hydrological models, and hypothesis testing to check the statistical significance of goodness-of-fit indices. That is, the framework evaluates the performance of a hydrological model using sample splitting for calibration and validation, and assesses the statistical significance of the Nash–Sutcliffe efficiency index (Ef), which is commonly used to assess the performance of hydrological models. The sample splitting scheme used is judged as acceptable if the Ef values exceed the threshold of hypothesis testing. According to the requirements of the hierarchical scheme for systematic testing of hydrological models, cross calibration and validation will help to increase the reliability of the splitting scheme, and reduce the effective range of sample sizes for both calibration and validation. It is illustrated that the threshold of Ef is dependent on the significance level, evaluation criteria (both regarded as the population), distribution type, and sample size. The performance rating of Ef is largely dependent on the evaluation criteria. Three types of distributions, which are based on an approximately standard normal distribution, a Chi square distribution, and a bootstrap method, are used to investigate their effects on the thresholds, with two commonly used significance levels. The highest threshold is from the bootstrap method, the middle one is from the approximately standard normal distribution, and the lowest is from the Chi square distribution. It was found that the smaller the sample size, the higher the threshold values are. Sample splitting was improved by providing more records. In addition, outliers with a large bias between the simulation and the observation can affect the sample values of Ef, and hence the output of the sample splitting scheme. Physical hydrology processes and the purpose of the model should be carefully considered when assessing outliers. The proposed framework in this paper cannot guarantee the best splitting scheme, but the results show the necessary conditions for splitting schemes to calibrate and validate hydrological models from a statistical point of view.

Drought is expected to increase in frequency, severity, and duration in the future due to global warming and this will greatly threaten the future socio-economic development. This study evaluates the spatiotemporal variation of future drought (2016–2100) in the Pearl River Basin (PRB) using the Palmer drought severity index (PDSI), the Variable Infiltration Capacity (VIC) model, and future climate projections based on the general circulation models (GCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) under three representative concentration pathway (RCP) scenarios. The results show that future drought conditions are expected to be more serious than historical (1960–2015) drought conditions in the PRB, especially under RCP8.5. The severity and variability of future drought conditions are also higher than for the historical period. The west Guangxi and South Guizhou provinces exhibit the highest increment in drought severity under the three RCP scenarios. At the seasonal scale, drought severity shows the highest increment in the winter with little change in summer; the summer drought severity increases in most areas of the PRB but the increment of the drought severity is lower than the winter. The number of future drought events is expected to decrease but the duration and severity are expected to increase, especially in the mid-west PRB and under high greenhouse gas (GHG) emission scenarios. In summary, in most areas of the PRB, the severity and variability of drought are expected to increase in the 21 st century, especially in the mid-west PRB and an increase in evapotranspiration is assumed to be the main underlying cause. Irrigation projects and agricultural production in the PRB might face serious threats of drought in the future.

Human activities and climate change have altered the spatial and temporal distribution of water availability which is a principal prerequisite for allocation of different water resources. In order to quantify the impacts of climate change and human activities on water availability and optimal allocation of water resources, hydrological models and optimal water resource allocation models should be integrated. Given that increasing human water demand and varying water availability conditions necessitate adaptation measures, we propose a framework to assess the effects of these measures on optimal allocation of water resources. The proposed model and framework were applied to a case study of the middle and lower reaches of the Hanjiang River Basin in China. Two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP4.5) were employed to project future climate, and the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the variability of flows under historical (1956–2011) and future (2012–2099) conditions. The water availability determined by simulating flow with the VIC hydrological model was used to establish the optimal water resources allocation model. The allocation results were derived under an extremely dry year (with an annual average water flow frequency of 95%), a very dry year (with an annual average water flow frequency of 90%), a dry year (with an annual average water flow frequency of 75%), and a normal year (with an annual average water flow frequency of 50%) during historical and future periods. The results show that the total available water resources in the study area and the inflow of the Danjiangkou Reservoir will increase in the future. However, the uneven distribution of water availability will cause water shortage problems, especially in the boundary areas. The effects of adaptation measures, including water saving, and dynamic control of flood limiting water levels (FLWLs) for reservoir operation, were assessed and implemented to alleviate water shortages. The negative impacts from the South-to-North Water Transfer Project (Middle Route) in the mid-lower reaches of the Hanjiang River Basin can be avoided through the dynamic control of FLWLs in Danjiangkou Reservoir, under the historical and future RCP2.6 and RCP4.5 scenarios. However, the effects of adaptation measures are limited due to their own constraints, such as the characteristics of the reservoirs influencing the FLWLs. The utilization of storm water appears necessary to meet future water demand. Overall, the results indicate that the framework for assessing the effects of adaptation measures on water resources allocation might aid water resources management, not only in the study area but also in other places where water availability conditions vary due to climate change and human activities.

Pre-occupation evaluation of latest generation satellite-based precipitation products (SPPs) is an essential step before the massive scale use. Taking the Beijiang River Basin as the case study, we used nine statistical evaluation indices and the Variable Infiltration Capacity (VIC) distributed hydrological model to quantitatively evaluate the performance and the hydrological utility of three Global Precipitation Measurement (GPM) Integrated Multi-satellitE Retrievals for GPM (IMERG) products: the near-real-time “Early” run and “Late” run IMERG products (IMERG-E and IMERG-L), and the post-real-time “Final” run IMERG product (IMERG-F) over south China during 2014–2015, with the last-generation Tropical Rainfall Measurement Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42-V7 product as comparison. The IMERG-F presents satisfactory accuracy with high correlation coefficient (CC = 0.63) and low relative bias (0.92%), while the IMERG-E and IMERG-L performs relatively poorly featuring low correlation (with CC of 0.49 and 0.52 respectively) with the ground observations. All of the three IMERG products present apparently higher probability of detection (POD, 0.64–0.67) but have higher false alarm ratio (FAR, ≧ 0.14) than the 3B42-V7. The hydrological simulation under scenario I (model calibrated by the gauge observations) shows that, the IMERG-F, with a high Nash–Sutcliffe coefficient of efficiency (NSCE) of 0.742, presents better hydrological performance than the 3B42-V7; the IMERG-E and IMERG-L perform poorly for the whole simulation period with NSCE lower than 0.35 and relative bias higher than 28% while perform satisfactorily during the flood season with apparently higher NSCE of 0.750 and 0.733 respectively. The hydrological simulation under scenario II (model calibrated by the 3B42-V7) shows that the performance of all the IMERG products was significantly improved. Generally, the IMERG-F has high accuracy and good hydrological utility, while the IMERG-E and IMERG-L products have satisfactory hydrological utility during the flood season and thus have great potential for the real-time application such as flood forecasting. The late-run IMERG-L presents little improvement in performance comparing with the early-run IMERG-E, therefore, the timelier IMERG-E is recommended to be firstly considered.

With high spatio-temporal resolution and wide coverage, satellite-based precipitation products can potentially fill the deficiencies of traditional in situ gauge precipitation observations and provide an alternative data source for ungauged areas. However, due to the relatively poor accuracy and high uncertainty of satellite-based precipitation products, it remains necessary to assess the quality and applicability of the products for each investigated area. This study evaluated the accuracy and error of the latest Tropical Rainfall Measuring Mission Multi-satellites Precipitation Analysis 3B42-V7 satellite-based precipitation product and validated the applicability of the product for the Beijiang and Dongjiang River Basins, downstream of the Pearl River Basin in China. The study first evaluated the accuracy, error, and bias of the 3B42-V7 product during 1998–2006 at daily and monthly scale via comparison with in situ observations. The study further validated the applicability of the product via hydrologic simulation using the variable infiltration capacity hydrological model for three hydrological stations in the Beijiang River Basin, considering two scenarios: a streamflow simulation with gauge-calibrated parameters (Scenario I) and a simulation after recalibration with the 3B42-V7 product (Scenario II). The results revealed that (a) the 3B42-V7 product produced acceptable accuracy both at the daily scale and high accuracy at the monthly scale while generally tending to overestimate precipitation; (b) the product clearly overestimated the frequency of no rainfall events at the grid cell scale and light rainfall (

Water demand prediction (WDP) is the basis for water allocation. However, traditional methods in WDP, such as statistical modeling, system dynamics modeling, and the water quota method have a critical disadvantage in that they do not consider any constraints, such as available water resources and ecological water demand. This study proposes a two-stage approach to basin-scale WDP under the constraints of total water use and ecological WD, aiming to flexibly respond to a dynamic environment. The prediction method was divided into two stages: (i) stage 1, which is the prediction of the constrained total WD of the whole basin (T w ) under the constraints of available water resources and total water use quota released by the local government and (ii) stage 2, which is the allocation of T w to its subregions by applying game theory. The WD of each subregion (T s ) was predicted by calculating its weight based on selected indicators that cover regional socio-economic development and water use for different industries. The proposed approach was applied in the Dongjiang River (DjR) basin in South China. According to its constrained total water use quota and ecological WD, T w data were 7.92, 7.3, and 5.96 billion m3 at the precipitation frequencies of 50%, 90%, and 95%, respectively (in stage 1). Industrial WDs in the domestic, primary, secondary, tertiary, and environment sectors are 1.08, 2.26, 2.02, 0.44, and 0.16 billion m3, respectively, in extreme dry years (in stage 2). T w and T s exhibit structures similar to that of observed water use, mainly in the upstream and midstream regions. A larger difference is observed between T s and its total observed water use, owing to some uncertainties in calculating T w . This study provides useful insights into adaptive basin-scale water allocation under climate change and the strict policy of water resource management.

Rainfall-induced landslide susceptibility assessment is currently considered an effective tool for landslide hazard assessment as well as for appropriate warning and forecasting. As part of the assessment procedure, a credible index weight matrix can strongly increase the rationality of the assessment result. This study proposed a novel weight-determining method by using random forests (RFs) to find a suitable weight. Random forest weights (RFWs) and eight indexes were used to construct an assessment model of the Dongjiang River basin based on fuzzy comprehensive evaluation. The results show that RF identified the elevation (EL) and slope angle (SL) as the two most important indexes, and soil erodibility factor (SEF) and shear resistance capacity (SRC) as the two least important indexes. The assessment accuracy of RFW can be as high as 79.71%, which is higher than the entropy weight (EW) of 63.77%. Two experiments were conducted by respectively removing the most dominant and the weakest indexes to examine the rationality and feasibility of RFW; both precision validation and contrastive analysis indicated the assessment results of RFW to be reasonable and satisfactory. The initial application of RF for weight determination shows significant potential and the use of RFW is therefore recommended.

Drought is regarded as an environmental disaster that has significantly impacted on economic and social development in recent decades, particularly in Southwest China (SWC). Here, we presented an analysis of spatiotemporal variations of meteorological drought in SWC. We computed the standardized precipitation evapotranspiration index using the Penman–Monteith equation (SPEI_pm) and explored spatiotemporal variational evolution of drought in SWC during 1962–2012 utilizing the Mann–Kendall test, continuous wavelet transform (CWT), and rotated empirical orthogonal function (REOF). We also analyzed the relationship between the rotated principal component time series (RPCs) and the 74 circulation indices. The results showed that (1) SWC displayed a dry trend at annual and seasonal scale with a 2–4-year significant period. The SWC can be divided into six sub-climate regions with different aridity and wetness features. (2) Among the six regions, the Eastern Yunnan Plateau showed an obvious dry trend while Hanzhong Basin and the Eastern Mountain Areas showed a wet trend that was not significant. There were 2–8-year periods of oscillation in general within the variation of the six regions. (3) The indices of the strength of the polar vortex in Asia (APVA) may affect the drought evolution of the whole study area. The change of drought in Eastern Yunnan Plateau and Sichuan Basin may be associated with Tibetan Plateau High.

One major threat to cities at present is the increased inundation hazards owing to changes in climate and accelerated human activity. Future evolution of urban inundation is still an unsolved issue, given large uncertainties in future environmental conditions within urbanized areas. Developing model techniques and urban inundation projections are essential for inundation management. In this paper, we proposed a 2D hydrodynamic inundation model by coupling SWMM and LISFLOOD-FP models, and revealed how future urban inundation would evolve for different storms, sea level rise and subsidence scenarios based on the developed model. The Shiqiao Creek District (SCD) in Dongguan City was used as the case study. The model ability was validated against the June 13th, 2008 inundation event, which occurred in SCD, and proved capable of simulating dynamic urban inundation. Scenario analyses revealed a high degree of consistency in the inundation patterns among different storms, with larger magnitudes corresponding to greater return periods. Inundations across SCD generally vary as a function of storm intensity, but for lowlands or regions without drainage facilities inundations tend to aggravate over time. In riverfronts, inundations would exacerbate with sea level rise or subsidence; however, the inland inundations are seemingly insensitive to both factors. For the combined scenario of 100-yr storm, 0.5 m subsidence and 0.7 m sea level rise, the riverside inundations would occur much in advance, whilst catastrophic inundations sweep across SCD. Furthermore, the optimal low-impact development found for this case study includes 0.2 km2 of permeable pavements, 0.1 km2 of rain barrels and 0.7 km2 of green roofs.

Owing to their essential influence on human society and natural environment exerted by inducing disasters, such as floods and droughts, further studies on precipitation extremes in China are needed. This study presents the regional frequency and spatial-temporal patterns of precipitation extremes in China based on a high-resolution (0.5° × 0.5°) daily precipitation dataset from 1961 to 2013. With fuzzy c-means, L-moments methods and other scientific statistical tests, a regional frequency analysis (RFA) is conducted, aiming to further understand the regional and spatial distribution of precipitation extremes across China. The results show that: (1) the whole Mainland China can be divided into 50 homogeneous regions on the basis of the characteristics of mean annual precipitation and location indices. (2) For most of the regions, Generalized Extreme Value (GEV), Generalized Normal (GNO) and Pearson type III (PE3) distributions of precipitation extremes fit well, according to the results of goodness-of-fit (GOF) test. (3) For RX1DAY, GEV has the best-fit distribution in the east, northeast and southwest of China, whereas GNO distribution mostly fits the northern and parts of southwest and southeast; in addition, regions which fit PE3 and Generalized Logistic (GLO) distribute dispersedly across the country. (4) For RX5DAY, GEV mainly fits in the middle, southwestern and southern; GNO and PE3 apply best to the northeastern and northern, respectively. (5) Return periods of 20, 50 and 100 years for their best-fit distributions decrease gradually from southeastern China to northwestern China. Compared with the results of GEV distribution fitted to each grid, RFA may provide more accurate estimates of rainfall quantiles. Definitely, the study results will not only benefit further understanding of the unique and complex features of extreme precipitation in the whole Mainland China but also contribute to the nation-scale flood prevention, control and management in the backdrop of the changing climate.

In recent decades, the occurrence and severity of drought in China has had devastating impact on social and economic development. The increase in drought has been attributed to global warming. We used the high-accuracy self-calibrating Palmer Drought Severity Index (scPDSI) to investigate the variation in drought in China between 1961 and 2009 using the Mann-Kendall (MK), continuous wavelet transform (CWT) and the rotated empirical orthogonal function (REOF) methods. We also analyzed the relationship between the rotated principal component time series (RPCs) and 74 circulation indices. The results revealed that: 1) all of China experienced a significant wet trend at annual and seasonal scale; an abrupt change in the drought pattern occurred around 1970 with a 2-8-year significant period; 2) eight major sub-climate regions were identified: Northwest China, Northeast-Inner Mongolia Plateau, Greater Khingan Range area, Northern Tibetan Plateau, Southern Tibetan Plateau, Central China, Huang-Huai-Hai Plain and Southeast China. Of these regions, the Southern Tibetan Plateau experienced a significant wet trend, but the Northeast-Inner Mongolia Plateau and Northern Tibetan Plateau became significantly drier. Using either annual or seasonal scales, Northwest China became significantly wetter and Central China became more arid. In addition, the period of each sub-climate region shared a significant 2-8-year band; 3) the polar vortex exhibited dominant patterns that affected most areas of China. The Pacific Decadal Oscillation had a significant influence on drought evolution, especially for Northwest China and the Huang-Huai-Hai plain. Additionally, the El Niño-Southern Oscillation also affected drought evolution, and the Central China was impacted by the Indian Ocean Dipole.

Reference evapotranspiration (ETo) is an important parameter for characterization of the hydrological cycle, and it is also important for agricultural, environmental and other studies. The ETo for 4189 grid points in China from 1961 to 2013 was calculated in this study utilizing the FAO Penman-Monteith method (P-M) based on an updated high-resolution (0.5° × 0.5°) gridded dataset. Five climatic variables including wind speed (WS), sunlight duration (SD), relative humidity (RH), maximum daily temperature (Tm) and minimum daily temperature (Tn), were selected to identify the contribution to variability of ETo. The temporal evolution and spatial distribution of each climatic variable was also investigated. Results indicate that (1) ETo distribution in China differed significantly both in seasonal and spatial scale in general, and annual ETo significantly decreased 6.84 mm/decade (P

Risk assessment is a preliminary step in flood management and mitigation, and risk zoning provides a quantitative measure of flood risk. The difficulty in flood risk zoning is to deal with the complicated non-linear relationship among indices and risk levels. To solve this problem, the ant colony algorithm based on rule mining (Ant-Miner) is promoted in this paper to map the regional flood risk at grid scale. For the case study in the Dongjiang River Basin in Southern China, 11 and 14 indices (without and with the socio-economic indices considered) are respectively chosen to construct the zoning model based on Ant-Miner. The results show that Ant-Miner exhibits higher accuracy and more simple rules that can be used to generate flood risk zoning map quickly and easily than decision tree method (DT); compared to random forest (RF) and fuzzy comprehensive evaluation (FCE), Ant-Miner has significant advantages both in implementation step-reducing and computing time-saving. Although the comprehensive measure and natural hazard measure of flood risk distributed similarly over the entire region, the former one which considered the socio-economic indices is more reasonable in term of real impact to natural and socio-economy. The areas with high-risk level obtained in this paper matched well with the integrated risk zoning map and the inundation areas of historical floods, suggesting that the proposed Ant-Miner method is capable of zoning the flood risk at grid scale. This study shows the potential to provide a novel and successful approach to flood risk zoning. Evaluation results provide a reference for flood risk management, prevention, and reduction of natural disasters in the study basin.

An in-pond raceway system (IPRS) is an effective intensive aquaculture practice for regions with high water consumption and limited land resources. Water flow and dissolved oxygen (DO) are important for sustainable aquaculture. Several innovations have been made in IPRS design and operation to increase water exchange and DO concentration; one of these is the aeration plug-flow device (APFD). The APFD is commonly used in China as the only power source for water recirculation in aquaculture ponds. Understanding of the hydrodynamics of the system is necessary to improve the design of the IPRS with APFD. To this end, we performed experimental studies on a model system. We measured three-dimensional velocity at various locations using an Acoustic Doppler Velocimeter. Velocity distribution and turbulence characteristics were assessed, and plug-flow characteristics were analysed. Two patterns of velocity and turbulence in horizontal sections were observed: near the APFD, the water flow was intensively pushed downstream and simultaneously recirculated; farther away, the reflux area gradually decreased and the velocity and turbulence distribution trended towards uniform. Secondary flows occurred in different directions, which improved the diffusion of materials and DO retention. The system is effectively self-circulating, and the plug-flow capability may be scaled up for commercial application.

Urban inundation management should take various forms to deal with different flood situations, rapid population growth, and climate change. Research on the advantages and disadvantages of grey infrastructure, such as deep tunnels and pipe networks, is necessary to apply hybrid green-grey infrastructure scientifically and efficiently. A novel urban flood model was applied in a highly urbanized region to evaluate the grey infrastructure. Green-grey approaches were also compared. The results showed that deep tunnels decreased the peak flood volume and shortened the time of peak flow. Pipe network improvements decreased the peak flood volume but did not affect the time of peak flow. However, the deep tunnels could not mitigate local inundations caused by insufficient sewer pipe capacity, whereas pipe network improvements could not mitigate inundations caused by backwater flooding. Moreover, pipe network improvements tended to generate new downstream inundation hot-spots. Green-grey infrastructures performed better than grey infrastructures for urban flood reduction. A hybrid green-grey approach was recommended. Suitable combinations of green-grey infrastructures improve the stability and effectiveness of urban flood management.

Climate change has emerged as a key issue for hydropower management and development in future. This study systematically evaluates the impact of climate change on reservoir inflow, hydropower output, sustainability, and efficiency under the representative concentration pathway (RCP) scenarios (RCP2.6, 4.5 and 8.5) by taking the Pearl River basin in China as the case. The variable infiltration capacity model is coupled with global climate models to project future hydropower changes. It is shown that future reservoir inflow and hydropower output significantly differ from the historical ones. Dry years in future are projected to become drier leading to decrease in hydropower output that in turn reduces hydropower reliability and resiliency and increases the vulnerability. Wet years would get wetter, but the hydropower output does not necessarily increase possibly due to more surplus water released from reservoirs during flood seasons. For normal years, neither of reservoir inflow and hydropower output displays obvious changes. Moreover, water use efficiency of the West River in wet years and that of the North River in wet, normal and dry years would be lower in future, while the East River during non-flood seasons in dry years is expected to have higher water use efficiency. Our study can potentially provide an insight into the response of hydropower to climate change and help policy-makers and stakeholders manage future hydropower generation.

By characterizing the patterns of temperature extremes over nine integrated agricultural regions (IARs) in China from 1961 to 2011, this study performed trend analyses on 16 extreme temperature indices using a high-resolution (0.5° × 0.5°) daily gridded dataset and the Mann-Kendall method. The results show that annually, at both daytime and nighttime, cold extremes significantly decreased but warm extremes significantly increased across all IARs. Overall, nighttimes tended to warm faster than daytimes. Diurnal temperature ranges (DTR) diminished, apart from the mid-northern Southwest China Region and the mid-Loess Plateau Region. Seasonally, DTR widely diminished across all IARs during the four seasons except for spring. Higher minimum daily minimum temperature (TNn) and maximum daily maximum temperature (TXx), in both summer and winter, were recorded for most IARs except for the Huang-Huai-Hai Region; in autumn, all IARs generally encountered higher TNn and TXx. In all seasons, warming was observed at daytime and nighttime but, again, nighttimes warmed faster than daytimes. The results also indicate a more rapid warming trend in Northern and Western China than in Southern and Eastern China, with accelerated warming at high elevations. The increases in TNn and TXx might cause a reduction in agriculture yield in spring over Northern China, while such negative impact might occur in Southern China during summer. In autumn and winter, however, the negative impact possibly occurred in most of the IARs. Moreover, increased TXx in the Pearl River Delta and Yangtze River Delta is possibly related to rapid local urbanization. Climatically, the general increase in temperature extremes across Chinese IARs may be induced by strengthened Northern Hemisphere Subtropical High or weakened Northern Hemisphere Polar Vortex.

Peak flows are the most important flood parameter which relatively reflects the highest level and potential destructive power of a flood. Understanding peak flow changes can effectively capture a flood characteristic and is essential for developing flood control strategies. This study aims to reveal how regional peak flows evolved in recent decades, mainly from a non-linear perspective. The Beijiang River Basin (BRB) was chosen for the analysis, and hydrological data from four hydrologic stations were used. Methods including ensemble empirical mode decomposition and rescaled range analysis were applied to advance the research. Results indicate a non-significant uptrend and a multiple periodicity of peak flows in BRB. However, short periods were more distinct than long ones. In the future, peak flows may continue to increase over time. Such changes in peak flows are possibly due to local reservoir operations and the changing South Asian Summer Monsoon (SASM). The research suggests an increasing flood risk and recommends more regional flood adaptations to avoid flood losses for BRB. Synchronously, it provides a reference for studies regarding periodicity and the future trend of peak flows in other regions.

Accelerated soil erosion is an undesirable process that adversely affects the conservation of water and soil. Rainfall erosivity is used to measure the potential ability of rain to cause erosion. This study explores spatio-temporal variations in rainfall erosivity in the Pearl River Basin of China during 1960–2012, at annual and seasonal scales based on a daily model proposed by Yu. Analysis methods including linear regression, Mann-Kendall and the Kriging interpolation technology were applied to determine fluctuating spatial and temporal patterns. Yu's model was proven suitable for the Pearl River Basin by comparison with another model proposed by Zhang. Computation results show an average annual rainfall erosivity of 9918.98 MJ·mm/(hm2·h) and that the Pearl River Delta region, most regions of the Dongjiang River Basin, and the Beijiang River Basin were all under considerable threat from rainfall erosion. The annual rainfall erosivity of the basin does not show significant or abrupt changes, and has fluctuated moderately over the past few decades. The rainfall erosivity of the basin shows an upward trend, and the probability of water and soil erosion caused by rainfall was increasing overall. The problem of water and soil loss in the Pear River Basin remains severe due to aggravating vegetation deterioration, rocky desertification, and climate change. Relevant response strategies and appropriate measures must be considered to guard against further deterioration of the basin.

A three dimensional finite volume model was developed to simulate the transient heat transfer through a flame manikin located in a combustion chamber with the advanced technique of computational fluid dynamics. The model was validated by compared with physical experiments performed by Donghua flame manikin system point by point, and then applied as a fundamental model to investigate the heat transfer through a simplified protective clothing system. Both of single and multiply layers clothing with contact combination were simulated by taking fabric as a three dimensional media. The temporal heat flux and temperature distribution of each layer of the clothing and skin were predicted. Results indicated that the air gap of 6.35 mm played a more critical role than the single-layer fire-proof clothing in deceasing heat transfer to the human skin. In the multi-layer garment system, the moisture barrier was the most effective layer on the thermal protection during the flash fire. The results of temporal heat flux and temperature could be used for further research of burn injury prediction and fabric parameters improvement.

Extremes of weather and climate can cause disasters such as floods and droughts. Further studies of precipitation extremes are crucial for enabling reliable projections of future changes. In this study, we used a high-resolution (0.5° × 0.5°) gridded precipitation data set to analyse these events across the 11 basins in China between 1961 and 2013 mainly by the Mann–Kendall and generalized extreme value methods. Our results indicated a wetter trend in the Tarim River Basin (TRB) but drier conditions in the central Yangtze River Basin (YRB), western Pearl River Basin and eastern Yarlung Tsangpo River Basin. There was an increasing risk of flooding in the mid-lower YRB and Minjiang River Basin (MRB), and an increasing risk of drought in the central Lantsang River Basin. The results revealed strengthened maximum 1-day precipitation (RX1DAY) in the Liaohe River Basin (LB), YRB, MRB and TRB, together with strengthened maximum 5-day precipitation (RX5DAY) in the Songhua River Basin, MRB and TRB during 1987–2013. RX1DAY and RX5DAY for return periods of 20 and 50 years gradually decreased from southeast to northwest. Along the south-eastern coastline of the Mainland and on Hainan Island, the RX1DAY for the 20- and 50-year return periods would exceed 165 and 195 mm, respectively, whereas the RX5DAY would exceed 270 and 320 mm for the same return periods. Furthermore, summer Southern Oscillation Index (SOI) positively impacted precipitation extremes in the Yellow River Basin and YRB, and autumn SOI negatively impacted the extremes of the next year in LB and YRB, while winter SOI negatively impacted the extremes of the next year in YRB. Additionally, the East Asia summer monsoon (EASM) and the South Asia summer monsoon (SASM) were both associated with precipitation extremes across China; however, EASM contributed more to these events than did the SASM.

In recent decades, the severe drought across agricultural regions of China has had significant impact on agriculture. The standardized precipitation evapotranspiration index (SPEI) has been widely used for drought analyses, however, SPEI is prone to be affected by potential evapotranspiration (PET). We thus examined the correlations between soil moisture anomalies and the SPEI calculated by the Thornthwaite, Hargreaves, and Penman&ndash, Monteith (PM) equations to select the most suitable for drought research. Additionally, the Mann&ndash, Kendall and wavelet analysis were used to investigate drought trends and to analyze and the impact of atmospheric circulation on drought in China from 1961 to 2018. The results showed that (1) PET obtained from the PM equation is the most suitable for SPEI calculation, (2) there were significant wetting trends in Northern China and the whole Chinese mainland and most of the wetting mutation points occurred in the 1970s and 1980s and the significant inter-annual oscillations period in the Chinese mainland was 2&ndash, 4 years, (3) the Chinese mainland and Northern China are strongly influenced by West Pacific Trade Wind, while Western Pacific Subtropical High Intensity and Pacific Subtropical High Area have primary impact on Southern China.

Floods are generally considered to be the most common natural disaster worldwide. Climate change and human activity are two key driving factors of flood formation, and it is difficult to determine how to quantitatively detect their relative impacts on flood susceptibility. As an important non-engineering measure of preventing floods and reducing losses, flood susceptibility assessment is a synthetic task that involves many factors. In this study, the flood susceptibility in Guangdong Province, China, was assessed based on a cloud model. The relative impacts of climate change and human activity on flood susceptibility were also quantitatively investigated from the spatial perspective. The results prove that the cloud model is a feasible, reasonable, and effective method for flood susceptibility assessment. Approximately 40% of the studied areas have changed their flood susceptibility level since 1985 due to the comprehensive impacts of climate change and human activity, of which about 56.3% converted from a low to high level, and 43.7% from a high to low level. About 35.7% of the areas changed their susceptibility level due to climate change, of which 55.8% converted from a low to high level and 44.2% from a high to low level. In contrast, only 9.8% of the areas changed the susceptibility level due to human activity, of which 57.2% converted from a low to high level and 42.8% from a high to low level. Generally, from the spatial perspective, climate change has a larger impact on flood susceptibility than human activity. This study aims to provide a novel idea to quantitatively detect the relative impacts of climate change and human activity on flood susceptibility from spatial perspective; the findings of this study are also expected to enhance the understanding on distribution rule of flood susceptibility in Guangdong Province and are conducive to taking targeted measures to reduce the flood risk.

In this study, Fe3O4 magnetic nanoparticles were synthesized in situ in the polyacrylamide/chitosan (PAAm/CS) hydrogel networks. The obtained hydrogels are characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The results confirm that the three-dimensional network structure of the hydrogels is incorporated with Fe3O4 nanoparticles. The adsorption properties of PAAm/CS/Fe3O4 hydrogels for methylene blue (MB) in aqueous solution were studied using Ultraviolet and visible spectrophotometry (UV–vis). The results show that when compared to PAAm/CS hydrogels, PAAm/CS/Fe3O4 hydrogels can adsorb MB with higher adsorption capacities of approximately 1603 mg/g, and the kinetics and isotherm models of the adsorption process could be better described by the pseudo-first order model and Langmuir isotherm model, respectively. Due to the facile preparation, high adsorption capacity, and low cost, the PAAm/CS/Fe3O4 hydrogels are good adsorbents for MB and exhibit significant potential in the treatment of sewage.

Anthropogenic activities have had a great impact on the characteristics of runoff and sediment load along the Pearl River in China in recent decades. We investigated the spatiotemporal variations, including the trends, abrupt changes, and periodicities of annual runoff and sediment load in the Pearl River by using the datasets from nine hydrological stations for the period of 1953&ndash, 2017. We found that annual runoff was stable during the study period, with only two stations in the upper reach showing decreasing trends. Annual sediment load has generally experienced a significant decreasing trend, while one of the stations in the middle reach showed an opposite trend due to severe rocky desertification and soil erosion in the local karst terrain. Abrupt changes in sediment load were mainly between the 1990s and 2000s, when many hydraulic projects were conducted, implying the significant impact of anthropogenic activities on river sediment load. Results also indicate 2&ndash, 4 year and 4&ndash, 8 year periodicities in both annual runoff and sediment load, with long periodicities less significant than the short ones. Our study is conducive to water and soil resource management in the Pearl River basin, whilst provides a guide for other basins, particularly those characterized by karst terrains where local desertification and soil erosion might likewise cause increase in river sediment load.

Evapotranspiration is a vital component of the land surface process, thus, a more accurate estimate of evapotranspiration is of great significance to agricultural production, research on climate change, and other activities. In order to explore the spatiotemporal variation of evapotranspiration under global climate change in the Pearl River Basin (PRB), in China, this study conducted a simulation of actual evapotranspiration (ETa) during 1960&ndash, 2014 based on the variable infiltration capacity (VIC) model with a high spatial resolution of 0.05&deg, The nonparametric Mann&ndash, Kendall (M&ndash, K) test and partial correlation analysis were used to examine the trends of ETa. The dominant climatic factors impacting on ETa were also examined. The results reveal that the annual ETa across the whole basin exhibited a slight but not significant increasing trend during the 1960&ndash, 2014 period, whereas a significant decreasing trend was found during the 1960&ndash, 1992 period. At the seasonal scale, the ETa showed a significant upward trend in summer and a significant downward trend in autumn. At the spatial scale, the ETa generally showed a decreasing, but not significant, trend in the middle and upper stream of the PRB, while in the downstream areas, especially in the Pearl River Delta and Dongjiang River Basin, it exhibited a significant increasing trend. The variation of the ETa was mainly associated with sunshine hours and average air pressure. The negative trend of the ETa in the PRB before 1992 may be due to the significant decrease in sunshine hours, while the increasing trend of the ETa after 1992 may be due to the recovery of sunshine hours and the significant decrease of air pressure. Additionally, we found that the &ldquo, paradox&rdquo, phenomenon detected by ETa mainly existed in the middle-upper area of the PRB during the period of 1960&ndash, 1992.

It is always a huge challenge to develop novel near-infrared (NIR) phototherapeutic agents suitable for imaging-guided cancer therapy. In order to clarify the positive heavy atom effects on the photodynamic and photothermal efficiencies of phototherapeutic agents, a series of chlorine-, bromide-, or iodine-substituted aza-BODIPYs (B2, B3, and B4, respectively) are designed and synthesized. Among them, B4 exhibits both excellent photodynamic and photothermal effects (singlet oxygen yield of B4 is 1.57 times more than that of B3) and excellent photothermal effects (1.3 °C higher than that of B3). Then, nanoparticles of B4 (IABNs) with excellent biocompatibility are prepared by coating hydrophobic B4 with hydrophilic polymer DSPE-mPEG5000 . IABN exhibits high photostability, excellent biocompatibility, and low dark toxicity both in vivo and in vitro. Furthermore, IABN shows the enhanced photodynamic effect and high photothermal conversion efficiency (34.8%). In addition, the strong fluorescence emission of IABN makes it suitable for fluorescence imaging-guided tumor therapy in vivo. Finally, IABN has successfully healed the Hela tumor-bearing mice under NIR fluorescence imaging- and photothermal imaging-guided synergistic photothermal and photodynamic therapy with low side effects, demonstrating that it is promising for future clinical applications.

Climate change and human activity are typically regarded as the two most important factors affecting runoff. Quantitative evaluation of the impact of climate change and human activity on runoff is important for the protection, planning, and management of water resources. This study assesses the contributions of climate change and human activity to runoff change in the Dongjiang River basin from 1960 to 2005 by using linear regression, the Soil and Water Assessment Tool (SWAT) hydrologic model, and the climate elasticity method. Results indicate that the annual temperature in the basin significantly increased, whereas the pan evaporation in the basin significantly decreased (95%). The natural period ranged from 1960 to 1990, and the affected period ranged from 1991 to 2005. The percentage of urban area during the natural period, which was 1.94, increased to 4.79 during the affected period. SWAT modeling of the Dongjiang River basin exhibited a reasonable and reliable performance. The impacts induced by human activity on runoff change were as follows: 39% in the upstream area, 13% in the midstream area, 77% in the downstream area, and 42% in the entire basin. The impacts of human activity on runoff change were greater in the downstream area than in either upstream and midstream areas. However, the contribution of climate change (58%) is slightly larger than that of human activity (42%) in the whole basin.

The mode of industrial park is becoming a vital national strategy of circular economy in China and a means to enhance energy efficiency, environmental performance, and economic competitiveness. It is becoming increasingly important to control the discharge of industrial wastewater from industrial parks in order to reduce water pollution. In this paper, as taking Chengdu Xinjin chemical cluster area for example, industrial layout of the park, environmental pollution treatment measures and management situation was analyzed surrounding with water environmental issues, factors of industrial park, like layout planning, industrial structure, management mode etc. were considered as significant influence on water environment. Enterprises in the park have different discharge standards and without any supervision. The influent of the wastewater treatment plant in the park is unstable, and the total phosphorus discharge exceeds the standard for a long time, and there is no large emergency pool in the park to prepare for sudden pollution incidents. In order to solve these problems, this paper puts forward some measures, such as setting up on-line monitoring, improving the standard of enterprise water discharge, and establishing emergency command system etc. In addition, some suggestions were put forward on how to improve the industrial park water environment status and management level, to provide references for the development of industrial park. The results could have supports for the design and optimization of wastewater treatment processes, as well as for evaluation of how centralized wastewater treatment plants can help to control water pollution.

Climate and land use/cover (LUC) are the two most significant factors that directly affect the runoff process. However, most research on runoff response has focused mainly on projected climate variation, while future LUC variability has been neglected. Therefore, the objective of this study is to examine the impacts of projected climate and LUC changes on runoff. Future climate scenarios are projected using the Quantile Mapping (QM) method, and future LUC scenarios are predicted with the Cellular Automaton-Markov (CA-Markov) model. Three different scenarios are simulated and compared to evaluate their impacts: Scenario 1 (LUC of 2010 and climate during the 2011–2050 period, abbreviated S1), Scenario 2 (LUC of 2010, 2020, 2030, 2040 and 2050 and climate of the historical wet year, normal year and dry year, abbreviated S2) and Scenario 3 (LUC of 2010, 2020, 2030, 2040 and 2050 and corresponding climate projections of 2011–2020, 2021–2030, 2031–2040 and 2041–2050 period, abbreviated S3). These three scenarios are then input into the Soil and Water Assessment Tool (SWAT) model to assess runoff responses. Beijiang River Basin, located in southern China, is used in this case study. The results obtained from S1, S2 and S3 show that runoff change in this basin is mainly caused by climate change; warmer temperatures and greater precipitation increase runoff. LUC change has little influence on runoff at the whole-basin scale, but changes in runoff components are more notable in the urban area than in the natural region at the sub-watershed level. The impact of LUC change in urbanized region on runoff components differ obviously among the wet, normal and dry years, and surface runoff and groundwater are found to be more sensitive to urbanization. Runoff depth is predicted to increase in this basin under the impacts of both climate and LUC changes in the future. Climate change brings greater increase in water yield and surface runoff, whereas LUC change leads to changes in allocation between surface runoff and groundwater in the urban region.