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Science China(Technological Sciences) 2015年第3期58卷 415-424页

作者： LI ZhanChao GU ChongShi WANG ZhengZhong WU ZhongRu College of water resources and Architectural engineering Northwest A&F University State Key Laboratory of hydrology-water resources and Hydraulic engineering Hohai University College of water Conservancy and Hydropower engineering Hohai University

research on on-line diagnosis method of crack behavior abnormality in concrete dams can provide support for timely grasping abnormality state of the crack itself and achieving real-time monitoring of the dam *** that samples of crack effects in concrete dams increase actually over monitoring time,a superiority criterion for the on-line diagnosis is determined so as to detect the abnormality moments timely and *** integrating the safety monitoring statistical model of crack effect variable with change point theory,a fluctuation method of regression coefficients is established for the on-line *** addition,each abnormality moment is detected by the cumulative sum of regression model *** indicate that abnormality of crack behavior in concrete dams can be characterized by structural instability of crack monitoring *** causes of crack behavior abnormality can be analyzed by the established method,which will play an important role in dam safety ***,taking the crack in a concrete gravity-arch dam as an example,the scientific rationality and validity of the established on-line diagnosis method are confirmed.

关键词： concrete dams crack behavior abnormality on-line diagnosis fluctuation of regression coefficients

An integrated suspended sediment transport monitoring and analysis concept

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International Journal of Sediment research 2014年第2期29卷 135-148页

作者： Marlene HAIMANN Marcel LIEDERMANN Petra LALK Helmut HABERSACK Christian Doppler Laboratory for Advanced Methods in River monitoring Modelling and EngineeringInstitute of Water ManagementHydrology and Hydraulic Engineering Department of WaterAtmosphere and EnvironmentBOKU-University of Natural Resources and Life SciencesVienna

A new integrated suspended sediment monitoring strategy applying direct and indirect technologies is *** sensors continuously record the turbidity at one point in the channel cross section close to the river bank and are calibrated by water samples taken close to the *** measurements are performed to establish the distribution of suspended sediment in a cross section(bottle samples combined with acoustic devices).Using correction factors(probe and cross-sectional factor) these monitoring methods are combined and it is,thus,possible to fully document the temporal and spatial variability of the suspended sediment transport and to estimate the suspended sediment load for certain time *** monitoring strategy was implemented at various measurement sites in Austria as well as at the Hainburg Road Bridge site on the Danube *** has already been successfully applied for three years at this measurement site and suspended sediment loads during high discharges up to a 15 year flood event have been *** evaluate the new monitoring methods the results were compared with load estimation methods found in the literature including averaging and ratio estimators as well as rating *** results prove that with the new methodology,the temporal variability of the suspended sediment transport can be detected more accurately compared with the other *** also demonstrate that the additional consideration of the spatial distribution of the suspended sediment concentration in the cross section is crucial as the mean concentration in the cross section can significantly exceed the concentration near the banks,especially at large rivers like the Danube River.

关键词： Suspended sediment Integrated suspended sediment monitoring programme Turbidity sensor Acoustic devices Load estimates

Runoff Modeling in Ungauged Catchments Using Machine Learning Algorithm-Based Model Parameters Regionalization Methodology

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engineering 2023年第9期28卷 93-104页

作者： Houfa Wu Jianyun Zhang Zhenxin Bao Guoqing Wang Wensheng Wang Yanqing Yang Jie Wang State Key Laboratory of Hydraulics and Mountain River engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China State Key Laboratory of hydrologywater resources and Hydraulic engineering Nanjing Hydraulic Research InstituteNanjing 210029China research center for Climate Change Ministry of Water ResourcesNanjing 210029China

Model parameters estimation is a pivotal issue for runoff modeling in ungauged *** nonlinear relationship between model parameters and catchment descriptors is a major obstacle for parameter regionalization,which is the most widely used *** modeling was studied in 38 catchments located in the Yellow–Huai–Hai River Basin(YHHRB).The values of the Nash–Sutcliffe efficiency coefficient(NSE),coefficient of determination(R2),and percent bias(PBIAS)indicated the acceptable performance of the soil and water assessment tool(SWAT)model in the *** descriptors belonging to the categories of climate,soil,vegetation,and topography were used to express the catchment characteristics related to the hydrological *** quantitative relationships between the parameters of the SWAT model and the catchment descriptors were analyzed by six regression-based models,including linear regression(LR)equations,support vector regression(SVR),random forest(RF),k-nearest neighbor(kNN),decision tree(DT),and radial basis function(RBF).Each of the 38 catchments was assumed to be an ungauged catchment in ***,the parameters in each target catchment were estimated by the constructed regression models based on the remaining 37 donor ***,the similaritybased regionalization scheme was used for comparison with the regression-based *** results indicated that the runoff with the highest accuracy was modeled by the SVR-based scheme in ungauged *** with the traditional LR-based approach,the accuracy of the runoff modeling in ungauged catchments was improved by the machine learning algorithms because of the outstanding capability to deal with nonlinear *** performances of different approaches were similar in humid regions,while the advantages of the machine learning techniques were more evident in arid *** the study area contained nested catchments,the best result was calculated with the similarity-based

关键词： Parameters estimation Ungauged catchments Regionalization scheme Machine learning algorithms Soil and water assessment tool model

Data augmentation for bias correction in mapping PM_(2.5) based on satellite retrievals and ground observations

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Geoscience Frontiers 2024年第1期15卷 17-28页

作者： Tan Mi Die Tang Jianbo Fu Wen Zeng Michael L.Grieneisen Zihang Zhou Fengju Jia Fumo Yang Yu Zhan College of Carbon Neutrality Future Technology Sichuan UniversityChengduSichuan 610065China Department of Environmental Science and engineering Sichuan UniversityChengduSichuan 610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengduSichuan 610200China Department of Land Airand Water ResourcesUniversity of CaliforniaDavisCA 95616United States Chengdu Academy of Environmental Sciences ChengduSichuan 610072China Sichuan Chengdu Ecological and Environment monitoring center ChengduSichuan 610011China

As most air quality monitoring sites are in urban areas worldwide,machine learning models may produce substantial estimation bias in rural areas when deriving spatiotemporal distributions of air *** bias stems from the issue of dataset shift,as the density distributions of predictor variables differ greatly between urban and rural *** propose a data-augmentation approach based on the multiple imputation by chained equations(MICE-DA)to remedy the dataset shift *** with the benchmark models,MICE-DA exhibits superior predictive performance in deriving the spatiotemporal distributions of hourly PM2.5 in the megacity(Chengdu)at the foot of the Tibetan Plateau,especially for correcting the estimation bias,with the mean bias decreasing from-3.4µg/m3 to-1.6µg/*** a complement to the holdout validation,the semi-variance results show that MICE-DA decently preserves the spatial autocorrelation pattern of PM2.5 over the study *** essence of MICE-DA is strengthening the correlation between PM2.5 and aerosol optical depth(AOD)during the data ***,the importance of AOD is largely enhanced for predicting PM2.5,and the summed relative importance value of the two satellite-retrieved AOD variables increases from 5.5%to 18.4%.This study resolved the puzzle that AOD exhibited relatively lower importance in local or regional *** results of this study can advance the utilization of satellite remote sensing in modeling air quality while drawing more attention to the common dataset shift problem in data-driven environmental research.

关键词： Aerosol optical depth Dataset shift Spatiotemporal Distribution Air quality monitoring Multiple imputation by chained equations

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中国碳收支:1980~2021年

Science Bulletin 2024年第1期69卷 114-124页

作者：夏晓圣任培阳王旭辉刘丹陈修治丹利何斌何洪林居为民梁敏琪陆星劼彭静覃章才夏江周郑博魏静乐旭于贵瑞朴世龙袁文平 School of Atmospheric Sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon CycleSun Yat-sen UniversityZhuhai 510245China Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100091China State Key Laboratory of Tibetan Plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Earth Surface Processes and Resource Ecology College of Global Change and Earth System ScienceBeijing Normal UniversityBeijing 100875China Synthesis research center of China’s Ecosystem research Network Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China International Institute for Earth System Science Nanjing UniversityNanjing 210023China Tianjin Key Laboratory of water resources and Environment Tianjin Normal UniversityTianjin 300387China Institute of Environment and Ecology Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Jiangsu Key Laboratory of Atmospheric Environment monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjing 210044China

As one of the world's largest emitters of greenhouse gases,China has set itself the ambitious goal of achieving carbon peaking and carbon ***,it is crucial to quantify the magnitude and trend of sources and sinks of atmospheric carbon dioxide(CO_(2)),and to monitor China's progress toward these *** state-of-the-art datasets and models,this study comprehensively estimated the anthropogenic CO_(2)emissions from energy,industrial processes and product use,and waste along with natural sources and sinks of CO_(2)for all of China during *** recognize the differences among various methods of estimating greenhouse emissions,the estimates are compared with China's National Greenhouse Gas Inventories(NGHGIs)for 1994,2005,2010,2012,and *** CO_(2)emissions in China have increased by 7.39 times from 1980 to 12.77 Gt CO_(2)a^(-1)in *** benefiting from ecological projects(e.g.,Three Norths Shelter Forest System Project),the land carbon sink in China has reached 1.65 Gt CO_(2)a^(-1)averaged through 2010-2021,which is almost 15.81 times that of the carbon sink in the *** average,China's terrestrial ecosystems offset 14.69%±2.49%of anthropogenic CO_(2)emissions through *** provincial-level administrative regions of China,Xizang and Qinghai,have achieved carbon neutrality according to our estimates,but nearly half of the administrative regions of China have terrestrial carbon sink offsets of less than 10%of anthropogenic CO_(2)*** study indicated a high level of consistency between NGHGIs and various datasets used for estimating fossil CO_(2)emissions,but found notable differences for land carbon *** estimates of the terrestrial carbon sinks of NGHGIs urgently need to be verified with process-based models which integrate the comprehensive carbon cycle processes.

关键词： CO_(2)emission Land carbon sink China Carbon neutrality Carbon budget

Patterns,magnitude,and controlling factors of hydraulic redistribution of soil water by Tamarix ramosissima roots

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Journal of Arid Land 2013年第3期5卷 396-407页

作者： TengFei YU Qi FENG JianHua SI HaiYang XI Wei LI research School of Arid Environment and Climate Change Lanzhou University Cold and Arid Regions Environmental and engineering research Institute Chinese Academy of Sciences Gansu hydrology and water resources engineering research center

Tamarix spp. （Saltcedar） is a facultative phreatophyte that can tolerate drought when groundwater is not accessed. In addition to deep water uptake, hydraulic redistribution （HR） is another factor contributing to the drought tolerance of Tarnarix spp. In this study, data on soil volumetric moisture content （0）, lateral root sap flow, and relevant climate variables were used to investigate the patterns, magnitude, and controlling factors of HR of soil water by roots of Tamarix ramosissima Ledeb. in an extremely arid land in Northwest China. Results showed evident diurnal fluctuations in 0 at the depths of 30 and 50 cm, indicating ＂hydraulic lift＂（HL）. 0 increased remarkably at 10 and 140 cm but decreased at 30 and 50 cm and slightly changed at 80 cm after rainfall, suggesting a possible ＂hydraulic descent＂（HD）. However, no direct evidence was observed in the negative flow of lateral roots, supporting HR （including HL and HD） of T. ramosissima. The HR pathway unlikely occurred via lateral roots; instead, HR possibly occurred through adventitious roots with a diameter of 2-5 mm and a length of 60-100 cm. HR at depths of 20-60 cm ranged from 0.01-1.77 mm/d with an average of 0.43 mm/d, which accounted for an average of 22% of the estimated seasonal total water depletion at 0-160 cm during the growing season. The climate factors, particularly vapor pressure deficit and soil water potential gradient, accounted for at least 33% and 45% of HR variations with depths and years, respectively. In summary, T. ramosissima can be added to the wide list of existing species involved in HR. High levels of HR may represent a considerable fraction of daily soil water depletion and substantially improve plant water status. HR could vary tremendously in terms of years and depths, and this variation could be attributed to climate factors and soil water potential gradient.

关键词： drought tolerance phreatophyte hydraulic redistribution root sap flow Tamarix ramosissima

Abnormality diagnosis of cracks in the concrete dam based on dynamical structure mutation

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Science China(Technological Sciences) 2011年第7期54卷 1930-1939页

作者： GU ChongShi LI ZhanChao XU Bo State Key Laboratory of hydrology-water resources and Hydraulic engineering Hohai University Nanjing 210098 China National engineering research center of water resources Efficient Utilization and engineering Safety Nanjing 210098 China College of water Conservancy and Hydropower engineering Hohai University Nanjing 210098 China

A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bifurcation to chaos is tested first using this method. Results indicate that it can distinguish inherent dynamics of time series and can detect mutations. Considering that cracks in the concrete dam constitute an open, dissipative and complex nonlinear dynamical system, a typical crack on the downstream face of a concrete gravity arch dam is analyzed with the proposed method. Two distinct mutations are discovered to indicate that the abnormality diagnosis of cracks in the concrete dam is achieved dynamically through this method. Furthermore, because it can be directly utilized in the measured crack opening displacement series to complete abnormality diagnosis, it has a good prospect for practical applications.

关键词： dynamical structure mutation cracks in the concrete dam method of the fuzzy cross-correlation factor exponent indynamics abnormality diagnosis of cracks

Spatial and temporal variation of water clarity in typical reservoirs in the Beijing-Tianjin-Hebei region observed by GF 1-WFV satellite data

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Journal of Oceanology and Limnology 2024年第4期42卷 1048-1060页

作者： Chang CAO Junsheng LI Xiaodong JIA Shenglei WANG Bo WAN Liaoning Earthquake Agency Shenyang 11000China Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China International research center of Big Data for Sustainable Development Goals Beijing 100094China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China

Rapidly monitoring regional water quality and the changing trend is of great practical and scientific significance,especially for the Beijing-Tianjin-Hebei(BTH)region of China where water resources are relatively scarce and inland water bodies are generally *** remote sensing data of the GF 1 satellite launched in 2013 have characteristics of high spatial and temporal resolution,which can be used for the dynamic monitoring of the water environment in small lakes and ***,the water quality remote sensing monitoring model based on the GF 1 satellite data for lakes and reservoirs in BTH is still lacking because of the considerable differences in the optical characteristics of the lakes and *** this paper,the typical reservoirs in BTH-Guanting Reservoir,Yuqiao Reservoir,Panjiakou Reservoir,and Daheiting Reservoir are taken as the study *** the atmospheric correction of GF 1-WFV,the relative radiation normalized atmospheric correction was adopted after comparing it with other methods,such as 6 S and *** the water clarity retrieval,a water color hue angle based model was proposed and outperformed other available published models,with the R 2 of 0.74 and MRE of 31.7%.The clarity products of the four typical reservoirs in the BTH region in 2013-2019 were produced using the GF 1-WFV *** on the products,temporal and spatial changes in clarity were analyzed,and the main influencing factors for each water body were *** was found that the clarity of Guanting,Daheiting,and Panjiakou reservoirs showed an upward trend during this period,while that of Yuqiao Reservoir showed a downward *** the influencing factors,the water level of the water bodies can be an important factor related to the water clarity changes in this region.

关键词： GF 1 satellite atmospheric correction clarity Beijing-Tianjin-Hebei spatial and temporal change analysis

White light emission in 0D halide perovskite[(CH_(3))_(3)S]_(2)SnCl_(6)·H_(2)O crystals through variation of doping ns^(2) ions

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Frontiers of Optoelectronics 2024年第1期17卷 57-66页

作者： Yitong Lin Yu Zhong Yangpeng Lin Jiawei Lin Lei Pang Zhilong Zhang Yi Zhao Xiao‑Ying Huang Ke‑Zhao Du Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical engineering Collage of Chemistry and Material ScienceFujian Normal UniversityFuzhou 350007China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Qinghai Environmental monitoring center Xining 810000China Strait Institute of Flexible Electronics(SIFE Future Technologies)Fujian Normal University and Strait Laboratory of Flexible Electronics(SLoFE)Fuzhou 350007China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing *** dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable ***,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation *** a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white *** intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical *** high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.

关键词： 0D Metal halide White light Perovskite Ions doping Excitation dependent

Ill-conditioned problems of dam safety monitoring models and their processing methods

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Science China(Technological Sciences) 2011年第12期54卷 3275-3280页

作者： GU ChongShi WANG YaChao PENG Yan XU BaoSon State Key Laboratory of hydrology-water resources and Hydraulic engineering Hohai University Nanjing 210098 China College of water-conservancy and Hydropower engineering Hohai University Nanjing 210098 China National engineering research center of water resources Efficient Utilization and engineering Safety Hohai University Nanjing 210098 China

The focus of this paper is the ill-conditioned problems in the dam safety monitoring model. The reasons to give rise to the ill-conditioned problems in statistical models,deterministic models and hybrid models are analyzed in detail,and the criterions for ill-conditioned models are investigated. It is shown that safety monitoring models are not easy to be ill-conditioned if the number of influence factors is less than seven. Moreover,the models have a high accuracy and can meet the engineering requirements. Another frequently encountered problem in establishing a safety monitoring model is the existence of inflection points,which are often present in the mathematical model for the hydraulic components in deterministic models and hybrid models. The conditions for inflection points are studied and their treatments are suggested. Numerical example indicates that the treatments proposed in this paper are effective in removing the ill-conditioned problems.

关键词： dam safety monitoring model ill-conditioned processing method