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Occurrence of polycyclic aromatic hydrocarbons in the estuarine sediments of the Taihu Lake and their associated toxic effects on aquatic organisms

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Pedosphere 2022年第6期32卷 833-843页

作者： Tian SUN Yanhua WANG Yan CHEN Mingli ZHANG Xinggong KONG School of Geography Nanjing Normal UniversityNanjing 210023(China) jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing 210023(China) key Laboratory of Virtual geographic Environment Nanjing Normal UniversityMinistry of EducationNanjing 210023(China)

Polycyclic aromatic hydrocarbons(PAHs)are ubiquitous toxic organic pollutants in the natural environment that are strongly associated with socioeconomic activities.Exploring the distribution,sources,and ecological toxicity of PAHs is essential to abate their pollution and biological risks.The 16 priority PAHs in different lakeside city estuarine sediments in the northern Taihu Lake in China were determined using gas chromatography-mass spectrometry.Results showed that total concentrations of PAHs(ΣPAHs)ranged from 672.07 to 5858.34 ng g^(^(-1)),with a mean value of 2121.37 ng g^(^(-1)).High-molecular-weight PAHs(4-6 rings)were dominant,accounting for 85%of theΣPAHs detected.Due to the barrier of gate/dam in the estuarine area,the concentrations of PAHs in the sediments were significantly different between the river mouth and lake side.Changes in total organic carbon(TOC)content and the spatial distribution of PAHs in the sediments were consistent.Sediment pollution assessment explored using the fuzzy evaluation model indicated 75%of slight PAH pollution.Some estuarine sediments(22%)concentrated in the east of the Wuli Lake in the Meiliang bay of the Taihu Lake were moderately or heavily polluted.The PAHs may lead to occasional detrimental biological consequences in the area.Diagnostic ratios and principal component analysis-multiple linear regression suggested vehicle emission and natural gas combustion as the primary PAH contributors(81%).

关键词： contamination source ecological toxicity grade fuzzy evaluation model pollution risk assessment principal component analysis-multiple linear regression total 16 polycyclic aromatic hydrocarbons toxic organic pollutant

Characterization of Air Pollution in Urban Areas of Yangtze River Delta,China

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Chinese geographical science 2017年第5期27卷 836-846页

作者： CHEN Tan DENG Shulin GAO Yu QU Lean LI Manchun CHEN Dong jiangsu provincial key Laboratory of geographic information science and technology Nanjing UniversityNanjing 210023China Department of geographic information science Nanjing UniversityNanjing 210093China Collaborative Innovation Center of South China Sea Studies Nanjing UniversityNanjing 210093China College of Territorial Resources and Tourism Anhui Normal UniversityWuhu 241000China

The hallmark of development in the Yangtze River Delta(YRD) of East China has been sprawling urbanization. However, air pollution is a significant problem in these urban areas. In this paper, we investigated and analyzed the air pollution index(API) in four cities(Shanghai, Nanjing, Hangzhou and Ningbo) in the YRD from 2001 to 2012. We attempted to empirically examine the relationship between meteorological factors and air quality in the urban areas of the YRD. According to the monitoring data, the API in Shanghai, Nanjing, Hangzhou slightly declined and that in Ningbo increased over the study period. We analyzed the inter-annual, seasonal, and monthly variations of API, from which we found that the air quality had different temporal changes in the four cities. It was indicated that air quality was poor in winter and spring and best in summer. Furthermore, different weather conditions affected air quality level. The wind direction was considered as an important and influential factor to air pollution, which has an impact on the accumulating or cleaning processes of pollutants. The air quality was influenced by the different wind directions that varied with seasons and cities.

关键词：长江三角洲地区空气污染指数污染特征城市空气质量快速城市化市区中国城市地区

A Modified Self-adaptive Method for Mapping Annual 30-m Land Use/Land Cover Using Google Earth Engine:A Case Study of Yangtze River Delta

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Chinese geographical science 2021年第5期31卷 782-794页

作者： QU Le’an LI Manchun CHEN Zhenjie ZHI Junjun School of Geography and Ocean science Nanjing UniversityNanjing 210023China School of Geography and Tourism Anhui Normal UniversityAnhui ProvinceWuhu 241002China jiangsu provincial key Laboratory of geographic information science and technology Nanjing UniversityNanjing 210023China

Annual Land Use/Land Cover(LULC)change information at medium spatial resolution(i.e.,at 30 m)is used in applications ranging from land management to achieving sustainable development goals related to food security.However,obtaining annual LULC information over large areas and long periods is challenging due to limitations on computational capabilities,training data,and workflow design.Using the Google Earth Engine(GEE),which provides a catalog of multi-source data and a cloud-based environment,we developed a novel methodology to generate a high accuracy 30-m LULC cover map collection of the Yangtze River Delta by integrating free and public LULC products with Landsat imagery.Our major contribution is a hybrid approach that includes three major components:1)a high-quality training dataset derived from multi-source LULC products,filtered by k-means clustering analysis;2)a yearly 39-band stack feature space,utilizing all available Landsat data and DEM data;and 3)a self-adaptive Random Forest(RF)method,introduced for LULC classification.Experimental results show that our proposed workflow achieves an average classification accuracy of 86.33%in the entire Delta.The results demonstrate the great potential of integrating multi-source LULC products for producing LULC maps of increased reliability.In addition,as the proposed workflow is based on open source data and the GEE cloud platform,it can be used anywhere by anyone in the world.

关键词： Land Use/Land Cover(LULC) self-adaptive Random Forest(RF) Google Earth Engine(GEE) Yangtze River Delta

Spatial Accessibility to Shopping Malls in Nanjing,China:Comparative Analysis with Multiple Transportation Modes

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Chinese geographical science 2020年第4期30卷 710-724页

作者： LI Ang CHEN Jie QIAN Tianlu ZHANG Wenhan WANG Jiechen jiangsu provincial key Laboratory of geographic information science and technology Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural ResourcesSchool of Geography and Ocean ScienceNanjing UniversityNanjing 210023China School of Architecture and Surveying Engineering Datong UniversityDatong 037009China jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing 210023China

This study attempts to evaluate the rationality of the spatial layout of shopping malls and identify the urban area with poor shopping mall accessibility,as well as to provide a reference and assist decision-making for planning.Using the case of Nanjing,China,this study developed a method to evaluate the accessibility of shopping malls by three transport modes(car traffic,public transit,and bicycle).Specially,we divide the urban space into a regular hexagonal grid and harvest the total travel time from each of 7204 hexagon centroids to each of 129 shopping malls using the Baidu Internet map.The door-to-door travel time approach is used to evaluate all travel stages(walking,waiting,transfer,and transportation)based on travel time calculations.We further divide the shopping malls into two levels(super-regional and regional)based on the Dianping App’s information and develop the indicator of accessibility to shopping malls:the number of shopping malls within tolerance time thresholds and apply the closest facility and cumulative opportunities methods to measure accessibility scores.The results show that the accessibility estimations vary greatly with transport modes.The accessibility of shopping malls presents a concentric ring trend centered on the city center under the car traffic and bicycle modes.And public transit accessibility tends to axially extend due to the topology of bus routes and metro lines.In particular,we observe that the accessibility of shopping malls in Nanjing has an uneven spatial distribution pattern,with high accessibility values in the central urban areas and lots of underserved areas in urban fringe regions.Based on the accessibility measurements,we finally map the poor accessibility area and propose corresponding implications for urban planning.

关键词： spatial accessibility shopping mall access transport mode door-to-door travel time internet maps

Methods for the construction of DEMs of artificial slopes considering morphological features and semantic information

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Journal of Mountain science 2022年第2期19卷 563-577页

作者： XU Yan ZHAO Ming-wei LU Jie WANG Chun JIANG Ling YANG Can-can HUANG Xiao-li geographic information and Tourism.College Chuzhou UniversityChuzhou 239000China State key Laboratory of Resources and Environmental information System Beijing 100101China College of Forestry Beijing Forestry UniversityBeijing 100083China

As human activities increase,artificially modified terrain is increasingly widely distributed in road,hydrological,and urban construction.Artificially modified terrain plays an important role in protecting from geological disasters and in the planning and design of urban landscapes.Compared with natural slopes,artificial slopes have obvious morphological characteristics.Traditional modeling methods are no longer suitable for digital elevation model(DEM)modeling of artificial slopes because they often seriously distort the DEM results.In this paper,from the perspective of morphological characteristics,artificial slopes are divided into two types,namely,regular slopes and irregular slopes,based on whether the top and bottom lines of the artificial slope are parallel.Then,according to the morphological characteristics of the two types of slopes,the following DEM construction methods are designed:the first method(perpendicular+inverse distance weighted)is suitable for regular slopes,and the second method(perpendicular+high-accuracy surface modeling)is suitable for irregular slopes.Finally,a DEM construction test is carried out using the artificial slopes in the study area.The results show that for the regular and irregular slopes in the study area,the construction method proposed in this paper has significant advantages in morphological accuracy over the traditional method(triangulated irregular network),and the elevation accuracy method is also superior to the traditional method(using this method,the mean error and standard deviation error of the regular slope DEM are 0.08 m and 0.13 m,respectively,and those of the irregular slope DEM are 0.08 m and 0.06 m).In addition,the top lines and bottom lines can be included in the DEM construction of the background area after processing the elevation information of the boundary line to realize a smooth transition in the boundary between the artificial slope and the background area.

关键词： Artificial slopes DEM Morphological characteristics Triangulated irregular network High-accuracy surface modeling

Modeling spatial and temporal change of soil erosion based on multi-temporal remotely sensed data

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Research in Cold and Arid Regions 2015年第6期7卷 702-708页

作者： Pei Liu PeiJun Du RuiMei Han Chao Ma YouFeng Zou key Laboratory of Mine Spatial information Technologies of SBSM Henan Polytechnic University School of Surveying and Mapping Land information Engineering Henan Polytechnic University jiangsu provincial key Laboratory of geographic information science and technology Nanjing University

In order to monitor the pattern, distribution, and trend of land use/cover change （LUCC） and its impacts on soil erosion, it is highly appropriate to adopt Remote Sensing （RS） data and geographic information System （GIS） to analyze, assess, simulate, and predict the spatial and temporal evolution dynamics. In this paper, multi-temporal Landsat TM/ETM＋ re- motely sensed data are used to generate land cover maps by image classification, and the Cellular Automata Markov （CA_Markov） model is employed to simulate the evolution and trend of landscape pattern change. Furthermore, the Re- vised Universal Soil Loss Equation （RUSLE） is used to evaluate the situation of soil erosion in the case study mining area. The trend of soil erosion is analyzed according to total/average amount of soil erosion, and the rainfall （R）, cover man- agement （C）, and support practice （P） factors in RUSLE relevant to soil erosion are determined. The change trends of soil erosion and the relationship between land cover types and soil erosion amount are analyzed. The results demonstrate that the CA_Markov model is suitable to simulate and predict LUCC trends with good efficiency and accuracy, and RUSLE can calculate the total soil erosion effectively. In the study area, there was minimal erosion grade and this is expected to con- tinue to decline in the next few years, according to our prediction results.

关键词： land use/cover change （LUCC） soil erosion CA_Markov model revised universal soil loss equation （RUSLE）

全球城市热辐射方向性制图揭示了城市气候遥感的潜在偏差

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science Bulletin 2023年第16期68卷 1809-1818,M0004页

作者：杜惠琳占文凤刘紫涵 E.Scott Krayenhoff TC Chakraborty 赵磊姜璐董攀李龙黄帆王莎莎徐于月 jiangsu provincial key Laboratory of geographic information science and technology International Institute for Earth System ScienceNanjing UniversityNanjing 210023China jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing 210023China School of Environmental sciences University of GuelphGuelph N1G 2W1Canada Atmospheric sciences and Global Change Division Pacific Northwest National LaboratoryRichland 99352USA Department of Civil and Environmental Engineering University of Illinois at Urbana-ChampaignUrbana 61820USA School of Geography and Ocean science Nanjing UniversityNanjing 210023China

城市热辐射方向性限制了遥感地表温度反演精度,阻碍了对全球城市气候(如城市地表能量通量估算和城市热环境评估)的准确理解.然而,全球不同气候背景城市热辐射方向性时空特征及其造成的城市地表能量通量和热岛强度遥感估算偏差仍不清楚,... 详细信息

城市热辐射方向性限制了遥感地表温度反演精度,阻碍了对全球城市气候(如城市地表能量通量估算和城市热环境评估)的准确理解.然而,全球不同气候背景城市热辐射方向性时空特征及其造成的城市地表能量通量和热岛强度遥感估算偏差仍不清楚,在全球尺度是否存在与城市热辐射方向性密切相关且易获取的地表和气候参量尚不明晰.本研究结合多角度卫星观测地表温度和遥感云平台,分析了全球5500多个城市的热辐射方向性特征,量化了其造成的全球城市地表能量通量和热岛强度遥感估算偏差,厘清了全球尺度城市热辐射方向性与关键地表和气候参量的关系.研究发现全球城市平均热辐射方向性强度在夏季白天下午高达5.4 K.在极端情况下,当地表温度观测天顶角位于±60°时,热辐射方向性使得全球城市地表显热通量和热岛强度分别低估45.4%和43.0%.研究进一步发现全球城市热辐射方向性与地表不透水面百分比和空气温度具有良好的统计关系,这为卫星遥感城市地表温度角度纠正提供了新思路.

关键词：热岛强度城市气候地表能量通量地表温度显热通量卫星观测空气温度卫星遥感

Sea-water-level prediction via combined wavelet decomposition,neuro-fuzzy and neural networks using SLA and wind information

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Acta Oceanologica Sinica 2020年第5期39卷 157-167页

作者： Bao Wang Bin Wang Wenzhou Wu Changbai Xi Jiechen Wang School of Geography and Ocean science Nanjing UniversityNanjing 210023China National Marine Environmental Forecasting Center Beijing 100081China Institute of geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China State key Laboratory of Resources and Environmental information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China jiangsu provincial key Laboratory of geographic information science and technology Nanjing UniversityNanjing 210023China jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing UniversityNanjing 210023China

Sea-water-level(SWL)prediction significantly impacts human lives and maritime activities in coastal regions,particularly at offshore locations with shallow water levels.Long-term SWL forecasts,which are conventionally obtained via harmonic analysis,become ineffective when nonperiodic meteorological events predominate.Artificial intelligence combined with other data-processing methods can effectively forecast highly nonlinear and nonstationary inflow patterns by recognizing historical relationships between input and output.These techniques are considerably useful in time-series data predictions.This paper reports the development of a hybrid model to realize accurate multihour SWL forecasting by combining an adaptive neuro-fuzzy inference system(ANFIS)with wavelet decomposition while using sea-level anomaly(SLA)and wind-shear-velocity components as inputs.Numerous wavelet-ANFIS(WANFIS)models have been tested using different inputs to assess their applicability as alternatives to the artificial neural network(ANN),wavelet ANN(WANN),and ANFIS models.Different error definitions have been used to evaluate results,which indicate that integrated wavelet-decomposition and ANFIS models improve the accuracy of SWL prediction and that the inputs of SLA and wind-shear velocity exhibit superior prediction capability compared to conventional SWL-only models.

关键词： sea-water level prediction ANFIS wavelet decomposition wind

Spatial-temporal variations in net primary productivity in the Arctic from 2003 to 2016

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Acta Oceanologica Sinica 2019年第8期38卷 111-121页

作者： Haili Li Changqing Ke Qinghui Zhu Su Shu jiangsu provincial key Laboratory of geographic information science and technology Nanjing University Nanjing 210023 China School of geographic and Oceanographic sciences Nanjing University Nanjing 210023 China Collaborative Innovation Center of Novel Software technology and Industrialization Nanjing 210023 China Navigation College Dalian Maritime University Dalian 116026 China

The area of Arctic sea ice has dramatically decreased, and the length of the open water season has increased;these patterns have been observed by satellite remote sensing since the 1970 s. In this paper, we calculate the net primary productivity(NPP, calculated by carbon) from 2003 to 2016 based on sea ice concentration products,chlorophyll a(Chl a) concentration, photosynthetically active radiation(PAR), sea surface temperature(SST), and sunshine duration data. We then analyse the spatiotemporal changes in the Chl a concentration and NPP and further investigate the relations among NPP, the open water area, and the length of the open water season. The results indicate that(1) the Chl a concentration increased by 0.025 mg/m^3 per year;(2) the NPP increased by 4.29 mg/(m^2·d) per year, reaching a maximum of 525.74 mg/(m^2·d) in 2016;and(3) the Arctic open water area increased by 57.23×10^3 km^2/a, with a growth rate of 1.53 d/a for the length of the open water season. The annual NPP was significantly positively related to the open water area, the length of the open water season and the SST.The daily NPP was also found to have a lag correlation with the open water area, with a lag time of two months.With global warming, NPP has maintained an increasing trend, with the most significant increase occurring in the Kara Sea. In summary, this study provides a macroscopic understanding of the distribution of phytoplankton in the Arctic, which is valuable information for the evaluation and management of marine ecological environments.

关键词： sea ice open water area chlorophyll a net primary productivity Arctic