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A visual-textual fused approach to automated tagging of flood-related tweets during a flood event

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International Journal of Digital Earth 2019年第11期12卷 1248-1264页

作者： Xiao Huang cuizhen wang Zhenlong Li Huan Ning Department of Geography University of South CarolinaColumbiaSCUSA

In recent years,social media such as Twitter have received much attention as a new data source for rapid flood *** timely response and large coverage provided by citizen sensors significantly compensate the limitations of non-timely remote sensing data and spatially isolated river ***,automatic extraction of flood tweets from a massive tweets pool remains a *** the Houston Flood in 2017 as a study case,this paper presents an automated flood tweets extraction approach by mining both visual and textual information a tweet contains.A CNN architecture was designed to classify the visual content of flood pictures during the Houston Flood.A sensitivity test was then applied to extract flood-sensitive keywords that were further used to refine the CNN classified results.A duplication test was finally performed to trim the database by removing the duplicated pictures to create the flood tweets pool for the flood *** results indicated that coupling CNN classification results with flood-sensitive words in tweets allows a significant increase in precision while keeps the recall rate in a high *** elimination of tweets containing duplicated pictures greatly contributes to higher spatio-temporal relevance to the flood.

关键词： Data mining flood social media CNN tweets geotagging

A 100 m population grid in the CONUS by disaggregating census data with open-source Microsoft building footprints

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Big Earth Data 2021年第1期5卷 112-133页

作者： Xiao Huang cuizhen wang Zhenlong Li Huan Ning Department of Geography University of South CarolinaColumbiaUSA Department of Informatics New Jersey Institute of TechnologyNew JerseyUSA

In the Big Data era,Earth observation is becoming a complex process integrating physical and social *** study presents an approach to generating a 100 m population grid in the Contiguous United States(CONUS)by disaggregating the US cen-sus records using 125 million of building footprints released by Microsoft in ***-use data from the OpenStreetMap(OSM),a crowdsourcing platform,was applied to trim original footprints by removing the non-residential *** trimming,several metrics of building measurements such as building size and build-ing count in a census tract were used as weighting scenarios,with which a dasymetric model was applied to disaggregate the American Community Survey(ACS)5-year estimates(2013-2017)into a 100 m population grid *** results confirm that the OSM trimming process removes non-residential buildings and thus provides a better representation of population distribution within complicated urban *** building size in the census tract is found in the optimal weighting *** product is 2.5Gb in size containing 800 million populated grids and is currently hosted by ESRI(http://***/19S4qK)for *** data can be accessed via https://***/10.7910/DVN/*** the accel-erated acquisition of high-resolution spatial data,the product could be easily updated for spatial and temporal continuity.

关键词： Population census high resolution population grid microsoft building footprints OpenStreetMap dasymetric mapping CONUS

Studies on the edwardsiellosis and characterization of pathogenic bacteria from diseased flounder (Paralichthys olivaceus L.) and turbot (Scophthalmus maximus L.)

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Acta Oceanologica Sinica 2006年第3期25卷 138-147页

作者： FANG Hai ZHANG Xiaojun CHEN cuizhen JIN Xiaomin wang Xiuyun Department of Animal Science Hebei Normal University of Science and Technology Qinhuangdao 066600 China

Edwardsiellosis of flounder and turbot occurring in different mariculture farms during 2001～ 2004 was examined, including the conditions of disease occurrence, clinical signs and pathological changes. The results showed that all diseased fishes expressed bacterial septicaemia. A total of 148 strains were identified using a combination of traditional physiological and biochemical tests and partial 16S rRNA gene analysis. In addition, the mole fraction G ＋ C ratio of the DNA of representative strain of isolates and serum homology were detected, and pathogenicity tests of isolates were conducted by experimental infection. The results revealed that 148 strains were identified as E. tarda of genus Edwardsiella, all the isolates are of serologic similarity, and have strong pathogenicity to flounder and turbot.

关键词： flounder (Paralichthys olivaceus L. ) turbot (Scophthalmus maximus L. ) edwardsiellosis pathogenic bacteria

Snow effects on alpine vegetation in the Qinghai-Tibetan Plateau

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International Journal of Digital Earth 2015年第1期8卷 58-75页

作者： Kun wang Li Zhang Yubao Qiu Lei Ji Feng Tian cuizhen wang Zhiyong wang Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina College of Geomatics Shandong University of Science and TechnologyShandongChina ASRC InuTeq Contractor to U.S.Geological Survey EROS CenterSioux FallsSDUSA School of Environment Science and Spatial Informatics China University of Mining and TechnologyJiangsuChina Department of Geography University of South CarolinaColumbiaSCUSA

Understanding the relationships between snow and vegetation is important for interpretation of the responses of alpine ecosystems to climate *** Qinghai-Tibetan Plateau is regarded as an ideal area due to its undisturbed features with low population and relatively high snow *** used 500 m Moderate Resolution Imaging Spectroradiometer(MODIS)datasets during 2001–2010 to examine the snow–vegetation relationships,specifically,(1)the influence of snow melting date on vegetation green-up date and(2)the effects of snow cover duration on vegetation *** results showed that the alpine vegetation responded strongly to snow phenology(i.e.,snow melting date and snow cover duration)over large areas of the Qinghai-Tibetan *** melting date and vegetation green-up date were significantly correlated(p<0.1)in 39.9% of meadow areas(accounting for 26.2% of vegetated areas)and 36.7% of steppe areas(28.1% of vegetated areas).Vegetation growth was influenced by different seasonal snow cover durations(SCDs)in different ***,the December–February and March–May SCDs played a significantly role in vegetation growth,both positively and negatively,depending on different water source ***’s positive impact on vegetation was larger than the negative impact.

关键词： phenology snow cover duration snow melting date NDVI vegetation green-up date

Assessing 40 years of spatial dynamics and patterns in megacities along the Belt and Road region using satellite imagery

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International Journal of Digital Earth 2021年第1期14卷 71-87页

作者： Zhongchang Sun Sisi Yu Huadong Guo cuizhen wang ZengXiang Zhang Ru Xu Aerospace Information Research Institute Chinese Academy of SciencesBeijingPeople’s Republic of China Key Laboratory Earth Observation Hainan Province Sanya Institute of Remote SensingSanyaPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China Department of Geography University of South CarolinaColumbiaSCUSA State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijingPeople’s Republic of China

The Belt and Road(B&R)region,a vital area with historical,economic,cultural and political significance,has undergone rapid urbanization in the past several decades,especially in the form of urban *** this study,20 megacities in the B&R region were selected to explore different spatiotemporal patterns of urban ***-oriented support vector machines(SVM),annual growth rate(AGR)models,and landscape metrics were employed to delineate the urban areas and characterize spatiotemporal characteristics and landscape patterns of these megacities during 1975–*** urban maps presented high overall accuracies(80.70%–95.90%)and overall Kappa coefficients(0.76–0.95).The study revealed that megacities in the B&R region have undergone different types of urban sprawl,mainly adopting a‘concentric circle’pattern in inland areas and a‘sector’pattern in coastal ***,six expansion modes were summarized according to the AGRs of individual *** existed in megacities of the developing and developed countries and among five ***,‘dispersion,gathering,and re-dispersion’and‘coalescence’were two major landscape patterns of megacities in developing and developed *** of this study can provide a scientific reference for urban planning and aid in sustainable development of local areas.

关键词： Belt and Road(B&R) megacities spatiotemporal expansion landscape pattern regional differentiations

Distribution of heavy metals in the topsoil of the Jining mining area

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Mining Science and Technology 2010年第3期20卷 395-399页

作者： HAO Junliang HAN Zuozhen wang cuizhen ZHOU Guangzhu LI Yinming College of Resource and Environmental Engineering Shandong University of Science and Technology Qingdao 266510 China College of Geological Science and Technology Shandong University of Science and Technology Qingdao 266510 China College of Chemical and Environmental Engineering Shandong University of Science and Technology Qingdao 266510 China

The geochemical baseline is the fundamental reference for environmental change and *** this article we describe cluster and regression analyses with a normalization *** elements Sc and Ag were chosen to calculate the environmental geochemical *** geoaccumulation index was calculated and mapped to indicate the environmental quality of the *** results show that the urban areas are barely polluted with Ni and Cr but the rural areas in the southern part of the city, and the western part of the lake,are polluted with Ni,Cr,and Cu at the second *** the other hand,the rural areas in the southern part of the city,and the western part of the lake,are polluted with As at a moderate *** other area is polluted at the second *** increase in As pollution occurs in a direction from northeast to *** Cd pollution follows a trend similar to As,with an additional smaller contaminated area polluted at levelⅢ.The Hg pollution typical of urban areas occurs in the main and northern parts of the *** geochemical accumulation index decreases from the city center to the *** highest pollution level reaches levelⅣ,which indicates that the soil is seriously polluted with *** southern part of the city and the rural areas to the west of the lake are not contaminated with *** factors and the disturbance from human activities are both possible major factors:further research is needed to identify them.

关键词： geochemical baseline heavy metal geoaccumulation index topsoil

Identifying marsh dieback events from Landsat image series (1998–2018) with an Autoencoder in the NIWB estuary, South Carolina

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International Journal of Digital Earth 2020年第12期13卷 1467-1483页

作者： Huixuan Li cuizhen wang Jean T.Ellis Yuxin Cui Gwen Miller James T.Morris Department of Geography University of South CarolinaColumbiaSCUSA Department of Computer Science and Engineering University of South CarolinaColumbiaSCUSA School of the Earth Oceanand EnvironmentUniversity of South CarolinaColumbiaSCUSA Belle Baruch Institute for Marine&Coastal Sciences University of South CarolinaColumbiaSCUSA

This study reports an inventory of marsh dieback events from spatial and temporal perspectives in the North Inlet-Winyah Bay(NIWB)estuary,South Carolina(SC).Past studies in the Gulf/Atlantic coast states have reported acute marsh dieback events in which marsh rapidly browned and thinned,leaving stubble of dead stems or mudflat with damaged ecosystem *** marsh dieback in SC,however,have been *** study identified all marsh dieback events in the estuary since *** 20 annually collected Landsat images,the Normalized Difference Vegetation Index(NDVI)series was extracted.A Stacked Denoising Autoencoder neural network was developed to identify the NDVI anomalies on the *** marsh dieback patches were extracted,and their inter-annual changes were *** showed a continuous,spatially variable multi-year dieback event in 1998–2005,which aligned with the reported dieback in the early 2000s from other *** identified patches mostly returned to normal within one year while the phenomenon reoccurred in other areas of the estuary during the prolonged dieback *** study presents the first attempt to explore long-term dieback dynamics in an estuary using satellite time *** provides valuable information in documenting marsh healthiness and environmental resilience on SC coasts.

关键词： Salt marsh dieback NOAA NERR satellite time series Autoencoder coastal remote sensing

Improved alpine grassland mapping in the Tibetan Plateau with MODIS time series: a phenology perspective

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International Journal of Digital Earth 2015年第2期8卷 133-152页

作者： cuizhen wang Huadong Guo Li Zhang Yubao Qiu Zhongchang Sun Jingjuan Liao Guang Liu Yili Zhang Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina Department of Geography University of South CarolinaColumbiaUSA Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijingChina

The Tibetan Plateau is primarily composed of alpine *** distributions of alpine grasses,however,are not well documented in this remote,highly uninhabited *** advantage of the frequently observed moderate resolution imaging spectroradiometer(MODIS)images(500-m,8-day)in 2010,this study extracted the phenological metrics of alpine grasses from the normalized difference vegetation index time *** the Support Vector Machine,a multistep classification approach was developed to delineate alpine meadows,steppes,and desert *** lakes,permanent snow,and barren/desert lands were also classified with a MODIS scene acquired in the peak growing *** ground data collected in the field and aerial experiments in 2011,the overall accuracy reached 93%when alpine desert grasses and barren lands were not *** comparison with the recently published national vegetation map,the alpine grassland map in this study revealed smoother transition between alpine meadows and steppes,less alpine meadows in the southwest,and more barren/deserts in the high-cold Kunlun Mountain in the *** variations better reflected climate control(***)of different climatic divisions on alpine *** improved alpine grassland map could provide important base information about this cold region under the pressure of rapidly changing climate.

关键词： Tibetan Plateau alpine grassland time-series analysis SVM

Characterizing the changing environment of cropland in the Songnen Plain, Northeast China, from 1990 to 2015

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Journal of Geographical Sciences 2019年第5期29卷 658-674页

作者：张远臧淑英孙丽阎炳和杨天鹏闫文佳 MEADOWS E Michael wang cuizhen QI Jiaguo Key Laboratory of Geographic Information Science(Ministry of Education) School of Geographic SciencesEast China Normal University Institute of Eco-Chongming East China Normal University Key Laboratory of Remote Sensing Monitoring of Geographic Environment College of Heilongjiang ProvinceHarbin Normal University Department of Environmental&Geographical Science University of Cape Town Department of Geography University of South Carolina Center for Global Change and Earth Observations and Department of Geography Michigan State University

Quantitative characterization of environmental characteristics of cropland(ECC)plays an important role in maintaining sustainable development of agricultural systems and ensuring regional food security. In this study, the changes in ECC over the Songnen Plain, a major grain crops production region in Northeast China, were investigated for the period 1990–2015. The results revealed significant changes in climate conditions, soil physical properties and cropland use patterns with socioeconomic activities. Trends in climate parameters showed increasing temperature(+0.49°C/decade, p < 0.05) and decreasing wind speed(–0.3 m/s/decade, p < 0.01) for the growing season, while sunshine hours and precipitation exhibited non-significant trends. Four topsoil parameters including soil organic carbon(SOC), clay, bulk density and pH, indicated deteriorating soil conditions across most of the croplands, although some do exhibited slight improvement. The changing amplitude for each of the four above parameters ranged within –0.052 to 0.029 kg C/kg, –0.38 to 0.30,–0.60 to 0.39 g/cm^3, –3.29 to 2.34, respectively. Crop production significantly increased(44.0 million tons) with increasing sown area of croplands(～2.5 million ha) and fertilizer application(～2.5 million tons). The study reveals the dynamics of ECC in the Songnen Plain with intensive cultivation from 1990 to 2015. Population growth, economic development, and policy reform are shown to strongly influence the spatiotemporal changes in cropland *** study potentially provides valuable scientific information to support sustainable agroecosystem management in the context of global climate change and national socioeconomic development.

关键词： Songnen Plain environmental characteristics of cropland climate change soil properties grain yield