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Tracking the evolution processes and behaviors of mesoscale eddies in the South China Sea：a global nearest neighbor filter approach

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Acta Oceanologica Sinica 2017年第11期36卷 27-37页

作者： YI Jiawei du yunyan WANG Dongxiao ZHOU Chenghu State Key Laboratory of Resources and Environmental Information System Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Tropical Oceanography (LTO) South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China

The eddy tracking approach is developed using the global nearest neighbor filter（GNNF） to investigate the evolution processes and behaviors of mesoscale eddies in the South China Sea（SCS）. Combining the Kalman filter and optimal data association technologies, the GNNF algorithm is able to reduce pairing errors to 0.2% in tracking synthetic eddy tracks, outperforming other existing methods. A total of 4 913 eddy tracks that last more than a week are obtained by the GNNF during 1993–2012. The analysis of a growth and a decay based on 3 445 simple eddy tracks show that eddy radius, amplitude, and vorticity smoothly increase during the first half of lifetime and decline during the second half following a parabola opening downwards. The genesis of eddies mainly clusters northwest and southwest of Luzon Island whereas the dissipations concentrate the Xisha Islands where the underwater bay traps and terminates eddies. West of the Luzon Strait, northwest of Luzon Island, and southeast of Vietnam are regions where eddy splits and mergers are frequently observed. Short disappearances mainly distribute in the first two regions. Moreover, eddy splits generally result in a decrease of the radius and the amplitude whereas eddy mergers induce growing up. Eddy intensity and vorticity, on the contrary, are strengthened in the eddy splits and diminished in mergers.

关键词： mesoscale ocean eddies eddy tracking eddy split eddy merger South China Sea

Multifractal filtering method for extraction of ocean eddies from remotely sensed imagery

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Acta Oceanologica Sinica 2006年第5期25卷 27-38页

作者： GE Yong du yunyan CHENG Qiuming LI Ce State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences ＆ Natural Re-sources Research Chinese Academy of Sciences Beijing 100101 China Department of Earth and Space Science and Engineering York University Toronto M3J 1P3 Canada State Key Laboratory of Geo-Processes and Mineral Resources China University of Geosciences Beijing 100083 China

Traditional methods of extracting the ocean wave eddy information from remotely sensed imagery mainly use the edge detection technology such as Canny and Hough operators. However, due to the complexities of ocean eddies and image itself, it is sometimes difficult to successfully detect ocean eddies using these methods. A mnltifractal filtering technology is proposed for extraction of ocean eddies and demonstrated using NASA MODIS, SeaWiFS and NOAA satellite data set in the typical area, such as ocean west boundary current. Results showed that the new method has a superior performance over the traditional methods.

关键词： remotely sensed imagery extraction of ocean eddies multifractal filtering

Analysis of ecological quality in Lhasa Metropolitan Area during 1990-2017 based on remote sensing and Google Earth Engine platform

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Journal of Geographical Sciences 2021年第2期31卷 265-280页

作者： HUANG Huiping CHEN Wei ZHANG Yuan QIAO Lin du yunyan Aerospace Information Research Institute CASBeijing 100094China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China

Based on a total of 519 images,the composite images with the lowest possible cloud cover were generated at pixel level with image synthesis method on Google Earth Engine(GEE)*** Remote Sensing Ecological Index(RSEI)was adopted,and calculated in an efficient way with the assistance of parallel cloud computing of the GEE *** RSEI was used in this paper to evaluate and monitor the eco-environmental quality of the Lhasa Metropolitan *** show that:(1)The ecological quality is better in the west than in the east of Lhasa Metropolitan Area,with Lhasa as an approximate dividing *** ecological quality improved and then deteriorated dramatically before 2000,with the mean RSEI value dropping from 0.51 to 0.46;the trend was followed by a gradual increase up until 2017,with the mean RSEI value increased from 0.46 to 0.55.(2)The RSEI is weakly and positively correlated with socioeconomic *** indicates that the population growth and economic development did not negatively influence the ecological quality,but actually boosted it.(3)The GEE can serve as an efficient computing platform for the assessment and monitoring of eco-environmental quality in vast regions.

关键词： Lhasa Metropolitan Area ecological quality remote sensing ecological index Google Earth Engine

Spatial information recognizing of ocean eddies based on virtual force field and its application

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Acta Oceanologica Sinica 2007年第4期26卷 44-52页

作者： LI Ce du yunyan SU Fenzhen YANG Xiaomei XU Jun State Key Laboratory of Resources and Environment Information System Institute of Geographic Science and Natural Resources Chinese Academy of Sciences Beijing 100101 China

A new approach to detecting ocean eddies automatically from remote sensing imageries based on the ocean eddy＇s eigen-pattern in remote sensing imagery and ＂force field-based shape extracting method＂ is proposed. First, the analysis on extracting eddies＇ edges from remote sensing imagery using conventional edge detection arithmetic operators is performed and returns digitized vector edge data as a result. Second, attraction forces and fusion forces between edge curves were analyzed and calculated based on the vector eddy edges. Thirdly, the virtual significant spatial patterns of eddy were detected automatically using iterative repetition followed by optimized rule. Finally, the spatial form auto-detection of different types of ocean eddies was done using satellite images. The study verified that this is an effective way to identify and detect the ocean eddy with a complex form.

关键词： ocean eddy spatial pattern recognizing force field detection

A model of sea surface temperature front detection based on a threshold interval

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Acta Oceanologica Sinica 2014年第7期33卷 65-71页

作者： PING Bo SU Fenzhen MENG Yunshan FANG Shenghui du yunyan School of Remote Sensing and Information Engineering Wuhan University Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Collaborative Innovation Center of South China Sea Studies

A model （Bayesian oceanic front detection, BOFD） of sea surface temperature （SST） front detection in satel- lite-derived SST images based on a threshold interval is presented, to be used in different applications such as climatic and environmental studies or fisheries. The model first computes the SST gradient by using a Sobel algorithm template. On the basis of the gradient value, the threshold interval is determined by a gradi- ent cumulative histogram. According to this threshold interval, front candidates can be acquired and prior probability and likelihood can be calculated. Whether or not the candidates are front points can be deter- mined by using the Bayesian decision theory. The model is evaluated on the Advanced Very High-Resolution Radiometer images of part of the Kuroshio front region. Results are compared with those obtained by using several SST front detection methods proposed in the literature. This comparison shows that the BOFD not only suppresses noise and small-scale fronts, but also retains continuous fronts.

关键词： sea surface temperature threshold setting Sobel algorithm edge detection front detection

Integration technology research on marine geographical information system

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Acta Oceanologica Sinica 2008年第6期27卷 40-48页

作者： XUE Cunjin SU Fenzhen du yunyan YANG Xiaomei State Key Laboratory of Resource and Environment Information System Institute of Geographical Science ＂and Natural Re-sources Chinese Academy of Sciences Beijing 100101 China Center for Earth Observation and Digital Earth Chinese Academy of Science Beijing 100191 China Graduate School Chinese Academy of Sciences Beijing 100039 China

It is urgent and necessary to integrate a marine geographical information system （MGIS） with marine remote sensing detection modules. On the basis of the current technology and features of applications, an open three-layer integration framework is designed. At the data layer, a two-level three-base integration mechanism based on the plug-in technology is applied; At the function layer, an integration mode based on API, DLL, EXE and COM is discussed; and at the application layer, a sharing mechanism based on the clients/service is adopted. As an example, the remote sensing integrated application information system of China＇s coastal zone and offshore （MaXplorer1. 0） with muhiecology remote sensing fusion and assimilation module, surge detection module as well as eight other thematic application modules is integrated, and the key technology of integration is discussed at different layers and in different modules. The result shows that it is possible to realize the conformity of technology and resources and to provide the incorporate technology platform for marine information operational functioning after applying the integration framework.

关键词： marine geographical information system ( MGIS) marine remote sensing application modules ( MRSAMs) systemintegration integration modes

Oceanographic ontology-based spatial knowledge query

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Acta Oceanologica Sinica 2005年第4期24卷 66-71页

作者： WANG Jinggui SU Fenzhen ZHOU Chenghu du yunyan YANG Xiaomei State Key Laboratory of Resources and Environmental Information Systems Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Institute of Sciences Research Zhujiang River Water Resources Commission Ministry of Water Resources Guangzhou 510611 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

The construction of oceanographic ontologies is fundamental to the ＂digital ocean＂. Therefore, on the basis of introduction of new concept of oceanographic ontology, an oceanographic ontology-based spatial knowledge query （OOBSKQ） method was proposed and developed. Because the method uses a natural language to describe query conditions and the query result is highly integrated knowledge, it can provide users with direct answers while hiding the complicated computation and reasoning processes, and achieves intelligent, automatic oceanographic spatial information query on the level of knowledge and semantics. A case study of resource and environmental application in bay has shown the implementation process of the method and its feasibility and usefulness.

关键词： spatial information query oceanographic ontology MGIS

Multisource Marine Environmental Information Grid Platform and Its Prototype System Research

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Geo-Spatial Information Science 2010年第4期13卷 269-274页

作者： XIAO Rulin SU Fenzhen du yunyan YANG Feng HE Yawen Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 11A Datun Road Chaoyang District Beijing 100001 China Satellite Environment Centre Ministry of Environmental Protection East Fengde Road Haidian District Beijing 100094 China Surveying and Mapping Engineering Department of Yellow River Conservancy Technical Institute Dongjing Street West Kaifeng 475003 China Yantai Institute of Coastal Zone Research for Sustainable Development Chinese Academy of Science 26 Yinhai Road Laishan District Yantai 264003 China

Based on the advantages of the openness,flexibility,high-efficiency,intelligence,and safety of grid,this paper focuses on the methods of marine environmental information sharing and integration in grid *** to the characteristics of marine information,which includes multisource,dynamic,and high-dimensional,this paper provides a framework and the technical solution for a multisource marine environmental information grid *** an experiment,the prototype takes the region of South China Sea as its study area and chooses three kinds of marine environmental information as the representative types for the marine *** realization of the prototype of multisource marine environmental information grid platform shows the feasibility and practicality of the framework and the technical solution.

关键词： grid GIS marine GIS web service data sharing information integration

Quantitative estimates of collective geo-tagged human activities in response to typhoon Hato using location-aware big data

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International Journal of Digital Earth 2020年第9期13卷 1072-1092页

作者： Zhang Liu yunyan du Jiawei Yi Fuyuan Liang Ting Ma Tao Pei State Key Laboratory of Resources and Environmental Information System Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China College of Resources and Environment University of Chinese Academy of SciencesBeijingPeople’s Republic of China Department of Geography Western Illinois UniversityMacombILUSA

Location-aware big data from social media have been widely used to quantitatively characterize natural disasters and disaster-induced *** is not clear how human activities collectively respond to a *** this study,we examined the collective human activities in response to Typhoon Hato at multi spatial scales using aggregated location request *** proposed a Multilevel Abrupt Changes Detection(MACD)methodological framework to detect and characterize the abrupt changes in location requests in response to Typhoon *** show that,at the grid level,most anomaly grids were located within a radius of 53 km around the typhoon *** the city level,there are significant spatial difference in terms of the human activity recovery duration(230 h on average).At the subnational level,the absolute magnitude of abrupt location request changes is strongly correlated with the typhoon-induced economic losses and the population affected.

关键词： Human response typhoon natural disaster locationaware data rapid disaster assessment