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SAR polarimetric change detection for flooded vegetation

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International Journal of Digital Earth 2013年第2期6卷 103-114页

作者： B.Brisco A.Schmitt K.Murnaghan S.Kaya A.Roth Canada Centre for remote sensing Earth Sciences SectorNatural Resources CanadaOttawaONCanada german remote sensing data center german aerospace centeroberpfaffenhofenwesslinggermany

Due to spatial and temporal variability an effective monitoring system for water resources must consider the use of remote sensing to provide *** Aperture Radar(SAR)is useful due to timely data acquisition and sensitivity to surface water and flooded *** ability to map flooded vegetation is attributed to the double bounce scattering mechanism,often dominant for this *** Ting Lake in China is an ideal site for evaluating SAR data for this application due to annual flooding caused by mountain snow melt causing extensive changes in flooded vegetation.A curvelet-based approach for change detection in SAR imagery works well as it highlights the change and suppresses the speckle *** paper addresses the extension of this change detection technique to polarimetric SAR data for monitoring surface water and flooded ***-2 images of Dong Ting Lake demonstrate this curvelet-based change detection technique applied to wetlands although it is applicable to other land covers and for post disaster impact *** tools are important to Digital Earth for map updating and revision.

关键词： SAR polarimetry change detection wetlands floods earth observa-tion land cover microwave remote sensing

The digital Earth Observation Librarian:a data mining approach for large satellite images archives

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Big Earth data 2020年第3期4卷 265-294页

作者： Mihai Datcu Alexandru-Cosmin Grivei Daniela Espinoza-Molina Corneliu Octavian Dumitru Christoph Reck Vlad Manilici Gottfried Schwarz german Aerospace center Remote Sensing Technology InstituteWesslingGermany Research center for Spatial Information University Politehnica of BucharestBucharestRomania german remote sensing data center German Aerospace CenterWesslingGermany

Throughout the years,various Earth Observation(EO)satellites have generated huge amounts of *** extraction of latent information in the data repositories is not a trivial *** methodologies and tools,being capable of handling the size,complexity and variety of data,are *** scientists require support for the data manipulation,labeling and information extraction *** paper presents our Earth Observation Image Librarian(EOLib),a modular software framework which offers innovative image data mining capabilities for TerraSAR-X and EO image data,in *** main goal of EOLib is to reduce the time needed to bring information to end-users from Payload Ground Segments(PGS).EOLib is composed of several modules which offer functionalities such as data ingestion,feature extraction from SAR(Synthetic Aperture Radar)data,meta-data extraction,semantic definition of the image content through machine learning and data mining methods,advanced querying of the image archives based on content,meta-data and semantic categories,as well as 3-D visualization of the processed *** is operated by DLR’s(german Aerospace center’s)Multi-Mission Payload Ground Segment of its remote sensing data center at Oberpfaffenhofen,germany.

关键词： Earth observation TerraSAR-X data mining system

Urbanization between compactness and dispersion:designing a spatial model for measuring 2D binary settlement landscape configurations

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International Journal of Digital Earth 2019年第6期12卷 679-698页

作者： Hannes Taubenbock Michael Wurm Christian GeiB Stefan Dech Stefan Siedentop german Aerospace center(DLR) German Remote Sensing Data Center(DFD)OberpfaffenhofenGermany ILS-Research Institute for Regional and Urban Development DortmundGermany

Measuring spatial patterns is a crucial task in spatial *** indicators have been developed to measure patterns in a quantitative ***,most comparative studies rely on relative comparisons,limiting their explanatory power to specific case *** by advancements in earth observation providing unprecedented resolutions of settlement patterns,this paper suggests a measurement technique for spatial patterns to overcome the limits of relative *** design a model spanning a feature space based on two metrics-largest patch index and number of *** feature space is defined as‘dispersion index’and covers the entire spectrum of possible two-dimensional binary(settlement)*** model configuration allows for an unambiguous ranking of each possible pattern with respect to spatial *** spatial resolutions of input data as well as selected areas of interest influence measurement results,we test dependencies within the ***,common other spatial metrics are selected for testing whether they allow unambiguous *** scenarios,we apply the model to artificially generated patterns representing all possible configurations as well as to real-world settlement classifications differing in growth dynamics and patterns.

关键词： Land cover spatial patterns landscape metrics dispersion index sensitivity analysis urban settlements remote sensing comparative spatial analysis

Urbanization in China from the end of 1980s until 2010 – spatial dynamics and patterns of growth using EO-data

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International Journal of Digital Earth 2019年第1期12卷 78-94页

作者： Lifeng Shia Hannes Taubenböck Zengxiang Zhang Fang Liu Michael Wurm Institute of remote sensing and Digital Earth Chinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China german remote sensing data center(DFD) German Aerospace Center(DLR)OberpfaffenhofenGermany

Urbanization in China has been experiencing a remarkable dynamism in the past 40 *** most evident implication of urbanization is the physical growth of *** analyze urban land growth rates and changes in spatial urban forms from the end of the 1980s to 2010 based on the authoritative National Land Use/Cover database of *** present new spatial measures that describe‘urban land growth types’and‘fluctuations in urban land growth’within the monitoring time span with a temporal interval of five-year *** evaluate the correlations between urban land growth rates and socioeconomic *** show that(1)distinct characteristics exist on the spatiotemporal evolutions of urban land growth rates in terms of area and perimeter,*** areas exhibit the most dramatic growth rates;(2)the spatial distribution characteristics of‘urban land growth types’and‘fluctuations in urban land growth’follow similar spatial patterns across China,*** differences exist between the eastern region and other regions;and(3)a moderate correlation exists between urban area growth rate and urban population growth rate at an R2 of *** contrast,we determine no significant correlation between urban area growth rate and tertiary industry value growth rate.

关键词： Urban land growth pattern spatial metrics remote sensing regional difference

Matrix expression of thermal radiative characteristics for an open complex

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Science China Earth Sciences 2002年第7期45卷 654-661页

作者：徐希孺范闻捷陈艮富 center of remote sensing and GIS of Beijing Normal University Beijing China Institute of remote sensing Peking University Beijing China Laboratory of remote sensing Information Sciences Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China

The directionality of thermal radiance of a homogeneous isothermal non-black plane surface is totally decided by its directional emissivity, which depends on the complex dielectric constant and roughness of surface. It can be expressed by $\bar L_\lambda (\theta _k ,T) = \bar \varepsilon _\lambda (\theta _\lambda )L_{b\lambda } (T)$ . This paper proves that it is necessary to express emissivity by a matrix when a target becomes an inhomogeneous non-isothermal open complex with complicated inner geometric structure. The matrix describes the inner radiative interaction among components accurately and also expresses its thermal radiative directionality and structural characteristics completely. Advantages of matrix expression are as follows: first, the physical mechanics of effective emissivity of an open complex is described in a simple and perfect way; second, it becomes easy to understand the principle and method to retrieve components temperature from multi-angle thermal remotely sensed data; and third, the differences of directionalities between an open complex and a homogeneous isothermal non-black plane body are expressed by just using an effective emissivity matrix instead of an emissivity vector. Formula $\bar L_\lambda (\theta _k ,T) = \varepsilon _\lambda (\theta _\lambda )L_{b\lambda } (T)$ in classic physics is only the special case of matrix expression; therefore, the matrix is a universal unconditional expression to describe the directionality of thermal radiance.

关键词： open complex, directionality of thermal radiance, structural characteristics of thermal radiance, matrix expression.

F4ESS-a framework for interdisciplinary data-driven earth system science

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International Journal of Digital Earth 2023年第1期16卷 3973-3986页

作者： Doris Dransch Daniel Eggert Mike Sips remote sensing and Geoinformatics Helmholtz Center Potsdam–German Research Center for GeosciencePotsdamGermany Geography Department Humboldt-University at BerlinBerlinGermany

Earth system science is an interdisciplinary effort to understand the fundamentals and interactions of environmental *** research is challenging since it demands the integration of scientific schemes and practices from different research fields into a collaborative work *** paper introduces the framework F4ESS that supports this integration.F4ESS provides methods and technologies that facilitate the development of integrative work environments for Earth system science.F4ESS enables scientists a)to outline structured and summarized descriptions of scientific procedures to facilitate communication and synthesis,b)to combine a large variety of distributed data analysis software into seamless data analysis chains and workflows,c)to visually combine and interactively explore the manifold spatiotemporal data and results to support understanding and knowledge *** F4ESS methods and technologies are generic and can be applied in various scientific *** discuss F4EsS in the context of the interdisciplinary investigation of flood events.

关键词： Earth system science interdisciplinary research scientific workflows integration

Study of thin cloud removal method for CBERS-02 image

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Science China(Technological Sciences) 2005年第S2期48卷 91-99页

作者： MA Jianwen1, GU Xingfa1, FENG Chun2 & GUO Jianning2 1. Institute of remote sensing Application, Chinese Academy of Sciences, Beijing 100101, China 2. China center for Resource Satellite data and Applications, Beijing 100073, China Institute of remote sensing Application Chinese Academy of Sciences Beijing China China center for Resource Satellite data and Applications Beijing China

The China Brazil Earth Resources Satellite (CBERS) ended the dependence on foreign satellites. Along with the series of CBERS and the enhancement of satellite applications, it is necessary to search correlative data processing methods. Because cloud appears in the atmosphere, an image with clear sky conditions is often hard to obtain. How to remove cloud is an important sector of increasing image quality. An improved homomorphism filtering method is adopted to remove thin cloud qualitatively at first, and all bands are selected to classify pixels. Based on the fact that visible band images contain more aerosol effects than infrared bands, visible bands are used to determine clear or hazy regions and the reflectances of different surface classes in clear regions are calculated. At last the mean reflectance of the same classes in clear and hazy regions is matched to remove cloud. The image visual effect is improved; meanwhile, the ground reflectance is retrieved to meet the needs of remote sensing quantification.

关键词： CBERS-02 cloud removal surface reflectance mean reflectance matching.

The correlation of multi-angle thermal infrared data and the choice of optimal view angles

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Science China Earth Sciences 2004年第6期47卷 570-576页

作者： FAN Wenjie1 & XU Xiru1,2 1.Institute of remote sensing and GIS of Peking University,Beijing 100871,China 2.center of remote sensing and GIS of Beijing Normal University,Beijing 100875,China Institute of remote sensing and GIS of Peking University Beijing China center of remote sensing and GIS of Beijing Normal University Beijing China

Based on the matrix formula of thermal infrared radiant system, the components temperature can be retrieved by the inversive matrix. Around the stability problem of retrieved result, the research work we did was focused on (i) the correlation of (wk,j) which is the key to affect the retrieval accuracy, (ii) a general method which can help us find the number of retrievable parameters and evaluate the retrieval error before its performance, (iii) the choice of “optimal viewing angle group” based on the formula of absolute error propagation. The row winter wheat field was chosen as an example. The results can provide a theoretical basis for multi-angle thermal infrared remote sensing and components temperature retrieval.

关键词： components temperature retrieval, correlation, number of retrievable parameters, optimal viewing angle group.

Retrieval of sea surface winds under hurricane conditions from GNSS-R observations

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Acta Oceanologica Sinica 2016年第9期35卷 91-97页

作者： JING Cheng YANG Xiaofeng MA Wentao YU Yang DONG Di LI Ziwei XU Cong State Key Laboratory of remote sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of Sciences National Engineering center for Geoinformatics Institute of Remote Sensing and Digital EarthChinese Academy of Sciences

Reflected signals from global navigation satellite systems（GNSSs） have been widely acknowledged as an important remote sensing tool for retrieving sea surface wind *** power of GNSS reflectometry（GNSS-R）signals can be mapped in delay chips and Doppler frequency space to generate delay Doppler power maps（DDMs）,whose characteristics are related to sea surface roughness and can be used to retrieve wind ***,the bistatic radar cross section（BRCS）,which is strongly related to the sea surface roughness,is extensively used in ***,a bistatic radar cross section（BRCS） map with a modified BRCS equation in a GNSS-R application is *** the BRCS map,three observables are proposed to represent the sea surface roughness to establish a relationship with the sea surface wind *** Hurricane Dennis（2005） GNSS-R data are then *** than 16 000 BRCS maps are generated to establish GMFs of the three ***,the proposed model and classic one-dimensional delay waveform（DW） matching methods are compared,and the proposed model demonstrates a better performance for the high wind speed retrievals.

关键词： global navigation satellite system-reflectometry Hurricane Dennis delay doppler maps bistatic radar cross section map sea surface wind speed