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Polynomial analysis of canopy spectra and biochemical component content inversion

science China Earth sciences 2005年第10期48卷 1780-1791页

作者： YAN Chunyan1, LIU Qiang1, NIU Zheng1, WANG Jihua2, HUANG Wenjiang2 & LIU Liangyun 2 1. state key laboratory of Remote {3. science, jointly sponsored by the institute of Remote {3. applications of Chinese Academy of sciences and beijing normal {{13., beijing 100101, China 2. National Engineering Research Center for Information Technology in Agriculture, beijing 100089, China state key laboratory of Remote {3. science jointly sponsored by the institute of Remote {3. applications of Chinese Academy of sciences and beijing normal {{13. beijing China National Engineering Research Center for Information Technology in Agriculture beijing China

A polynomial expression model was developed in this paper to describe directional canopy spectra, and the decomposition of the polynomial expression was used as a tool for re-trieving biochemical component content from canopy multi-angle spectra. First, the basic formula of the polynomial expression was introduced and the physical meaning of its terms and coeffi-cients was discussed. Based on this analysis, a complete polynomial expression model and its decomposition method were given. By decomposing the canopy spectra simulated with SAILH model, it shows that the polynomial expression can not only fit well the canopy spectra, but also show the contribution of every order scattering to the whole reflectance. Taking the first scattering coefficients a10 and a01 for example, the test results show that the polynomial coefficients reflect very well the hot spot phenomenon and the effects of viewing angles, LAI and leaf inclination angle on canopy spectra. By coupling the polynomial expression with leaf model PROSPECT, a canopy biochemical component content inversion model was given. In the simulated test, the canopy multi-angle spectra were simulated by two different models, SAILH and 4-SCALE re-spectively, then the biochemical component content was retrieved by inverting the coupled polynomial expression + PROSPECT model. Results of the simulated test are promising, and when applying the algorithm to measured corn canopy multi-angle spectra, we also get relatively accurate chlorophyll content. It shows that the polynomial analysis provides a new method to get biochemical component content independent of any specific canopy model.

关键词： polynomial expression, canopy spectra, decomposition, biochemical component content, inversion.

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Radiometric cross-calibration of the CBERS-02 CCD camera with the TERRA MODIS

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science China(Technological sciences) 2005年第S2期48卷 44-60页

作者： LI Xiaoying1,2,3. GU Xingfa1,3.4, MIN Xiangjun5, YU Tao1,3. FU Qiaoyan5, ZHANG Yong1,2,3.& LI Xiaowen1,3.1. state key laboratory of Remote {3. science, jointly sponsored by the institute of Remote {3. applications of Chinese Academy of sciences and beijing normal {{13., beijing 100101, China 2. Graduate {{13. of Chinese Academy of sciences, beijing 10003., China 3. The Center for National Spaceborne Demonstration, beijing 100101, China 4. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 5. China Center for Resource Satellite Data and Application, beijing 10083., China 1. state key laboratory of Remote {3. science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University 100101 Beijing China 2. Graduate university of Chinese Academy of sciences 100039 Beijing China 3. The Center for National Spaceborne Demonstration 100101 Beijing China 4. Institut National de la Recherche Agronomique Climat Sol Environnement 84914 Avignon France 5. China Center for Resource Satellite Data and Application 100830 Beijing China

For the application of the CCD camera, the most important payload on CBERS-02, the key is to provide long-term stable radiometric calibration coefficients. Although the vicarious calibration had been proved successful, it had its limitations such as test site requirement and unsuitable for historical data. Cross-calibration is one of the alternative methods, but it needs synchro surface spectrum to achieve spectral band matching factors. Our effort is to probe the influences on these factors. Simulations with a lot of surface spectrum showed that the factors changed with the viewing geometry, atmospheric condition and surface targets. However, simulating with the same viewing geometry and atmospheric condition, the spectral band matching factors of the same or similar surface targets’ spectrum acquired from different dates and different places would like to be consistent to each other within 1%―5%. Thus, the synchro measurement data can be substituted by the same or similar target from other source. Based on this method, using the MODIS as the reference, the cross-calibration was performed for CCD camera. The research demonstrated that the traditional method with single calibration site was inappropriate for CCD camera, since the offsets for its four spectral bands were not zeros. With four calibration sites, these offsets were obtained. And the camera was detected to degrade with dates based on four times of cross-calibrations.

关键词： CBERS-02 CCD camera cross-calibration the spectral band matching factors.

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Biomass estimation and uncertainty analysis based on CBERS-02 CCD camera data and field measurement

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science China(Technological sciences) 2005年第S2期48卷 116-128页

作者： CHEN Liangfu1,2, GAO Yanhua1,3. CHENG Yu1,3. WEI Zheng1,3. XIAO Qing1,4, LIU Qinhuo1, YU Tao1, LIU Qijing5, GU Xingfa1 & TIAN Guoliang1 1. state key laboratory of Remote {3. science, institute of Remote {3. applications, Chinese Academy of sciences, beijing 100101, China 2. Geography and Environment College, Jiangxi normal university, Nanchang 3.0027, China 3. Graduate university of Chinese Academy of sciences, beijing 10003., China 4. beijing Research institute of Uranium Geology, beijing 100875, China 5. institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101, China 1. state key laboratory of Remote {3. science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China 2. Geography and Environment College Jiangxi Normal University 330027 Nanchang China 3. Graduate university of Chinese Academy of sciences 100039 Beijing China 4. beijing Research institute of Uranium Geology 100875 Beijing China 5. institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

The study site is located in Qianyanzhou experimental station and the surrounding area. Based on CBERS-02 satellite data and field measurement, we not only discussed the relationship between NDVI and biomass of two species of coniferous plantations, namely, Pinus massoniana Lamb and Pinus elliottii Engelm, but also introduced the biomass models based on NDVI. The comparison between measured biomass in Qianyanzhou and biomass derived from CBERS-02 CCD data showed that it is feasible to estimate biomass based on NDVI. But its limitations cannot be ignored. This kind of model depends on the dominant vegetation species. There are some effect factors in estimating biomass based on NDVI. This paper analyzes these factors based on fine-resolution CBERS-02 CCD data and some conclusions are drawn: In Qianyanzhou, the area with good vegetation coverage, the nonlinearity of NDVI has little influence on scaling-up of NDVI. As a result of surface heterogeneity, scaling-up can cause NDVI within each pixel to change. Because scaling-up can cause pixel attribute to change, the applicability of biomass model is one of the sources of error in estimating biomass.

关键词： NDVI biomass scaling effect scaling-up.

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An efficient rendering method for large vector data on large terrain models

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science China(Information sciences) 2010年第6期53卷 1122-1129页

作者： YANG Ling1,ZHANG LiQiang1,KANG ZhiZhong2,XIAO ZhiQiang1,PENG JunHuan2,ZHANG XingMing1 & LIU Liu11state key laboratory of Remote {3. science,jointly sponsored by beijing normal university and the institute of Remote {3. applications of Chinese Academy of sciences,{13.,China 2Department of Geodesy and Geomatics,School of Land science and Technology,China university of Geosciences,beijing 100083.China 1. state key laboratory of Remote {3. science Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100875 China2. Department of Geodesy and Geomatics School of Land Science and Technology China University of Geosciences Beijing 100083 China

This paper presents an efficient way to render large-scale vector maps on level-of-detail(LOD) digital elevation models(DEMs).By using the frame buffer and Voronoi diagram,we achieve a rapid simplification of large-scale vector maps while keeping their original topological *** the simplified maps,we establish level-of-detail vector map *** the detailed level,we use the stencil shadow volume approach to render the map accurately,and in the coarse level we use substitute techniques to render the map approximately yet more *** method proposed in this paper is universally applicable to rendering vector maps on various LOD terrain models,and the overlaying performance is independent of the complexity of underlying terrain *** use of the view frustum culling and sub-region index techniques,the impact of complexity of vector maps is reduced,and the rendering time is restricted to a certain ***,we can achieve seamless and rapid rendering of large-scale vector maps on LOD terrain surfaces.

关键词： large-scale vector maps LODs view-dependent visualization

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Change of surface cover greenness in China between 2000 and 2010

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Chinese science Bulletin 2012年第22期57卷 2835-2845页

作者： LIU Shuang1,4& GONG Peng1,2,3.state key laboratory of Remote {3. science, jointly sponsored by institute of Remote {3. applications of Chinese Academy of sciences,and beijing normal {{13., beijing 100101, China 2institute for Global Change Studies & Center for Earth System science, Tsinghua {{13., beijing 100084, China 3.epartment of Environmental science, Policy and Management, {{13. of California, Berkeley, CA94720, USA 4Graduate {{13. of Chinese Academy of sciences, beijing 100049, China state key laboratory of Remote {3. science Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate university of Chinese Academy of sciences Beijing China institute for Global Change Studies & Center for Earth System science Tsinghua University Beijing China Department of Environmental science Policy and Management University of California Berkeley USA

Surface greenness reflects the situation of vegetation *** index calculated from the Red and Near Infrared bands of remote sensing images,whose values indicate the level of photosynthetic activity,is monotonically related to surface greenness when vegetation canopy does not fully cover the background *** for desert regions,vegetation index is positively correlated with vegetation ***,vegetation index can be used to study the change in greenness of desert *** study collected MODIS normalized Difference Vegetation Index (NDVI) data from 2000 to 2010 and analyzed their change over China in this *** results showed that an increasing trend of NDVI occurred over 66.84% (OLS fitting) or 64.27% (LAD fitting) of China,indicating that China's greenness is increasing ***,desertification of China *** showing large increase in greenness are found in Shaanxi,Shanxi,Ningxia,Henan,Shandong,Qinghai,and Gansu while regions with large decrease in greenness are found in Northeast Inner Mongolia,South Tibet,Jiangsu,and *** of Qinghai,Gansu,Xinjiang and South Tibet could probably be driven by climate *** of greenness in Northeast Inner Mongolia was related to agricultural *** of greenness in Jiangsu and Shanghai was related to rapid *** factors did not exhibit obvious correspondence to the large increase in greenness in Shaanxi,Shanxi,Ningxia and Gansu,indicating that the changes might have been caused by human *** reduction of desert areas in China could probably have been caused by human management and protection at the national scale.

关键词：中国地表覆盖归一化植被指数植被覆盖度沙漠地区 NDVI 西藏南部气候因素

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Spatial prediction and analysis of Himalayan marmot plague natural epidemic foci in China based on HJ-1 satellite data

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science China Earth sciences 2010年第S1期53卷 8-15页

作者： GAO MengXu1,4,LI XiaoWen1,2,CAO ChunXiang1,ZHANG Hao1,LI Qun3.ZHOU Hang3.HE QiSheng1,4,XU Min1,4,ZHAO Jian1,4,ZHENG Sheng1,4 & CHEN Wei1,4 1state key laboratory of Remote {3. science,jointly sponsored by the institute of Remote {3. applications of Chinese Academy of sciences and beijing normal {{13.,beijing 100101,China 2School of Geography,beijing normal {{13.,beijing 100875,China 3.ffice for Disease Control and Emergency Response,Chinese Center for Disease Control and Prevention,beijing 102206,China 4Graduate {{13. of Chinese Academy of sciences,beijing 100049,China 1. state key laboratory of Remote {3. science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China4. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. School of Geography Beijing Normal University Beijing 100875 China3. Office for Disease Control and Emergency Response Chinese Center for Disease Control and Prevention Beijing 102206 China

Plague,caused by the gram-negative bacterium Yersinia pestis,is a serious and rapidly progressing illness in humans that can be fatal if not treated *** Qinghai-Tibet Plateau is the largest area of natural Himalayan marmot(Marmota himalayana) plague foci in China and covers more than 63.000 *** County in Gansu Province is a part of this natural focus of plague and was chosen as a study *** study used an ecological niche modeling(ENM) approach to predict the potential distribution of the Himalayan *** and Disaster Monitor Satellite(HJ-1) data was used to investigate environment factors that affect plague host animal *** animal point data from active surveillance was combined with environmental variables from the HJ-1 satellite and other databases,and the models of the potential distribution of Himalayan marmot were produced with the Genetic Algorithm for Rule-Set Production(GARP).The probability of marmot presence was divided into 0-5%,5%-20%,20%-40%,40%-80%,and 80%-100% *** with 80%-100% probability exhibited the greatest potential for the presence of Himalayan *** to the predicted potential distribution of Himalayan marmot in the study area,active surveillance of plague hosts and plague control and prevention could be more efficient.

关键词： Himalayan marmot plague spatial prediction GARP HJ-1 satellite

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Remote sensing based shrub above-ground biomass and carbon storage mapping in Mu Us desert,China

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science China(Technological sciences) 2010年第S1期53卷 176-183页

作者： XU Min 1,2,CAO ChunXiang 1,TONG QingXi 1,LI ZengYuan 3.ZHANG Hao 1,HE QiSheng 1,2,GAO MengXu 1,2,ZHAO Jian 1,2,ZHENG Sheng 1,2,CHEN Wei 1,2 & ZHENG LanFen 1 1state key laboratory of Remote {3. science,jointly sponsored by the institute of Remote {3. applications of Chinese Academy of sciences and beijing normal {{13.,beijing 100101,China 2 Graduate School of the Chinese Academy of sciences,beijing 100049,China 3.Research institute of Forest Resources and Information Techniques,Chinese Academy of Forestry,beijing 10009,China 1. state key laboratory of Remote {3. science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China 2. Graduate School of the Chinese Academy of sciences Beijing 100049 China 3. Research institute of Forest Resources and Information Techniques Chinese Academy of Forestry Beijing 10009 China

The estimation of above-ground biomass(AGB) and carbon storage is very important for arid and semi-arid ***-1A/B satellite data combined with field measurement data was used for the estimation of shrub AGB and carbon storage in the Mu Us desert,*** correlations of shrub AGB and spectral reflectance of four bands as well as their combined vegetation indexes were respectively analyzed and stepwise regression analysis was employed to establish AGB prediction *** prediction equation based on ratio vegetation index(RVI)was proved to be more suitable for shrub AGB estimation in the Mu Us desert than *** AGB and carbon storage were mapped using the RVI based prediction model in *** statistics showed the western Mu Us desert has relatively high AGB and carbon storage,and that the gross shrub carton storage in Mu Us desert reaches 16 799 200 t,which has greatly contributed to the carbon fixation in northern China.

关键词： above-ground biomass carbon storage Mu Us desert HJ-1A/B remote sensing

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An improved line-of-sight method for visibility analysis in 3. complex landscapes

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science China(Information sciences) 2010年第11期53卷 2185-2194页

作者： LIU Liu1, ZHANG LiQiang1, MA JingTao2, ZHANG Liang3. ZHANG XingMing1, XIAO ZhiQiang1 & YANG Ling1 1state key laboratory of Remote {3. science, jointly sponsored by beijing normal university and the institute of Remote {3. applications of Chinese Academy of sciences, {13., China 2PTV America, Inc. 1145 Broadway Plaza Ste 605, Tacoma, WA 98407, USA 3.chool of Geomatics and Urban Information, beijing university of Civil Engineering and Architecture, beijing 100044, China 1. state key laboratory of Remote {3. science Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100875 China2. PTV America Inc. 1145 Broadway Plaza Ste 605 Tacoma WA 98407 USA3. School of Geomatics and Urban Information Beijing University of Civil Engineering and Architecture Beijing 100044 China

This paper presents an efficient method for implementing visibility analysis on complex landscapes based on an improved LOS (line of sight) algorithm. The method determines the viewshed by analyzing the geometric relationship between the target points and viewpoint. It differentiates the visibility of the target points by the elevation information. Eventually the visual results related to the given viewpoint are rendered on three-dimensional landscapes. The visibility of some target points is computed by comparing their elevations with the viewpoint's height, thus is able to enhance the efficiency of the visibility analysis. This method can not only be applied in the visibility analysis of forest scenes, but also used in the analysis of the urban environment. Experiments show that the proposed method results in high efficiency and precision.

关键词： line of sight visibility analysis complex landscapes visual permeability

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Monitoring Glacier and Supra-glacier Lakes from Space in Mt. Qomolangma Region of the Himalayas on the Tibetan Plateau in China

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Journal of Mountain science 2009年第3期6卷 211-220页

作者： YE Qinghua ZHONG Zhenwei KANG Shichang Alfred Stein WEI Qiufang LIU Jingshi key laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences (CAS) Beijing 100085 China state key laboratory of Remote {3. science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China International institutefor Geo-Information science and Earth Observation (ITC) PO Box 67500 AA Enschede The Netherlands

Because of the large number and remoteness, satellite data, including microwave data and optical imagery, have commonly been used in alpine glaciers surveys. Using remote sensing and Geographical Information System （GIS） techniques, the paper presents the results of a multitemporal satellite glacier extent mapping and glacier changes by glacier sizes in the Mt. Qomolangma region at the northern slopes of the middle Himalayas over the Tibetan Plateau. Glaciers in this region have both retreated and advanced in the past 3. years, with retreat dominating. The glacier retreat area was 3.23.km2 （or o.75 km^2 yr^-1 during 1974 and 1976, 8.68 km^2 （or 0.3. km^2 yr^-1 during 1976 and 1992, 1.44 km^2 （or 0.12 km^2 yr^-1） during 1992-2ooo. 1.14 km^2 （or 0.22 km^2 yr^-1 during 2000-2003. and 0.52 km^2 （or 0.07 km^2 yr^-1 during 2003.2008, respectively. While supra-glacier lakes on the debris-terminus of the Rongbuk Glacier were enlarged dramatically at the same time, from 0.05 km^2 in 1974 increased to 0.71 km^2 in 2008, which was more than 13.times larger in the last 3. years. In addition, glacier changes also showed spatial differences, for example, glacier retreat rate was the fastest at glacier termini between 5400 and 5700 m a.s.l than at other elevations. The result also shows that glaciers in the middle Himalayas retreat almost at a same pace with those in the western Himalayas.

关键词： Glacier lake Remote sensing Mr. Qomolangma region Himalayas Tibetan Plateau

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In flight MTF monitoring and compensation for CCD camera on CBERS-02

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science China(Technological sciences) 2005年第S2期48卷 29-43页

作者： GU Xingfa1,2,3. LI Xiaoying1,2,4, MIN Xiangjun5, YU Tao1,2, SUN Jijuan5, ZENG Yong1,2,4, XU Hua1,2 & GUO Ding2,6 1. state key laboratory of Remote {3. science, jointly sponsored by the institute of Remote {3. applications of Chinese Academy of sciences and beijing normal {{13., beijing 100101, China 2. The Center for National Spaceborne Demonstration, beijing 100101, China 3. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 4. Graduate {{13. of Chinese Academy of sciences, beijing 10003., China 5. China Center for Resource Satellite Data and Application, beijing 10083., China 6. {{13. of Electronic science and Technology of China, Chengdu 610054, China state key laboratory of Remote {3. science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University 100101 Beijing China The Center for National Spaceborne Demonstration 100101 Beijing China Institut National de la Recherche Agronomique Climat Sol Environnement 84914 Avignon France Graduate university of Chinese Academy of sciences 100039 Beijing China China Center for Resource Satellite Data and Application 100830 Beijing China university of Electronic science and Technology of China 610054 Chengdu China

In this article, the approach of simulating ideal tarp scene was proposed to determine the MTF for CCD camera on CBERS-02. The MTF acquired from this technique was compared to those from some common methods. MTFs achieved from different approaches were employed to compensate the CCD images based on three restoration algorithms: the iterative method, the Wiener filter and the modified inverse filter (MIF). The two-dimensional MTF was established with the value at frequency 0.5 for 45° directional MTF as the value at its four corners. This article addressed the variations of the restored CCD images with different techniques of constructing two-dimensional MTF, restoring algorithms and determining the in-flight MTFs. Results showed images restored with the MTF determined from the technique of simulating ideal tarp scene represent the real scene best. And the restoration technique based on the MIF would produce better restored images than the other two techniques. This research also demonstrated that the two-dimensional MTF used for restoration should be interpolated under the control of the MTF for 45° axis, rather than by multiplying the cross-orbit MTF with along-orbit MTF.

关键词： CBERS-02 CCD MTF the technique of simulating ideal tarp scene.

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