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Retrieving crop leaf area index by assimilation of MODIS data into a crop growth model

Science china Earth Sciences 2010年第5期53卷 721-730页

作者： WANG DongWei1,2.3, WANG JinDi1,2.& LIANG ShunLin4 1 State key laboratory of {2. {2. Science, Jointly Sponsored by beijing Normal University and Institute of {2. {2. Applications, CAS, beijing 100875, china 2.school of geography, beijing key laboratory of environmental remote sensing and digital city, beijing Normal University, beijing 100875, china 3 Haihe River Water Conservancy Commission, Tianjin 300170, china 4 Department of geography, University of Maryland, College Park, MD 2.742. USA State key laboratory of {2. {2. Science Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing Applications CAS Beijing China school of geography Beijing Key Laboratory of Environmental Remote Sensing and Digital City Beijing Normal University Beijing China Haihe River Water Conservancy Commission Tianjin China Department of geography University of Maryland College Park USA

Leaf area index (LAI) is an important parameter in monitoring crop growth. One of the methods for retrieving LAI from remotely sensed observations is through inversion of canopy reflectance models. Many model inversion methods fail to account for variable LAI values at different crop growth stages. In this research, we use the crop growth model to describe the LAI changes with crop growth, and consider a priori LAI values at different crop growth stages as constraint information. The key approach of this research is to assimilate multiple canopy reflectance values observed at different growth stages and a priori LAI values into a coupled crop growth and radiative transfer model sequentially using a variational data assimilation algorithm. Adjoint method is used to minimize the cost function. Any other information source can be easily incorporated into the inversion cost function. The validation results show that the time series of MODIS canopy reflectance can greatly reduce the uncertainty of the inverted LAI values. Compared with MODIS LAI product at Changping and Shunyi Counties of {2., this method has significantly improved the estimated LAI temporal profile.

关键词： inversion leaf area index crop growth model time series MODIS

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Study on NDVI-T_s space by combining LAI and evapotranspiration

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Science china Earth Sciences 2006年第7期49卷 747-754页

作者： HAN Lijuan1,2.3, WANG Pengxin4, YANG Hua1,2.3, LIU Shaomin1,2.3 & WANG Jindi1,2.3 1. Research Center for remote sensing and GIS, {2. of geography, beijing Normal University, beijing 100875, china 2. State key laboratory of remote sensing Science, beijing 100875, china 3. beijing key laboratory for remote sensing of Environment and digital Cities, beijing 100875, china 4. Department of Information Management, College of Information and Electronic Engineering, china Agricultural University, beijing 100083, china Research Center for remote sensing and GIS School of Geography Beijing Normal University Beijing China State key laboratory of {2. {2. Science Beijing China beijing key {2. for {2. sensing of Environment and digital Cities Beijing China Department of Information Management College of Information and Electronic Engineering China Agricultural University Beijing China

This paper focuses on interpreting the different spatial relationships between NDVI and Ts, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Tempera-ture-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and Ts are useful for describing, validating and updating land surface models.

关键词： NDVI, land surface temperature, evapotranspiration, leave area index.

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Information flow and controlling in regularization inversion of quantitative remote sensing

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Science china Earth Sciences 2005年第1期48卷 74-83页

作者： YANG Hua, XU Wangli, ZHAO Hongrui, CHEN Xue & WANG Jindi Research Center for remote sensing and GIS, {2. of geography, beijing Normal University, State key laboratory of remote sensing Science, beijing key laboratory for remote sensing of Environment and digital Cities, beijing 100875, china Department of Mathematics, beijing Normal University, beijing 100875, china Research Center for remote sensing and GIS School of Geography Beijing Normal University State Key Laboratory of Remote Sensing Science Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities Beijing China Department of Mathematics Beijing Normal University Beijing China

In order to minimize uncertainty of the inversed parameters to the largest extent by making full use of the limited information in remote sensing data, it is necessary to understand what the information flow in quantitative remote sensing model inversion is, thus control the information flow. Aiming at this, the paper takes the linear kernel-driven model inversion as an example. At first, the information flow in different inversion methods is calculated and analyzed, then the effect of information flow controlled by multi-stage inversion strategy is studied, finally, an information matrix based on USM is defined to control information flow in inversion. It shows that using Shannon entropy decrease of the inversed parameters can express information flow more properly. Changing the weight of a priori knowledge in inversion or fixing parameters and partitioning datasets in multi-stage inversion strategy can control information flow. In regularization inversion of remote sensing, information matrix based on USM may be a better tool for quantitatively controlling information flow.

关键词： regularization inversion, information flow, Shannon entropy decrease, information matrix.

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Synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data

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Science china(Technological Sciences) 2008年第S2期51卷 176-187页

作者： BAO YunFei1,2,CAO ChunXiang1,ZHANG Hao1,CHEN ErXue3,HE QiSheng1,2,HUANG HuaBing1,LI ZengYuan3,LI XiaoWen1,4 & GONG Peng1 1 State key laboratory of remote {2. Science,jointly sponsored by the Institute for remote {2. Applications of Chinese Academy of Sciences and beijing Normal University,beijing 100101,china 2 Graduate University of the Chinese Academy of Sciences,beijing 100049,china 3 Institute of Forest Resource Information Technique,the Chinese Academy of Forestry,beijing 100091,china 4 Research Center for remote {2. and GIS,Department of geography and beijing key laboratory for remote {2. of Environment and digital Sites,beijing Normal University,beijing {2.},china State key laboratory of {2. {2. Science jointly sponsored by the Institute for Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate University of the Chinese Academy of Sciences Beijing China Institute of Forest Resource Information Technique the Chinese Academy of Forestry Beijing China Research Center for remote sensing and GIS Department of Geography and Beijing Key Laboratory for Remote Sensing of Environment and Digital Sites Beijing Normal University Beijing China

We proposed a method to separate ground points and vegetation points from discrete return,small footprint airborne laser scanner data,called skewness change *** method,which makes use of intensity of laser scanner data,is especially applicable in steep,and forested *** does not take slope of forested area into account,while other algorithms consider the change of slope in steep forested *** ground points and vegetation points can be used to estimate digital terrain model(DTM) and fractional vegetation cover,respectively.A few vegetation points which were classified into the ground points were removed as noise before the generation of *** method was tested in a test area of 10000 square meters.A LiteMapper -5600 laser system was used and a flight was carried out over a ground of 700―800 *** this tested area,a total number of 1546 field measurement ground points were measured with a total station TOPCON GTS-602.and TOPCON GTS -7002.for validation of DTM and the mean error value is -18.5 cm and the RMSE(root mean square error) is ±2..9 cm.A data trap sizes of 4m in diameter from airborne laser scanner data was selected to compute vegetation fraction *** of fractional vegetation cover was carried out using 15 hemispherical photographs,which are georeferenced to centimeter accuracy by differential *** gap fraction was computed over a range of zenith angles 10° using the gap light analyzer(GLA) from each hemispherical *** R2.for the regression of fractional vegetation cover from these ALS data and the respective field measurements is *** this study presents a method for synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data.

关键词： LIDAR intensity skewness synchronous DTM fractional vegetation cover

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Development of environmental monitoring satellite systems in china

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Science china Earth Sciences 2010年第S1期53卷 1-7页

作者： LI GuoPing1 & CAO ChunXiang2.1 school of Earth and Space Sciences,Peking University,beijing 100871,{2. 2.State key laboratory of remote sensing Science,Jointly Sponsored by the Institute of remote sensing Applications of Chinese Academy of Sciences and beijing Normal University,beijing 100101,{2. school of Earth and Space Sciences Peking University Beijing China State key laboratory of {2. {2. Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China

With the increase in global environmental problems,the necessity and urgency of remote {2. technology being applied to environmental monitoring has been widely recognized around the *** has launched the environment and disaster monitoring and forecasting small satellite constellation HJ-1A/B and the FY3 atmosphere and environmental satellite,but they still cannot fully satisfy requirements for environmental *** paper summarizes the current status of satellite environmental monitoring in china and the existing problems of inadequate load design and low data utilization efficiency,and discusses the demand for environmental monitoring *** on the development of foreign satellite systems for environmental monitoring,the future development and key tasks of the environmental monitoring satellite system in china is discussed,as are some related initiatives.

关键词： environmental satellite environmental monitoring global climate change specialty load satellite system

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Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow River basin

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Science china(Technological Sciences) 2004年第Z1期47卷 1-13页

作者： YANG Shengtian1 & LIU Changming1, 2.1. school of environmental Sciences, {2. Normal University, beijing 100875, china 2. Institute of Geographic Science and Natural Resources Research, {2. 100101, china school of environmental Sciences Beijing Normal University Beijing China Institute of Geographic Science and Natural Resources Research Beijing China

Based on the AVHRR pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1982.1998, soil moisture of all layers of soil-profile (0—1 m) in the Yellow River basin over the 17 years are calculated by the remote sensing model of calculating soil water. The Yellow River basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Huayuankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow River basin are analyzed for the period from 1982.to 1988 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow River are obtained, which include the annual precipitation of 4000 km3, the evapotranspiration of 3000-3500 km3, and the soil moisture transformation of ?500- 500 km3. Consequently, we analyzed the process of the water cycle in the Yellow River over the 17 years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

关键词： the Yellow River, soil moisture, remote sensing, hydrologic cycle.

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Principle of small target detection for hyperspectral imagery

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Science china Earth Sciences 2007年第8期50卷 1225-1231页

作者： GENG XiuRui1,2.3 & ZHAO YongChao2.3,4 1 Research Center for remote sensing and GIS, Department of {2., beijing Normal University, beijing 100875, china 2.State key laboratory of remote sensing Science, Chinese Academy of Sciences, beijing 100101, china 3 Institute of Erectronics, Chinese Academy of Sciences, beijing 100080, china 4 Center for for Assessment and Monitoring of Forest and environmental Resources and Division of Ecosystem Sciences University of California Berkeley, CA 9472.-3114, USA Research Center for remote sensing and GIS Department of Geography Beijing Normal University Beijing China State key laboratory of {2. {2. Science Chinese Academy of Sciences Beijing China Institute of Erectronics Chinese Academy of Sciences Beijing China Center for for Assessment and Monitoring of Forest and environmental Resources and Division of Ecosystem Sciences University of California Berkeley USA

This paper generalizes the progress of algorithms in small target detection for hyperspectral imaging, and finds that whitening the image is the key point of many methods in small target detection. An al-gorithm is presented to detect desired targets by converting large targets into small ones based on the weighted sample autocorrelation matrix.

关键词： hyperspectral whiten target detection

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Study on Water Consumption Coefficient of People's Living and Its Regional Disparity in the North of china

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Chinese Journal of Population,Resources and Environment 2005年第2期3卷 20-26页

作者： Wang Jing’ai 1-3, Mao Rui 3,4, Yang Mingchuan 3,4 & Zhou Junju 11 College of geography & remote {2. 2.key laboratory of Regional geography of beijing Normal University 3 key laboratory of environmental Change and Natural Disaster of Ministry of Education of china 4 College of Resources Science & Technology, beijing Normal University,{12., china College of geography and remote {2. Beijing 100048 China key laboratory Of Regional {2. of {2. Normal University China key laboratory of {2. Change and Natural Disaster of Ministry of Education of{2. Beijing 100048 China College of Resources Science and Technology Beijing Normal University Beijing 100875 China

By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62. 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2.00), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 2.0-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.

关键词： The north of china precipitation zone water consumption coefficient of people’s living

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Scale effects of leaf area index inversion based on environmental and disaster monitoring satellite data

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Science china Earth Sciences 2010年第S1期53卷 92-98页

作者： ZHANG Hao1,LI XiaoWen1,2.CAO ChunXiang1,YANG Hua2.GAO MengXu1,3,ZHENG Sheng1,3,XU Min1,3,XIE DongHui2.JIA HuiCong1,JI Wei1,ZHAO Jian1,3,CHEN Wei1,3 & NI XiLiang1,3 1 State key laboratory of {2. {2. Science,Jointly Sponsored by Institute of {2. {2. Applications,Chinese Academy of Sciences and beijing Normal University,beijing 100101,china 2.State key laboratory of {2. {2. Science,Jointly Sponsored by beijing Normal University and Institute of {2. {2. Applications of Chinese Academy of Sciences,beijing 100875,china 3 Graduate University of Chinese Academy of Sciences,beijing 100049,china State key laboratory of {2. {2. Science Jointly Sponsored by Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Beijing China State key laboratory of {2. {2. Science Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China

The spatial distribution of sub-pixel components has an impact on retrieval accuracy,and should be accounted for when inverting a three-dimensional adiative transfer model to retrieve leaf area index(LAI).To investigate this effect,we constructed three realistic scenarios with the same LAI values and other properties,except that the simulated plants had different *** implemented the radiosity method to subsequently produce synthetic bidirectional reflectance factor(BRF) datasets based upon these simulated *** inversion was conducted using these data,which showed that spatial distribution affects retrieval *** inversion was also conducted for LAI based on charge-coupled device(CCD) data from the Environment and Disaster Monitor Satellite(HJ-1),which depicted both forest and drought-resistant crop land *** showed that heterogeneity in coarse-resolution remote sensing data is the main error source in LAI *** spatial distribution of global fractal dimension index,which can be used to describe the area of sub-pixel components and their spatial distribution modes,shows good consistency with the coarse resolution LAI inversion error.

关键词： HJ-1 leaf area index scale effect spatial distribution

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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 {2. {2. Science,Jointly Sponsored by beijing Normal University and the Institute of {2. {2. Applications of Chinese Academy of Sciences,beijing 100875,china 2.epartment of Geodesy and Geomatics,school of Land Science and Technology,china University of Geosciences,beijing 100083,china State key laboratory of {2. {2. Science Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing China Department of Geodesy and Geomatics School of Land Science and Technology China University of Geosciences Beijing 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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