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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, school of geography, beijing normal university, {4. key laboratory of Remote sensing science, beijing key laboratory for Remote sensing of Environment and Digital Cities, beijing 100875, {14. Department of Mathematics, beijing normal university, beijing 100875, {14. 1. 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 100875 Beijing China 2. Department of Mathematics Beijing Normal University 100875 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.

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

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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 Remote sensing {4., Jointly Sponsored by beijing normal university and Institute of Remote sensing 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 2074., USA 1. state key laboratory of Remote sensing {4. Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing Applications CAS Beijing 100875 China2. School of Geography Beijing Key Laboratory of Environmental Remote Sensing and Digital City Beijing Normal University Beijing 100875 China3. Haihe River Water Conservancy Commission Tianjin 300170 China4. Department of Geography University of Maryland College Park MD 20742 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 beijing, this method has significantly improved the estimated LAI temporal profile.

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

Multiple time scale evaluation of the energy balance during the maize growing season,and a new reason for energy imbalance

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science china Earth sciences 2009年第1期52卷 108-117页

作者： GUO JianXia1,2,BIAN LinGen3 & DAI YongJiu2 1 Meteorological Observation Center of china Meteorological Administration,beijing 100081,china 2 state {4. laboratory of Remote sensing science,school of geography and Remote sensing science,beijing normal university,beijing 100875,china 3 Chinese Academy of Meteorological sciences,beijing 100081,china Meteorological Observation Center of china Meteorological Administration Beijing 100081 China state key laboratory of Remote sensing {4. School of Geography and Remote Sensing Science Beijing Normal University Beijing 100875 China

Energy imbalance is a common problem associated with the measurement of surface energy using the eddy covariance *** the evaluation of the energy balance,people usually pay more attention to the statistical result that the effective energy(the sum of sensible and latent heat) is systematically lower than the available energy(the difference of net radiation and ground heat flux).However,little attention has been paid to the existence of the reversed situation when the effective energy is larger than the available energy or their contribution to the overall energy closure *** this paper,based on the analysis of the energy balance on multiple time scales across the maize growth season,we conclude that the non-synchronization of energy components is the main reason for the existence of the reversed *** shifting the phase of the effective energy components half an hour ahead,the rates of energy closure over all time scales are improved and dramatically reduce the number of the half-hourly samples when the energy ratio exceeds 1 or is below *** to the characteristics of the energy distribution and transformation over multiple time scales,latent heat is always the main type of energy cost,and the residual of the energy balance increases with the growth of the maize plant surpassing the sensible heat for seventy *** is suggested that the heat storage and photosynthetic energy play an important role in the energy balance during the growing period of maize.

关键词： maize energy balance multiple time scale energy hysteresis

Estimating surface evapotranspiration using combined MODIS and CBERS-02 data

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science china(Technological sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2, LIU Qinhuo1, TANG Yong1,3, TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2, ZHENG Hongsheng4.& CHEN Jiayi4.1. state key laboratory of Remote sensing {4., Institute of Remote sensing Applications, Chinese Academy of {4.s, beijing 100101, china 2. Research Center for Remote sensing and GIS, Department of geography, beijing normal university, beijing 100875, china 3. Graduate {14. of Chinese Academy of {4.s, beijing 100039, china 4. Department of Atmospheric Physics, Peking {14., beijing 100871, china 1. state key laboratory of Remote sensing {4. Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02 data were used to produce land use class of Baiyangdian area, Hebei Province, china in the autumn of 2004. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

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 sensing 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, beijing 100875, china College of geography and Remote sensing Beijing 100048 China key laboratory of Environmental Change and Natural Disaster of Ministry of Education of china 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(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.4. and 2.33 times respectively from the westto the east, in which 200-4.0mm 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

Analysis of forest backscattering characteristics based on polarization coherence tomography

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science china(Technological sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2,CHEN ErXue 3,CHENG Jian 4.& CAO ChunXiang 21 Institute of Geo-Spatial Information science and Technology,university of Electronic science and Technology of china,Chengdu 610054.china 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,china 3Institute of Forest Resources Information Technique of Chinese Academy of Forestry,beijing 100091,china 4.school of Electronic Engineering,university of Electronic science and Technology of china,Chengdu 610054.china state key Lab Remote sensing Sci Beijing 100101 Peoples R China beijing normal Univ Beijing 100101 Peoples R China Univ Elect Sci & Technol china Inst Geospatial Informat Sci & Technol Chengdu 610054 Peoples R China Chinese Acad Forestry Inst Forest Resources Informat Tech Beijing 100091 Peoples R China Univ Elect Sci & Technol china Sch Elect Engn Chengdu 610054 Peoples R China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function

Monitoring of rice crop using ENVISAT ASAR data

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science china Earth sciences 2006年第7期49卷 755-763页

作者： DONG Yanfang1, 2, SUN Guoqing1,3 & PANG Yong4.1. state key laboratory of Remote sensing {4., Institute of Remote sensing Applications, Chinese Academy of {4.s, beijing 100101, china 2. Graduate university of Chinese Academy of {4.s, beijing 100039, china 3. Department of geography, university of Maryland, College Park, MD 2074., USA 4. Forest Remote sensing Lab, Research Institute of Forest Resource and Information Technology, Chinese Academy of For-estry, beijing 100091, china 1. state key laboratory of Remote sensing {4. Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China 2. Graduate university of Chinese Academy of sciences Beijing 100039 China 3. Department of geography University of Maryland College Park MD 20742 USA 4. Forest Remote sensing Lab Research Institute of Forest Resource and Information Technology Chinese Academy of Forestry Beijing 100091 China

Because of the cloudy conditions during the rice growth period, rice is one of the agri-cultural crops most suited to monitoring with the SAR instruments. Backscatter response measured by SAR is correlated with rice conditions, including height, density, biomass and structure, which are variable at different growing stages. In this paper, multi-date ENVISAT ASAR Alternating Polarization Mode (APMode) imageries were acquired during the rice crop growing cycle. At the same time, the rice parameters were measured in field. A continuous canopy model was used to compute the back-scattering from rice fields during the growth cycle, and the relationship between rice parameters and radar backscattering coefficients from both ASAR and modeling was analyzed. The effects of polari-zation, incidence angle and polarization on radar backscattering coefficients were analyzed. It was found that simulated radar backscatter has similar trends as ASAR data. This will be meaningful for the further research of rice parameters estimation from ASAR data. Different features show signifi-cantly different signatures in ASAR images and they follow some certain laws, so rice area can be accurately mapped by using multi-temporal SAR images, then rice yield can be estimated.

关键词： rice, ASAR, radar backscattering, model.

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 geography, beijing normal university, beijing 100875, {4. 2 state key laboratory of Remote sensing science, Chinese Academy of sciences, beijing 100101, {4. 3 Institute of Erectronics, Chinese Academy of sciences, beijing 100080, {4. 4.Center for for Assessment and Monitoring of Forest and Environmental Resources and Division of Ecosystem sciences university of California Berkeley, CA 94.20-3114. USA 1. Research Center for Remote sensing and GIS Department of Geography Beijing Normal University Beijing 100875 China 2. state key laboratory of Remote sensing {4. 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 94720-3114 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

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 sensing {4.,jointly sponsored by the Institute for Remote sensing Applications of Chinese Academy of {4.s and beijing normal university,beijing 100101,china 2 Graduate university of the Chinese Academy of {4.s,beijing 10004.,china 3 Institute of Forest Resource Information Technique,the Chinese Academy of Forestry,beijing 100091,china 4.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 100875,china state key laboratory of Remote sensing {4. jointly sponsored by the Institute for Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China Graduate university of the Chinese Academy of sciences Beijing 100049 China Institute of Forest Resource Information Technique the Chinese Academy of Forestry Beijing 100091 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 100875 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 154. 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 ±20.9 cm.A data trap sizes of 4. 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