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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, School of Geography, {2. Normal University, {2. 100875, China 2. state key laboratory of remote sensing science, {2. 100875, China 3. {2. key laboratory for remote sensing of Environment and Digital Cities, {2. 100875, China 4. Department of Information Management, College of Information and Electronic Engineering, China Agricultural University, {2. 100083. China Research Center for remote sensing and GIS School of Geography Beijing Normal University Beijing China state key {2. of {3. {3. science Beijing China beijing key {2. for {3. {3. 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.

Water target based cross-calibration of CBERS-02.CCD camera with MODIS data

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science China(Technological sciences) 2005年第S2期48卷 61-71页

作者： TANG Junwu1,2. GU Xingfa2. NIU Shengli1, MA Chaofei1 & MIN Xiangjun3.1. National Satellite Ocean Application Service (NSOAS), beijing 100081, China {3.,{2., China 3. China Center for Resource Satellite Data and Applications (CRESDA), beijing 100083. China National Satellite Ocean Application Service (NSOAS) Beijing 100081 China

In order to make quantitative watercolor sensing with China-Brazil Earth Resources Satellite (CBERS-02. CCD camera, the MODIS data with higher accuracy is used to cross-calibrate the CCD camera over water targets. In homogeneous clear water area, two pairs of images obtained over the same area on the same day by the two sensors are selected. The top-of-atmosphere (TOA) radiances of the multispectral bands of CCD are calculated with the water and aerosol parameters from MODIS based on a water-atmosphere radiative transfer algorithm. The stripes in CCD image that caused by unequal response of the CCD array detectors are firstly removed before making the cross-calibration. The same part of CCD detectors is selected for the calibrations in the two images to eliminate the residual error of destriping and uniformity correction for the focus plane irradiance. It is shown that the calibration results from two different images are consistent. The error of this method is about 5%.

关键词： CBERS-02 CCD MODIS radiometric calibration cross-calibration. DOI: 10.13.0/05ze1006

Semi-Supervised Classification based on Gaussian Mixture Model for remote imagery

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science China(Technological sciences) 2010年第S1期53卷 85-90页

作者： XIONG Biao1,ZHANG XiaoJun1 & JIANG WanShou1,2.1 state key {2. of Information Engineering in Surveying,Mapping and remote {3.,Wuhan University,Wuhan 43.079,China 2.state key {2. of remote {3. science,{13.,China state key {2. of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China state key {2. of {3. {3. science Beijing China

Semi-Supervised Classification (SSC),which makes use of both labeled and unlabeled data to determine classification borders in feature space,has great advantages in extracting classification information from mass *** this paper,a novel SSC method based on Gaussian Mixture Model (GMM) is proposed,in which each class’s feature space is described by one *** show the proposed method can achieve high classification accuracy with small amount of labeled ***,for the same accuracy,supervised classification methods such as Support Vector Machine,Object Oriented Classification,*** be provided with much more labeled data.

关键词： remote sensing image classification Semi-Supervised Classification Gaussian Mixture Model EM algorithms

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 {2. laboratory of {3. sensing science,School of Geography and {3. 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 China state key {2. of {3. {3. science School of Geography and Remote Sensing Science Beijing Normal University Beijing China Chinese Academy of Meteorological sciences Beijing 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

A new trust region algorithm for image restoration

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science China Mathematics 2005年第2期48卷 169-184页

作者： WEN Zaiwen & WANG Yanfei state key {2. of Scientific Engineering Computing, Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and System {3.s, Chinese Academy of {3.s, beijing 100080, China National key {2. on remote sensing {3., Institute of remote sensing Applications, Chinese Academy of {3.s, beijing 100101, China state key {2. of Scientific Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China National key laboratory on {2. {3. {3. Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China

The image restoration problems play an important role in remote sensing and astronomical image analysis. One common method for the recovery of a true image from corrupted or blurred image is the least squares error (LSE) method. But the LSE method is unstable in practical applications. A popular way to overcome instability is the Tikhonov regularization. However, difficulties will encounter when adjusting the so-called regularization parameter a. Moreover, how to truncate the iteration at appropriate steps is also challenging. In this paper we use the trust region method to deal with the image restoration problem, meanwhile, the trust region subproblem is solved by the truncated Lanczos method and the preconditioned truncated Lanczos method. We also develop a fast algorithm for evaluating the Kronecker matrix-vector product when the matrix is banded. The trust region method is very stable and robust, and it has the nice property of updating the trust region automatically. This releases us from tedious finding the regularization parameters and truncation levels. Some numerical tests on remotely sensed images are given to show that the trust region method is promising.

关键词： trust region algorithm, image restoration, Lanczos method, Kronecker matrix-vector product, preconditioning.

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 {3. key {2. of remote {3. science,Jointly Sponsored by Institute of remote {3. Applications,Chinese Academy of sciences and beijing Normal University,beijing 100101,China 2.{3. key {2. of remote {3. science,Jointly Sponsored by beijing Normal University and Institute of remote {3. Applications of Chinese Academy of sciences,beijing 100875,China 3.Graduate University of Chinese Academy of sciences,beijing 100049,China state key {2. of {3. {3. science Jointly Sponsored by Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Beijing China state key {2. of {3. {3. 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

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 {2. of remote {3. science, Institute of remote {3. Applications, Chinese Academy of sciences, beijing 100101, China 2. Graduate University of Chinese Academy of sciences, beijing 10003., China 3. Department of Geography, University of Maryland, College Park, MD 2.742. USA 4. Forest remote {3. Lab, Research Institute of Forest Resource and Information Technology, Chinese Academy of For-estry, beijing 100091, China state key {2. of {3. {3. science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of sciences Beijing China Department of Geography University of Maryland College Park USA Forest remote sensing Lab Research Institute of Forest Resource and Information Technology Chinese Academy of Forestry Beijing 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.

The primary results of quantitative ocean color retrieval in China coastal area with CBERS CCD data

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science China(Technological sciences) 2005年第S2期48卷 161-176页

作者： TANG Junwu1,2. MA Chaofei1, NIU Shengli1, WANG Xiaomei1, SONG Qingjun1 & DING Jing1 1. National Satellite Ocean Application Service, beijing 100081, China 2. state key laboratory of remote sensing science,{2., China National Satellite Ocean Application Service Beijing 100081 China

Using the techniques of quantitative ocean color sensing, the in-water ocean color algorithms for sediment and chlorophyll-a retrieval are established for CBERS-02.CCD broad spectral bands based on in situ data. The remote sensing reflectance of water is derived from CCD radiance data by a clear water atmospheric correction algorithm. Then, the sediment and chlorophyll-a concentrations are retrieved from CCD image. The sediment retrieval is quite satisfactory, but the chlorophyll-a retrieval is not so good because of the broadband width and low signal-to-noise ratio of the CCD camera.

关键词： CBERS-02 CCD ocean color sensing atmospheric correction retrieval of water constituents.

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,China 2.{2. key {3. 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 School of Earth and Space sciences Peking University Beijing China state key {2. of {3. {3. 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 sensing 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 {2. 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