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Photosynthetically active radiation retrieval based on HJ-1A/B satellite data

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s.ience china Earth s.iences 2010年第S1期53卷 81-91页

作者： LI Li1,XIN XiaoZhou1,sU GaoLi1,2 & LIU QinHuo1 1 state key laboratory of remote s.ns.ng s.ience,ins.itute of remote s.ns.ng applications,chines. academy of s.iences.beijing 100101,china 2 Zhejiang Climate Center,Hangzhou 310017,china state key laboratory of remote s.ns.ng s.ience Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China Zhejiang Climate Center Hangzhou China

Photosynthetically active radiation(PAR) is essential for plant photosynthesis and carbon cycle,and is also important for meteorological and environmental *** advance china's disaster and environmental monitoring capabilities,the HJ-1A/B satellites have been placed in Earth *** of their environmental monitoring objectives is the study of *** simulated direct solar,scattered and environment radiation between 400 and 700 nm under different atmospheric parameters(solar zenith angle,atmospheric water vapor,atmospheric ozone,aerosol optical thickness,surface elevation and surface albedo),and then established a look-up table between these input parameters and *** on the look-up table,we used HJ-1A/B aerosol and surface albedo outputs to derive the corresponding *** of inversed instantaneous and observed PAR values using HJ-1 Heihe experimental data had a root mean square error of 25.2 W m-2,with a relative error of 5.9%.The root mean square error for accumulated daily PAR and observed values was 0.49 MJ m-2,with a relative error of 3.5%.Our approach improved significantly the computational efficiency,compared with using directly radiation transfer *** also studied the sensitivity of various input parameters to photosynthetically active radiation,and found that solar zenith angle and atmospheric aerosols were sensitive PAR *** albedo had some effect on PAR,but water vapor and ozone had minimal impact on PAR.

关键词： Photosynthetically active radiation 6s HJ-1A/B satellites

Polynomial analysis of canopy spectra and biochemical component content inversion

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s.ience china Earth s.iences 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 s.ns.ng s.ience, Jointly sponsored by the ins.itute of remote s.ns.ng applications.of chines. academy of s.iences.and beijing Normal University, beijing 100101, china 2. national Engineering Research Center for Information Technology in Agriculture, beijing 100089, china Jointly sponsored by the ins.itute of remote s.ns.ng applications.of chines. academy of s.iences.and beijing Normal University national Engineering Research Center for Information Technology in Agriculture

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.

A Restarted Conjugate Gradient Method for Ill-posed Problems

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Acta Mathematicae Applicatae sinica 2003年第1期19卷 31-40页

作者： Yan-fei Wanglaboratory of remote s.ns.ng Information s.iences. ins.itute of remote s.ns.ng applications, chines. academy of s.iences. P.O. Box 9718, beijing 100101, chinastate key laboratory of scientific and Engineering Computing, ins.itute of Computational Mathematics and scientific/Engineering computing, chines. academy of s.iences. P.O. Box 2719, beijing 100080, china laboratory of remote s.ns.ng Information s.iences Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China state key laboratory of scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering computing Chinese Academy of Sciences Beijing China

Abstract This paper presents a restarted conjugate gradient iterative algorithm for solving ill-posed problems. The damped Morozov's discrepancy principle is used as a stopping rule. Numerical experiments are given to... 详细信息

关键词： keywords Ill-posed problems restarted CG damped discrepancy principle.

Change of surface cover greenness in china between 2000 and 2010

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chines. s.ience Bulletin 2012年第22期57卷 2835-2845页

作者： LIU shuang1,4& GOng Peng1,2,31state key laboratory of remote s.ns.ng s.ience, Jointly sponsored by ins.itute of remote s.ns.ng applications.of chines. academy of s.iences.and beijing Normal University, beijing 100101, china 2ins.itute for Global Change studies & Center for Earth system s.ience, Tsinghua University, beijing 100084, china 3Department of Environmental s.ience, Policy and Management, University of California, Berkeley, CA94720, UsA 4Graduate University of chines. academy of s.iences. beijing 100049, china state key laboratory of remote s.ns.ng s.ience Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate University of chines. academy of s.iences Beijing China ins.itute for Global Change studies & Center for Earth system s.ience Tsinghua University Beijing China Department of Environmental s.ience 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 s.ns.ng 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

A spectral Index for Estimating soil salinity in the Yellow River Delta Region of china Using EO-1 Hyperion Data

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Pedosphere 2010年第3期20卷 378-388页

作者： WEng Yong-Ling GOng Peng ZHU Zhi-Liang Department of surveying and Mapping Engineering College of Transportation Southeast University Nanjing 210096(China) state key laboratory of remote s.ns.ng s.ience Institute of Remote Sensing Applications of the Chinese Academy ofSciences and Beijing Normal University Beijing 100101 (China) Department of Environment s.ience Policy and Management University of California Berkeley CA 94720 (USA) EROs Data Center U.S. Geological Survey Sioux Falls SD 57198 (USA)

soil salinization is one of the most common land degradation processes. In this study, spectral measurements of saline soil samples collected from the Yellow River Delta region of china were conducted in laboratory and hyperspectral data were acquired from an EO-1 Hyperion sensor to quantitatively map soil salinity in the region. A soil salinity spectral index (ssI) was constructed from continuum-removed reflectance (CR-reflectance) at 2052 and 2203 nm, to analyze the spectral absorption features of the salt-affected soils. There existed a strong correlation (r = 0.91) between the ssI and soil salt content (ssC). Then, a model for estimation of ssC with ssI was established using univariate regression and validation of the model yielded a root mean square error (RMsE) of 0.986 and an R2 of 0.873. The model was applied to a Hyperion reflectance image on a pixel-by-pixel basis and the resulting quantitative salinity map was validated successfully with RMsE = 1.921 and R2 = 0.627. These suggested that the satellite hyperspectral data had the potential for predicting ssC in a large area.

关键词： hyperspectral reflectance soil salt content spectral absorption features

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 s.ience 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 s.ns.ng s.ience Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China International ins.itutefor Geo-Information s.ience 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 s.ns.ng 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 35 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 0.36 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 35 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 s.ns.ng Mr. Qomolangma region Himalayas Tibetan Plateau

Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us sandland

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s.ience china Earth s.iences 2010年第S1期53卷 26-33页

作者： CHEN Wei1,2,CAO ChunXiang1,HE Qisheng1,2,GUO HuaDong3,ZHAng Hao1,2,LI RenQiang4,ZHEng sheng1,2,XU Min1,2,GAO MengXu1,2,ZHAO Jian1,2,LI sha1,NI XiLiang1,2,JIA HuiCong1,JI Wei1,TIAN Rong1,2,LIU Cheng1,2,ZHAO YuXing5 & LI JingLu6 1 state key laboratory of remote s.ns.ng s.ience,Jointly sponsored by the ins.itute of remote s.ns.ng applications.of chines. academy of s.iences.and beijing Normal University,beijing 100101,china 2 Graduate University of chines. academy of s.iences.beijing 100049,china 3 Center for Earth Observation and Digital Earth,chines. academy of s.iences.beijing 100190,china 4 china key laboratory of Ecological Network Observation and Modeling,ins.itute of Geographical s.iences.and Natural Resources Research,chines. academy of s.iences.beijing 100101,china 5 Ordos Forestry sand Control s.ience ins.itute,Dongsheng 017000,china 6 Inner Mongolia Biomass Thermoelectricity Limited Company,Wushen 017300,china state key laboratory of remote s.ns.ng s.ience Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate University of chines. academy of s.iences Beijing China Center for Earth Observation and Digital Earth Chinese Academy of Sciences Beijing China china key laboratory of Ecological Network Observation and Modeling Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Ordos Forestry sand Control s.ience ins.itute Dongsheng China Inner Mongolia Biomass Thermoelectricity Limited Company Wushen China

The leaf area index(LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the *** addition,it is used by most process-oriented ecosystem *** paper investigates the potential of HJ-1 CCD data combined with linear spectral unmixing and an inverted geometric-optical model for the retrieval of the shrub LAI in Wushen Banner of Inner Mongolia in the Mu Us ***(Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric *** was extracted using the threshold of the normalized difference vegetation index,with which water bodies and farmland were separated,in combination with a vegetation map of the People's Republic of china(1:1000000).Using the geometric-optical model,we derive the per-pixel reflectance as a simple linear combination of two components,namely sunlit background and *** fraction of sunlit background is related to the shrub *** the support of HJ-1 CCD data,we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ *** addition,we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub *** total,18 sample plots collected in Wushen Banner of Inner Mongolia are used for *** results of the shrub LAI show good agreement with R2 of 0.817 and a root-mean-squared error of 0.173.

关键词： shrub leaf area index inversion HJ-1 data geometric-optical model MODTRAN Mu Us sandland

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

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s.ience china(Information s.iences. 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 s.ns.ng s.ience, Jointly sponsored by beijing Normal University and the ins.itute of remote s.ns.ng applications.of chines. academy of s.iences. beijing 100875, china 2PTV America, Inc. 1145 Broadway Plaza ste 605, Tacoma, WA 98407, UsA 3school of Geomatics and Urban Information, beijing University of Civil Engineering and Architecture, beijing 100044, china state key laboratory of remote s.ns.ng s.ience Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing China PTV America Inc. Tacoma USA school of Geomatics and Urban Information Beijing University of Civil Engineering and Architecture Beijing 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

study on Developing Mechanism of Rubber-tea-chicken Agro-forestry Model in Tropical Area of china

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Study on Developing Mechanism of Rubber-tea-chicken Agro-for...