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Monitoring of rice crop using ENVISAT ASAR data

science{1. Earth {2. 2006年第7期49卷 755-763页

作者： dong yanfang1, 2. sun guoqing1,{2., 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 2.742. USA 4. Forest remote sensing Lab, Research {12. of Forest Resource and Information Technology, chinese academy of For-estry, beijing 100091, china 1. state {1. {2. of remote sensing science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China 2. Graduate University of{1. Beijing 100039 China 3. Department of Geography University of Maryland College Park MD 20742 USA 4. Forest remote {1. 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.

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Estimating forest aboveground biomass using HJ-1.Satellite CCD and ICESat GLAS waveform data

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science{1. Earth {2. 2010年第S1期53卷 16-25页

作者： GUO ZhiFeng1,CHI Hong1,2 & sun guoqing1,3 1state key laboratory of remote sensing science,Jointly Sponsored by the institute of remote sensing applications of chinese academy of sciences and beijing Normal University,institute of remote sensing applications,chinese academy of sciences,beijing 100101,china 2Graduate University of chinese academy of sciences,beijing 100049,china 3Department of Geography University of Maryland,College Park,MD 20742,USA 1. state {1. {2. of remote sensing science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Department of Geography University of Maryland College Park MD 20742 USA

The ecosystem in northeastern china and the Russian Far East is a hotspot of scientific research into the global carbon *** aboveground biomass(AGB) is an important component in the land surface carbon *** this study,using forest inventory data and forest distribution data,the AGB was estimated for forest in Daxinganlin in northeastern china by combining charge-coupled device(CCD) data from the Small Satellite for Disaster and Environment Monitoring and Forecast(HJ-1. and Geo{2. Laser Altimeter System(GLAS) waveform data from the Ice,Cloud and land Elevation Satellite(ICESat).The forest AGB prediction models were separately developed for different forest types in the research area at GLAS footprint level from GLAS waveform parameters and field survey plot biomass in the Changqing(CQ) Forest Center,which was calculated from forest inventory *** resulted statistical regression models have a R2.0.68 for conifer and R2.0.71.for broadleaf *** models were used to estimate biomass for all GLAS footprints of forest located in the study *** GLAS footprint biomass coupled with various spectral reflectivity parameters and vegetation indices derived from HJ-1.satellite CCD data were used in multiple regression analyses to establish biomass prediction models(R2.0.55 and R2.0.52.for needle and broadleaf respectively).Then the models were used to produce a forest AGB map for the whole study area using the HJ-1.*** data obtained from forest inventory data of the Zhuanglin(ZL) Forest Center were used as independent field measurements to validate the AGB estimated from HJ-1.CCD data(R2.0.71..About 80% of biomass samples had an error less than 2. t ha-1.and the mean error of all validation samples is 5.74 t *** pixel-level biomass map was then stratified into different biomass levels to illustrate the AGB spatial distribution pattern in this *** was found that HJ-1.wide-swath data and GLAS waveform data can be combined to estim

关键词： Disaster and Environment Monitoring and Forecast Satellite ICESat GLAS waveform boreal forest forest aboveground biomass multiple linear regression

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Improvement of a 3D radar backscattering model using matrix-doubling method

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science{1. Earth {2. 2010年第7期53卷 1029-1035页

作者： NI WenJian1,2. GUO ZhiFeng1 & sun guoqing3 1 {2. 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,{12. 2.Graduate University of chinese academy of sciences, beijing 100049,{12. 3 Department of Geography, University of Maryland, College Park, MD 2.042. USA 1. state {1. {2. of remote sensing science jointly sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Department of Geography University of Maryland College Park MD 27042 USA

Radiative transfer models have been widely used to simulate the radar backscattering from forested areas. A three-dimensional radar backscatter model of forest canopy developed in previous studies takes full account of spatial position of trees in a forest stand, and the interactions among crown, trunk and ground surface. The model predicted well for the co-polarized backscatter measurements, but underestimated the backscattering for cross-polarization, primarily because only the first-order scattering within tree crowns was considered in the model. The backscattering at cross-polarization depends strongly on multiple scatter- ing within tree crowns. To produce good estimations for cross-polarized component, the matrix-doubling method is employed here to compute multiple-scattering within the crown. The modified model is compared with the original model, and the field forest measurements and AIRSAR data are used for validation of the modified model. The cross-polarization backscattering is improved in different degrees for different crown structures and at different bands.

关键词： remote sensing forestry electromagnetic propagation radar backscattering model matrix-doubling

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Long-term(2.1.-2.2.)mapping of winter wheat in the North china Plain using Landsat data:classification with optimal zoning strategy

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Big Earth Data 2024年第3期8卷 494-521页

作者： Yifei Liu Xuehong Chen Jin Chen Yunze Zang Jingyi Wang Miao Lu Liang sun Qi {1. Bingwen Qiu Xiufang Zhu state {1. {2. of remote sensing science Institute of Remote Sensing Science and EngineeringFaculty of Geographical ScienceBeijing Normal UniversityBeijingChina beijing Engineering Research Center for Global Land {1. {2. Products Institute of Remote Sensing Science and EngineeringFaculty of Geographical ScienceBeijing Normal UniversityBeijingChina state {1. {2. of Crop Gene Resources and Breeding Institute of Crop SciencesChinese Academy of Agricultural Sciences(CAAS)BeijingChina state {1. {2. of Efficient Utilization of Arid and Semi-arid Arable Land in Northern china Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijingChina key {1. of Spatial Data Mining&Information Sharing of Ministry of Education Academy of Digital China(Fujian)Fuzhou UniversityFuzhouChina

security and formulating agricultural *** data are the only available source for long-term winter wheat mapping in the North china Plain due to the fragmented landscape in this *** various methods,such as index-based methods,curve similarity-based methods and machine learning-based methods,have been developed for winter wheat mapping based on {1. {2.,the former two often require satellite data with high temporal resolution,which are unsuitable for Landsat data with sparse *** learning is an effective method for crop classification using Landsat ***,applying machine learn-ing for winter wheat mapping in the North china Plain encounters two main issues:1.the lack of adequate and accurate samples for classifier training;and 2.the difficulty of training a single classifier to accomplish the large-scale crop mapping due to the high spatial heterogeneity in this *** address these two issues,we first designed a sample selection rule to build a large sample set based on several existing crop maps derived from recent Sentinel data,with specific consideration of the confusion error between winter wheat and winter rapeseed in the available crop ***,we developed an optimal zoning method based on the quadtree region splitting algorithm with classification feature consistency criterion,which divided the study area into six subzones with uni-form classification *** each subzone,a specific random forest classifier was trained and used to generate annual winter wheat maps from 2.1. to 2.2. using Landsat 8 OLI *** sample validation confirmed the high accuracy of the produced maps,with an average overall accuracy of 91.1.and an average kappa coefficient of 0.81. across different *** derived winter wheat area also has a good correlation(R2.0.949)with census area at the provincial *** results underscore the reliability of the produced annual winter wheat *** experiments demonstrate that

关键词： Winter wheat mapping Landsat machine learning North china Plain optimal zoning

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Assessment of Slope-Adaptive Metrics of GEDI Waveforms for Estimations of Forest Aboveground Biomass over Mountainous Areas

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Journal of remote {1. 2021年第1期2021卷 180-196页

作者： Wenjian Ni Zhiyu Zhang guoqing {1. state {1. {2. of remote sensing science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100101China University of chinese academy of sciences Beijing 100049China Department of Geographical sciences University of MarylandCollege ParkMD 20742USA

Waveform broadening effects of large-footprint lidar caused by terrain slopes are still a great challenge limiting the estimation accuracy of forest aboveground biomass(AGB)over mountainous ***-adaptive metrics of waveforms were proposed in our previous ***,its validation was limited by the unavailability of enough reference *** study made full validation of slope-adaptive metrics using data acquired by the Global Ecosystem Dynamics Investigation(GEDI)mission,meanwhile exploring GEDI waveforms on estimations of forest *** types of waveform metrics were employed,including slope-adaptive metrics(RHT),typical height metrics relative to ground peaks(RH),and waveform parameters(WP).In addition to terrain slopes,two other factors were also explored including the geolocation issue and signal start and ending points of *** showed that footprint geolocations in the first version GEDI data products were shifted to the left forward of nominal geolocations with a distance of about 2. m~30 m and were substantially corrected in the second version;the fourth and fifth groups of signal start and ending points of waveforms had worse performance than the rest of the four groups because they used the maximum and minimum signal thresholds,*** airborne laser scanner(ALS)data as reference,the root mean square error(RMSE)of terrain slopes extracted from the digital elevation model of the shuttle radar topography mission(SRTM DEM)was about 3°.The coefficients of determination(R^(2.)of estimation models of forest AGB based on RH metrics were improved from 0.48 to 0.68 with RMSE decreased from 1..7 Mg/ha to 1..4 Mg/ha by the second version *** RHT and WP metrics gave the best and the worst estimation accuracy,*** further improved R^(2. to 0.77 and decreased RMSE to 1..0 Mg/ha using terrain slopes extracted from SRTM DEM with a resolution of 1.arc second.R^(2. of estimation models based on RHT was finally

关键词： terrain estimation ground

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Characterization of ASTER GDEM elevation data over vegetated area compared with lidar data

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International Journal of Digital Earth 2015年第3期8卷 198-211页

作者： Wenjian Ni guoqing {1. Kenneth J.Ranson state {1. {2. of remote sensing science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina Department of Geographical sciences University of MarylandCollege ParkMDUSA Biospheric sciences Branch NASA’s Goddard Space Flight CenterGreenbeltMDUSA

Current researches based on areal or spaceborne stereo images with very high resolutions(<1.m)have demonstrated that it is possible to derive vegetation height from stereo *** second version of the Advanced Spaceborne... 详细信息

Current researches based on areal or spaceborne stereo images with very high resolutions(1.m)have demonstrated that it is possible to derive vegetation height from stereo *** second version of the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model(ASTER GDEM)is the state-of-the-art global elevation data-set developed by stereo ***,the resolution of ASTER stereo images(1. m)is much coarser than areal stereo images,and the ASTER GDEM is compiled products from stereo images acquired over 1. *** forest disturbances as well as forest growth are inevitable in 1. years time *** this study,the features of ASTER GDEM over vegetated areas under both flat and mountainous conditions were investigated by comparisons with lidar *** factors possibly affecting the extraction of vegetation canopy height considered include(1.co-registration of DEMs;({1.spatial resolution of digital elevation models(DEMs);(3)spatial vegetation structure;and(4)terrain *** results show that the accurate coregistration between ASTER GDEM and national elevation dataset(NED)is necessary over mountainous *** correlation between ASTER GDEM minus NED and vegetation canopy height is improved from 0.3{1. to 0.43 by degrading resolutions from 1.arc-second to 5 arc-second and further improved to 0.6 if only homogenous vegetated areas were considered.

关键词： vegetation canopy height ASTER GDEM NED photogrammetry stereo-mapping

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融合车载影像与点云的道路边界提取与矢量化

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武汉大学学报（信息科学版） 2024年第4期49卷 631-639页

作者：李庞胤米晓新丁鹏辉孙为晨张华祖刘翀董震杨必胜武汉大学测绘遥感信息工程国家重点实验室湖北武汉430079 时空数据智能获取技术与应用教育部工程研究中心湖北武汉430079 青岛市勘察测绘研究院青岛市海陆地理信息集成与应用重点实验室山东青岛266034

车载激光点云的数据不完整和影像连续帧之间的地物重影现象给提取连续、完整的道路边界带来了巨大挑战。提出了一种融合点云与全景影像的道路边界提取与矢量化方法。首先,分别从点云和全景影像中提取初始道路边界点,然后基于非闭合Snak... 详细信息

车载激光点云的数据不完整和影像连续帧之间的地物重影现象给提取连续、完整的道路边界带来了巨大挑战。提出了一种融合点云与全景影像的道路边界提取与矢量化方法。首先,分别从点云和全景影像中提取初始道路边界点,然后基于非闭合Snake模型融合两种数据源中的道路边界点,实现结构化和非结构化道路边界的准确提取与矢量化。该融合过程首先基于点云中的道路边界构建特征图,并以车载影像中的道路边界提取结果为初始轮廓,然后基于道路边界的几何特性构建非闭合Snake模型,最后通过求解该模型实现多源道路边界点的融合,并完成道路边界线的矢量化。将该方法应用于2.城市场景数据集,结果表明:该方法可有效提取形状多样的结构化和非结构化道路边界,对由于遮挡导致的数据不完整和多帧影像中的地物重影具有较强的鲁棒性,对城区道路边界提取的精度、召回率、F1.分别优于95.43%、89.2.%、93.38%。

关键词：道路边界提取移动激光扫描(MLS) 多模态数据融合

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Numerical analysis of landslide-generated debris flow on July 3, 2.2. in Izu Mountain area, Shizuoka County, Japan

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Journal of Mountain science 2022年第6期19卷 1738-1747页

作者： sun Tong sun {2.-ya WANG Xie-kang MA Qiang GOURBESVILLE Philippe NOHARA Daisuke state {1. {2. of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China china {1. of Water Resources and Hydropower Research Beijing 100038China Universite Cote d'Azur Nice 06903France Sustainable Society laboratory KAJIMA Technical Research {1. Kyoto University 6110011Japan

With the increasing of extreme rainfall frequency, landslides accompanied by mudslides often lead to serious casualties and property damage. On 3rd July 2.2., a debris flow occurred in Izu Mountain area, Shizuoka County, Japan, and then resulted in 2. deaths and 1.1.houses destroyed, where houses were mainly built along the banks of the creek. In order to analyse the landslide state and distribution, a two-dimensional debris flow dynamic model(Massflow) was selected to simulate the process of the landslide-generated debris flow. When the model results are considered together with remote {2. images, the volume distribution of the unstable landslide is also able to be determined. The results show that(1. the affected areas are mainly concentrated at the outfall of the gully and on both sides of the streets.(2. The pore pressure ratio is an important factor affecting the damage range of this debris flow.(3) The increase of the pore pressure ratio in the landslide make the movement distance of debris flow increase significantly.

关键词： Izu Mountain Landslide Debris flow Numerical simulation Pore pressure ratio

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Scale Effect of Climate and Soil Texture on Soil Organic Carbon in the Uplands of Northeast china

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Pedosphere 2010年第4期20卷 525-535页

作者： WANG Dan-Dan SHI Xue-Zheng WANG Hong-Jie D. C. WEINDORF YU dong-Sheng {1. Wei-Xia REN Hong-Yan ZHAO {2.-Cun state {1. {2. of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of SciencesNanjing 210008 （China） College of remote {1. Nanjing University of Information Science and Technology Nanjing 210044 （China） Louisiana state University AgCenter Baton Rouge Louisiana 70803 （USA） Graduate University of the chinese academy of sciences Beijing 100049 （China）

Understanding how spatial scale influences commonly-observed effects of climate and soil texture on soil organic carbon （SOC） storage is important for accurately estimating the SOC pool at different scales. The relationships among climate factors, soil texture and SOC density at the regional, provincial, city, and county scales were evaluated at both the soil surface （0-2. cm） and throughout the soil profile （0-1.0 cm） in the Northeast{1. uplands. We examined 1.02. profiles obtained from the Second National Soil Survey of{1.. The results indicated that the relationships between climate factors and SOC density generally weakened with decreasing spatial scale. The provincial scale was optimal to assess the relationship between climate factors and SOC density because regional differences among provinces were covered up at the regional scale. However, the relationship between soil texture and SOC density had no obvious trend with increasing scale and changed with temperature. There were great differences in the impacts of climate factors and soil texture on SOC density at different scales. Climate factors had a larger effect on SOC density than soil texture at the regional scale. Similar trends were seen in Heilongjiang and eastern Inner Mongolia at the provincial scale. But, soil texture had a greater effect on SOC density compared with climate factors in Jilin and Liaoning. At the city and county scales, the influence of soil texture on SOC density was more important than climate factors.

关键词： factor precipitation spatial scale temperature

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ICESat-2.被冠层高度和地表高程数据产品用于森林高度提取的效果评价

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遥感学报 2021年第6期25卷 1294-1307页

作者：董佳臣倪文俭张志玉孙国清中国科学院空天信息创新研究院遥感科学国家重点实验室北京100094 中国科学院大学资源与环境学院北京100049 美国马里兰大学地理系马里兰州College Park 美国20742

由美国宇航局(NASA)研制的新一代冰、云和陆地高程卫星(ICESat-2.于2.1.-09-1.发射成功,其搭载的先进地形激光测高系统(ATLAS)采用微脉冲多波束光子计数激光雷达技术,可用于全球高程线采样数据的获取。目前公开发布了9种数据产品,其中... 详细信息

由美国宇航局(NASA)研制的新一代冰、云和陆地高程卫星(ICESat-2.于2.1.-09-1.发射成功,其搭载的先进地形激光测高系统(ATLAS)采用微脉冲多波束光子计数激光雷达技术,可用于全球高程线采样数据的获取。目前公开发布了9种数据产品,其中包括植被冠层高度和地表高程数据产品(ATL08),为全球森林结构参数的估算提供了新的契机。本文以美国宾夕法尼亚州斯奈德县和印度尼西亚西加里曼丹吉打邦为研究区,在温带森林和热带雨林两种不同的生态系统立地条件下,对ICESat-2.ATL08数据产品用于森林高度估算的效果进行评价。首先建立了地形高程数据产品(ATL03)与ATL08数据产品的关联规则,以获取分别记录在这两种产品中的光子空间分布信息和分类信息;进而以机载小光斑激光雷达数据为参考,对ATL08数据产品的光子分类可靠性及其用于森林高度估算的准确性进行了分析评价。结果表明:(1.在温带森林情况下,ATL08数据产品提供的平均冠层高度和最大冠层高度与参考数据的相关系数(R~2.分别为0.54和0.61.相对误差分别为1..78%和1..71.,表明ATL08数据产品的光子分类结果能够用于刻画森林冠层结构和林下地形;(2.在热带雨林情况下,到达地面的光子数量相较于温带森林明显减少,地面光子类型识别的可靠性低,ATL08数据产品提供的平均冠层高度和最大冠层高度与参考数据的相关系数(R~)分别为0.2.和0.1.;(3)森林覆盖度的增大会导致ATL08计算的冠层高度误差增大,热带雨林平均冠层高度的误差随着坡度增大有增大趋势,在坡度为0°—1.°、1.°—2.°和2.°—30°共3组情况下,误差分别为5.7 m、6.6 m和9.3 m。因此,在高森林覆盖度情况下,现有的ATL08数据产品难以直接用于森林高度的提取。

关键词： ICESat-2 ATLAS ATL08 森林结构参数

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