| 基于野外观测和TM数据的锡林浩特典型草原MODIS/LAI产品验证 |
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| 引用本文： | 王圆圆,王猛,李贵才,王军邦,杨忠东,戎志国.基于野外观测和TM数据的锡林浩特典型草原MODIS/LAI产品验证[J].草业学报,2011,20(4):252-260. |
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| 作者姓名： | 王圆圆 王猛 李贵才 王军邦 杨忠东 戎志国 |
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| 作者单位： | 1.中国气象局中国遥感卫星辐射测量和定标重点开放实验室 国家卫星气象中心,北京 100081;2.中国科学院地理科学与资源研究所,北京100101;3.中国科学院研究生院,北京 100049 |
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| 基金项目： | 公益性行业科研专项[GYHY(QX)2007-6-9,GYHY200906036];国家自然科学基金(40501048)资助 |
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| 摘 要： | 通过2008年夏季生长季的3期LAI野外观测和TM图像的处理分析,对锡林浩特国家观象台附近24 km2典型草原区的MODIS/LAI产品精度从时空2种维度进行了评估。结果显示,在时间维度上,MODIS/LAI产品可以较为准确的体现草地植被生长轨迹;在空间维度上,MODIS/LAI产品与TM/LAI反演结果有相似的变化趋势。以TM/LAI结果为参考真值,MODIS/LAI产品的相对均方根误差约为24%,并存在10.8%的正偏差,表明有一定程度的高估。误差分析结果显示,MODIS/LAI产品精度主要受到土壤背景光谱以及地表均匀程度的影响,在LAI较小的区域,以及在草地空间异质性因受人类活动而增强的7月初和8月末,MODIS/LAI产品误差更大。
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| 关 键 词： | MODIS/LAI产品 TM/ETM+数据 典型草原 |
| 收稿时间： | 2010-06-11 |
Research on validating MODIS/LAI product in a typical semi-arid steppe of Xilinhot in Northern China |
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| WANG Yuan-yuan,WANG Meng,LI Gui-cai,WANG Jun-bang,YANG Zhong-dong,RONG Zhi-guo.Research on validating MODIS/LAI product in a typical semi-arid steppe of Xilinhot in Northern China[J].Acta Prataculturae Sinica,2011,20(4):252-260. |
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| Authors: | WANG Yuan-yuan WANG Meng LI Gui-cai WANG Jun-bang YANG Zhong-dong RONG Zhi-guo |
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| Institution: | 1.Key Lab of Radiometric Calibration and Validation for Environmental Satellites, China Meteorological Administration (LRCVES/CMA), National Satellite Meteorological Center, Beijing 100081, China;2.Institute of Geographic Sciences and Natural Resources, CAS, Beijing 100101, China;3.Graduate School of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | MODIS/LAI product in a typical semi-arid steppe of Xilinhot in Northern China was validated based on three comprehensive field surveys which were carried out during July-August 2008 in the study area.LAI was measured in 25 m×25 m plots by a destructive harvest method of 80 intensive plots and 20 scattered plots.Three TM/ETM+ images acquired during the field survey periods were collected and processed.The validation work covered two parts: Time series analysis and spatial pattern analysis.In time series analysis,MODIS/LAI track in the intensive sampling region extracted from DOY169 to DOY241 were compared with ground measured values.In spatial pattern analysis,LAI map with 30 m spatial resolution were first derived by building a regression line between LAI and TM band 5(1.6 μm),and then aggregated to 1 km spatial resolution based on MODIS grids.Results indicated that in the temporal domain MODIS/LAI product can correctly reflect grass growth trends;In the spatial domain it showed a similar pattern with TM/LAI(1 km).Using the TM/LAI as reference,the relative RMSE of MODIS/LAI was about 24% and a positive bias(10.8%) existed,suggesting slight over-estimation.Error distribution analysis revealed that the MODIS/LAI product was less accurate in regions with lower LAI values,probably due to soil contamination.Moreover,the relative RMSE of the MODIS/LAI product was higher at the beginning of July and the end of August when the heterogeneity of grass cover increased as a result of human activities. |
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| Keywords: | MODIS/LAI product TM/ETM+ data typical steppe |
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