联合Terra/Aqua MODIS多角度多光谱数据反演冬小麦叶面积指数  

Winter wheat leaf area index retrieval with multi-angle and multi-spectral Terra/Aqua MODIS data

作　　者：何维[1,2,3] 杨华[1,2,3] 

机构地区：[1]北京师范大学地理学与遥感科学学院,北京100875 [2]北京师范大学/中科院遥感应用研究所遥感科学国家重点实验室,北京100875 [3]环境遥感与数字城市北京市重点实验室,北京100875

出　　处：《农业工程学报》2013年第4期204-212,I0007,I0008,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(40671129);国家高技术研究发展计划(863计划)(2008AA12Z107)

摘　　要：Terra与Aqua双星搭载的MODIS传感器可实现每日上下午分别对同一地点观测一次,并且由于卫星轨道漂移形成累积连续多天的多角度观测特点,加上多通道的光谱响应,极大地丰富了地表目标的观测信息,为LAI等地表参数的实时准确反演提供了可能。该文利用MODIS双星高质量的连续多天的多波段地表反射率数据,结合PROSAIL(PROSPECT+SAIL,properties spectra+scattering by arbitrarily inclined leaves)模型和查找表方法反演冬小麦LAI,并与MODIS LAI产品及野外采样点实测LAI对比,结果表明,联合双星高质量的多角度多波段数据能够较准确反演冬小麦LAI,其反演结果无论从空间分布还是时序变化特征来讲,较MODIS LAI产品更符合实际情况,也更接近地面实测值。该文的研究为充分利用MODIS数据的角度和光谱信息反演小麦等农作物的LAI提供了一定的借鉴。MODIS sensors, carried onboard Terra and Aqua satellites, scan the same location daily at a fixed time. Because of the sequential multidirectional information contributed by satellite orbit drift along with multi-channel spectral responses, MODIS data greatly enriches the observations of land surface targets, which makes it possible to estimate the land surface parameters accurately and timely, such as leaf area index （LAI）. Many researchers have focused on LAI estimation using MODIS data, among whom most used the multispectral data of a single satellite in one day or eight days, while few comprehensively utilized the multispectral and multidirectional information obtained by the both MODIS sensors in some sequence of days. MODIS LAI products have developed a series of generations, the fifth version （MODIS V005） has integrated data from both Terra and Aqua. It is proven that this version is improved with single satellite data, however, it only utilizes red and near-infrared band observations. It has been suggested that taking the shortwave infrared band observations into consideration can help improve the accuracy of LAI estimation. Moreover, some validation studies indicate that there are still some limitations in applying current MODIS LAI products, e.g., LAI is overestimated or underestimated to some extent in different regions. Therefore, this paper investigates the methods of winter-wheat LAI retrieval using multispectral and multidirectional observations ofTerra/Aqua MODIS in consecutive days. In this study, data preprocessing, including cloud status and data quality checking, was used first to remove the observations with partial or complete cloud cover, cloud shadow, or low pixel quality in the study area. Then, LAI, average leaf angle （ALA）, chlorophyll content （Cab）, water content （Cw） and dry matter content （Cm） were selected as the inversion parameters through sensitivity analysis. Other parameters were fixed by drawing upon previous studies and a priori knowledge obtained from

关 键 词：遥感 波 反射 反演 叶面积指数 MODIS数据 冬小麦 

分 类 号：S127[农业科学—农业基础科学]