遥感提取叶面积指数的地形影响分析  

Analysis of Topographical Effect on Retrieval of LAI from Remotely Sensed Data

作　　者：夏学齐[1] 田庆久[1] 杜凤兰[1] 

机构地区：[1]南京大学国际地球系统科学研究所,江苏南京210093

出　　处：《遥感信息》2004年第2期16-19,37,共5页Remote Sensing Information

摘　　要：结合 1∶5 0 0 0 0DEM对贵州省黎平县内研究区的ETM +遥感影像进行地形纠正 ,分别使用地形纠正前后的图像建立植被指数与实测杉木林、阔叶林、竹林的叶面积指数相关关系 ,从而对研究区森林叶面积指数进行计算。研究表明 ,利用遥感影像计算山地丘陵林区叶面积指数时地形是一个重要的影响因素 ,它致使遥感影像提取的叶面积指数出现一定的偏差。因此 ,本文从电磁波辐射传输理论着手 ,采用一种地形影响去除方法 ,即先把遥感图像归一化为没有地形影响下的亮度图像 ,再通过该亮度图像提取森林叶面积指数 ,并通过实地观测数据验证了该地形纠正方法的有效性。同时 。Landsat ETM+data were corrected topographically with 1∶50 000 DEM. By using the data before and after topographical correction respectively,the correlations between LAI, which were measured from China Fir, broadleaf forest, and bamboo, and NDVI are established. Analysis between LAI measured on the spot and the calculated from images shows that topographical effect of remotely sensed image makes the retrieval of LAI not very accurate and topographic effect must be taken into consideration. A method of topographical correction based on radiation transmission given in this paper is an effective method, which normalizes the remote sensing image into the data without topographical effect. The paper also shows a method for estimating Atmospheric Path Radiance, which correlates a topographical factor and DN values in the remote sensing image.

关 键 词：遥感 地形纠正 叶面积指数 森林 

分 类 号：TP7[自动化与计算机技术—检测技术与自动化装置]