基于地面激光雷达数据反演森林冠层真实叶面积指数

项目名称： 基于地面激光雷达数据反演森林冠层真实叶面积指数

项目编号： No.41201337

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 地理学

项目作者： 郑光

作者单位： 南京大学

项目金额： 25万元

中文摘要： 森林冠层真实叶面积指数对植被冠层二向性反射特性、林冠内部的太阳辐射分布、森林生态系统碳循环和全球变化等方面的研究具有重要的生态学意义和实用价值。本研究在光学叶面积指数观测理论的基础上，采取室内实验和野外观测相结合的方式，以马尾松针叶林和栎林阔叶林为研究对象，结合"点云切片算法"和"点云法向量重建算法"，利用地面激光雷达扫描系统生成三维点云数据，获取单株立木或森林样方林冠结构的关键参数，进而估算整个林冠及其不同高度的真实叶面积指数。基于三维点云数据估算真实叶面积指数的方法可提高传统光学仪器二维观测的精度，可为航空、星载激光雷达和卫星遥感数据估算真实叶面积指数提供理论基础和验证手段，也可为基于过程的森林生态系统的碳、水循环模型提供可靠的输入参数。

中文关键词： 叶面积指数；地面激光雷达；三维点云；消光系数；聚集度指数

英文摘要： True leaf area index (TLAI) has great ecological meanings and practical values in researches on directional reflectance characteristic of forest canopy, radiation regime within canopy, carbon cycle of forest ecosystem and global changes. This project will first develop the method which could retrieve key forest canopy parameters in indoor environment using TLS for coniferous and broadleaf artifical trees, and then outdoor experiments will be taken in natural forests for both coniferous and broadleaf tree species as well. The point cloud data (PCD) generated using TLS for both indoor and outdoor experiments will be collected. Based on the theories of optical instrument based LAI measurement, the TLAI for both whole canopy and horizontal layers with different height could be obtained by processing the PCD using "point cloud slicing algorithm" and "normal vector reconstruction algorithm". The TLS-based TLAI estimation method could not only improve the estimation accuracy of optical instrument based measurement, but also will provide a strong theoretical foundation and validation tool for the aerial laser scanning (ALS), space-bore light detection and ranging (lidar), or satellite based TLAI estimation.TLS-based ture leaf area index could provide relaible input parameter to the process-based ecologial model to simul

英文关键词： leaf area index；terrestrial laser scanning；3D point cloud data；extinction coefficient；clumping index