森林冠层叶面积密度激光雷达遥感反演

项目名称： 森林冠层叶面积密度激光雷达遥感反演

项目编号： No.41471294

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 李世华

作者单位： 电子科技大学

项目金额： 86万元

中文摘要： 叶面积密度（LAD）是每单位地面面积每单位高度范围内的总单面叶面积，是表示叶面积垂直分布的重要参数，准确反演森林冠层LAD对于研究森林碳、氮循环、叶片生化组分垂直分布、生物量估算等具有重要意义。 项目将在辐射传输理论的支持下基于地基和机载激光雷达（LiDAR）数据探索森林冠层垂直分布特征表达规则；通过大量观测实验，获取不同生长条件森林样方的地基三维激光点云和森林结构参数数据，建立适用于冠层叶片与非光合组织准确分离的点云分割算法，实现叶片点云数据的精确提取；结合基于体元的冠层分析方法（VCP），构建地基LiDAR数据的树林冠层LAD反演模型；针对地基LiDAR冠层顶部容易出现盲区和无法开展大面积反演的特点，利用机载小光斑波形LiDAR数据反演森林冠层上部LAD，协同地基LiDAR对冠层下部LAD的准确反演构建森林冠层LAD协同反演模型；发展LAD反演误差分布模型，评价模型与观测的不确定性。

中文关键词： 叶面积密度；小光斑激光雷达；全波形激光雷达；森林冠层；植被结构参数

英文摘要： Leaf area density (LAD) is defined as the total one-sided leaf area per unit layer volume. It is very important for estimating leaf chemical components vertical distribution and biomass. Accurate retrieval of LAD over forest canopies will improve our understanding of forest carbon and nitrogen cycle. Based on the vegetation canopy transfer modeling, this project is designed to explore the fusion of terrestrial and airborne light detection and ranging( LiDAR) data for retrieving LAD of forest canopies. With long term plot level observations, multi-temporal terrestrial LiDAR data is acquired to estimate forest structural parameters, and algorithms for point cloud segmentation are developed to discriminate the leaves and non-photosynthetic tissues, and accurately extract LiDAR points of leaves; With the support of voxel-based canopy profiling (VCP) method, LAD retrieve model is developed for forest canopies using terrestrial LiDAR data; Since the terrestrial LiDAR system can not capture point cloud of upper canopies, and it is also difficult to acquire dataset over large area, LiDAR data acquired by airborne small foot-print full-waveform system is adopted to retrieve LAD of upper forest canopies, with synergic utilization of terrestrial LiDAR data, the LAD of forest canopies could be retrieved over large area. The accuracy and uncertainty of the LAD estimation model is evaluated by comparing the results of separated LiDAR data sets with those of the combined method.

英文关键词： leaf area density;small-footprint LiDAR;full-waveform LiDAR;forest canopy;vegetation structural parameters