星载光子计数激光雷达数据森林高度及林下地形反演研究进展

Research progress on retrieving forest canopy height and subcanopy topography from spaceborne photon-counting LiDAR data

森林高度是衡量森林生物量、森林生态系统碳汇的重要参数,位于森林下的地形(林下地形)是支撑国家重大基础设施建设、灾害监测的战略信息资源。新一代星载激光雷达ICESat-2/ATLAS采用一种多波束微脉冲的光子计数技术,以10 kHz的重复频率对地发射激光脉冲,从而导致出现间隔为0.7 m、光斑半径为8.5 m的重叠光斑。相比于ICESat-1/GLAS,ICESat-2/ATLAS具有更高的空间采样率以及对坡度的不敏感性,是目前反演森林高度参数和林下地形的重要手段。本文介绍了ICESat-2/ATLAS的主要参数指标,总结了各类误差因素对ATL08官方产品的影响,分析了各种森林区光子点云滤波方法、ICESat-2林下地形反演方法及森林高度参数反演方法的适用性及面临的主要问题,展望了ICESat-2/ATLAS光子点云滤波、林下地形及森林高度参数反演的发展趋势及应用前景。

Forest height is an important parameter to measure forest biomass and carbon sink of the forest ecosystem.The topography under the forest(sub-canopy topography)is a strategic information resource supporting national infrastructure construction and disaster monitoring.The new generation space-borne lidar ICESat-2/ATLAS adopts a multi-beam micro-pulse photon counting technology for the first time,with a repetition frequency of 10 kHz to the ground.Compared with ICESat-1/GLAS,ICESat-2/ATLAS has a higher spatial sampling rate and insensitivity to slope and is currently important data for inverting the forest canopy height of forest ecosystems and sub-canopy topography.Some main indicators of ICESat-2/ATLAS were introduced and the influence of various errors on ATL08 products were summarized.The applicability of various photon point cloud filtering methods sub-canopy topography inversion and forest canopy height inversion were analyzed.The research progress and application prospects on photon point cloud filtering,sub-canopy topography inversion,and forest canopy height retrieval were put forward.