Retrieval of forest canopy height in a mountainous region with ICESat-2 ATLAS

作者：Shiyun Pang, Guiying Li, Xiandie Jiang, Yaoliang Chen, Yagang Lu, Dengsheng Lu · 发表于：Forest Ecosystems · 年份：2022 · DOI：10.1016/j.fecs.2022.100046 · 被引用次数：33 · 研究领域：Remote Sensing and LiDAR Applications、Remote Sensing in Agriculture、Forest Ecology and Biodiversity Studies

Forest canopy height is one of the important forest parameters for accurately assessing forest biomass or carbon sequestration. ICESat-2 ATLAS provides the potential for retrieval of forest canopy height at global or regional scale, but the current canopy height product (ATL08) has coarse resolution and high uncertainty compared to airborne LiDAR-derived canopy height (hereafter ALCH) in mountainous regions, and is not ready for such applications as biomass modeling at finer scale. The objective of this research was to explore the approach to accurately retrieve canopy height from ATLAS data by incorporating an airborne-derived digital terrain model (DTM) and a data-filtering strategy. By linking ATLAS ATL03 with ATL08 products, the geospatial locations, types, and (absolute) heights of photons were obtained, and canopy heights at different lengths (from 20 to 200 m at 20-m intervals) of segments along a track were computed with the aid of airborne LiDAR DTM. Based on the relationship between the numbers of canopy photons within the segments and accuracy of ATLAS mean canopy height compared to ALCH, a filtering method for excluding a certain portion of unreliable segments was proposed. This method was further applied to different ATLAS ground tracks for retrieval of canopy heights and the results were evaluated using corresponding ALCH. The results show that the incorporation of high-precision DTM and ATLAS products can considerably improve the retrieval accuracy of forest ca...