Improved terrain estimation from spaceborne lidar in tropical peatlands using spatial filtering
Improved terrain estimation from spaceborne lidar in tropical peatlands using spatial filtering
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DOI：
10.1016/j.srs.2022.100074
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发表时间：
2022-12
影响因子：
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通讯作者：
A. Cobb;R. Dommain;R. Sukri;F. Metali;B. Bookhagen;C. Harvey;Hao Tang
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文献类型：
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作者：
A. Cobb;R. Dommain;R. Sukri;F. Metali;B. Bookhagen;C. Harvey;Hao Tang
据估计，热带泥炭地以部分分解的有机物或泥炭的形式拥有70 Pg C或更多的碳储量。泥炭可能经过数千年的积累，形成被称为泥炭圆顶的缓慢堆积的沉积物，在几公里的距离上有几米的起伏。热带泥炭丘的丘状形状解释了这些景观中大部分的碳储存，但它们微妙的地形起伏很难测量。由于世界上许多热带泥炭地都是偏远而难以到达的，来自NASA在国际空间站（ISS）上的全球生态系统动力学调查（GEDI）和在冰、云和陆地高程卫星2 （ICESat-2）天文台上的先进地形激光高度计系统（ATLAS）仪器等任务的星载激光测高数据可以帮助描述这些沉积物。参考婆罗洲岛文莱达鲁萨兰国Belait区的机载激光雷达数据集，我们评估了从GEDI波形数据获得的地面高程检索，以及ATLAS的单光子数据。GEDI L2A版本2，算法1质量数据的空间滤波将机载激光雷达获得的地面高程的平均绝对偏差从8.35 m降至1.83 m，均方根误差从15.98 m降至1.97 m，无偏均方根误差从13.62 m降至0.72 m。同样，ATLAS ATL08 version 3对夜间强光束地面光子进行空间滤波后，平均绝对偏差从1.51 m降至0.64 m，均方根误差从3.85 m降至0.77 m，无偏均方根误差从3.54 m降至0.44 m。我们的结论是，尽管地面检索稀疏，这些星载平台可以提供有用的数据，热带泥炭地地表高度，如果后处理与空间滤波器。
Tropical peatlands are estimated to hold carbon stocks of 70 Pg C or more as partly decomposed organic matter, or peat. Peat may accumulate over thousands of years into gently mounded deposits called peat domes with a relief of several meters over distances of kilometers. The mounded shapes of tropical peat domes account for much of the carbon storage in these landscapes, but their subtle topographic relief is difficult to measure. As many of the world's tropical peatlands are remote and inaccessible, spaceborne laser altimetry data from missions such as NASA's Global Ecosystem Dynamics Investigation (GEDI) on the International Space Station (ISS) and the Advanced Topographic Laser Altimeter System (ATLAS) instrument on the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) observatory could help to describe these deposits. We evaluate retrieval of ground elevations derived from GEDI waveform data, as well as single-photon data from ATLAS, with reference to an airborne lidar dataset covering an area of over 300 km2in the Belait District of Brunei Darussalam on the island of Borneo. Spatial filtering of GEDI L2A version 2, algorithm 1 quality data reduced mean absolute deviations from airborne-lidar-derived ground elevations from 8.35 m to 1.83 m, root-mean-squared error from 15.98 m to 1.97 m, and unbiased root-mean-squared error from 13.62 m to 0.72 m. Similarly, spatial filtering of ATLAS ATL08 version 3 ground photons from strong beams at night reduced mean absolute deviations from 1.51 m to 0.64 m, root-mean-squared error from 3.85 m to 0.77 m, and unbiased root-mean-squared error from 3.54 m to 0.44 m. We conclude that despite sparse ground retrievals, these spaceborne platforms can provide useful data for tropical peatland surface altimetry if postprocessed with a spatial filter.