全球生态系统动力学调查(global ecosystem dynamics investigation,GEDI)雷达是美国2018年12月发射的全波形激光雷达系统,可以为全球地面高程及森林冠层高度提供数据支持。为适应不同地表环境,GEDI L2A产品提供了6种不同算法来估算地面高程及森林冠层高度,这些算法的选择会影响地表参数的提取精度。以机载LiDAR得到的数字地形模型和冠层高度模型为参考数据,评估第2版GEDI L2A数据在不同植被覆盖度下不同算法的适应性以及对地面高程和森林冠层高度精度的影响。结果表明,在覆盖度小于0.2时,算法4的结果最优,在覆盖度大于等于0.8时算法2的结果最优,其余覆盖度下算法1的结果最优。将本文根据植被覆盖度选择的最优算法与GEDI L2A默认最优算法进行比较,整体看来本文的结果优于GEDI L2A默认最优算法的结果,特别是在覆盖度小于0.8,坡度大于等于10°时,本文选择的最优算法能有效提高GEDI L2A产品对地面高程和森林冠层高度估算的精度。
刘丽娟
,
王成
,
聂胜
,
朱笑笑
,
习晓环
,
王金亮
. GEDI L2A不同算法对地面高程和森林冠层高度精度的影响分析[J]. 中国科学院大学学报, 2022
, 39(4)
: 502
-511
.
DOI: 10.7523/j.ucas.2021.0076
The global ecosystem dynamics investigation(GEDI) is a full-waveform LiDAR system launched by United States in December 2018, which can provide data support for global ground elevation and forest canopy height. In order to adapt to different surface environments, GEDI L2A products provide 6 different algorithms to estimate ground elevation and forest canopy height. The choice of these algorithms will affect the extraction accuracy of surface parameters. In this paper, the digital terrain model and canopy height model obtained by airborne laser scanning data are used as reference data to evaluate the adaptability of different algorithms of the second version of GEDI L2A data under different vegetation coverage values and the impact on the accuracy of ground elevation and forest canopy height. The results show that when the vegetation coverage is less than 0. 2, the result of algorithm 4 is the best, when the coverage is greater than or equal to 0. 8, the result of algorithm 2 is the best, and the result of algorithm 1 is the best under the remaining coverage values. Comparing the optimal algorithm selected in this paper according to the vegetation coverage with the GEDI L2A default optimal algorithm, the results of this paper are generally better than those of the GEDI L2A default optimal algorithm, especially when the coverage value is less than 0. 8 and the slope is greater than or equal to 10°. The optimal algorithm selected in this paper can effectively improve the accuracy of GEDI L2A products for estimating ground elevation and forest canopy height.
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