Lidar remote sensing has proven to be a powerful tool for estimating ground elevation, canopy height, and additional vegetation parameters, which in turn are valuable information for the investigation of ecosystems. Spaceborne lidar systems, like the Global Ecosystem Dynamics Investigation (GEDI), can deliver these height estimates on a near global scale. This paper analyzes the accuracy of the first version of GEDI ground elevation and canopy height estimates in two study areas with temperate forests in the Free State of Thuringia, central Germany. Digital terrain and canopy height models derived from airborne laser scanning data are used as reference heights. The influence of various environmental and acquisition parameters (e.g., canopy cover, terrain slope, beam type) on GEDI height metrics is assessed. The results show a consistently high accuracy of GEDI ground elevation estimates under most conditions, except for areas with steep slopes. GEDI canopy height estimates are less accurate and show a bigger influence of some of the included parameters, specifically slope, vegetation height, and beam sensitivity. A number of relatively high outliers (around 9–13% of the measurements) is present in both ground elevation and canopy height estimates, reducing the estimation precision. Still, it can be concluded that GEDI height metrics show promising results and have potential to be used as a basis for further investigations.

中文翻译：

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欧洲温带森林中GEDI地形高程和冠层高度估计的准确性评估：环境和采集参数的影响

事实证明，激光雷达是估算地面标高，冠层高度和其他植被参数的有力工具，而这些参数反过来又对生态系统研究具有重要意义。像全球生态系统动力学调查（GEDI）这样的星载激光雷达系统可以在接近全球范围内提供这些高度估计值。本文分析了德国中部自由州图林根州两个带温带森林的研究区的GEDI地面高程和冠层高度估计的第一版的准确性。从机载激光扫描数据得出的数字地形和树冠高度模型用作参考高度。评估了各种环境和采集参数（例如，树冠覆盖，地形坡度，波束类型）对GEDI高度度量的影响。结果表明，在大多数情况下，除具有陡坡的地区外，GEDI地面标高的估算值始终具有很高的准确性。GEDI冠层高度的估计值不太准确，并且显示其中某些参数的影响较大，特别是坡度，植被高度和波束敏感性。地面标高和树冠高度估计中都存在许多相对较高的离群值（大约占测量值的9-13％），从而降低了估计精度。仍然可以得出结论，GEDI高度度量显示出令人鼓舞的结果，并且有可能被用作进一步研究的基础。植被高度和光束敏感性。地面标高和树冠高度估计中都存在许多相对较高的离群值（大约占测量值的9-13％），从而降低了估计精度。仍然可以得出结论，GEDI高度度量显示出令人鼓舞的结果，并且有可能被用作进一步研究的基础。植被高度和光束敏感性。地面标高和树冠高度估计中都存在许多相对较高的离群值（大约占测量值的9-13％），从而降低了估计精度。仍然可以得出结论，GEDI高度度量显示出令人鼓舞的结果，并且有可能被用作进一步研究的基础。