基于地基激光雷达监测不同地表覆盖条件的土壤侵蚀试验研究

土壤侵蚀量是土壤退化风险评估的重要指标，地基激光雷达(TLS)为土壤侵蚀量动态监测提供新技术手段，但野外不同地表覆盖条件对监测精度的影响尚不明确。基于2019年11月和2021年7月在鹰潭红壤生态实验站获取的地表裸露、石块、稀疏象草、马尾松、马尾松+石块，马尾松+稀疏象草等不同地表覆盖条件的6个径流小区两期TLS数据，运用移动曲面拟合滤波和反距离加权插值方法估算土壤侵蚀量，结合实测侵蚀量数据评价TLS精度，并探讨不同地表覆盖条件下TLS的最小变化识别度(minLOD)。研究表明，TLS监测精度与土壤侵蚀量呈正相关关系，更适用于中等强度以上或长时间发生明显侵蚀的土壤侵蚀区监测。不同地表覆盖条件下minLOD为4 ~ 60 mm，TLS监测相对误差(RE)依次为：地表裸露(RE= -9.4%)<马尾松+石块(RE=12.6%)<石块(RE=15.5%)<稀疏象草(RE= -18.9%)<马尾松(RE=23.4%)<马尾松+稀疏象草(RE= -25.2%)；地表覆盖条件不仅影响土壤侵蚀强度、地表粗糙度，也产生点云滤波及空间插值误差，进而影响TLS识别minLOD准确度和土壤侵蚀监测精度。本研究为野外复杂地表条件下TLS监测土壤侵蚀提供参考。

Experimental Research on Soil Erosion Monitoring of Different Ground Cover Conditions Using Terrestrial Laser Scanning (TLS)

The amount of soil erosion is a key indication for assessing the risk of soil degradation. Terrestrial laser scanning (TLS) is a new technical tool for monitoring soil erosion in real time, but its monitoring accuracy under various ground cover conditions is still unclear. In this study, two TLS scans with six different ground cover conditions were undertaken in Yingtan Red Soil Ecological Experimental Station in November 2019 and July 2021. Moving surface fitting filtering and the inverse distance weighted interpolation methods were used to create DEM. The erosion mass and accuracy of TLS were assessed using a combination of DEM datasets and a minimal level of detection. The results showed that there was significant positive correlation between the accuracy of TLS and soil erosion amount. TLS was better suited for monitoring the areas with moderate erosion intensity or higher, as well as the areas with significant erosion over time. Ground cover conditions not only influenced the intensity of soil erosion and surface roughness, but also caused point cloud filtering and spatial interpolation errors, which affecting TLS recognition minLOD and soil erosion monitoring accuracy. This study can provide reference for TLS monitoring of soil erosion in the wild under complicated surface conditions.