Integrating terrestrial and airborne lidar to calibrate a 3D canopy model of effective leaf area index
Integrating terrestrial and airborne lidar to calibrate a 3D canopy model of effective leaf area index
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DOI：
10.1016/j.rse.2013.05.012
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发表时间：
2013-09-01
影响因子：
13.5
通讯作者：
van Gorsel, Eva
中科院分区：
文献类型：
--
作者：
Hopkinson, Chris;Lovell, Jenny;van Gorsel, Eva
基于针鼠验证仪（EVI）的地面激光扫描（TLS）为校准多程机载激光扫描（ALS）点云分布提供了一种有效、准确的方法，用于绘制澳大利亚新南威尔士Tumbarumba研究基地1公里直径的成熟桉树森林的有效叶面积指数（lae）和叶片剖面。基于图的TLS叶片轮廓被用作训练数据集，用于推导缩放函数，用于从一致的ALS点云校准有效叶面积指数（LAIe）。研究结果表明：a) TLS扫描站11.3 m半径范围内回波总数的平均比例为64%；增加半径降低了由于遮挡的细节水平；b)利用全回报、一次回报和二次回报，TLS层剖面与ALS叶片百分位分布（PD）之间的关系不是线性相关的；c) TLS LAIe profile和ALS PD之间的回归表明，使用5阶多项式对所有收益（r(2) = 0.95）具有更好的对应性；SE = 0.09 m(2) m(-2))，优于准物理Weibull标度函数。将校准程序应用于GIS环境下的ALS数据，以创建半径为500 m的LAIe三维地图。然后，利用这种局部三维lae校准作为计算头顶冠层消光系数参数(k)的基础，从而便于使用比尔-朗伯定律假设将空间lae估计升级到更大的域。(C) 2013爱思唯尔公司版权所有。
Terrestrial laser scanning (TLS) with the Echidna Validation Instrument (EVI) provides an effective and accurate method for calibrating multiple-return airborne laser scanning (ALS) point cloud distributions to map effective leaf area index (LAIe) and foliage profile within a 1-km diameter test site of mature eucalyptus forest at the Tumbarumba research site, New South Wales, Australia. Plot-based TLS foliage profiles are used as training datasets for the derivation of a scaling function applied to calibrate effective leaf area index (LAIe) from a coincident ALS point cloud. The results of this study show that: a) the mean proportion of the total number of returns within 11.3 m radius of the TLS scan station was 64%. Increasing the radius decreased the level of detail due to occlusion; b) the relationship between TLS LAIe profile and ALS foliage percentile distribution (PD) using all, primary and secondary returns are not linearly related; and c) regressions between TLS LAIe profile and ALS PD, demonstrate better correspondence using a 5th order polynomial applied to all returns (r(2) = 0.95; SE = 0.09 m(2) m(-2)) than aquasi-physically-based Weibull scaling function. The calibration routine was applied to ALS data within a GIS environment to create a 500 m radius 3D map of LAIe. This localised 3D calibration of LAIe was then used as the basis to calculate the overhead canopy extinction coefficient parameter (k), and thereby facilitate upscaling of spatial LAIe estimates to larger domains using a Beer Lambert Law assumption. (C) 2013 Elsevier Inc. All rights reserved.