CCZO -- LiDAR -- LiDAR features for the Calhoun CZO forest plots -- Calhoun CZO -- (2015-2015)

Dataset includes LiDAR features for 35 forest plots located at the Calhoun CZO. Both LiDAR data acquisition and field measurements using LAI-2000 (LI-COR, 1992) were performed during summer 2014. LAI-2000 is an optical device used to estimate Leaf Area Index (LAI, hemisurface area of foliage per unit horizontal ground surface area) and canopy gap fraction at five zenith angles. The LiDAR data were processed to match with the LAI-2000 measurements, and thus LiDAR returns arriving at angles more than 15 degrees were excluded before any calculations were performed.

Processing chain of LiDAR data included: 1) merging .las files which have forest plots near the edges, 2) calculating the ground surface, 3) removing noise, 4) removing duplicates, 5) extracting returns for the forest plots using a 15-m circle, 6) excluding returns arriving at an angle bigger than ±15 degrees, 7) calculation of return heights, 8) classifying returns to ground and vegetation based on return heights (limit set to 1.37-m), 9) calculation of LiDAR features for all forest plots.

The LiDAR features provided in this dataset are updated version of those presented earlier by Majasalmi et al. (2015).

References:

Majasalmi, T., Palmroth, S., Cook, W., Brecheisen, Z., Richter, D. (2015): Estimation of LAI, fPAR and AGB based on data from Landsat 8 and LiDAR at the Calhoun CZO. Calhoun CZO 2015 Summer Science Meeting. http://criticalzone.org/calhoun/publications/pub/majasalmi-et-al-2015-estimation-of-lai-fpar-and-agb-based-on-data-from-land/

LI-COR, 1992. LAI-2000 Plant Canopy Analyzer, Instruction manual. ftp://ftp.licor.com/perm/env/LAI-2000/Manual/LAI-2000_Manual.pdf

本数据集收录了位于Calhoun CZO的35个森林样地中的激光雷达特征。激光雷达数据的采集与使用LAI-2000（LI-COR，1992年）进行的实地测量均在2014年夏季进行。LAI-2000是一种光学设备，用于估算叶面积指数（LAI，单位水平地表面积的叶冠半球面积）以及冠层间隙分数，测量角度为五个顶角。激光雷达数据经过处理以与LAI-2000测量值相匹配，因此在任何计算之前，排除角度超过15度的激光雷达回波。激光雷达数据处理流程包括：1）合并边缘附近的森林样地.las文件，2）计算地表，3）去除噪声，4）去除重复数据，5）使用15米圆圈提取森林样地的回波，6）排除角度大于±15度的回波，7）计算回波高度，8）根据回波高度将回波分类为地面和植被（限制设置为1.37米），9）计算所有森林样地的激光雷达特征。本数据集中的激光雷达特征为Majasalmi等（2015年）先前呈现版本的更新版。参考文献：Majasalmi, T., Palmroth, S., Cook, W., Brecheisen, Z., Richter, D. (2015): 基于Calhoun CZO的Landsat 8和激光雷达数据的LAI、fPAR和AGB估算。Calhoun CZO 2015年夏季科学会议。http://criticalzone.org/calhoun/publications/pub/majasalmi-et-al-2015-estimation-of-lai-fpar-and-agb-based-on-data-from-land/。LI-COR, 1992. LAI-2000植物冠层分析仪，用户手册。ftp://ftp.licor.com/perm/env/LAI-2000/Manual/LAI-2000_Manual.pdf