Continuous canopy and understory spectral reflectance measurements of a sparse black spruce forest at Poker Flat Research Range (PFRR), interior Alaska (Year 2024)

Plant phenology timings, such as spring green-up and autumn senescence, are essential state information characterizing biological responses and terrestrial carbon cycles. Current efforts for the in-situ reflectance measurements are not enough to obtain the exact interpretation of how seasonal spectral signature responds to phenological stages in boreal evergreen needleleaf forests. This data set shows the in situ continuous measurements of spectral reflectance in a boreal forest in interior Alaska. We deployed two field-based spectroradiometer systems in an open black spruce forest. These two spectroradiometer systems were used to obtain canopy scale (overstory + understory) and understory reflectances. The data set includes the overstory and understory incoming and reflected hemispherical spectral irradiance data (Level 1), and spectral reflectance computed by the in- and out-going spectral data (Level 2). Because the reflected hemispherical irradiance contains the reflection from tower structure for overstory measurements. The further reflectance correction was applied for the measurements at the tower top level (Level 3).

植物物候时间（如春季返青与秋季衰老）是表征生物响应及陆地碳循环的关键状态信息。目前原位反射率测量的研究力度尚不足以准确阐释北方常绿针叶林的季节光谱特征如何响应物候阶段。本数据集呈现了阿拉斯加内陆一处北方森林的原位连续光谱反射率测量结果。我们在一片开阔黑云杉林中部署了两套野外光谱辐射计系统，用于获取冠层尺度（上层植被+下层植被）及下层植被的反射率数据。数据集包含上层与下层植被的入射及反射半球光谱辐照度数据（Level 1），以及通过入射与出射光谱数据计算得到的光谱反射率（Level 2）。由于上层植被测量的反射半球辐照度包含塔架结构的反射信号，因此对塔顶层级的测量数据进行了进一步反射率校正（Level 3）。