SIF and Vegetation Indices in the US Midwestern Agroecosystems, 2016-2021

This dataset contains half-hourly ground solar-induced chlorophyll fluorescence (SIF) and vegetation indices including NDVI, EVI, Red edge chlorophyll index, green chlorophyll index, and photochemical reflectance index at seven crop sites in Nebraska and Illinois for the period 2016-2021. Four sites were located at Eddy Covariance (EC) tower sites (sites US-Ne2, US-Ne3, US-UiB, and US-UiC), and three sites were located on private farms (sites Reifsteck, Rund, and Reinhart). The sites were either miscanthus, corn-soybean rotation or corn-corn-soybean rotation. The spectral data for SIF retrieval and hyperspectral reflectance for vegetation index calculation were collected by the FluoSpec2 system, installed near planting, and uninstalled after harvest to collect whole growing-season data. Raw nadir SIF at 760 nm from different algorithms (sFLD, 3FLD, iFLD, SFM) are included. SFM_nonlinear and SFM_linear represent the Spectral fitting method (SFM) with the assumption that fluorescence and reflectance change with wavelength non-linearly and linearly, respectively. Additional data include two SIF correction factors including calibration coefficient adjustment factor (f_cal_corr_QEPRO) and upscaling nadir SIF to eddy covariance footprint factor (ratio_EC footprint, SIF pixel), and measured FPAR from quantum sensors and Rededge NDVI calculated FPAR. The data are provided in comma-separated values (CSV) format.

本数据集收录了2016年至2021年间，内布拉斯加州和伊利诺伊州七个作物种植点的半小时地面太阳诱导叶绿素荧光（SIF）及其植被指数，包括NDVI、EVI、红边叶绿素指数、绿色叶绿素指数以及光合反射率指数。其中四个地点位于爱迪共变（EC）塔站点（站点编号US-Ne2、US-Ne3、US-UiB和US-UiC），另外三个地点位于私人农场（站点编号Reifsteck、Rund和Reinhart）。这些地点的作物种植类型包括Miscanthus、玉米-大豆轮作或玉米-玉米-大豆轮作。SIF检索和植被指数计算所需的超光谱反射率数据由FluoSpec2系统收集，该系统在播种前安装，收获后拆卸，以收集整个生长季节的数据。数据中包含了来自不同算法（sFLD、3FLD、iFLD、SFM）的760纳米原始下视SIF。SFM_nonlinear和SFM_linear分别代表假设荧光和反射率随波长非线性（SFM_nonlinear）和线性（SFM_linear）变化的谱拟合方法（SFM）。附加数据包括两个SIF校正因子，即校准系数调整因子（f_cal_corr_QEPRO）和将下视SIF向上扩展至涡度相关足迹因子（比例_EC足迹，SIF像素），以及来自量子传感器的测量FPAR和基于Rededge NDVI计算的FPAR。数据以逗号分隔值（CSV）格式提供。