Stationary field spectrometer measurements

Processed stationary field spectroscopy measurementes. Time series were collected with solar powered long-term installations (LTI) using the RoX field spectrometer within the frame of the mDRONES4RIVERS project in the years 2019, 2020 and 2021 respectively. Measurement were recorded at the southern tip of the island Nonnenwerth in 2019 and 2020, over a side arm of the Rhine in Emmericher Ward 2019, 2020, 2021 (as Emmerich I) and in a ditch at the side arm in Emmericher Ward 2020 and 2021 (as Emmerich II) in Germany. LTI Nonnenwerth was investigating dewberry (Rubus caesius), LTI Emmerich I was investigating sediment dynamics and mixed pioneering vegetation and LTI Emmerich II was investigating mainly mixed pioneering vegetation. The incoming radiance is measured with optics of hemispherical (~180°) field of view and the reflected radiance with conical (~25°) field of view. Zip repositories contain folders named according to LTI place and year of recording. They include human radable.csv files for raw RoX data, calibrated radiance and reflectance in subfolders named after date of recording, a folder with time-lapse photographs of the footprint (only for Emmerich I and Emmerich II) and an ALL_INDEX file, each. For reflectance and radiance files, the first collumn contains the associated central wavelengths, the first row the time of recording, each subsequent field of the table contains the calibrated radiance (in W m-2 sr-1 nm-1) or reflectance (unitless) values. The ALL_INDEX file contains meta data, computed vegetation indices(VI) and quality flags for the time series.本数据集为经预处理的固定式野外光谱测量数据。时间序列数据由搭载RoX型野外光谱仪的太阳能供电长期监测站（Long-Term Installations, LTI）采集，采集工作分别于2019、2020、2021年在mDRONES4RIVERS项目框架下开展。2019年与2020年，测量点位设于德国农嫩韦特岛（Nonnenwerth）南端；2019、2020、2021年，测量点位设于德国埃默里希沃德的莱茵河支流区域（记为Emmerich I）；2020与2021年，补充测量点位设于埃默里希沃德该支流旁的沟渠区域（记为Emmerich II）。其中，LTI Nonnenwerth用于研究灰毛悬钩子（Rubus caesius），LTI Emmerich I用于研究沉积物动力学与混合先锋植被，LTI Emmerich II则主要针对混合先锋植被开展观测。 入射辐射采用视场角约180°的半球形光学系统进行测量，反射辐射则采用视场角约25°的锥形光学系统测量。压缩包内的文件夹以监测站地点与记录年份命名，每个文件夹下包含按记录日期命名的子文件夹，其内存储有人类可读的.csv格式原始RoX数据、定标后的辐射亮度与反射率文件；另有足迹区域延时摄影照片文件夹（仅Emmerich I与Emmerich II提供），以及各对应项目的ALL_INDEX元数据文件。对于反射率与辐射亮度文件，表格第一列为对应的中心波长，第一行为记录时刻，表格其余字段分别存储定标后的辐射亮度（单位：W·m⁻²·sr⁻¹·nm⁻¹）或无单位的反射率数值。ALL_INDEX文件包含元数据、计算得到的植被指数（Vegetation Index, VI）以及时间序列质量标记。