Visible, Near Infrared, Shortwave Infrared and Thermal Infrared Laboratory Spectra of Samples of Compositionally Variable Dune Fields in the Western United States and Alaska - Sample DS2

This data represents laboratory reflectance and emissivity spectral measurements of dune sand samples collected from a variety of dune types and mineralogical compositions from eight dune field locations in Alaska, Arizona, California, Colorado, Idaho, Nevada and New Mexico (labeled and designated as samples DS-1 through DS-8). Each sample were sieved into various size classes and measured both prior to and after sieving. Visible through Near Infrared through Shortwave Infrared (~0.4 - 2.5 microns) reflectance were measured using an artificial light source attached to an Analytical Spectral Devices (ASD) spectrometer. Hemispherical reflectance measurements spanning Mid-IR wavelengths, including the Thermal Infrared (~2.0 - 15.0 microns), were measured using a Nicolet FTIR spectrometer with a gold integrating sphere attachment. These latter measurements were converted from wavenumber to wavelength, and inverted to measure emissivity. TIR spectral measurements were conducted for most of our eight dune samples prior to sieving and does not include measurements of various size fractions, except for one sample (DS-8). VSWIR reflectance measurements are included for each of the full composite samples prior to sieving, as well as selected size fractions after sieving such as the smallest (e.g. pan fraction) and largest measurable size fractions. This metadata entry describes the CSV spectral files associated with sample DS-2, in particular.

本数据集为实验室获取的沙丘砂样本的反射率与发射率光谱测量数据，样本采集自阿拉斯加州、亚利桑那州、加利福尼亚州、科罗拉多州、爱达荷州、内华达州以及新墨西哥州共8处沙丘场，涵盖多种沙丘类型与矿物组成，样本编号为DS-1至DS-8。所有样本均经过筛分分级处理，并分别在筛分前后开展测量。可见光-近红外至短波红外（~0.4~2.5微米）波段的反射率，通过搭载人工光源的分析光谱设备（Analytical Spectral Devices, ASD）光谱仪完成测量。覆盖中红外波段（含热红外~2.0~15.0微米）的半球反射率测量，则采用搭载金积分球附件的Nicolet FTIR光谱仪完成。该类中红外波段测量数据由波数转换为波长，并通过反演运算得到发射率。热红外（Thermal Infrared, TIR）光谱测量针对本次采集的8个沙丘砂样本中的多数开展，且均为筛分前的样本数据，未包含不同粒径分级的测量结果，仅样本DS-8为例外。可见光-近红外至短波红外（Visible through Near Infrared through Shortwave Infrared, VSWIR）反射率测量数据，涵盖全部筛分前的完整混合样本，以及筛分后选取的典型粒径分级样本，例如最小粒径（如盘留组分）与最大可测量粒径分级样本。本元数据条目专门针对与样本DS-2相关的CSV格式光谱文件进行说明。