Effective snow grain radius (re) is mapped at high resolution using near-infrared hyperspectral imaging (NIR-HSI). The NIR-HSI method can be used to quantify re spatial variability, change in re due to metamorphism, and visualize water percolation in the snowpack. Results are presented for three different laboratory-prepared snow samples (homogeneous, ice lens, fine grains over coarse grains), the sidewalls of which were imaged before and after melt induced by a solar lamp. The spectral reflectance in each ~3 mm pixel was inverted for re using the scaled band area of the ice absorption feature centered at 1030 nm, producing re maps consisting of 54 740 pixels. All snow samples exhibited grain coarsening post-melt as the result of wet snow metamorphism, which is quantified by the change in re distributions from pre- and post-melt images. The NIR-HSI method was compared to re retrievals from a field spectrometer and X-ray computed microtomography (micro-CT), resulting in the spectrometer having the same mean re and micro-CT having 23.9% higher mean re than the hyperspectral imager. As compact hyperspectral imagers become more widely available, this method may be a valuable tool for assessing re spatial variability and snow metamorphism in field and laboratory settings.

中文翻译：

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使用紧凑型高光谱成像仪进行原位有效雪粒尺寸映射

有效雪粒半径（re) 使用近红外高光谱成像 (NIR-HSI) 以高分辨率绘制。NIR-HSI 方法可用于量化re空间变异性，变化re由于变质作用，并可视化积雪中的水渗透。展示了三种不同的实验室制备的雪样（均质、冰透镜、细颗粒超过粗颗粒）的结果，其侧壁在太阳能灯诱导融化之前和之后成像。每个~3 mm像素中的光谱反射率被反转re使用以 1030 nm 为中心的冰吸收特征的缩放带区域，产生re由 54 740 个像素组成的地图。由于湿雪变质作用，所有雪样在融化后都表现出晶粒粗化，这可以通过re熔融前和熔融后图像的分布。NIR-HSI 方法与re从现场光谱仪和 X 射线计算机显微断层扫描 (micro-CT) 中检索，导致光谱仪具有相同的平均值re和显微 CT 的平均值高出 23.9%re比高光谱成像仪。随着紧凑型高光谱成像仪变得越来越广泛，这种方法可能是评估的有价值的工具re野外和实验室环境中的空间变异性和雪变质作用。