Size discrimination of inorganic suspended particles based on the analysis of hyperspectral attenuation measurements

Abstract

A method is described for discriminating the size of inorganic suspended particles based on hyperspectral attenuation spectra. In this study, the beam attenuation spectra of different samples with different suspended sediment sizes (i.e., from mud, <5 μm, to fine sand, 125-250 μm), were measured in the laboratory using a hyperspectral attenuation meter (VIPER instrument with a 5 cm path length and 1.7 nm spectral resolution). In order to classify the measured spectra according to their relative similarity, a hierarchical cluster analysis has been applied and the results have been represented in a Multi-dimensional scaling graphic. Our results show that the changes in the attenuation spectral signature are according to the particle size. The applied methodology clearly allows discriminating samples with different particle size ranges. The hyperspectral attenuation meter can therefore be considered a powerful instrument for these purposes, because of the high spectral resolution and relative lower cost compared to other commercial instruments. Furthermore, it is possible to design hyperspectral attenuation meters with smaller size and relatively low-consumption that could be incorporated into different observing autonomous platforms, such as gliders, profilers and autonomous underwater vehicles