Evaluation of SENTINEL-2 products-based algorithms in estimating water pollutants of the River Niger in Bamako

Abstract

Monitoring surface water quality on a spatio-temporal scale is of paramount importance. Several algorithms have been calibrated and validated using satellite observations to assess pollutants in surface waters in many localities worldwide. This study assessed the potential of sentinel-2 data to estimate the spatiotemporal distribution of chlorophyll-a, organic matter, and total suspended matter in the water of the Niger River in Bamako. Among the Sentinel-2 bands containing the spectral signatures of the considered pollutants, three spectral indices (based on the ratio of the characteristic band reflectance) were selected from the literature. Multivariate analysis was then used to set_up Algorithms between these indices and the in-situ measured concentrations. The most optimal index was thus identified and applied to assess the spatio-temporal distribution of water pollutants in the Niger River in Bamako and its surroundings. The results of this study showed seasonal variability in the water pollutants in the Niger River. This highlights the potential of Sentinel-2 products for water quality analysis.