An application of C2-Net atmospheric corrections for chlorophyll-a estimation in small reservoirs

This study assesses Sentinel 2 remote sensing data for estimating chlorophyll-a concentrations in 32 small reservoirs located in the Spanish region of Extremadura. The atmospheric correction algorithms C2RCC, C2X, and C2XC were used to obtain chlorophyll-a estimations. In-situ measurements of chlorophyll-a were collected from ninety-four water samples in the study area, and their values were used to validate the satellite-derived estimates. The results showed that the C2RCC atmospheric correction algorithm outperformed the other two algorithms, with a Mean Absolute Average Error (MAAE) of 4.79 mg/m(3) for non-hypertrophic reservoirs. C2X and C2XC algorithm performed inaccurately, with extreme RMSE and MAAE values. Spearman correlation coefficients are good for the three methods applied. The findings could be of interest to regional water management authorities and researchers in monitoring water quality in small reservoirs.