Evaluation of Acolite Software for Atmospheric and Glint Correction in Sentinel-2 Imagery: Implications for Algae Bloom Monitoring in Eutrophic Reservoirs

The high biomass productivity recorded in eutrophic waters leads to qualitative and quantitative changes in the phytoplankton community, resulting in massive algal blooms. This study evaluates the use of Acolite software on Sentinel-2 (S2) imagery for atmospheric and glint correction and its implications for monitoring algal blooms in a eutrophic reservoir. We analyse two dates comparing the corrected reflectance with the field reflectance data and find that glint correction improves the results in one but has the opposite effect in another. By analysing the spectra of the image, we can identify algal scum as a problem for this correction and propose to use the Floating Algae Index to to flag as suspected floating algae and in consequence not correct that pixel for remnant sunglint.