Evaluation of high resolution remote sensing reflectance products in European lakes

Sentinel-2/MSI (S2-MSI) is mainly designed to provide information on land surfaces for applications in agriculture, forestry, mapping, global change research, etc. However, its performance in terms of signal-to-noise ratio (SNR) is sufficient to be used for water quality monitoring, especially in coastal and inland waters. Compared to mainstream ocean colour sensors (MODIS-AQUA, VIIRS and Sentinel-3/OLCI), S2-MSI offers great advantages in terms of spatial resolution enabling the development of the new generation of inland water quality products. Monitoring of water quality by satellite requires high quality atmospheric correction to separate the aerosol and marine contributions to the top of atmosphere radiance observed by the satellites. Determination of the aquatic part of the observed signal, i.e. the normalized water-leaving radiance (Lwn), is crucial as this parameter is the basis of all derived aquatic parameters, including total suspended matter (TSM) and chlorophyll a (CHL-a). The radiometric validation of S2-MSI data is presented here with a focus on European lakes including Lake Balaton, Lake Mantua, Lake Garda, Lake Geneva, Curonian Lagoon and Lake Marken. An intercomparison is performed between different atmospheric correction procedures: (i) ACOLITE, (ii) iCOR, (iii) 6SV, (iv) Sen2Cor and (v) ATCOR. Their performance is validated with in-situ reflectance data collected within the FP7-INFORM project.