Variability of bio-optical parameters of the SE Baltic Sea coastal waters based on in situ and satellite data

In our study we present validation activities associated with satellite MERIS image processing aimed at estimating chlorophyll a (chl a), coloured dissolved organic matter (CDOM) and total suspended matter (TSM) in the Lithuanian Baltic Sea coastal waters. Eight MERIS full-resolution Level 1b images, acquired during late spring and summer 2010, were processed using five, neural network-based processors for optically Case 2 coastal and inland waters: FUB, C2R, Eutrophic, Boreal, and standard MERIS Level 2. Results showed that the FUB processor provided the most accurate estimates of the concentration of chl a and TSM. In situ CDOM absorption was most accurately estimated using the Boreal processor. SE Baltic Sea at the Lithuanian coast is connected to the hypereutrophic Curonian Lagoon. The outflow region remains oligohaline with temporary and irregular salinity fluctuations from 0 to 7(8) PSU mainly driven by wind. Over the salinity gradient we observed patchy distribution of optically active constituents that may cause the changes of optical water properties. In order to understand the impact of the lagoon waters outflow to the coastal region on the validation results, during the summer 2012 inherent and apparent optical properties were measured and remote sensing reflectance was analysed over the investigation region.