Variability of Bio-Optical Parameters in the SE Baltic Sea Coastal Waters
Vaiciute, Diana¹; Bresciani, Mariano²; Matta, Erica²; Braga, Federica³; Bucas, Martynas^1
1Coastal Research and Planning Institute, Klaipeda Univesity, LITHUANIA; ²Optical Remote Sensing Group, CNR-IREA, ITALY; ³Institute of Marine Science, CNR- ISMAR, ITALY

In our study we present validation activities associated with satellite MERIS image processing and aimed at estimating chlorophyll 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 or 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 chlorophyll 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 through the artificially deepened Klaipeda strait. 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 over the salinity gradient. In order to understand the impact of the lagoon waters outflow to the coastal region on the validation results, for the first time in the summer of 2012 over the investigation region inherent and apparent optical properties were measured and remote sensing reflectance was analysed. In our study we present validation activities associated with satellite MERIS image processing and aimed at estimating chlorophyll 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 or 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 chlorophyll 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 through the artificially deepened Klaipeda strait. 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 over the salinity gradient. In order to understand the impact of the lagoon waters outflow to the coastal region on the validation results, for the first time in the summer of 2012 over the investigation region inherent and apparent optical properties were measured and remote sensing reflectance was analysed.