Advances in phytoplankton mapping in inland waters using MERIS
Ramón Peña-Martínez(1) , Jose Antonio Domínguez-Gómez(1)
, and Antonio Ruiz-Verdú(1)
Centre for Hydrographic Studies - CEDEX,
Pº Bajo Virgen del Puerto, 3,
We report the results on the validation of models for phytoplankton pigment mapping using MERIS in Spanish inland waters. Validation field campaigns have been carried out in several reservoirs during 2004 and 2005, measuring the concentrations of the two modelled pigments, chlorophyll-a and phycocyanin. The latter is characteristic of cyanobacteria, a group of aquatic organisms of especial relevance in water quality management. Its detection is based on the ratio of MERIS bands 9 and 6 (centred at 620 nm), whereas for chlorophyll-a the ratio of bands 9 and 7 is used. The remote sensing of the pigments allows an estimation of the phytoplankton biomass as well as an approach to its composition.
The validation has been carried out using empirical models, developed from reflectance and pigment data obtained in spanish reservoirs, and semi-empirical models previously validated in other regions. Besides the field data, an important support for validation has been the imagery obtained with the ESA's experimental satellite CHRIS/Proba over Rosarito reservoir (Spain), as well as several airborne campaigns with the CASI-2 and AHS sensors. The accuracy of the different algorithms for pigment detection is analysed, as well as the observed errors in the reflectance retrieval using the current atmospheric correction methods.