Spectral characterization of ocean color images during phytoplankton blooms at Lagoa dos Patos

Patos Lagoon (PL) is one of the optical complex environment best studied in Brazil, and it large spatial extent, allows the union of different in situ and remote sensing measures, enabling a better understandment of how the optical components in water can influence its color. Phytoplankton blooms have great ecological and economic relevance, and the development of simple methodologies for your monitoring of vital importance. The present work used ocean color products from daily MODIS/Aqua and SeaWiFS images during the years 2002-2005, meteorological model data for precipitation and wind speed and chlorophyll-a and sailinity data obtained in situ. It was detected that remote sensing reflectance spectra is controlled by the regime of El Niño and La Niña, intra annual and spatial changes (p<0.05), ande the water color from PL in general, characteristic of environments with high CDOM/sediments concentration or with mixed domain. Assuming that the phytoplankton dominate light absorption coefficient during phytoplankton blooms, and that PL possible blooms are restricted to diatom and cyanobacteria, a classification model was developed to discriminate the occurance of those events. The proposed model allows for the classification of optically complex waters according to the predominant optical component, and it is pioneer in the exploration of data from MODIS/Aqua sensor to detect phytoplankton blooms in lagunar environment (AU)