par Astoreca, Rosa ;Rousseau, Véronique ;Ruddick, Kevin;Parent, Jean-Yves ;Van Mol, Barbara;Lancelot, Christiane
Référence XVIII Ocean Optics Conference(9-13 October 2006: Montréal, QC, Canada), Proceedings Ocean Optics XVIII Conference, October 9-13, Montreal, Quebec
Publication Publié, 2006
Publication dans des actes
Résumé : Detecting phytoplankton species from space is a challenge particularly relevant for mapping undesirable algal blooms in eutrophicated coastal waters. Such is the case in the Southern Bight of the North Sea, where high concentrations of chlorophyll-a corresponding to blooms of the colonial haptophyte Phaeocystis globosa and diatoms have been reported. Laboratory studies on pure cultures show clear differences between the absorption spectra of diatoms and Phaeocystis globosa. However, it is not clear if these groups can be discriminated from space based on remote sensing reflectance data in these turbid waters where other components of the water (CDOM, suspended matter) are contributing largely to the total absorption, especially in the blue part of the spectrum. In order to find differences in the absorption signature that could be extrapolated to the reflectance, we analysed a large dataset of absorption and water-leaving reflectance measurements performed in the Belgian Coastal water of the Southern Bight of the North Sea. These spectra were compared to those of pure cultures of the main blooming species and related to the phytoplankton community composition. The water-leaving reflectance spectra were further explored to see the change in response to total absorption spectrum variability of diatom or Phaeocystis dominated conditions. An algorithm based on these changes was proposed to detect the presence of the chlorophyll-c3 absorption feature at 467 nm. Finally, the possibility of extrapolating this information to satellite data was evaluated.

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