Cyanobacteria blooms are recurrent in the Baltic Sea with increasing frequency and intensity, but their accurate quantification through satellite imagery is challenged by many factors, including satellite coarse spatial resolution, atmospheric correction issues, cyanobacteria irregular vertical and horizontal spatial distribution. This study investigates the temporal evolution of the in situ remote sensing reflectance RRS during these blooms, benefitting from multispectral measurements from the Ocean Colour component of the Aerosol Robotic Network (AERONET-OC). Spectral features that may show potential to identify cyanobacteria and their development stages are investigated. The capability and uncertainties in reproducing these features by the Ocean Colour products of Copernicus Sentinel-3 Ocean and Land Colour Instrument (OLCI) are also assessed. Satellite derived RRS values are compared to AERONET-OC radiometric data, showing high uncertainties particularly pronounced at the blue centre-wavelengths. On the other hand, band-differences in the green-red spectral region exhibit less dependence on atmospheric correction issues with mean absolute relative differences comprised between 8.3% and 9.6%, when considering data affected by the presence of cyanobacteria. A first comparison with in situ data of phytoplankton biovolume shows the potential for these band differences to identify cyanobacteria near-surface presence also at lower concentrations respect to other existing algorithms, being at the same time not sensitive to algal blooms usually occurring in spring.
Primary Presenter: Ilaria Cazzaniga, Joint Research Centre - European Commission (ilaria.cazzaniga@ec.europa.eu)
Authors:
Ilaria Cazzaniga, European Commission - Joint Research Centre (Ilaria.Cazzaniga@ec.europa.eu)
Giuseppe Zibordi, European Commission - Joint Research Centre (giuseppe.zibordi@eoscience.eu)
Frédéric Mélin, European Commission - Joint Research Centre (Frederic.Melin@ec.europa.eu)
IN SITU AND SATELLITE-DERIVED RADIOMETRIC SPECTRAL FEATURES OF CYANOBACTERIA BLOOMS IN THE BALTIC SEA
Category
Scientific Sessions > SS102 Inland and Coastal Aquatic Ecosystems Monitoring from In Situ and Satellite Radiometric Measurements
Description
Time: 11:00 AM
Date: 9/6/2023
Room: Sala Menorca A