Since 2021, two autonomous HYPERNETS stations are operated in contrasted French coastal waters: one in the center of the optically complex Berre coastal lagoon by the Mediterranean Sea and one at the mouth of the highly turbid Gironde Estuary along the Atlantic coast. Optimized quality controls have been designed and applied to the hyperspectral radiometric measurements, namely the downwelling irradiance, sky and water radiance signals, recorded following a strict viewing geometry every 15 mn during daytime on the two stations. The resulting water reflectance spectra are proved to be of high quality (e.g., detailed saturations effects at short visible wavelengths, correlation with water turbidity). They allow assessing the performance of different atmospheric (and glint) correction algorithms applied to high (Sentinel2-MSI and Landsat8/9-OLI) and medium (Sentinel3-OLCI and MODIS) spatial resolution satellite data, based on numerous match-ups. A new method is proposed for the inversion of the measured hyperspectral water reflectance signal into concentration of suspended particulate matter (SPM) but also inherent optical properties and associated spectral slopes which contain useful information on SPM size distribution and composition.

Primary Presenter: David Doxaran, CNRS / Sorbonne University (david.doxaran@imev-mer.fr)

Authors:

Alexandre Corizzi, LOV CNRS/SU  (alexandre.corizzi@imev-mer.fr)

Boubaker Elkilani, LOV CNRS/SU  (boubaker.elkilani@imev-mer.fr)

Samuel Martin, LOV CNRS/SU  (samuel.martin@imev-mer.fr)

Constant Mazeran, SOLVO  (constant.mazeran@solvo.fr)

David Doxaran, CNRS  (david.doxaran@imev-mer.fr)