Optical properties of the Eastern Mediterranean Sea

The ocean's turbidity and optical properties are determined by the interaction of sunlight radiation with suspended particles and dissolved matter of the water body's surface layers. Variations in the optical properties can affect the upper ocean's heat content, thus modifying the stratification and the mixed layer dynamics. These variations can be monitored using satellite products, along with in-situ observations, and their impact on ocean circulation can be analyzed through numerical modeling. For the oligotrophic Eastern Mediterranean, there is a gap of in-situ data used to evaluate remote sensing observations. Furthermore, this region receives significant atmospheric deposition of particulate inorganic matter through African dust, as well as from river discharges. These constituents' contribution in optical properties modulation is often considered negligible for oligotrophic regions, where the various parameters have been calculated based on chlorophyll variations. To fill this gap, in situ measurements of beam attenuation coefficient at 660 nm (c, in m^-1)⁽¹⁾ provided by the Hellenic Centre for Marine Research (HCMR) were assessed, and a gridded dataset was constructed using Data-Interpolating Variational Analysis (DIVA), for the Aegean Sea, Eastern Mediterranean, for the years 1991-2019. The aim is to validate the accuracy of satellite products for this region using this dataset. Towards this goal, available satellite ocean color products of the ocean's inherent optical properties will be used to estimate c values, which will be compared to the in-situ dataset.

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