Spatial variability of Inherent Optical Properties in the perialpine lakes

Accurate estimation of biogeochemical substances from remote observations requires knowledge of Inherent Optical Properties (IOPs) and their mass specific representation (SIOPs). Corresponding measurements are rather scarce for perialpine lakes, which represent distinctively different optical properties than high latitude or low elevation inland waters. The aim of our research is (i) to document the IOPs and SIOPs variability in the perialpine region, (ii) to investigate how IOPs relate to the water constituents’ bio-chemical properties; (iii) to demonstrate the applicability of empirical and/or semi-analytical relationships that used Rrs to predict OACs and IOPs. We collected an extensive bio-optical dataset to determine the special variability of IOPs in perialpine lakes. In this study we focused on 76 measurements conducted in 5 lakes (L. Geneva, L. Biel, L. Greifen, L. Brienz and L. Morat). The lakes span from oligotrophic to mesotrophic waters which are common situations in this region. L. Brienz is a very bright lake due to its waters dominated by fine mineral particles limiting the light availability for biological organism to grow. Comparatively, all other lakes are dominated by green algae with highest concentrations in L Greifen and L Morat. L Biel is similar to L. Geneva with clear waters and occasional phytoplankton blooms. The documentation of IOPs and SIOPs in the perialpine region will advance our understanding of optically complex waters and support the development of remote sensing algorithm of Case-2 waters for sensors like OLCI (ESA) on Sentinel-3