Characterization of the Fluorescence Peak on Remote Sensing Reflectance For Different Conditions of Lakegarda

The presence of phytoplankton in the oceans and freshwaters basins provides relevant ecological indications about water quality. Its abundance influences the interaction between the solar light and the water body, which in turn can be detected by remote sensing techniques. The water leaving light field contains information about all the processes that occur in the water body itself, including the complex interactions with phytoplankton. While elastic scattering is mostly ascribed to the phytoplankton surface, the absorption and fluorescence processes occur at the chlorophyll-a molecules level. Thus, measurements of the fluorescence signal emitted represents a suitable proxy to identify phytoplankton abundance in inland waters. In this context, the aim of this work is to establish and quantify how the fluorescence signal affects the Remote Sensing Reflectance (Rrs). For this purpose, radiative transfer simulations computed by Hydrolight code were generated for various levels of chlorophyll content, fluorescence quantum yield and optical properties, typical of a clear blue lake (Lake Garda, Italy). This work would form the basis for better exploiting satellite observations from upcoming hyperspectral missions (FLEX, PRISMA, Sentinel-10, HyspIRI).