Mapping phytoplankton fluorescence properties with hyperspectral EnMAP data

Kurzfassung

Phytoplankton exhibits a characteristic fluorescence peak near 685 nm with a full width at half maximum of approximately 25 nm. At high concentrations, the emission wavelength (λₑ) may shift toward longer wavelengths due to reabsorption effects. The fluorescence quantum yield (Φ), defined as the ratio of emitted to absorbed photons within the 400–700 nm spectral range, quantifies the efficiency of photosynthesis and serves as a key indicator of light stress and nutrient limitation in primary production. We present a method to retrieve Φ and λₑ from hyperspectral measurements using inverse modeling. This approach has been implemented in the software WASI. Initial results demonstrate the capability to map Φ and λₑ, alongside phytoplankton composition and concentration, using hyperspectral data from the EnMAP sensor under conditions of high chlorophyll-a concentrations.