Retrieving quantum yield of sun-induced chlorophyll fluorescence near surface from hyperspectral in-situ measurement in productive water

Magnitude and quantum yield (η) of sun induced chlorophyll fluorescence are determined in widely varying productive waters with chlorophyll concentrations from 2- 200 mg/m³. Fluorescence was estimated using linear fitting of in-situ measured surface reflectance with elastic and inelastic reflectance spectra. Elastic reflectance spectra were obtained from Hydrolight simulations with measured absorption and attenuation spectra as inputs. η is then computed based on a depth integrated fluorescence model and compared with Hydrolight calculation results. Despite the large variability of coastal environments examined the η values are found to vary over a relatively narrow range 0.1%-1% with mean values of 0.33%±0.17%.