A Three-Component Model of Ocean Color and Its Application in the Ebro River Mouth Area

A three-component reflectance model that takes into account the contributions of dissolved organic matter, phytoplankton, and mineral particles is described. The principle of inversion of the model, in terms of chlorophyll a plus phaeopigments concentration, chl, sediment refractive index, mr, and absorption coefficient of yellow substance at 440 nm, ay(440), is exposed. The inversion procedure is applied to experimental data collected in the Ebro river plume area. The obtained estimates of chl are accurate only in order of magnitude. However, we demonstrate that mr and ay(440) determinations are robust against chl variations within −50%, +100% of experimental values. Investigation of possible variations with wavelength of mr, using measured concentrations and ay(440) estimates, evidences a slight dependency as was previously observed. We support in conclusion that the inversion procedure could be exploited in a two-step process. First ay(440) and the mean value of mr are estimated from measured water quality parameters. Then mr is calculated at each wavelength, considering ay(440) value determined in the first step.