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 contributio ns of dissolved organic matter, phytoplankton, and mineral particles is des cribed. The principle of inversion of the model, in terms of chlorophyll a plus phaeopigments concentration, chl, sediment refractive index, m(r), and absorption coefficient of yellow substance at 440 nm, a(y)(440), is expose d. 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 the m(r) and a(y)(440) determin ations are robust against chl variations within -50%, +100% of experimental values. Investigation of possible variations with wavelength of m(r), usin g measured concentrations and a(y)(440) estimates, evidences a slight depen dency as was previously observed. We support in conclusion that the inversi on procedure could be exploited in a two-step process. First a(y)(440) and the mean value of m(r) are estimated from measured water quality parameters . The m(r) is calculated at each wavelength considering a(y)(440) value det ermined in the first step. (C) Elsevier Science Inc., 2000.