Modelling the Particulate Backscattering Coefficients of Turbid and Productive Coastal Waters

An optical model is developed to predict the spectral backscattering coefficients of phytoplankton (bbph(λ)) and non-living particles (bbss(λ)) in turbid and productive coastal waters. This model computes bbph(λ) and bbss(λ) values based on the measured absorption and attenuation coefficients and water constituents’ concentrations. The predicted values are validated with independent in-situ data from four different water types and compared with results from the independent model. The findings revealed that, in sediment-dominated coastal waters, the backscattering coefficient of phytoplankton is relatively smaller than that of non-living particles. In productive waters, the contribution by phytoplankton is significant due to high chlorophyll a concentration and the influence of complex morphology, intracellular structure and composition of phytoplankton. The results further showed that living algal matter in turbid productive waters may have a significant influence on the backscattering process and its spectral dependency which will have important implications for our understanding of the relationship between the backscattering to scattering ratio, particle size distribution and related properties.