Reflectance sensitivity to solid suspended sediment stratification in coastal water and inversion: A case study

A two-flow radiative transfer model is used to study the sensitivity of spectral reflectance to variations of solid suspended matter (SSM) concentration with depth. Examples are given of the variations of reflectance spectra with depth profiles of SSM. We developed an inversion method for the model restricted to the simple case of a two-layer ocean. The method was tested on various documented experimental data. A majority of stratified cases were detected by the method. Reasonably good estimates of the mean sediment concentration of the upper layer were obtained. Only the order of magnitude of the thickness of the upper layer and the mean concentration of the lower layer were recovered. The influence of chlorophyll (CHL) concentration profile on reflectance spectra was found to be weak for such high SSM concentrations. Our inverse algorithm, of low computational cost, could be envisaged in a remote-sensing perspective provided complementary studies.