Polarimetric Imaging of the Ocean Surface for Satellite-Based Ocean Color Applications

The degree of linear polarization of above-water radiance contains information on the attenuation-to-absorption ratio in the surface layer of the ocean. With additional inversion algorithms to retrieve size distribution, backscattering ratio and bulk refractive index of marine particle populations, polarization is thus an important component in the retrieval of optical and microphysical properties in the ocean. Accordingly, in preparation of the upcoming PACE mission, we used an artificial dataset of water IOPs and atmospheric properties in conjunction with radiative transfer simulations to explore the potential of a neural network approach for systematic conversion of top-of-atmosphere polarization values first into abovewater polarization, then finally into an estimation of local optical and microphysical properties. Additionally, we used polarization images acquired in situ during a cruise in the Gulf of Mexico to study wave slope statistics as derived from a modified polarimetric slope sensing technique and found them to compare well with the classic wave slope variances of Cox and Munk.