Remote Sensing Of The Ocean Surface Refractive Index From Polarimetric Observations of the PACE sensors

The Fresnel laws of specular reflection directly connect remote sensing observations of light polarization within the sunglint region to the ocean surface refractive index. This parameter is instrumental to identify areas affected by oil, whose operational detection is a primary goal of this work, or any other floating substance capable of modifying the refractive index of pure seawater. With suitable polarimeters finally scheduled for launch onboard the PACE mission, we examine several aspects linked to the application of this retrieval strategy to HARP-2 and SPEXone. The method was devised based on observations available from the NASA GISS Research Scanning Polarimeter, which offers superior performance in terms of observational wavelengths, angular sampling, and polarimetric accuracy. We are therefore particularly interested in quantifying the degradation in retrieval accuracy expected for the PACE sensors due to their more limited capabilities. We will also analyze the contributions to the satellite-measured signal of sunglint and water-leaving radiances across the spectrum, useful to potentially extend the method to visible wavelengths where atmospheric scattering is significant.