Sentinel-2 low/medium radiometry validation

The third method developed in the frame of the S2RadVal project shall allow to validate Sentinel-2 low/medium radiances which are more subject to instrument response non-linearity. The approach is based on a comparison of Sentinel-2 signal over coastal waters and theoretical TOA signal simulated in the same conditions (geometries, atmosphere, sea surface reflectance). The performance of the method requires to accurately account for sea surface reflectance, the atmospheric effects and select an appropriate radiative transfer model. Several comparisons will be carried out in this context: Normalised water leaving radiance from the AERONET-OC vs. simulated water leaving radiances, 6SV vs. LibRadTran, etc.