A Couple Surface-atmosphere Model to Perform Radiometric Intercomparison of Optical Sensors over Libya-4
A Monte Carlo vector radiative transfer model interfacing a fixed plane parallel atmosphere and a modified Rahman-Pinty-Verstraete BRDF model with 4 free parameters is used to simulate top-of-atmosphere reflectance time series over the so-called Libya-4 site. First, the 4 free parameters of the BRDF model are inverted against MERIS observations covering the 2006-2009 period in 15 spectral bands. These surface parameters are then spectrally interpolated and used as input to the radiative transfer model to allow simulation of top-of-atmosphere reflectance time series of any sensor with spectral responses in the MERIS spectral range. ATSR-2, AATSR, MODIS-A, MERIS 2nd reprocessing, Proba-V and VEGETATION-2 data are radiometrically intercompared. Application of this model to Sentinel-2 / MSI and Sentinel-3 / OCLCI is discussed.