Correspondence between in-situ derived water reflectances from Río de la Plata and Kubelka-Munk model in the RED/NIR/SWIR range

GOSSN, J.I; DOGLIOTTI, A.I.

Conferencia; HIGHROC Science Conference; 2017

In previous studies, suchas in Shen et al. 2010, water reflectance is modelled as a function of IOPs via the Kubelka-Munkapproximation of the Equation of Radiative Transfer. In this work, a total of133 reflectance measurements (103 ASD, 30 RAMSES/Trios) in turbid waters of Ríode la Plata were fitted via a simulated annealing optimization algorithm to aKubelka-Munk theoretical expression of reflectance, in the spectral range600-1000 nm, in which only the presence of non-algal particles (and watermolecules) was considered. Two distinct RMSEs were used as cost functions inthe simulated annealing optimization procedure: one calculated in hyperspectralmode, in the range 600-1000 nm (with the exception of the spectral rangecentered at the chlorophyll peak absorption at 670 nm) to check the globalgoodness of the model, and one computing difference between ​ in situ andmodelled "baseline residuals", defined as the reflectance peak afterbaseline subtraction of three consecutive triplets of the S3/OLCI bandscentered at 620-709-779-865-1016 nm. This last cost function was evaluated tounderstand if these three "baseline-residuals" are potentiallysuitable and provide enough information to retrieve (highly scattering) waterreflectances in the aforementioned OLCI bands without the​ need​ of​ prior​ atmospheric​ signal​ removal, via the​ Kubelka-Munk​ reflectance​ model.