On the impact of alternative processing on AERONET-OC LWN

Accounting for advances in above-water radiometry and aiming at exploring their impact on actual field measurements to better support an informed exploitation in ocean color applications, this study investigated alternative processing solutions for the determination of the normalized water-leaving radiance LWN from the Ocean Color component of the Aerosol Robotic Network (AERONET-OC). The comparison of LWN from collocated above- and in-water reference data for a marine region exhibiting moderately optically complex waters emphasized the importance of applying (i) quality control tests to remove measurement sequences affected by environmental perturbations such as sun glint, (ii) spectral r factors determined accounting for the sole sky-glint contributions, and (iii) water-type specific corrections for bidirectional effects. A significant finding from those analyses was an appreciably better performance of r factors determined neglecting polarization with respect to those accounting for it. The work also revealed that the impact of the alternative processing solutions with respect to the basic AERONET-OC one is particularly significant in regions exhibiting optically complex waters. In specific, the results indicated a general increase of LWN spectral values from a few up to tens of percent for sites characterized by highly absorbing or scattering waters with differences generally enhanced by the application of r factors determined accounting for polarization effects. Overall, these results indicate that the adoption of any alternative method would suggest the need for further comprehensive assessments of above-water radiometry focusing on the impact of polarization effects across diverse optically complex waters and illumination conditions.

ZIBORDI Giuseppe;  D'ALIMONTE Davide;  BULGARELLI Barbara;  KAJIYAMA Tamito;  SLUTSKER Ilya; 

2025-12-19

AMER METEOROLOGICAL SOC

JRC144242

1520-0426 (online),   

https://journals.ametsoc.org/view/journals/atot/42/12/JTECH-D-25-0038.1.xml,    https://publications.jrc.ec.europa.eu/repository/handle/JRC144242,   

10.1175/JTECH-D-25-0038.1 (online),