Posters

Poster Session 4, Thursday, October  6, 11:00–12:40

Poster 20

BRDF correction of S3 OLCI water reflectance products

Within the ocean color program of EUMETSAT, this study investigates correction methods to minimize the effects of the Bidirectional Reflectance Distribution Function (BRDF) on Copernicus Sentinel-3 OLCI data. For any sun-viewing geometry, the goal is to compute the fully normalized water reflectance, resulting from the same Inherent Optical Properties (IOPs), but with the sun located at the zenith and the sensor looking towards nadir. By doing so, the dependence of the satellite-measured reflectances on any factor that is not the IOPs is minimized. The BRDF corrections included in the study are those proposed by Morel et al. 2002, Park and Ruddick 2005, Lee et al. 2011, He et al. 2017, and Twardowski and Tonizzo 2018. With specific reference to this latter scheme, the developments account for the OLCI viewing geometry and the application in turbid waters. Performance and validity ranges of the BRDF corrections are examined with both simulated and field data, and advantages and drawbacks of each approach are discussed. The analysis also benefits from the definition of a common set of input parameters derived from IOPs in terms of single versus multiple scattering, and pure seawater versus particles scattering. The BRDF-correction schemes are then implemented as modular components of the OLCI L2 processor, and their operational results are assessed based on match-ups with in-situ measurements, Fourier analysis, as well as OLCI-A and B tandem observations. The input/output interface is designed for independent applications, such as the inclusion of the BRDF-correction schemes in the in-situ community processor. 

Davide D’Alimonte, AEQUORA, [email protected], 0000-0001-7217-7057 

Tamito Kajiyama, Aequora, [email protected], 0000-0002-3148-9705

Marco Talone, ICM, Barcelona, Spain, [email protected] 

Jaime Pitarch Portero, CNR ISMAR, Roma, Italy, [email protected]

Vittorio Brando, CNR ISMAR, Roma, Italy, [email protected] 

Constant Mazeran, SOLVO, Antibes, France, [email protected] 

Michael Twardowski, FAU, Florida, USA, [email protected] 

Srinivas Kolluru, FAU, Florida, USA, [email protected] 

Alberto Tonizzo, AWF Consulting, Florida, USA, [email protected] 

Ewa Kwiatkowska, EUMETSAT, Darmstadt, Germany, [email protected], 0000-0003-1602-5301

David Dessailly, EUMETSAT, Darmstadt, Germany, [email protected] 

Juan Ignacio Gossn, EUMETSAT, Darmstadt, Germany, [email protected], 0000-0001-9277-6882