FRM4SOC Phase-2 Radiometric Field Inter-Comparison (FICE) at the Acqua Alta Oceanographic Tower (AAOT)

Venice, Italy
10 – 20 July 2022


Test the methods, guidelines, community processor, and databases developed in the FRM4SOC phase-2The AAOT tower project. Also to assess differences in radiometric quantities (Ed, Li, Lt, Rrs and Lw) determined under the same calibration and environmental conditions by the FICE-AAOT participants using a range of above-water and in-water radiometric systems (including automated systems such as sun-tracker, floating profiler) and their own processing chain and a community processor that is being developed in the project.


Acqua Alta Oceanographic Tower (AAOT), Venice, Italy.


The AAOT platform has a long history of optical measurements to support and validate both NASA and European Space Agency (ESA) ocean colour missions [Zibordi et al. 2004, 2006, 2009a, b]. An autonomous optical measurement system was developed at the tower in 2002, which data has been widely used by the ocean colour community for satellite validation via the AERONET-OC network [Zibordi et al. 2002, 2009b]. Easy access to infrastructure; daily rent also includes the use of boats for in-water deployments. Previous radiometric field inter-comparisons, financed by ESA, have been conducted at the AAOT for Envisat MERIS [Zibordi et al. 2012] and Sentinel-3 OLCI [Tilstone et al. 2020].

Water type

Optical Case 1 (clear open sea waters) for 60% of the year [Zibordi et al. 2009b]; 40% optical Case 2 (turbid coastal) depending on wind direction and swell.

Experimental design

Above- and in-water systems will be used.
Above water: TriOS RAMSES; Seabird HyperSAS; SunTracker systems PANTHYR, SoRAD, HYPSTAR, HyperSAS pySAS robot.
In-water: TriOS RAMSES floating buoy, Seabird floating radiometer HyperOCR, HyperPRO II free-falling optical profiler


Gavin Tilstone, PML


Tilstone, G.; Dall’Olmo, G.; Hieronymi, M.; Ruddick, K.; Beck, M.; Ligi, M.; Costa, M.; D’Alimonte, D.; Vellucci, V.; Vansteenwegen, D.; Bracher, A.; Wiegmann, S.; Kuusk, J.; Vabson, V.; Ansko, I.; Vendt, R.; Donlon, C.; Casal, T. Field Intercomparison of Radiometer Measurements for Ocean Colour Validation. Remote Sens. 2020, 12, 1587.

Zibordi, G.; D’Alimonte, D.; Berthon, J.-F. An evaluation of depth resolution requirements for optical profiling in coastal waters. J. Atmos. Ocean. Tech. 2004, 21, 1059–1073.

Zibordi, G., Melin, F., Berthon, J.-F. Comparison of SeaWiFS, MODIS and MERIS radiometric products at a coastal site. Geophys. Res. Lett. 2006, 33, L06617.

Zibordi, G.; Berthon, J.-F.; Mélin, F.; D’Alimonte, D.; Kaitala, S. Validation of satellite ocean color primary products at optically complex coastal sites: Northern Adriatic Sea, Northern Baltic Proper and Gulf of Finland. Remote Sens. Environ. 2009, 113, 2574–2591.

Zibordi, G.; Mélin, F.; Berthon, J.; Holben, B.; Slutsker, I.; Giles, D.; D’Alimonte, D.; Vandemark, D.; Feng, H.; Schuster, G. AERONET-OC: A Network for the Validation of Ocean Color Primary Products. J. Atmos. Ocean. Tech. 2009, 26, 1634–1651.

Zibordi, G.; Hooker, S.B.; Berthon, J.-F.; D’Alimonte, D. Autonomous above–water radiance measurement from an offshore platform: A. field assessment. J. Atmos. Ocean. Tech. 2002, 19, 808–819.

Zibordi, G., Ruddick, K., Ansko, I., Moore, G., Kratzer, S., Icely, J. and Reinart, A. In situ determination of the remote sensing reflectance: an inter-comparison. Ocean Science 2012, 8 (4), 567–586.