Specialised research infrastructure supporting Copernicus satellite ocean colour validation activities through the provision of highly accurate in situ reference measurements such as: spectral water-leaving radiance and remote sensing reflectance; seawater absorption, scattering and back scattering coefficients; relevant phytoplankton pigments concentration. The infrastructure comprises an analytical laboratory, a radiometric laboratory for the calibration and characterization of optical sensors, field facilities for autonomous and manned measurements across seas of relevance for environmental and climate investigations.
Laboratory measurements for satellite ocean colour validation activities:
- Determination of seawater absorption coefficients for pigmented and non-pigmented particles, and coloured dissolved organic matter, through high spectral resolution Spectrophotometric Techniques.
- Determination of the concentration of significant phytoplankton pigments through High Performance Liquid Chromatography.
Field measurements for satellite ocean colour validation activities:
- Measurement of marine and atmospheric optical quantities (i.e., water-leaving-radiance and aerosol optical depth) through autonomous radiometers included in the Ocean Colour component of the Aerosol Robotic Network (AERONET-OC) operated at marine sites of European relevance (i.e., the Gustaf Dalen, Irbe and Helsinki Lighthouses in the Baltic Sea; the Gloria, Galata and Section-7 Platforms in the Black Sea; the Acqua Alta Oceanographic Tower in the Adriatic Sea; the Casablanca Platform in the Western Mediterranean Sea) as well as at the italian San Marco Launch Platform in the Indian Ocean off the coast of Kenya) and the Plocan site in the Canary Islands.
- Comprehensive water sampling and measurements of seawater inherent and apparent optical properties (i.e., absorption, scattering and backscattering coefficients; remote sensing reflectance) through profiling systems deployed during oceanographic campaigns performed in marine regions of European relevance.
Laboratory calibration and characterization of optical sensors:
- Absolute radiometric calibrations in the visible and near-infrared of radiance and irradiance sensors, essential for manned and autonomous optical measurements in view of ensuring NMI traceability to field measurements performed in support of Copernicus satellite ocean colour validation activities.
- Characterisation of optical radiometers to ensure comprehensive quantification of uncertainties affecting the measurements applied for validation activities. These characterizations include the determination of: immersion factors for in-water radiance and irradiance sensors; spectral response, non-cosine response of both in-air and in-water irradiance sensors; non-linear response; stray light perturbations; polarization sensitivity; temperature response.
G. Zibordi and K. J. Voss, In situ optical radiometry in the visible and near infrared. In Optical Radiometry for Oceans Climate Measurements, Experimental Methods in the Physical Sciences volume 47, G. Zibordi, C. Donlon and A. Parr Ed.s, Elsevier - Academic Press, Amsterdam (December 2014).
G. Zibordi, K. J. Voss, B. C. Johnson and J. L. Mueller. Protocols for Satellite Ocean Colour Data Validation: In Situ Optical Radiometry. IOCCG Ocean Optics and Biogeochemistry Protocols for Satellite Ocean Colour Sensor Validation, Volume 3.0 (2019). IOCCG, Dartmouth, NS, Canada.
H. Claustre, S.B. Hooker, L. Van Heukelem, J.-F. Berthon, R. Barlow, J. Ras, ... and J. C. Marty. An intercomparison of HPLC phytoplankton pigment methods using in situ samples: application to remote sensing and database activities. Marine Chemistry, 85(1), 41-61,2004.
S. Tassan, and G.M. Ferrari. An alternative approach to absorption measurements of aquatic particles retained on filters. Limnology and Oceanography, 40(8), 1358-1368, 1995.
G. Zibordi, S. Hooker, J.L. Mueller, S. McLean, G. Lazin. Characterization of the immersion factor for a series of in-water optical radiometers. Journal of Atmospheric and Oceanic Technology, 21:501-514, 2004.
G. Zibordi. Immersion factor of in-water radiance sensors: assessment for a class of radiometers. Journal of Atmospheric and Oceanic Technology, 23: 302-313, 2006.
J.-F. Berthon, M. Lee, E. Shybanovand G. Zibordi. Measurements and modelling of the volume scattering function in the Northern Adriatic Sea. Applied Optics, 46, 5189-5203, 2007.
G. Zibordi, B. Holben, I. Slutsker, D. Giles, D. D’Alimonte, F. Mélin, J.-F. Berthon, D. Vandemark, H. Feng, G. Schuster, B. Fabbri, S. Kaitala, J. Seppälä. AERONET-OC: a network for the validation of Ocean Color primary radiometric products. Journal of Atmospheric and Oceanic Technology, 26, 1634-1651, 2009.
F. Mélin and G. Zibordi. Vicarious Calibration of Satellite Ocean Color Sensors at Coastal Sites. Applied Optics, 49, 798-810, 2010.
G. Zibordi, J.-F. Berthon, F. Mélin and D. D’Alimonte. Cross-site consistent in situ measurements for satellite ocean color applications: the BiOMaP radiometric dataset. Remote Sensing of Environment,115, 2104–2115, 2011.
G. Zibordi, F.Mélin and J.-F.Berthon. Trends in the bias of primary satellite ocean color products at a coastal site. Geoscience and Remote Sensing Letters 9, 1056-1060, 2012.
G. Zibordi, F. Mélin J.-F. Berthon and E. Canuti. An Assessment of MERIS Ocean Color Products for European Seas. Ocean Science 9, 521-533, 2013.
M. Gergely and G. Zibordi. An Assessment of AERONET-OC LWNUncertainties. Metrologia 51, 40–47, 2014.
B. Bulgarelli, V. Kisselev, G. Zibordi. Simulation of Adjacency Effects in Coastal Waters: A Case Study. Applied Optics, 53, 1523–1545, 2014.
G. Zibordi, F. Mélin, J.-F. Berthon, and M. Talone. In Situ Autonomous Radiometry Measurements for Satellite Ocean Color Validation in the Western Black Sea. Ocean Science 11, 275–286, 2015.
M. Talone, G. Zibordi, I. Ansko, A.C. Banks, J. Kuusk.Stray light effects in above-water remote sensing reflectance from hyperspectral radiometers. Applied Optics, 55(15), 3966–3977, 2016.
M. Talone and G. Zibordi. Polarimetric characteristics of a class of hyperspectral radiometers. Applied Optics, 55(35), 10092–10104, 2016.
G. Zibordi, M. Talone and L. Jankowski. Response to temperature of a class of in situ hyperspectral radiometers. Journal of Atmopsheric and Oceanic Technology, 34, 1795–1805, 2017.
M. Talone, G. Zibordi and Z. Lee. Correction for the non-nadir viewing geometry of AERONET-OC above-water radiometry data: an estimate of uncertainties. Optics Express, 26, A541–A561, 2018.
B. Bulgarelli, G. Zibordi and F. Mélin. Minimization of adjacency effects in SeaWiFS primary data products from coastal areas. Optics Express, 26, A709–A728, 2018.
M. Talone and G. Zibordi.Nonlinear response of a class of hyper-spectral radiometers. Metrologia, 55, 747–758, 2018.
M. Talone and G. Zibordi. Spectral assessment of deployment platform perturbations in above-water radiometry, Optics Express, 28, A878–A889, 2019.
G. Zibordi, E. Kwiatkowska, F. Mélin, M. Talone, I. Cazzaniga, D. Dessailly, J. I. Gossn. Assessment of OLCI-A and OLCI-B radiometric data products across European seas. Remote Sensing of Environment, 272, 112911, 2022.