POSTER SESSION 1
15:30–17:30, Monday, September 14
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ABSTRACT 1241 | POSTER 33
ASSESSING SATELLITE-DERIVED CHLOROPHYLL-A AND KD USING BGC-ARGO DATA AND TRIPLE COLLOCATION
The validation of bio-optical algorithms for recent satellite missions remains challenging due to the limited availability of in situ data. While new missions offer improved accuracy and enhanced capabilities for ocean observation, their early exploitation might be constrained by limited concurrent in situ data, whereas historical datasets, despite being reference measurements, are sparse and unevenly distributed in time and space. Yet, the Biogeochemical-Argo (BGC-Argo) program represents a valuable resource for the validation of recent satellite missions. This global network of autonomous profiling floats delivers near-real-time observations of bio-optical properties such as chlorophyll-a concentration (CHL) across a wide range of oceanic environments, including extreme conditions.
However, as autonomous optical sensors, BGC-Argo measurements are subject to uncertainties and potential biases that often limited their use in satellite validation frameworks.
In this study, we apply a triple collocation analysis to assess the consistency and random errors of CHL and diffuse attenuation coefficient (Kd) products in both recent satellite mission and BGC-Argo. This statistical approach estimates the random error of each dataset without assuming any as a reference truth, based on the covariance between three independent sources. For CHL, the analysis combines OLCI, BGC-Argo, and Copernicus Marine model data. For Kd, OLCI and BGC-Argo data are complemented with Sentinel-5P observations.
Our results highlight the strong potential of BGC-Argo data for satellite product validation, while also identifying limitations and sources of uncertainty associated with this approach.
Marine Bretagnon, ACRI-ST, Sophia-Antipolis, France, [email protected], https://orcid.org/0000-0002-4429-6961
Raphaëlle Sauzède, Sorbonne Université, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-mer, France, raphaë[email protected]
Hervé Claustre, Sorbonne Université, CNRS, Laboratoire d’Océanographie de Villefranche (LOV), Villefranche-sur-mer, France, [email protected]
Philippe Bryère, ACRI-ST, Sophia-Antipolis, France, [email protected]
Julia Uitz, Sorbonne Université, CNRS, Laboratoire d’Océanographie de Villefranche (LOV), Villefranche-sur-mer, France, [email protected]
Catherine Schmechtig, OSU Ecce Terra, UMS 3455, CNRS and Université Pierre et Marie Curie, Paris, France, [email protected]
Héloïse Lavigne, ACRI-ST, Sophia-Antipolis, France, [email protected]
Antoine Mangin, ACRI-ST, Sophia-Antipolis, France, [email protected]
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