The Aerosol Robotic Network (AERONET), originally developed to evaluate aerosol optical properties and validate satellite retrievals of those properties at various scales with measurements from worldwidedistributed autonomous Sun photometers [Holben et al., 1998],since January 2006 has been extended to support marine remote sensing and monitoring applications. This new network component, called AERONETOcean Color (AERONET‐OC), provides the additional capability of measuring the radiance emerging from the sea—the ‘water‐leaving radiance’—with modified Sun photometers installed on offshore platforms such as lighthouses, oceanographic towers, and derricks.AERONET‐OC is proving to be instrumental in supporting satellite ocean color validation activities through standardized measurements performed at different sites with identical measuring systems and protocols, calibrated using a single reference source and method, and processed with the same code. Recent investigations [Zibordi et al., 2006] suggest that in order to generate accurate climate data records from remote sensing data, time series of in situ measurements from a cadre of AERONET‐OC sites could play a major role in the assessment and merging of radiometric products from different ocean color missions.