The Marine Optical Laboratory of the Joint Research Centre (JRC) in Ispra installed an AERONET-OC SeaPRISM radiometer on a unique site on Lake Varese to support satellite ocean color validation activities. The measurements from the instrument help to validate the fitness for purpose of data from satellites.

The AERONET-OC network (operated by NASA) was set up to validate data on oceans from satellites. The network relies on Cimel CE318T SeaPRISM sun-photometers which have been installed on fixed marine and inland-water structures such as offshore towers, lighthouses, oil platforms, and similar platforms. Each instrument autonomously measures both atmospheric optical depth and water-leaving radiance. The data is continuously transmitted to the network and processed to retrieve aerosol optical thickness and normalised water-leaving radiance at different wavelengths. 

Satellite ocean color validation requires long-term, standardised and autonomous in situ measurements collected under real operating conditions across a range of water types, so that atmospheric correction schemes and bio-optical algorithms can be checked against ground truth.