Validation of SeaWiFS and MODIS Aqua/Terra aerosol products in coastal regions of European marginal seas

The aerosol products associated with the ocean colour missions SeaWiFS and MODIS (both Aqua and Terra) are assessed with AERONET field measurements collected in four European marginal seas for which fairly large uncertainties in ocean colour in-water products have been documented: the northern Adriatic, the Baltic, Black and North Seas. On average, more than 500 match-ups are found for each basin and satellite mission, showing an overall consistency of validation statistics across the three missions. The median absolute relative difference between satellite and field values of aerosol optical thickness tau(a) at 443 nm varies from 12% to 15% for the three missions at the northern Adriatic and Black Sea sites, and from 13% to -26% for the Baltic and North Sea sites. It is in the interval 16-31% for the near-infrared band. The spectral shape of tau(a) is well reproduced with a median bias of the Angstrom exponent varying between -15% and +14%, which represents a clear improvement with respect to previous versions of the atmospheric correction scheme. These results show that the uncertainty associated with tau(a) in the considered coastal waters of the European marginal seas is comparable to global validation statistics.