The Mediterranean Ocean Colour Observing System - system development and product validation

This paper presents the Mediterranean Ocean Colour Observing System in the framework of the growing demand of near real-time data emerging within the operational oceanography international context. The main issues related to the satellite operational oceanography are tied to the following: (1) the near real-time ability to track data flow uncertainty sources; (2) in case of failure, to provide backup solutions to end-users; and (3) to scientifically assess the product quality. We describe the major scientific and technological steps made to develop, maintain and improve the operational system and its products. A method for assessing the near real-time product quality is developed and its limitation discussed. Main results are concerned with the degradation, starting from mid-2010, of the MODIS Aqua channel at 443 nm with its successive recovery thanks to the new calibration scheme implemented in the recently released SeaDAS version 6.4. The product validation analysis highlights that SeaWiFS chlorophyll product over the Mediterranean Sea is the best performing in comparison with those of MODIS and MERIS. Despite their general good agreement with in situ observations, MODIS- and MERIS-derived chlorophyll present a slight and systematic underestimation of the in situ counter part. The most relevant implications induced by these results are discussed from an operational point of view.