MEDIUM RESOLUTION IMAGING SPECTROMETER (MERIS) VALIDATION: EARLY RESULTS AT THE BOUSSOLE SITE (MEDITERRANEAN SEA)

The early results of the BOUSSOLE project, which is part of the overall MERIS calibration/validation programme, are presented in this extended abstract (“BOUSSOLE ” is a French acronym; in English it basically means “A buoy for the collection of a long-term time-series of optical data”). 1. GENERAL OBJECTIVES A prerequisite to building long-term (over decades) archives of ocean colour, in response to the need for assessing the response of the oceanic biota to climate changes, is to accurately calibrate the top-of-atmosphere satellite observations, then to validate the surface geophysical parameters derived from these observations, and to develop and maintain this capability over long periods of time. Ensuring coherence between these geophysical products, as derived from different sensors, is also an important aspect to consider. When ocean colour observations from different sensors are considered in view of data merging, their cross-calibration and validation might be facilitated if they could be “anchored ” on continuous long-term in situ stations [1]. Deploying and maintaining moorings that operate in a continuous way is, however, a difficult program. In response to these concerns, we have proposed to carry out match-up analyses and vicarious calibration experiments, based on a data set to be built from a permanent marine optical buoy. This new type of marine optical buo