The use of ocean color data provided by satellite sensors has expanded considerably in the "bio-geochemical" oceanographic community. The information these observations provide on phytoplankton biomass of the ocean is important for issues related to (1) the ocean carbon cycle (primary production and associated fluxes), (2) the role of the ocean in climate change (2D dynamics, assimilation in global models ...), (3) the physics of the oceanic mixed layer (influence on vertical heat deposition), and (4) the monitoring of coastal zones and fisheries. It is also necessary that the measurements taken at the top of the atmosphere by satellite sensors are correctly interpreted. This requires (1) maintaining an excellent calibration of the instruments, (2) using the best possible techniques to extract the useful signal - the "marine signal" - from the total signal that is measured at the top of the atmosphere, and (3) to correctly invert this signal which informs us about the optical properties of surface ocean waters. The BOUSSOLE project concerns these 3 points.

Initiated in 2001, the BOUSSOLE Program aims at establishing a long-term series of bio-optical parameters. The acquisition of such a dataset makes it possible to calibrate the satellite observations of the color of the ocean, to validate the products which are derived from it (chlorophyll, reflectances, etc.) and to increase the fundamental knowledge in marine optics and bio-optics.

For these purposes, a mooring was installed in 2003 in the Ligurian Sea in the "Dyfamed" study area. It acquires bio-optical data continuously and at high frequency (1 minute of acquisition every 15 minutes). Since 2001, the monthly cruises have been used to maintain the buoy and to acquire additional data that the mooring can not provide. These additional measurements include: CTD profiles, HPLC pigments, phytoplankton absorption, particulate and dissolved solids, dry weight, radiance and irradiance profiles, inherent optical properties profiles, atmospheric measurements (aerosols).