Coastal waters impacted by riverine inputs play a main role in the export and burial of terrigeneous particles. Ocean colour remote remote sensing allows to retrieve surface suspended particulate matter (SPM) concentrations. To improve spatial and temporal resolutions, it can be combined with bio-optical in situ measurements and numerical modelling. The Rhône river is the main source of freshwater and particulate inputs in the Gulf of Lion (Western Mediterranean Sea). The aim of the thesis is to study the seasonal variability of the Rhône river SPM inputs and their fate at the land-ocean interface. In situ bio-optical measurements have been acquired from oceanographic vessels and ProvBio autonomous profiling floats. The SPM concentrations have been retrieved from MERIS and MODIS satellite sensors. The hydro-sedimentary model (Mars-3D) is used to simulate the hydrodynamic circulation and the sediment dynamic in the Gulf of Lion using the measured Rhône liquid and solid discharges as inputs. Regional proxys have been identified and tested to follow the dynamic of SPM within the water column from in situ bio-optical measurements. A regional algorithm has been developed to map SPM concentrations from satellite sensors measurements. The combination of these two tools shows the dependence of SPM export to Rhone river freshwater discharge and wind. During flood events, the SPM are mainly exported within surface waters. From a weak to a moderate Rhône river freshwater discharge and strong wind, SPM are tranported close to the bottom. The hydro-sedimentary model allows to better understand some processes although improvement are still required.
