Oceanographic real time measurement on buoyancy beacon feedback in Rhone delta and Gulf of Fos

Abstract

Abstract:The instrumentation implanted since 2003 on two buoyancy beacons in the Gulf of Fossur-Mer and in the delta margin provides local oceanographic and meteorological real time data. The device is based on Doppler technology sensors fixed on the beacon pipe. Meteorological sensors, acquisition and data transmission systems are clamped to the emerged structure close to Aide to Navigation (AtoN) and their energy systems. The monitoring of this equipment and analysis of recorded observations for nearly four years allows to specify uncertainties linked to this kind of measurement and provides a reliable feedback on the exploitation of the observatory. A data base of simultaneous measurements of beacons structure behavior (tilting measurement) and oceanographic and meteorological parameters have been used to design new buoyancy beacon (Lavezzi in Bonifacio Strait, Corsica; Marseille Port Authority; ...). The analysis of current measurement enables to characterize current profiles on the water column located above sensors, to distinguish flow stratification effects and wind-current correlations. Although originally designed to monitor the structure behavior and to supply wave climate to marine pilots, the system has developed deffered time applications. For example, sediment dredge bottom discharge has been optimized in the Gulf of Fos and frequency analysis of sea level has been compared to coastal tide gauge data for the historical Rhone flood in December 2003 (MAILLET et al. , 2006).