Oceanographic Real-Time Measurement on Buoyancy Beacon Feedback in the Rhône Delta and Gulf of Fos (France)

Abstract

The instrumentation implanted since 2003 on two buoyancy beacons (BFI) in the Gulf of Fos-sur-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 device and analysis of recorded observations for nearly 4 years allows specifying uncertainties linked to this kind of measurement and provides a reliable feedback on the exploitation of the observatory.

A database of simultaneous measurements of beacons structure behavior (tilting measurement) and oceanographic and meteorological parameters has been used to design new BFIs for future projects (Lavezzi in Bonifacio Strait, Corsica, Port of Marseilles Authority, etc.).

Analysis of the current measurement enables one to characterize the current profiles on the water column located above sensors, and 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 different 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 Rhône flood in December 2003.