Simulation of SPOT Satellite Imagery for Charting Shallow-Water Benthic Communities in the Mediterranean

Abstract. In order to simulate SPOT-typc satellite imagery, remote sensing of the Bay of San Cyprianu (Corsica) was carried out using a radiation sensor mounted in an aircraft. The resulting simulated image was calibrated using a chart of the benthos produced by SCUBA diving. We show that remote sensing by satellite should be able to resolve certain bottom types and benthic communities in water down to a depth of 12 m.     

Theoretical visibility curves of late type stars

Theoretical visibility curves are presented for one carbon and one oxygen star. We aim to show the importance of measurements at wavelengths across the band.     

Modelling the global ocean tides: modern insights from FES2004

During the 1990s, a large number of new tidal atlases were developed, primarily to provide accurate tidal corrections for satellite altimetry applications. During this decade, the French tidal group (FTG), led by C. Le Provost, produced a series of finite element solutions (FES) tidal atlases, among which FES2004 is the latest release, computed from the tidal hydrodynamic equations and data assimilation. The aim of this paper is to review the state of the art of tidal modelling and the progress achieved during this past decade. The first sections summarise the general FTG approach to modelling the global tides. In the following sections, we introduce the FES2004 tidal atlas and validate the model against in situ and satellite data. We demonstrate the higher accuracy of the FES2004 release compared to earlier FES tidal atlases, and we recommend its use in tidal applications. The final section focuses on the new dissipation term added to the equations, which aims to account for the conversion of barotropic energy into internal tidal energy. There is a huge improvement in the hydrodynamic tidal solution and energy budget obtained when this term is taken into account.     

A Map of the Posidonia oceanica Beds of Marina ďElbu (Corsica, Mediterranean)

Abstract. A large-scale map of the Posidonia oceanica seagrass beds as well as other benthic substrata and communities was compiled for a cove of a marine reserve free from pollution and man-made disturbance. An extensive diving survey of the cove and the interpretation of aerial colour photographs were used. The greater part of the cove is occupied by the P. oceanica meadow. Patches of dead "matte" were observed at a depth of between 7 and 14 m. They may be the result of a natural hydrodynamic equilibrium between building and erosion.     

Rare earth element distribution in Plio-Quaternary volcanic rocks from southern Peru

Rare-earth element abundances of calc-alkaline andesitic rocks from southern Peru show that these rocks cannot be produceed by a single stage process. The high content of LILE, particularly LREE requires their derivation from a source already enriched in these elements and having a distinctly fractionated REE pattern. It is suggested that ascending hydrous fluids, released from the subducted oceanic lithosphere, enriched the upper mantle in LILE by zone refining. The partial melting of such an enriched upper mantle, followed by fractional crystallization, could produce andesitic rocks. REE data indicate that shoshonitic rocks from southern Peru can be derived from an unfractionated garnet-bearing peridotite by a low degree of partial melting.     

Deltaic plain development and environmental changes in the Petite Camargue, Rhone Delta, France, in the past 2000 years

The deltaic plain of the Petite Camargue which constitutes the western part of the Rhone Delta, began its main progradation around 2000 yr ago. Several delta lobes follow each other and have participated in the deltaic evolution. The deltaic lobes have distinct morphologies which reflect the dynamic fluvial and marine processes under the influence of climatic and human controls. Two delta lobe systems were built by the Daladel and Peccaïs channels, after which a deflected wave-influenced delta lobe was formed by the La Ville and Saint-Roman channels. The latest channel, the Rhone Vif channel, is skewed because this channel was completely canalized and engineered up to its mouth in the beginning of the 16th century. Since the avulsion of this channel about 1550 A.D., the coastline of the Petite Camargue has been especially affected by the influence of waves and currents. The spits replaced the beach ridges which juxtaposed themselves and have migrated westward since the 16th century. The formation of the western part of the delta in the last 2000 yr is affected by not only the fluvial sedimentary fluxes and the coastal dynamics to the mouth but also climatic change and human influence.