Publications scientifiques

This paper describes the assembly of an updated quasi-global dataset of higher-frequency sea level information obtained from tide gauges operated by many agencies around the world. We believe that the construction of such a dataset is fundamental to scientific research in sea level variability and also to practical aspects of coastal engineering. A first version of the dataset was used in approximately a dozen published studies, and this second version is about twice the size, containing longer and more geographically representative sea level records.

The paper concerns the wind influence on bottom shear stress and salinity levels in a Mediterranean semi-enclosed coastal lagoon (Etang de Berre), with respect to a replanting program of Zostera noltii. The MARS3D numerical model is used to analyze the 3D current, salinity and temperature distribution induced by three meteorological, oceanic and anthropogenic forcings in this lagoon. The numerical model has been carefully validated by comparison with daily observations of the vertical salinity and temperature profiles at three mooring stations, for one year.

Ecosystem engineers are organisms that modulate natural resources enabling the survival of other species. They drive environmental change and contribute to several coastal functional attributes such as landscape heterogeneity, sedimentary processes, and coastal protection. Our study focuses on the case of Lanice conchilega, a tube-building ecosystem engineer whose aggregations impact sedimentary processes. This polychaete forms biogenic tube aggregations distributed on the coasts of the northern hemisphere from the shallow intertidal to depths of 1900 m.

In the coastal ocean zones, satellite altimetry data processing and interpretation poses specific difficulties, due to the interaction of the radar signal with land topography, inaccuracies in some of the geophysical corrections and to the fast changes in the sea level. In order to optimize the completeness and the accuracy of the sea surface height information derived from satellite altimetry in coastal ocean areas, a dedicated post-processing software, called X-TRACK, has been developed by the Center of Topography of the Ocean and Hydrosphere in Toulouse.

Radar water level sensors provide several advantages over the older water level instruments. They require less effort to install than float-well, bubbler, or pressure sensor systems. Radar sensors require less maintenance than traditional water-level sensors because they are not in contact with the water. Because radar is a “non-contact” measurement method, it is not susceptible to being obstructed by sediment or debris and does not require that sediment be flushed from a stilling well. Radar water-level sensors may not work at all sites.

For at least 20 years, nadir altimetry satellite missions have been successfully used to first monitor the surface elevation of oceans and, shortly after, of large rivers and lakes. For the last 5–10 years, few studies have demonstrated the possibility to also observe smaller water bodies than previously thought feasible (river smaller than 500 m wide and lake below 10 km²). The present study aims at quantifying the nadir altimetry performance over a medium river (200 m or lower wide) with a pluvio-nival regime in a temperate climate (the Garonne River, France).

Le projet relatif à la reconstruction et au contrôle de la série analogique des hauteurs d’eau observées à Saint-Nazaire, financé par le MEEM, la région Pays de Loire et par le Shom, a débuté le 19 août 2013. Cette étude s’inscrit dans le cadre du programme international GLOSS (Global Sea Level Observing System) de la Commission océanographique intergouvernementale (COI) de l’UNESCO et du SOERE – SO SONEL.

Le Passage du Gois est une chaussée submergée à chaque marée. Il permet de relier le continent à l’île de Noirmoutier à marée basse en traversant la Baie de Bourgneuf. L’érosion constatée le long de la chaussée côté Sud remet en cause sa pérennité. Une analyse des processus hydro-sédimentaires à l’origine de cette érosion a été réalisée pour la DREAL Pays-de-la-Loire dans le cadre d’un projet de classement du site. Le Gois est à l’origine une édification sédimentaire issue d’un hydrodynamisme particulier dans la baie.