Publications scientifiques

Chronic flooding, occurring at high tides under calm weather conditions, is occasionally taking place today in the low-lying areas of the Petit-Cul-de-sac marin (Guadeloupe, West Indies, French Antilles). This area includes critical industrial, harbor and major economic infrastructures for the island. As sea level rises, concerns are growing regarding the possibility for repeated chronic flooding events, which would alter the operations at these critical coastal infrastructures without appropriate adaptation.

Dans les environnements côtiers, les interactions entre les processus morphodynamiques, océanographiques et anthropiques (agissant sur différentes échelles de temps) contrôlent l'évolution des systèmes littoraux. Cette thèse est axée sur une échelle de temps séculaire afin de déterminer l'influence non seulement des activités humaines, mais aussi l'impact du changement climatique.

We investigated the long-term changes of the principal tidal component M₂ over the North Atlantic coasts, from 1846 to 2018. We analysed 9 tide gauges with time series starting no later than 1920. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M₂ variations are consistent at all the stations in the North East Atlantic (Newlyn, Brest, Cuxhaven), whereas some discrepancies appear in the North West Atlantic.

A dense network of instruments has been deployed within harbors along the Mediterranean coast, in the Toulon Metropole area, between the Hyères islands and the Sanary Bay in the framework of the observation network HTM-NET. Each station is equipped with two piezometric sensors, the first immersed and the second emerged, which allows the calculation of the water level. Both piezometric sensors are also equipped with a temperature sensor. Water level and temperature data are analyzed and discussed, also considering meteorological data provided by Météo-France stations.

The Global Sea-Level Observing System (GLOSS, https://www.gloss-sealevel.org/) is an international programme conducted under the auspices of the Intergovernmental Oceanographic Commission (IOC)of UNESCO. GLOSS aims at the establishment of high quality global and regional sea level networks for application to climate, oceanographic and coastal sea level research. The programme became known as GLOSS as it provides data for deriving the 'Global Level of the Sea Surface'.

River mouths along sandy coastlines are influenced by alongshore transport of littoral sands and the interaction of hydrodynamics processes at the river mouth. These interaction are responsible for opening/closure of river outlets and subsequent episodes of sand bypassing by spitbreaching. Here, we study these mechanisms of alongshore sediment bypassing at a river mouth along the French Mediterranean coast. Over the last 6 years, bypassing processes were found to be associated with spit elongation and spit breaching.

The analysis of long-term tide gauge data collected in the Northeast Atlantic Ocean reveals that the seasonal cycle of mean sea level (hereafter MSL) exhibits amplitudes of up to 0.4 m. The position of MSL is of fundamental importance for many issues such as storm-induced flooding or the morphodynamics of shallow inlets, yet the underlying mechanisms are not fully understood. We characterize the seasonal cycle based on field observations complemented with a numerical hindcast.

Intertidal flats lying as a buffer zone between land and sea provide critical services including protection against storm surges and coastal flooding. These environments are characterized by a continuous redistribution of sediment and changes in topography. Sea level rise, anthropogenic pressures, and their related stressors have a considerable impact on these areas and are expected to put them under more stress; hence the increased need for frequent and updated topography maps.

The multipath signals of GNSS can act as a tide gauge via a technology called Global Navigation Satellite Systems multipath reflectometry (GNSS-MR), which is based on the relationship between multipath frequency and height to sea surface. In addition to the traditional frequency extraction method of Lomb–Scargle periodogram (LSP), wavelet analysis can be applied to extract instantaneous multipath frequencies of GPS L1, thus improving data utilization.