Publications scientifiques

In addition to traditional tide gauges, the ground-based global navigation satellite system reflectometry (GNSS-R) that utilizes signal-to-noise ratio data from a single GNSS receiver has become another promising alternative for sea level monitoring. However, its application is limited by retrieval precision, especially in large tidal variation environments. On the other hand, previous studies have focused on performance improvement by using post-processing strategies, which cannot support practical (near-) real-time applications.

Since 2008 a network of five sea-level monitoring stations was progressively installed in French Polynesia. The stations are autonomous and data, collected at a sampling rate of 1 or 2 min, are not only recorded locally, but also transferred in real time by a radio-link to the NOAA through the GOES satellite. The new ET34-ANA-V80 version of ETERNA, initially developed for Earth Tides analysis, is now able to analyze ocean tides records.

L’étude présentée sur les oscillations résonantes dans des bassins semi-ouverts de la côte provençale est basée sur l’analyse des données de niveaux issus de stations du réseau d’observation HTM-NET, composées de deux capteurs piézométriques, l’un immergé et l’autre émergé, permettant de connaitre la pression atmosphérique, le niveau d’eau et la température avec une période d’échantillonnage de 2 min. Elle concerne les baies de La Ciotat, de Sanary, la Rade de Toulon (grande et petite rades), le Golfe de Giens et la Rade d’Hyères.

Sea level changes are a complex and quite discussed topic in the media, mostly because of their relationship with “climate change”. The first instruments to evaluate sea level changes are the Tide Gauges (TG) that began to register data in 1700, at Amsterdam. The TG registrations are validated and homogenized, to be comparable, by PSMSL (Permanent Service for Mean Sea Level). The longest record is the one in Brest (France) that begins in 1807. They register the Relative Sea Level (RSL). In fact, the data show that the vertical movements on the continent strongly affect the RSL curves.

Coastal water level measurements represent one of the earliest geophysical measurements and allow an assessment of historical sea level rise and trends in tides, river flow and storm surge. However, recovery and digitization of archival tidal records have been much less widespread and systematic than, for example meteorological records. In this contribution, we discuss data rescue efforts and lessons learned in France, the United States and the United Kingdom, countries with early and extensive tide gauge networks by the mid-19th century.

La Grande Plage de Biarritz a connu plusieurs événements de tempêtes extrêmes ces dernières décennies qui ont causé d’importants dégâts matériels sur les ouvrages et bâtiments situés en front de mer. Ces événements ont conduit à la mise en place d’une stratégie de protection des infrastructures et des usagers qui intègre notamment le déploiement d’une digue amovible en sacs de sable sur le perré situé en haut de plage.

Bayesian networks are probabilistic graphical models that are increasingly used to translate hydraulic boundary conditions during storm events into onshore hazards. However, comprehensive databases that are representative of the extreme and episodic nature of storms are needed to train the Bayesian networks. Such databases do not exist for many sites and many Bayesian networks are trained on data generated by process-based models. To our knowledge, they have not been trained exclusively on observational data for storm impact modeling.

This article presents a curated database of the sea-level measurements acquired by the network of the five geodetic tide gauges managed over French Polynesia by the Geodesy Observatory of Tahiti from 13 June 2009 to 28 January 2021.