Publications scientifiques

L'une des conséquences du changement climatique est la remontée du niveau moyen des mers. C'est cette conséquence qui est prise pour hypothèse principale dans ce travail. La méthode utilisée pour déterminer l'évolution des franchissements s'appuie sur deux sites d'études sur le littoral français : Deauville et Saint Malo.

Les études d'aléa de submersion marine s'attachent à définir des valeurs extrêmes pour les niveaux marins et les houles et à combiner ces valeurs afin de produire un aléa de référence à la côte. Pourtant, ces phénomènes résultent souvent d'un même événement météorologique générateur : les tempêtes. Météo-France, le Cetmef et le Shom ont uni leurs efforts pour étudier les tempêtes menaçant le littoral breton et déterminer des événements extrêmes, dont on déduirait les paramètres hydrodynamiques pour l'étude des risques de submersion marine.

Observatoire du niveau de la mer assez méconnu, le marégraphe de Marseille a été construit à la fin du XIX^e siècle pour fixer le niveau zéro au-dessus duquel sont exprimées les altitudes du territoire français continental. Il abrite un instrument d’enregistrement, dit « marégraphe totalisateur », encore en parfait état de fonctionnement et aujourd’hui unique au monde dans sa catégorie.

The pre-operational system PREVIMER provides coastal observations and forecasts along French coasts. It provides, among other variables, currents, sea levels, surges and waves. This paper describes the development and validation of a high temporal (15 minutes) and spatial (250 m) resolution modeling system, based on MARS hydrodynamic model (Lazure and Dumas 2008), along the Atlantic and English Channel coasts.

Moving water has a special fascination, and the regular tidal movements of coastal seas must have challenged human imagination from earliest times. Indeed, the ancients who were able to link the regular movements of the sea to the movements of the sun and moon regarded tides as a tangible terrestrial manifestation of the powers of the celestial gods. For them the tides had religious significance; for us there are obviously many practical and scientific reasons for needing to know about and understand the dynamics of the oceans and coastal seas.

We present a synthesis of tide gauge data recorded on June 26–28, 2011, along the NE Atlantic and the English Channel coastlines, which show a significant sea level disturbance observed from Portugal to England during several hours. Though the amplitude was low (a few centimeters at most), the main disturbance was observed in about 30 harbors. The phenomenon started in south Spain and Portugal in the last hours of 26 June and reached the French west coastline on 27 June, at about noon.

We present sea level observations derived from the analysis of signal-to-noise ratio (SNR) data recorded by five coastal GPS stations. These stations are located in different regions around the world, both in the northern and in the southern hemisphere, in different multipath environments, from rural coastal areas to busy harbors, and experience different tidal ranges.

The objective of this study is to document the circulation in the vicinity of La Réunion and Mauritius islands, i.e., within 500 km offshore, on the intraseasonal time scale, using a high-resolution realistic modeling strategy. The simulated sea level anomalies, water mass properties, and large-scale circulation compare favorably with satellite and in situ observations. Our high-resolution simulation suggests that the currents around the islands are maximal locally, oriented southwestward, to the southeast of both islands which is not visible in low-resolution satellite observations.