Long Waves And Sea Level Variations

Infragravity waves, called “long waves”, which period is between one and ten minutes, are an important part in coastal hydrodynamics. However they are often neglected in models and studies but their effects can be deciding for sedimentary transportation on the coast and marine submersions. Their amplitude can be one meter. But their generation and liberation is still not well understood. In coastal areas, the long waves can be amplified in harbors such as in Port-Tudy where the seiches are due to infragravity waves. They create strong currents which can cause damages and can stop port activities. This study is part of the final project for the studies at ENSTA-BRETAGNE and for the master in Marine Geophysics at IUEM. The subject is the long waves and sea level variations. The aim is to quantify the long waves amplitude using a spectral analysis of existing data (tide gauge data and pressure data) and to model their propagation and generation. The study was realized with data from Ifremer, the SHOM and MEDDTL/DDTM17/SPC-Littoral Atlantique.

N. Collouard - Ifremer - ENSTA Bretagne