Prévisions et rejeux des états de mer du globe à la plage

ABSTRACT SHOM has developed a multi-scale wave forecasting system from the global ocean to the beach, combining several relatively coarse models and high resolution coastal zooms. This system is operated as part of the Previmer project, for multiple applications ranging from naval operations to coastal engineering, remote sensing and investigations of ocean circulation (drift, mixing'). Offshore hindcasts prove to be very accurate with errors generally between 9 and 15% against in situ 3-hourly averaged values of Hm0 and Tm02. In coastal areas, errors are typically larger, often exceeding 20%. This increase in error is partly due to a poor modelling of the directional distribution of the offshore wave energy.