Contribution of Satellite Altimetry to Wave Analysis and Forecasting
Jean-Michel Lefevre(1) , Lotfi Aouf(1) , Chafih Skandrani(1) , and Pierre Queffeulou(2)
42 av. G. Coriolis,
(2) IFREMER, BP 70, 29280 Plouzane, France
During the last decade, the performance of wave models has significantly improved in term of wave analysis and forecasting, thanks to a better quality of the wind forcing fields, to the refinement of numerical wave model and to the assimilation of satellite altimeter data. Today, four satellite altimeters are in operation and the positive impact of altimeter data assimilation in numerical wave models at global scale has been proved and estimated by several authors .
Data assimilation at regional scale is presently an issue of interest and the knowledge of spatial correlation functions for prediction errors have to be derived for small basins where complicated structures are expected due to very high time and space variability of wind speed.
Altimeter data are the only observation providing us with spatial distribution of wave properties that can be used to derive the required error correlation functions.
Because of their global coverage, altimeter data are also very valuable for assessing the impact of other satellite data for wave analysis and forecasting. In particular, the usefulness of Advanced Synthetic Aperture Radar (ASAR) for such purpose has been recently investigated by using altimeter data.
Buoys data are mainly located in the Northern hemisphere and in coastal areas while altimeter data are uniformly distributed over the ocean making them very useful to locate wave model errors in order to improve wave model parameterization of source terms and wave model numerical aspects.