The assimilation of CFOSAT wave data in the wave model MFWAM : Ready for operational use ?

Lotfi Aouf (Division Marine et Océanographie Météo-France, France)

CoAuthors

Alice Dalphinet (Meteo-France, France); Daniele Hauser (CNRS/LATMOS, France); Bertrand Chapron (IFREMER, France); cedric tourain (CNES, France)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: CFOSAT

Presentation type: Type Oral

During the first months of the calibration/validation phase of CFOSAT, the wave scatterometer SWIM shows good skill to detect dominant wave trains composing the directional wave spectra, and also an accurate significant wave heights at the nadir look. The level 2 wave products include directional wave spectra from several beams 6, 8 and 10°. The expectations are very high in terms of operational wave forecasting and also a better directional sea state properties for the ocean/wave coupling at the air/sea interface. This work consists in preparing the assimilation of CFOSAT wave data in the operational global wave model MFWAM of Météo-France. Several assimilation runs have been implemented during the verification phase including upgraded processing to improve the level 2 products. We investigated the contribution of the assimilation of several SWIM wave products such the combined wave spectra and the wave spectra at the different beams. the optimization of the assimilation system has been implemented by accounting the azimuthal wavelength cutoff for SWIM wave spectra. The validation of the results has been performed in comparison with independent altimeters data and buoys.
The results show a significant improvement of integrated wave parameters in different ocean basins. One can mention that the comparison with independent altimeters wave data indicates a better scatter index of significant wave height roughly 20%, when we assimilated the SWIM nadir wave height and combined wave spectra. We also examined the persistency of the assimilation which stays efficient after 3 days in the forecast period. In this study we examined the impact of using SWIM wave data in storm cases and cyclonic seasons in the indian and Atlantic oceans.
Further discussions and comments will be presented in the final paper.
 

Oral presentation show times:

Room Start Date End Date
The Monroe Hub Thu, Oct 24 2019,12:00 Thu, Oct 24 2019,12:15
Lotfi Aouf
Division Marine et Océanographie Météo-France
France
lotfi.aouf@meteo.fr