CoAuthors

Alice Dalphinet (Meteo France, France)

To keep the reliability of wave parameters from Copernicus Marine Services (CMEMS) at a good level, it is important to update the assimilation system in wave model with new altimeter mission such as Sentinel-6MF (S6MF). This work consists in assessing the impact of using Significant Wave Height (SWH) from S6MF in global and regional operational wave model MFWAM. We implemented long period assimilation experiment of low resolution SWH from S6MF latest level 2 processing for both SAR and LRM modes. The validation of model output have been performed in comparison with independent wave data from altimeters and buoys. The results shows significant improvement of scatter index of SWH in average by ~15 %. We also remarked a better performance for the assimilation of retrieved SWH from SAR mode compared to the ones provided by LRM (MLE3) in different ocean basins namely, high and mid latitudes and the tropics.
The most striking result concerns the capacity of S6MF to correct efficiently high SWH exceeding 15 m such as ones observed in severe storms at the Southern Ocean.
In this work we also examined the impact of high resolution SWH (20Hz) from S6MF. To this end we implement a robust filtering to remove corrupted data particularly in coastal areas. Assimilation runs have been performed for regional (Iberian-Biscay-ireland) high resolution configuration of the model MFWAM with a grid size of 2 km. The assimilation scheme has been adapted in terms of correlation length in the optimal interpolation scheme.
We perfomed a comparison between the assimilation of HR SWH from S6MF and the assimilation of 5Hz SWH provided by CFOSAT. The validation of the results have conducted with coastal buoys network provided by CMEMS in situ TAC. Further we investigated the use of directional wave spectra from CFOSAT in order to analyse the quality of HR SWH depending on long swell conditions.
More comments and conclusions will be summarized in the final presentation.