Assimilation of high frequency altimeter wave data in regional wave model for the french coastal areas

Alice Dalphinet (Météo-France, France)


Celia Louarn (Météo-France, France); Lotfi Aouf (Météo-France, France); Annabelle Ollivier (CLS, France); Salvatore Dinardo (He Space, Deutschland)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: Application development for Operations

Presentation type: Type Poster

1 Hz altimeter significant wave heights (Cryosat-2, Saral, Jason 3, Sentinel-3) are commonly used in the assimilation of operational wave model MFWAM at Météo-France for many years. This contributes to a significant improvement of the sea state forecast at the first time steps of the run. The regional configuration of the model MFWAM at 2,5 km for the French coasts did not benefit yet from the assimilation of altimeters. The goal of this work consists in implementing the assimilation of high frequency altimeters wave data in the operational regional wave model.
The 20Hz wave data are provided by Sentinel 3, through two datasets: SAMOSA+ reprocessing by GPOD SARvatore Service (Dinardo et al. 2017) and CNES S3PP products obtained with innovative LR-RMC processing (Boy et al, OSTST 2017, Tran et al OSTST 2019). First, the wave data have been filtered out from corrupted values and then smoothed to a resolution of roughly 1 km along track. Diagnostics on the product show a good quality of the signal.
Afterward the data have been assimilated in the model MFWAM dedicated to French coasts (2,5 km) during a several months period. The results are compared with the run with assimilation of the 1 Hz altimeter wave data. The validation of the results of both datasets is performed in comparison with coastal buoys and independent altimeters. We focused on some storm cases generating high sea state in the coastal area in the Mediterranean sea and in the channel. We also investigated the use of other altimeters wave data such Saral or CFOSAT missions. The processing in the ground segment of CFOSAT was designed to optimize the high frequency quality of significant wave height estimates.
The study explores the quality of high frequency wave height measurement and the interest of taking into account observations from 20 Hz altimeter data into regional wave model.

Poster show times:

Room Start Date End Date
The Gallery Tue, Oct 22 2019,16:15 Tue, Oct 22 2019,18:00
The Gallery Thu, Oct 24 2019,14:00 Thu, Oct 24 2019,15:45
Alice Dalphinet