On the signature of long swell for the SAR-mode wave height of Cryosat-2

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

CoAuthors

Laurent Phalippou (Thales-Alenia-Space, France)

Event: 2015 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and retracking (SAR and LRM)

Presentation type: Type Oral

The SAR Radar ALtimeter (SRAL) of the Sentinel-3 mission will operate continuously in the SAR mode over the oceans. The wave heights that will be retrieved in that mode needs to be validated before operational assimilation in wave models. This paper reports on the results of a comparison over a long period between the SAR mode wave heights obtained with CryoSat-2 and wave model significant wave heights. The impact of assimilating SAR mode wave data in the wave model MFWAM is also shown.

Two sets of wave data from SAR mode of Cryosat-2 have been provided by the French space agency CNES. The first set of data starts from May until september 2012, and it is retrieved by the processing called V13.The second set of data starts from November 2013 until March 2014, and it is retrieved by an upgraded processing called V14.

Several assimilation tests with the wave model MFWAM are performed for these periods. The results are validated with independent altimeter wave data and available buoys data. A comparison with the assimilation of LRM-mode wave data from Cryosat-2 is also examined. The results show slightly better scatter index of significant wave height when using the SAR mode wave heights.

The comparison between the wave model MFWAM and SAR mode wave heights reveals significant biases when long swell travels parallel to the satellite ground tracks. This feature is slightly reduced for V14 processed data. Further discussions will be presented in this paper.
 

Oral presentation show times:

RoomStart DateEnd Date
Grand Ballroom 1 Tue, Oct 20 2015,16:28 Tue, Oct 20 2015,16:40
Lotfi Aouf
Division Marine et Océanographie Météo-France
France
lotfi.aouf@meteo.fr