New directional wave satellite observations : Towards improved wave forecasts and climate description in Southern Ocean

Type Article
Date 2021-03
Language English
Author(s) Aouf L1, Hauser D2, Chapron Bertrand3, Toffoli A4, Tourrain C5, Peureux Charles6
Affiliation(s) 1 : Météo-France, CNRM-DirOP, Toulouse, France
2 : LATMOS/IPSL, Guyancourt, France
3 : IFREMER, Brest, France
4 : The University of Melbourne, Melbourne, Australia
5 : CNES, Toulouse, France
6 : CLS, Brest, France
Source Geophysical Research Letters (0094-8276) (American Geophysical Union), 2021-03 , Vol. 48 , N. 5 , P. e2020GL091187 (10p.)
DOI 10.1029/2020GL091187
WOS© Times Cited 3
Note This article also appears in: China-France Oceanography Satellite (CFOSAT): Scientific Applications
Keyword(s) assimilation, directional, Southern Ocean, SWH, wave age, wave number
Abstract

In spite of continuous improvements of ocean wave models in the last decades, large errors still remain in particular under strongly forced conditions, often encountered in the Southern Ocean, where strong westerly winds generate some of the fiercest waves on Earth in almost unlimited fetch conditions. The newly launched China‐France Oceanography SATellite (CFOSAT) provides directional spectra of ocean waves for both wind seas and swells. Compared to Synthetic Aperture Radar (SAR), it can resolve shorter wavelengths in all directions, which dominate in non‐fully developed wind waves. Here, the assimilation of these CFOSAT wave number components is proved to bring more accurate predictions of wave growth compared to the assimilation of significant wave height alone. A notable reduction of model bias is found in the Southern Ocean, especially in the Pacific Ocean sector. Results further exhibit a downward shift of the wave age, consistent with theoretical wave growth curves.

Plain Language Summary

This work focuses on the importance of using directional wave observations to improve model wave prediction in the Southern Ocean. The results indicate a significant impact on the transition from a wind‐dependent sea to a well‐developed sea. A direct consequence of this work will concern a better understanding of the wave climate in the Southern Ocean and therefore an improvement of coupled ocean/waves/atmosphere systems.

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How to cite 

Aouf L, Hauser D, Chapron Bertrand, Toffoli A, Tourrain C, Peureux Charles (2021). New directional wave satellite observations : Towards improved wave forecasts and climate description in Southern Ocean. Geophysical Research Letters, 48(5), e2020GL091187 (10p.). Publisher's official version : https://doi.org/10.1029/2020GL091187 , Open Access version : https://archimer.ifremer.fr/doc/00668/77996/