Directional and frequency spread of surface ocean waves from SWIM measurements - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research. Oceans Année : 2021

Directional and frequency spread of surface ocean waves from SWIM measurements

Résumé

The China France Oceanography Satellite (CFOSAT) launched in 2018 now routinely provides directional ocean wave spectra at the global scale. It consists of analyzing the normalized radar cross-section measured by the near-nadir pointing Ku-Band real-aperture scanning radar SWIM (Surface Waves Investigation and Monitoring). The significant wave height, dominant wavelength and direction are provided as the main parameters, but here we analyze additional parameters, namely the frequency width of the omni-directional spectra, the directional spread of the dominant waves, and the related Benjamin-Feir index. This latter was proposed in the literature to estimate the probability of extreme waves. We discuss the geographical distributions of these parameters, their relation with sea-state conditions, and their similarities and diferences with respect to the same parameters obtained from the MFWAM numerical wave model and buoy data. Wef ind that the SWIM omni-directional spectra are narrower and more peaked than the model spectra and that these differences are more obvious in the high sea-state conditions encoun31 tered in the Southern Ocean. We nd that under the intense conditions of the Southern Ocean, the SWIM directional spread at the peak is the smallest for swell, the largest for young wind seas, and takes intermediate values for mature wind seas. The directional Benjamin-Feir index is similar for SWIM and MFWAM, but this is mainly due to compensating effects in the parameters contributing to this index. The results indicate that these shape parameters may be used in the future to better describe the wave space-time evolution.
Fichier principal
Vignette du fichier
LeMerle_etal_SWIMspectra_JGR_accepted2021_pourHAL.pdf (26.59 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03261817 , version 1 (16-06-2021)

Identifiants

Citer

Eva Le Merle, Danièle Hauser, Charles Peureux, Lotfi Aouf, Patricia Schippers, et al.. Directional and frequency spread of surface ocean waves from SWIM measurements. Journal of Geophysical Research. Oceans, 2021, 126 (7), pp.e2021JC017220. ⟨10.1029/2021JC017220⟩. ⟨hal-03261817⟩
178 Consultations
96 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More