Air-Sea Turbulent Fluxes From a Wave-Following Platform During Six Experiments at Sea

Denis Bourras; Rémi Cambra; Louis Marié; Marie-Noelle Bouin; Lucio Baggio; Hubert Branger; Houda Beghoura; Gilles Reverdin; Boris Dewitte; Aurélien Paulmier; Christophe Maes; Fabrice Ardhuin; Ivane Pairaud; Philippe Fraunié; Christophe Luneau; Danièle Hauser

Air-Sea Turbulent Fluxes From a Wave-Following Platform During Six Experiments at Sea

Denis Bourras ¹ Rémi Cambra ² Louis Marié ³ Marie-Noelle Bouin ⁴ Lucio Baggio ⁵ Hubert Branger ⁶ Houda Beghoura ³ Gilles Reverdin ^{7, 8} Boris Dewitte ^{9, 10, 11, 12} Aurélien Paulmier ⁹ Christophe Maes ³ Fabrice Ardhuin ³ Ivane Pairaud ³ Philippe Fraunié ¹ Christophe Luneau ¹³ Danièle Hauser ¹⁴

1 MIO - Institut méditerranéen d'océanologie

2 France Energies Marines [Brest]

3 LOPS - Laboratoire d'Océanographie Physique et Spatiale

4 CNRM - Centre national de recherches météorologiques

5 LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales

6 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre

7 LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques

8 PROTEO - Processus et interactions de fine échelle océanique

LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques

9 LEGOS NOUMEA - Laboratoire d'Etudes en Géophysique et Océanographie Spatiales

10 CEAZA - Centro de Estudios Avanzados en Zonas Aridas

11 Departamento de Biología Marina [Coquimbo]

12 ESMOI - Millennium Nucleus Center for Ecology and Sustainable Management of Oceanic Island

13 OSU PYTHEAS - Institut Pythéas

14 SPACE - LATMOS

LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales

Abstract : Turbulent fluxes at the air‐sea interface are estimated with data collected in 2011 to 2017 with a low‐profile platform during six experiments in four regions. The observations were carried out with moderate winds (2‐10 m s^‐1) and averaged wave heights of 1.5 m. Most of the time, there was a swell, with an averaged wave age (the ratio between wave phase speed and wind speed) being equal to 2.8±1.6. Three flux calculation methods are used, namely the eddy‐covariance (EC), the inertial‐dissipation (ID), and the bulk methods. For the EC method, a spectral technique is proposed to correct wind data from platform motion. A mean bias affecting the friction velocity (u_*) is then evaluated. The comparison between EC u_* and ID u_* estimates suggests that a constant imbalance term (ϕ_imb) equal to 0.4 is required in the ID method, possibly due to wave influence on our data. Overall, the confidence in the calculated u_* estimates is found to be on the order of 10%. The values of the drag coefficient (C_D) are in good agreement with the parameterizations of Smith (1988) in medium‐range winds and of Edson et al. (2013) in light winds. According to our data, the inverse wave age varies linearly with wind speed, as in Edson et al. (2013), but our estimates of the Charnock coefficient do not increase with wind speed, which is possibly related to sampling swell‐dominated seas. We find that the Stanton number is independent from wind speed.

Document type :

Journal articles

Domain :

Physics [physics] / Physics [physics] / Atmospheric and Oceanic Physics [physics.ao-ph]

Complete list of metadatas

https://hal-insu.archives-ouvertes.fr/insu-02160613
Contributor : Catherine Cardon <>
Submitted on : Wednesday, June 19, 2019 - 7:19:32 PM
Last modification on : Monday, September 2, 2019 - 2:46:16 PM

Air-Sea Turbulent Fluxes From a Wave-Following Platform During Six Experiments at Sea

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Air-Sea Turbulent Fluxes From a Wave-Following Platform During Six Experiments at Sea

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