Turbulent air-sea fluxes in the Gulf of Guinea during the AMMA experiment

Denis Bourras (1) , Alain Weill (1) , Guy Caniaux (2) , Laurence Eymard (3, 4) , Bernard Bourlès (5) , S. Letourneur (6) , D. Legain (2) , Erica Key (7) , François Baudin (6) , B. Piguet (2) , O. Traullé (2) , G. Bouhours (2) , B. Sinardet (8) , J. Barrié (2) , Jean-Paul Vinson (9) , F. Boutet (10, 3) , Christophe Berthod (11, 6) , Aurélien Clémençon (6)

1 ESTER - LATMOS
2 CNRM - Centre national de recherches météorologiques
3 IPSL - Institut Pierre-Simon-Laplace
4 LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
5 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
6 DTI - Division technique INSU/SDU
7 RSMAS - Rosenstiel School of Marine and Atmospheric Science
8 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne
9 LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
10 CETP - Centre d'étude des environnements terrestre et planétaires
11 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)

Turbulent fluxes at the air‐sea interface were estimated in the framework of the African Monsoon Multidisciplinary Analysis (AMMA) international program. A specific flux measurement mast was designed so as to minimize aerodynamic flow distortion and vibrations. The mast was installed on the research vessel Atalante that cruised in the Gulf of Guinea during the onset of the African monsoon, in June-July 2006. Turbulent fluxes were calculated with an eddy covariance method and with a spectral method. Calculation of eddy correlation fluxes required a correction of flow distortion at turbulent scales, which was performed with a new statistical technique. Application of the spectral flux calculation method revealed that an imbalance term was required, in agreement with results from earlier experiments, and indicated that the value of the Kolmogorov constant (0.55) should not be modified. Bulk exchange coefficients calculated are in good agreement with earlier parameterizations in medium wind conditions.

Domaines: Océan, Atmosphère; Physique Atmosphérique et Océanique [physics.ao-ph]; Géophysique [physics.geo-ph]

Denis Bourras, Alain Weill, Guy Caniaux, Laurence Eymard, Bernard Bourlès, et al.. Turbulent air-sea fluxes in the Gulf of Guinea during the AMMA experiment. Journal of Geophysical Research. Oceans, 2009, 114, pp.C04014. ⟨10.1029/2008JC004951⟩. ⟨hal-00605939⟩