On the Impact of Long Wind-Waves on Near-Surface Turbulence and Momentum Fluxes

Type Article
Date 2020-03
Language English
Author(s) Ayet AlexORCID1, 2, Chapron Bertrand1, Redelsperger Jean-Luc3, Lapeyre Guillaume2, 3, Marié Louis1
Affiliation(s) 1 : Univ. Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Brest, France
2 : LMD/IPSL, CNRS, École Normale Supérieure, PSL Research University, Paris, France
3 : Univ. Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Brest, France
Source Boundary-layer Meteorology (0006-8314) (Springer Science and Business Media LLC), 2020-03 , Vol. 174 , N. 3 , P. 465-491
DOI 10.1007/s10546-019-00492-x
WOS© Times Cited 3
Keyword(s) Air-sea fluxes, Wall-bounded turbulence, Wave boundary layer, Wind stress, Wind-waves
Abstract

We propose a new phenomenological model to represent the impact of wind-waves on the dissipation of turbulence kinetic energy near the sea surface. In this model, the momentum flux at a given height results from the averaged contribution of eddies attached to the sea surface whose sizes are related to the surface geometry. This yields a coupling between long wind-waves and turbulence at heights of about 10 m. This new wind-and-waves coupling is thus not exclusively confined to the short wave range and heights below 5 m, where most of the momentum transfer to the waves is known to occur. The proposed framework clarifies the impact of wind-waves on Monin–Obukhov similarity theory, and the role of long wind-waves on the observed wind-wave variability of momentum fluxes. This work reveals which state variables related to the wind-wave coupling require more accurate measurements to further improve wind-over-waves models and parametrizations.

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