Imbalance Term in the TKE Budget over Waves

In an attempt to reconciliate air-sea momentum flux estimates derived from open sea observations, from large eddy simulation output fields, and from wind-wave tank measurements, a series of dedicated experiments were conducted in the wind-wave tank of the Large Air-Sea Facility of Marseille, France....

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Bibliographic Details
Main Authors: Linta Vonta, Denis Bourras, Saïd Benjeddou, Christopher Luneau, Julien Touboul, Philippe Fraunié, Alexei Sentchev, Antoine Villefer
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Atmosphere
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Online Access:https://www.mdpi.com/2073-4433/16/4/412
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Summary:In an attempt to reconciliate air-sea momentum flux estimates derived from open sea observations, from large eddy simulation output fields, and from wind-wave tank measurements, a series of dedicated experiments were conducted in the wind-wave tank of the Large Air-Sea Facility of Marseille, France. The turbulent friction velocity, upon which the momentum flux depends, was estimated from wind measurements by applying four classical methods including the eddy-covariance method and the inertial-dissipation method. The collected data were used to investigate some characteristics of the wave-influenced boundary layer that were predicted by previous simulations, and to quantify a wave-dependent term of the turbulent kinetic energy equation, the so-called imbalance term <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>ϕ</mi><mi>imb</mi></msub></semantics></math></inline-formula>. Our results show that the turbulent stress decreases toward lower heights where the effect of waves is large, as in the simulations, and that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>ϕ</mi><mi>imb</mi></msub></semantics></math></inline-formula> is in the range 0.3 to 0.7, which is comparable to the value found with open sea data (0.4). These preliminary results have to be confirmed with wave-following probes, because the estimated eddy-covariance flux slightly varied with height, thus it could not be strictly considered to be equal to a constant total flux.
ISSN:2073-4433