Observations of isolated wave-turbulence interactions in the stable atmospheric boundary layer

Turbulence measurements of the stable atmospheric boundary layer made at Halley station in Antarctica are presented. the interaction between small-scale turbulence and larger solitary wave disturbances is investigated. Spectral methods are used to separate the wave and turbulence parts of the flow, and the appropriateness of this approach is discussed. Both individual wave events and an average of 18 wave events are studied. the transport of wave-induced velocity by wave-induced turbulence is found to be mostly upwards, whilst a strong downward turbulent heat flux accompanies each wave. Waves are often found to be associated with a burst of low-level turbulence which occurs later than the perturbation in the mean shear. the effect of the turbulence on the wave is shown to be small, whilst the instantaneous local effect of the wave on the turbulence appears to be approximately linear in the wave amplitude. Comparisons are made between the observations and numerical predictions. These tend to confirm the need for at least second-order closure schemes for the turbulence modelling.

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