Research Applications
Wave-Turbulence Interactions
Another application of the TLS data is the study of the generation of turbulence by ducted gravity waves. Unlike propagating gravity waves, the fluctuations of the temperature and velocity fields induced by ducted gravity waves can be sustained for many cycles. Because it is sustained for long periods of time, this may be an important source of turbulent energy and the effect on the NBL dynamics and structure is not well known.
TLS data collected at constant altitude above the top of the Nocturnal boundary layer (i.e. in the residual layer) revealed the presence of enhancements or bursts of turbulence found to be synchronized with the troughs of the wave-induced temperature and velocity fluctuations.
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Shown in the figure below are the wave-induced fluctuations of velocity (top left panel) and temperature (bottom left panel) which were measured by the TLS (dashed lines) while flying at constant height.
Modal solutions of the temperature and velocity fields where then calculated numerically in order to compute the wave-induced fluctuations of the gradient Richardson number Ri. The Ri time series is used as a tool for predicting the appearance of enhanced turbulence activity. A comparison between the wave-induced Ri fluctuations (top right panel) and the corresponding ε time series shows the clear correlation between troughs of Ri and events of enhanced turbulence.
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For further details see the related publication:
2005 - Meillier Y, Frehlich R, Jones RM, Balsley B: “Modulation of small-scale turbulence by ducted gravity waves above the nocturnal boundary layer”. Submitted to JOURNAL OF THE ATMOSPHERIC SCIENCES |
216 UCB