Laboratory experimental study of the atmospheric energy spectra

What is it about?

A long-standing question is what causes the -5/3 slope in the atmospheric spectra at the mesoscale: is it turbulence? Gravity waves? Something else? In this work, we use a laboratory experiment-the differentially heated rotating annulus-to investigate the problem. Our experimental spectra show striking similarities to the atmospheric one. By separating the spectra into the vortex and wave component, it emerges that at the large-scale end of the mesoscale the gravity waves observed in the experiment cause a flattening of the spectra and provide most of the energy. At smaller scales, our data analysis suggests a transition towards a turbulent regime with a forward energy cascade up to where dissipation by diffusive processes occurs.

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