Anisotropic turbulence and Rossby waves in an easterly jet: An experimental study

Anisotropic macroturbulence and diffusion associated with a westward zonal jet: From laboratory to planetary atmospheres and oceans

“…An analogous length scale in the spherical geometry was identified in simulations in [60]. As evident from (8), although scalesL β and L β are proportional, only the scale L β is constantindependent and, thus, better suitable for the use in PV monotonizing algorithm [16]. The scaleL β , on the other hand, plays an important role in diffusion processes [29].…”

“…The analysis necessary for developing such diagnostics can be conveniently performed in a well-controlled environment of a laboratory facility. In our previous investigation, a facility at the University of Rome was used to explore and quantify the effect of the PV monotonizing on a flow field and the relationship between L M and L β [16]. The present study extends this analysis to turbulent diffusion in a basic flow associated with a westward jet.…”

“…If and when a flow features inverse energy transfer and otherwise approaches the regime of zonostrophic turbulence [9,16], the spectra are expected to become…”

“…Additional critical scales are those marking the respective thresholds of spectral anisotropy. They correspond to crossovers between the Kolmogorov and steep spectra developing in slow manifolds in the directions along which waves do not propagate [16,79]. Those scales are proportional to, respectively, L O and L β and denoted L O andL β .…”

“…The determination of L T , which is often quite straightforward, is thus practically equivalent to estimating from L O . In the latter case, the sorting algorithm yields a scale L M that was found commensurate with the scale L β = ( /β 3 ) 1/5 [16] where is the rate of the up-scale energy transfer [17][18][19]. In analogy to L O , turbulence dominates the dynamics on scales shorter than L β while Rossby waves prevail on longer scales [20].…”