Barotropic beta plane turbulence

[krishnapriyavr0]

Hi,
Recently I came across this work in PRL https://doi.org/10.1103/PhysRevLett.110.224501 regarding the emergence of large-scale structures in Barotropic beta-plane turbulence. I was wondering if I could use your code in the webpage given here https://fourierflows.github.io/GeophysicalFlowsDocumentation/dev/literated/singlelayerqg_betaforced/ can be used to learn and reconstruct the plots this work? I am also interested to know how to calculate the nonzonal mean flow (nzmf) index mentioned in this paper and also in your other works. I would greatly appreciate any help. Thank you.

[navidcy]

hi @krishnapriyavr0,

regarding the work by Bakas & Ioannou, you can definitely reproduce their nonlinear simulations using GeophysicalFlows.jl using the SingleLayerQG. The example you point out is a great starting point to reproduce these results. But to reproduce the solutions for the flow statistics (eqs. 2a-2b, 3) you would need to first implement them in a new module.

The nzmf index is described in the 2nd paragraph of p. 224501-2. Given the solution (prob.sol) which is in spectral space already, you can compute it by summing the appropriate non-zonal modes as described in the paper. I'm not sure if this is what you need -- does this answer your question?

[krishnapriyavr0]

Hi,
Your answer is really helpful. Thank you so much. One more question on the non-zonal modes. Is it kl:K<K_f where we are looking at the product of k and l or whether we are looking at modes where k<K_f and l<K_f? I ask this question with my limited knowledge on zonal flows.
Thank you.

[navidcy]

I believe they mean search amongst all k, l so that (k^2+l^2)^{1/2}< Kf - ΔKf

[navidcy]

Indeed their notation is a bit ambiguous at that point. There is also another paper by them at JFM which they may include more details. http://users.uoa.gr/~pjioannou/papers/vortex_jfm.pdf

[krishnapriyavr0]

Sure. I will check it out. Thank you so much for the help.

[krishnapriyavr0]

Hi @navidcy
I just have one more doubt related to forcing in beta plane turbulence. I understand the code force the vorticity equation with stochastic excitation that is delta-correlated in time and while spatially homogeneously and isotropically correlated. I was wondering if i can implement rapidly decorrelating spatially homogeneous, stochastic force which is assumed to be a random function both in space and time. This type of forcing was previously used in Lilly(1969) and Srinivasan and Young (2012) using this code? Should I just change the functional form of 'forcing_spectrum' to do so? Could you please share any materials that can give me more information on this?
Thank you