In the previous comment I referenced the [Rajchenbach article on Faraday waves](

There is a telling assertion within that article:

> "For instance, to the best of our knowledge, the dispersion relation (relating angular frequency ω and wavenumber k) of parametrically forced water waves has astonishingly not been explicitly established hitherto. Indeed, this relation is often improperly identified with that of free unforced surface waves, despite experimental evidence showing significant deviations"

What they are suggesting is that too much focus has been placed on natural resonances and the dispersion relationships within a free fluid volume. Whereas the forced response is clearly as important if not more, and that the forcing will show through in the solution of the equations. If you haven't inferred by now, I have been pursuing this strategy for a while, and the Rajchenbach article is the first case that I have found made of what I always thought should be an obvious premise. That's a peer-reviewed article and the fact that the reviewers allowed the "astonishingly" adjective in the paper is what makes it telling. It's astonishing in the equivalent sense that Rajchenbach & Clamond are pointing out that a pendulum's motion will be impacted by a periodic push. IOW, astonishing in the sense that it should be obvious!

So, what I take from it is that there has been a misguided focus on unconstrained or free fluid flow, as opposed to solving the dynamics of a Newtonian fluid within an enclosing container. Read through it and see if you come up with a similar understanding.

Further, what I am finding is that in the cases of ENSO and QBO, the fundamental seasonality forcing does not jump out at you, but in fact is mixed into the stew and is not revealed by conventional methods. What you need is a good model of the physics and novel means of extracting the parameters from the dynamics, such as using the Mathieu equation for fluid dynamics -- as Rajchenbach suggests and I have been advocating for ENSO. That's why it hasn't been obvious over the years, and the continuing claim being made that ENSO and QBO are driven by natural/chaotic resonances lives on ...