Gavin Schmidt of NASA states here that the predictability level of ENSO is at 6-months:
> "Since the 1980s, we’ve had sufficient understanding of ENSO to be able to predict the occurrence and speed of these waves and, consequently, the variability of ocean temperatures in the Eastern Pacific about six months in advance."
Also a paper by Dunkerton on the QBO
Dunkerton says the current QBO model is validated by lab experiments undertaken on a scale model, which is described in the [previous post](15527/#Comment_15527). Actually I think that setup confirms my closed form analysis, as the approximation I make along the equator turns a rotating sphere into a rotating cylinder.
and a blog posting:
I added the following comment but it went into moderation, so I will reproduce here:
Ultimately, the reason that QBO can be modeled is that it stays along the equator and behaves with a reduced dimensionality inside what amounts to a waveguide. Right at the equator, the Coriolis forces precisely cancel and the system of equations that govern fluid flow on a rotating sphere can be simplified and thus analyzed in closed form. These equations were originally formulated by the mathematician Pierre Laplace in the late 1700’s to try to understand the dynamics of ocean tides.
In fact, the QBO essentially is a manifestation of an atmospheric tide governed by external forces — the current consensus is that gravity waves are responsible. Yet, on close examination these gravity waves happen to be perfectly aligned with the gravitational tractive forcing of the lunar nodal cycle. The pull of the moon as it crosses the equator then controls the direction of the QBO cross-wind.
The nodal lunar cycle is 27.212 days, so how does the 28 month period of the QBO cycle come about? That’s actually quite straightforward to understand. The cycle “beats” with the solar seasonal cycle creating a stronger pulse that occurs every 2.369 years or approximately 28 months. These are pulses of acceleration, which when integrated become a velocity and turn into these almost squared-off sinusoidal oscillations that are characteristic of the QBO wind. Anyone that has done any signal processing knows that the integral of a sequence of delta spikes results in a square wave.
That’s the key observation that the AGW-denier Richard Lindzen missed when he formulated his original QBO theory over 40 years ago. He didn’t see the lunar tidal connection and so created his own half-baked explanation of what drove the oscillations. Everyone seemed to follow his lead and so we have gone down a deep rabbit hole of complexity to try to understand QBO ever since.
What happens outside of the equatorial latitudes is that the Coriolis forces start to exert themselves, which then will create the twisting vortices in the jet stream which are much more difficult to analyze. We do know that the polar vortex has shown correlation with the direction of the QBO.
But we really have to start somewhere and the best place is to work the foundational models from scratch. It will take a while to unwind from what Lindzen inflicted on us with his limited QBO theory over 40 years ago.