nad asked:

> "You claimed that 2.34 is an important moon period. How does this come about?"

The important periods are interferences of 27.212 days (the Draconic lunar month) with a strongly peaked *seasonal* signal.

so in terms of frequencies where $f = 365.242/27.212 y^{-1}$, the list is

$ 1/f, 1/f-1, 1/f-2, ... , 1/f-13, 1/f -14, ... $

The frequency that is closest to $1 y^{-1}$ is $1/f-13$ = 0.422. This has a period of the reciprocal of this or 2.369 years. More in-depth math [here](http://contextearth.com/2015/11/17/the-math-of-seasonal-aliasing/)

This is sometimes referred to as "nonlinear aliasing" or "natural aliasing" as it comes about from the nonlinear product of more than 1 frequency, leading to a spread of selected harmonics.

There is a good explanation of the effect in this meteorology book : "Mesoscale Dynamics", Yuh-Lang Lin, Cambridge University Press, 2007

![nonlinear](http://imageshack.com/a/img921/4153/t8MMRg.png)

That book references the AGW skeptic Roger Peilke, who wrote about the effect more recently here, "Mesoscale Meteorological Modeling", Roger A. Pielke Sr. Elsevier, 2013

![nonlinear2](http://imageshack.com/a/img923/8332/Kga45H.png)

It can also lead to noisy, spiky behavior in periodograms: [Assessing statistical significance of periodogram peaks](http://arxiv.org/pdf/0711.0330.pdf)

So according to textbooks on meteorology, this effect can occur. And to top that off, this behavior is described in textbooks on *mesoscale* phenomena, of which the QBO of stratospheric winds is a prime example at the extreme upper end of the scale.

> "By the way did you look also at other cycles in the terrestial planet system?"

The moon and the sun have first-order effects on the earth's tides, and the other planets are second-order. So if the QBO is a tidal effect, which is what I am proposing, the other planets should probably be considered but only after the first-order effects are verified.

Thanks for the questions, as it provoked me to do a Google search on nonlinear aliasing. I knew about this from engineering experience but didn't realize how well known it is in climate modeling. Why is it not surprising that an AGW skeptic such as Pielke, or other AGW-denying QBO experts such Lindzen or Salby, would not pick up on this when it was right under their noses? Isn't that rich?

> "You claimed that 2.34 is an important moon period. How does this come about?"

The important periods are interferences of 27.212 days (the Draconic lunar month) with a strongly peaked *seasonal* signal.

so in terms of frequencies where $f = 365.242/27.212 y^{-1}$, the list is

$ 1/f, 1/f-1, 1/f-2, ... , 1/f-13, 1/f -14, ... $

The frequency that is closest to $1 y^{-1}$ is $1/f-13$ = 0.422. This has a period of the reciprocal of this or 2.369 years. More in-depth math [here](http://contextearth.com/2015/11/17/the-math-of-seasonal-aliasing/)

This is sometimes referred to as "nonlinear aliasing" or "natural aliasing" as it comes about from the nonlinear product of more than 1 frequency, leading to a spread of selected harmonics.

There is a good explanation of the effect in this meteorology book : "Mesoscale Dynamics", Yuh-Lang Lin, Cambridge University Press, 2007

![nonlinear](http://imageshack.com/a/img921/4153/t8MMRg.png)

That book references the AGW skeptic Roger Peilke, who wrote about the effect more recently here, "Mesoscale Meteorological Modeling", Roger A. Pielke Sr. Elsevier, 2013

![nonlinear2](http://imageshack.com/a/img923/8332/Kga45H.png)

It can also lead to noisy, spiky behavior in periodograms: [Assessing statistical significance of periodogram peaks](http://arxiv.org/pdf/0711.0330.pdf)

So according to textbooks on meteorology, this effect can occur. And to top that off, this behavior is described in textbooks on *mesoscale* phenomena, of which the QBO of stratospheric winds is a prime example at the extreme upper end of the scale.

> "By the way did you look also at other cycles in the terrestial planet system?"

The moon and the sun have first-order effects on the earth's tides, and the other planets are second-order. So if the QBO is a tidal effect, which is what I am proposing, the other planets should probably be considered but only after the first-order effects are verified.

Thanks for the questions, as it provoked me to do a Google search on nonlinear aliasing. I knew about this from engineering experience but didn't realize how well known it is in climate modeling. Why is it not surprising that an AGW skeptic such as Pielke, or other AGW-denying QBO experts such Lindzen or Salby, would not pick up on this when it was right under their noses? Isn't that rich?