Shown above, is the flux optical depth anomalie for the Earth's atmosphere between 1948 and 2007. It turns out that this is a rough measure the total column density of water vapor in the Earth's atmosphere from year to year over this time period.
Shown below, is a comparison between the polar Fast Fourier Transform (FFT) of the flux optical depth anomalie between 1964 and 2001, and a periodogram of the ENSO/SOI over the same time period.
[N. Sidorenkov, Astronomy Reports, Vol. 44, No. 6, 2000, pp 414 - 419, translated from Astronomischeskii Zhurnal, Vol. 77, No. 6, 2000, pp 474 - 480]
Remarkably, the 6.2 (& 6.0), 4.8, 3.6, 2.4, and 2.1-year periodicities in the ENSO/SOI periodogram of Siderenkov (2000), are also clearly evident in the FFT of the flux optical depth anomalies data.
Four of these six long-term periodicities (i.e. 2.4, 3.6, 4.8, and 6.0 years) are sub-harmonics of the 1.2 year period of the Earth's free nutation i.e. the Chandler Wobble. In addition, all six of the long-term periodicities are very close to the super-harmonics of the 18.6 year period of the Earth's forced nutation (i.e. 6.2, 4.7, 3.7, 2.3, and 2.1 years) ie. the periodic precession of the line-of-nodes of the Lunar orbit.
This data tells us that the ENSO must play a major role in setting the overall column density of water vapor in the Earth's atmosphere. In addition, it indicates that the ENSO must also be an important factor in setting the World's means temperature, since water vapor is the dominant greenhouse gas in the Earth's atmosphere.
What is even more remarkelable, is the fact that common frequencies seen in the two data sets are simply those that would be expected if ENSO phenomenon was the resonant response of the Earth's (atmospheric/oceanic) climate system brought about by a coupling between the Earth's forced (18.6 year Nodical Lunar Cycle) and unforced (1.2 year Chandler Wobble) nutations.