Two recent articles prompted a few ideas

From last year, https://watchers.news/2022/11/10/study-shows-how-earth-sun-distance-dramatically-influences-annual-weather-cycles-in-the-equatorial-pacific-in-a-22-000-year-cycle/ points to:

Two annual cycles of the Pacific cold tongue under orbital precession

Which says that

“Because the distance effect annual cycle (from perihelion to perihelion, otherwise called the anomalistic year, 365.259636 d (ref. ⁶)) is slightly longer than the tilt effect annual cycle (from equinox to equinox, otherwise known as the tropical year, 365.242189 d (ref. ⁶)), the LOP increases over time. A complete revolution of the LOP is the precession cycle, about 22,000 yr (ref. ³⁸). “

The claim is that the exact timing and strength of the annual cycle extreme is important in initiating an El Nino or La Nina cycle. as the Longitude of Perihelion (LOP) moves over time, so that when this aligns with the solstice/equinox events, the ENSO behavior will mirror the strength of the forcing.

Next article

ENSO-related centennial and millennialscale hydroclimate changes recorded from Lake Xiaolongchi in arid Central Asia over the past 8000 years

They note 800 year cycles in the observations

This is not a 22,000 year cycle (as stated its actuallly closer to 21,000), but it’s possible that if tidal cycles play a part of the forcing, then a much shorter paleo cycle may emerge. Consider that the Mf tidal cycle of 13.66 days will generate a cycle of ~3.81 years when non-linearly modulated against the tropical year (seasonal cycle), but ~3.795 years modulated against the perigean or anomalistic year (nearest approach to the sun).

The difference between the two will reinforce every 783 years, which is close to the 800 year cycle. Aliasing and sideband frequency calculations reveal these patterns.