A recent paper that claims that tides have a greater influence than surface wind on the forcing dynamics of ENSO.
> Lin, J. & Qian, T. [Switch Between El Nino and La Nina is Caused by Subsurface Ocean Waves Likely Driven by Lunar Tidal Forcing](https://www.nature.com/articles/s41598-019-49678-w.pdf). Sci Rep 9, 1–10 (2019).
> "Here, we demonstrate that the switch between El Nino and La Nina is caused by a subsurface ocean wave propagating from western Pacifc to central and eastern Pacifc and then triggering development of SST anomaly. This is based on analysis of all ENSO events in the past 136 years using multiple long-term observational datasets. The wave’s slow phase speed and decoupling
from atmosphere indicate that it is a forced wave. Further analysis of Earth’s angular momentum budget and NASA’s Apollo Landing Mirror Experiment suggests that the subsurface wave is likely driven by lunar tidal gravitational force."
This is essentially the same thing I have been suggesting -- it just doesn't make sense that a surface wind can drive the sub-surface water sloshing at the thermocline. Take a look at this post from a few years ago from NOAA. They show the following chart of deeper water temperature anomaly (300 feet deep!) while saying with a straight face that surface wind is causing it.
> [Slow slosh of warm water across Pacific hints El Niño is brewing](https://www.climate.gov/news-features/featured-images/slow-slosh-warm-water-across-pacific-hints-el-ni%C3%B1o-brewing)
> "As the warm surface water is pushed westward by the prevailing winds, cool water from deeper in the ocean rises to the surface near South America. This temperature gradient—warm waters around Indonesia and cooler waters off South America—lasts only as long as the easterly winds are blowing."
Give credit to Lin & Qian for pointing out how implausible it is to suggest that wind alone can push water around to that extent. Obviously, tidal forces are the one agent that can influence the reduce gravity imbalance on the deeper thermocline (as hypothesized long ago by the legendary physical oceanographers [Munk and Wunsch](https://www.sciencedirect.com/science/article/pii/S0967063798000703)). Yet no real response from anyone else on a paper that directly contradicts the research consensus.
 Just to indicate how conflicting the research is on the topic of atmosphere versus ocean causality, there's [this paper](https://phys.org/news/2019-10-method-global-picture-mutual-atmosphere.html)
>"The ability to anticipate changes to the ocean or atmosphere based on information from the other system provides society with the opportunity to prepare for future impacts, such as to agriculture and fisheries," said Wills.
>"This is a very important paper in the history of predictability research," said Shukla, "It will surely inspire further research by the predictability research community. In particular, this paper identifies geographical regions on the globe over which there exists potential predictability which can be harvested for improving operational predictions."