ENSO is likely just a larger scale manifestation of ocean tides, applying long-period lunisolar forcing to the Pacific ocean's thermocline. This results in a cyclic sloshing that alternately exposes warmer and colder water to the surface. I presented this model at last year's AGU. The treatment applies the math of hydrodynamic sloshing, which is a conventional approach for volumes of liquids. The latest validation checks the model against 300 years of ENSO coral proxy data. It works arguably as well as conventional tidal analysis of ocean SLH, but on a much larger scale.