A wave crosses the Pacific Ocean, bounces off the shore, and returns to change the water temperature. This journey takes about six months. That is why El Niño arrives not immediately but with a delay. Scientists have built an equation that accounts for this delay, and they did so not by guesswork but through rigorous calculation.
The new model shows that temperature oscillations become slower and closer to what is observed in reality. The period increased from 2–3 years to 3.5–4.5 years, while real El Niño occurs every 4–7 years. This means the equation better reflects nature. This approach can also be applied to other climate phenomena where the past influences the future.
The delay in the El Niño model corresponds to the time it takes for Rossby waves to cross the Pacific basin, reflect off the western boundary, and return as Kelvin waves. This journey takes about half a year.