Technical Note: Multi-centennial scale analysis and synthesis of an ensemble mean response of ENSO to solar and volcanic forcings

The response of El Ni o Southern Oscillation (ENSO) to solar and volcanic radiative forcings over the past millennium is reanalyzed and extrapolated based on historical data and numerical experiments employing the Zebiak–Cane (ZC) model of the tropical Pacific coupled ocean–atmosphere system. The results suggest a self-similarity of the centennial scale component of the reconstructed ENSO record with a shift in frequencies around 1700 AD when the frequencies almost double. This shift of regime puts forward the non-linearity of ENSO climate with a possible centennial scale forecast, suggesting an ENSO trend toward La Ni a conditions for the next three decades.