Each El Nino is different, in equatorial sea surface temperature (SST) and teleconnection. El Nino/the Southern Oscillation (ENSO) is often conceptually modeled as a coupled oscillation between central Pacific (Nino4) wind and eastern Pacific SST (Nino3.4) variability. Using satellite observations and ocean model experiments, we show that atmospheric convection and wind variability within the Nino3 region holds the key to El Nino diversity.

Historically the term of El Nino evolved from referring to a local coastal warming off Peru to a Pacific-wide phenomenon of global influence. In March 2017, a major coastal El Nino took place off Peru while much of the equatorial Pacific was in a La Nina state. Likewise on the other side the Pacific, a record Indian Ocean dipole took place in September 2019 while Nino3 SST was close to normal. These are some recent examples of extreme events that deviate markedly from canonical ENSO behavior. Understanding the physical causes of such extreme events is crucial to improving climate prediction.