ENSO transitions - a game of domino

You can think about past ENSO events as a game of domino. The chain of dominoes symbolises the sequence of ENSO events which gradually increases in length each year. While some tiles are blank representing neutral conditions or a “joker”, other tiles show El Niño and La Niña conditions. To play by the rules, only matching ends must touch each other.

When we looked at the sequence of ENSO events or domino tiles during the observed period, we first did an inventory of tiles. We found some expected observations like tiles expressing a high likelihood of an La Niña event to follow an El Niño event. This tile, or transition as we call it, is one of the most common tiles in the games. But what we also found was that some tiles are missing or simply don’t exist.