The El Niño Cycle, Explained In Charts

It's more likely than not that we're going to see a strong El Niño this year. But just how does the cycle that pushes El Niño forward work? This series of charts explains.

While we still don't fully understand the precise mechanism of the cycle, the interaction between El Niño and opposite pattern La Niña can be clearly seen in this series of sea surface temperature and rainfall anomaly maps for every year since 1985.

NASA's Earth Observatory, who put together the maps using data from the Advanced Very High Resolution Radiometer, explains:

El Niño and La Niña reflect the two end points of an oscillation in the Pacific Ocean. The cycle is not fully understood, but the times series illustrates that the cycle swings back and forth every 3-7 years. Often, El Niño is followed immediately by La Niña, as if the warm water is sloshing back and forth across the Pacific. The development of El Niño events is linked to the trade winds. El Niño occurs when the trade winds are weaker than normal, and La Niña occurs when they are stronger than normal. Both cycles typically peak in December.

You can see the stark contrast between the strongest El Niño year of the last few decades in 1997 and the strongest La Niña year in 1988 even more starkly when looking at the anomaly maps side-by-side. That's 1997 on top and 1988 right below it.

1997

The El Niño Cycle, Explained In Charts

1988

The El Niño Cycle, Explained In Charts

Of course, if El Niño predictions for 2014 are correct, this year could also end up looking quite a lot like 1997.