Figure 5.27

El Niño and La Niña events. (A) Sea surface temperature anomalies in the equatorial Pacific Ocean during El Niño and La Niña events stand in stark contrast. El Niño’s most prominent feature is the migration of warm water to the eastern end of the Pacific basin. During La Niña, this warm water is replaced by unusually cold water. (B) Sea surface temperature anomalies since 1965 are plotted for the eastern equatorial Pacific Ocean. Temperatures are given in relation to the long-term average. Temperatures 0.5°C above the long-term average are El Niño events, and temperatures 0.5°C below the long-term average are La Niña events.

(A. Data from NOAA)