Led by the work of Sir Gilbert Walker in the 1930s, climatologists determined that El Niño occurs simultaneously with the Southern Oscillation.
Led by the work of Sir Gilbert Walker in the 1930s, climatologists determined that El Niño occurs simultaneously with the Southern Oscillation. The Southern Oscillation is a change in air pressure over the tropical Pacific Ocean. When coastal waters become warmer in the eastern tropical Pacific (El Niño), the atmospheric pressure above the ocean decreases. Climatologists define these linked phenomena as El Niño-Southern Oscillation (ENSO). Today, most scientists use the terms El Niño and ENSO interchangeably.