El Niño and La Niña

The climate of eastern and northern Australia is influenced by the southern oscillation, which is a seesawing of atmospheric pressure between an area just to the north of Australia and the central Pacific Ocean. Abnormally high atmospheric pressure over northern Australia is generally associated with the onset of widespread drought. This event is known as El Niño. For eastern and northern Australia the southern oscillation is the second most important cause of climatic variation, the annual seasonal cycle being the most significant. Such events are usually preceded or followed by the opposite extreme. When the air pressure over northern Australia is abnormally low, rainfall tends to be above average over much of eastern and northern Australia. This event is known as La Niña.

El Nino Diagram with text.png

El Nino and La Nina animation