大象传媒

Is weather becoming more extreme?

Extreme weather conditions are becoming more common in some parts of the world. Global climate change is influencing the frequency and intensity of extreme weather events.

Ocean currents

El Ni帽o and La Ni帽a are complex weather patterns resulting from variations in ocean temperatures in the east-central equatorial Pacific Ocean, between 120掳 west and 180掳 (the International Date Line).

El Ni帽o and La Ni帽a are opposite phases of the ENSO (El Ni帽o-Southern Oscillation) cycle - a term describing the fluctuations in temperature between the ocean and atmosphere in this part of the planet.

El Ni帽o means 'the little boy' in Spanish, and is often referred to as the warm phase of the ENSO - being represented by periods of unusually warm water in the Pacific Ocean around the month of December.

El Ni帽o is a current of warm water flowing from Australia to South America just below the Equator. It affects both Australia and North America. La Ni帽a affects Asia, South America and North America.

La Ni帽a translates as 'the little girl' in Spanish, and can be referred to as the cold phase of the ENSO. It creates below average temperatures in the east-central Pacific.

El Ni帽o and La Ni帽a episodes usually occur approximately every two to seven years, and last for between nine and twelve months (although can sometimes go on for years). The frequency of their appearance is unpredictable, but El Ni帽o conditions occur more often than La Ni帽a.

The presence of El Ni帽o and La Ni帽a conditions can have a significant influence on weather patterns across a large part of the globe, including changes to rainfall patterns (often leading to flooding) and wind patterns (alterations to the trade winds), as well as making changes to sea temperatures.