Satellite observations of the Pacific suggests that the El Niño phenomenon is finally beginning to decline, Science Correspondent Dr David Whitehouse reports.

For the past 15 months a sophisticated radar system that surveys the oceans from space has been monitoring the El Niño weather phenomenon.

El Niño is shown in red (Nasa)

The Nasa satellite data has produced a series of cross sections through the Pacific showing the temperature of the ocean as well as the height of the sea level.

Recent observations suggest that El Niño's warm waters are cooling and that colder waters are moving east across the Pacific, which could mean that El Niño is on its way out.

El Niño events occur roughly every 7 years and last between 12 and 18 months.

They begin when a region of the west Pacific warms causing a warm water current to travel east along the equator to South America. The effects on weather systems are worldwide.

This year, El Niño has been particularly harsh. There have been droughts in Australia, Papua New Guinea, Africa and some parts of the United States. There has also been a delayed monsoon in South East Asia, floods in other regions of the United States and storms along the Pacific coast of North and South America.

The current El Niño phenomenon has also slightly affected the length of the day making it a tenth of a second longer.

Even worse, some scientists suggest that El Niño events may occur more frequently in the future, possibly every 3 years or so.
 

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