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

El Ni�o 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 Ni�o's warm waters are cooling and that colder waters are moving east across the Pacific, which could mean that El Ni�o is on its way out.

El Ni�o 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 Ni�o 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 Ni�o 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 Ni�o events may occur more frequently in the future, possibly every 3 years or so.