Front Page

UK

World

Business

Sci/Tech

Sport

Despatches

World News in Audio


On Air

Cantonese

Talking Point

Feedback

Low Graphics

Help

Site Map

Tuesday, December 2, 1997 Published at 11:59 GMT



Special Report

El Niño - a spanner in the weather machine
image: [ Diagram shows the switch in currents and winds which upset the weather ]
Diagram shows the switch in currents and winds which upset the weather

El Niño is a naturally-occurring climatic event in the eastern Pacific which plays havoc with the world's weather system.

Under normal conditions warm ocean currents flow west towards the Asian continent and the underlying cold nutrient-rich water rises along the east Pacific coast of the Americas.

Every few years this trend reverses and the warmer currents flow east and the cooler ocean body sinks. Trade winds dwindle and sometimes reverse direction as the ocean temperature warms.

The changes to the weather can be quite dramatic, with increased rainfall in the southern United States and South America, and drought conditions in the west Pacific including Australia and Indonesia.

The atmosphere is also affected by the sea temperature as evaporation from the vast pool of warm water in the Pacific generates violent thunderstorms. These convection storms affect the high altitude winds of the jet stream leading to widespread weather changes.

Recent severe weather around the globe has been blamed on El Niño, and the World Bank and Inter-American Development Bank are already preparing more than $500m in loans to help Peru and Ecuador cope with the onslaught.


 





Back to top | BBC News Home | BBC Homepage

©

Link to BBC Homepage

[an error occurred while processing this directive] [an error occurred while processing this directive]
  Relevant Stories

06 Nov 97 | Special Report
Science struggling to predict El Niño devastation

06 Nov 97 | Special Report
El Niño could double the tuna catch

26 Oct 97 | World
The Advent of El Nino

 
  Internet Links

El Niño information - UN's World Meteorological Organisation

What is El Niño? - NOAA

El Niño Southern Oscillation home page


The BBC is not responsible for the content of external internet sites.