El Niño

LEVEL 1

What is “El Nino”? It is a phenomenon that occurs near South America but has effects far beyond South America. Some El Nino events have lasted longer than a year.

What happens during an El Nino year?Pacific waters off the coast of South America warm up.

LEVEL 1

Why do the Pacific water warm up in an El Nino year?

Normally, winds blow from east to west across the ocean and drag warm surface air along in the same direction. That means that there is a shallow layer of warm water over much cooler water below in the eastern Pacific.

In an El Nino year, the normal winds don’t blow as heavily. This means that ocean currents reverse and warm water moves to the eastern Pacific.

El Niño Years

1902-1903

1905-1906

1911-1912

1914-1915

1918-1919

1923-1924

1925-1926

1930-1931

1932-1933

1939-1940

1941-1942

1951-1952

1953-1954

1957-1958

1965-1966

1969-1970

1972-1973

1976-1977

1982-1983

1986-1987

1991-1992

1994-1995

1997-1998

Level 1When does El Nino occur? It occurs about every two to seven years.

Level 2 -- Patterns

Where does El Nino occur and where does it impact?

El Nino occurs in the Pacific Ocean. Areas of impact seem to be mostly equitorial or in the Southern Hemisphere

Level 3: Why might these patterns exist?

There is a see-saw type shift in air pressure between the eastern and western halves of the Pacific. When pressure rises in the east, it will fall in the west. This pressure causes the winds to act differently. The warm waters in the Pacific (near the equator) put more moisture into the air; this causes an increase in rain events over a much bigger area than normal. El Nino can affect wind currents in the upper air. Since major wind currents steer the weather systems in middle latitude areas (e.g.: North America) typical storm paths in the U.S. are shifted. Shifting of major air wind currents causes weather and short-term climate changes in other parts of the globe. Places such as Australia, Indonesia, Brazil, India and Africa might experience drought conditions because rainstorms are shifted away from these areas. Argentina, South China, Brazil and Japan might get an increase in rainstorms that cause

long periods of heavy rains and flooding.

Level 4: Why should we care about this?

The greatest impacts of El Nino are felt in Latin America and the Caribbean: drought and floods are the biggest problems. Because of warm waters by Peru, fish and plant life is dramatically reduced, affecting the livelihood of MANY fishermen. By further studying El Nino, it might be possible to predict when it will happen. People would be able to plan ahead with their crops and livestock, and countries could have effective flood plans in place.

March 25, 1997 November 15, 2004

The patterns of El Niño over a 7 year period.

El Nino impacts in Arizona

El Nino and its impact on Uganda

El Nino and its impact on India

El Nino causes mudslides in Peru

Level 4: Why should we care about this?How might farmers in South America plan ahead for an El Nino year?

Answer: In Brazil, for example, there are many cattle ranches. During El Nino, that area has high temperatures and little precipitation. Farmers would probably want to buy grain ahead of time and store it for the El Nino year as it will save them money and cattle loss. They may also want to put in a system for capturing and storing (and maybe purifying) water. This way they will have water from “normal years” saved to give to their cattle.

Level 5: What if…?

1.What if the El Nino took place in the Atlantic Ocean instead of the Pacific Ocean?

2.What if global warming increases?