8 Questions on El Niño and La Niña

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http://forum.santabanta.com/showthread.htm?286003-El-Ni%C3%B1o-vs-La-Ni%C3%B1a

Eric AngatTeacher

Essential Question

How do the oceans affect the weather and climate?

El Nino is the warming of the Pacific Ocean.

1.What is El Nino?2.How often does El Nino happen?3.What happens to the water of the

Pacific Ocean during El Nino?4. How are South America and

Australia affected by El Nino?5.What is La Nina?6.How do the oceans affect the

weather?

La Nina•Pacific temperature cooler than normal•Last 9-12 months•Pacific Ocean drops 3-5 degrees•Reoccurs every 3-7 years•Cause by a decrease of ocean temp and increase in trade wind strength•Westward wind gets stronger•Allowing low cooler water to surface toward South America•Cloud build up in Southeast Asia•Wet period in middle eastern U.S•Drought in South-eastern U.S•Flood in Australia•Brings nutrients to south American coast•Cooler and snowier Canadian winter•Up welling of cool water

El Nino•Warm ocean current flow along equator•Occur every 4-7 years•Trade wind weakens during El Nino•Water flows downhill to the east•Less warm air rises in the west•As a result less wind is created•Wind can no longer push warm water from the coast of South America•Warm water pushes cooler, unwilling water•No up welling to fertilize phytoplankton•El Niño produces a lot of evaporation•More cloud build up in South America

1.What is El Nino?

2. How often does El Nino happen?

3. What unusual happen to the water of the Pacific Ocean, West of South America during El Nino?

4. How is South America and Australia affected by El Nino?

A chaotic weather phenomenon. Characterized by the warming of the Pacific Ocean.

Appears every 3-7 years, and tends to happen around December.

Unusual warming of ocean water. No one knows how.

South America has more rainfall and Australia experiences drought.

5. What is La Nina?

6. How do the oceans affect the weather?

It is the cooling of the Pacific Ocean. Causes flooding in Australia.

The unusual heating and cooling of the ocean creates and imbalance that alters the global wind patterns.

7. What are the effects of El Nino and La Nina?

El Nino results to stronger Trade Winds and warmer Pacific Ocean.Flooding in South America, drought in Southeast Asia and Australia. Ice storms, drought, and mudslides in North America.La Nina results to weaker Trade Winds and cooler Pacific Ocean. Weather is opposite to El Nino.

Trade Winds are winds near the equator.

Equator

Trade Winds ( northeast)

Trade Winds (southeast)

Trade Winds are strong during El Nino.

Trade Winds are weak during La Nina.

8. How is the United States affected by El Nino?

Drought

Very Cold

Severe Storms

Storms, precipitation

Weak (WE), Moderate (ME), and Strong El Niño (SE).

Table 1.  Consensus List of El Niño and La Niña YearsWinter WRCC CDC CPC MEI Consensus1950-51 C+ C C C La Niña1951-52 W+   W-    1952-53          1953-54 W    W-    1954-55     C C-  1955-56 C+   C+ C Strong La Niña1956-57 C   C- C- Weak La Niña1957-58 W W W+ W El Niño1958-59     W+  W-  1959-60          1960-61          1961-62       C-  1962-63       C-  1963-64 W   W-    1964-65 C   C C- La Niña1965-66 W+ W W W El Niño1966-67       C-  1967-68       C-  1968-69     W W-   1969-70 W   W    1970-71 C   C C La Niña1971-72 C   C- C- Weak La Niña1972-73 W+ W W+ W Strong El Niño1973-74 C+ C C+ C+ Strong La Niña1974-75 C   C- C- Weak La Niña1975-76 C+ C C+ C Strong La Niña1976-77 W   W-    1977-78 W+   W- W- El Niño1978-79          1979-80      W- W-  1980-81          1981-82          1982-83 W+ W W+ W+ Strong El Niño1983-84     C-    1984-85     C-  C-  1985-86          1986-87     W W  1987-88 W+ W- W W- El Niño1988-89 C+ C- C+ C Strong La Niña1989-90          1990-91     W+    1991-92 W W W+ W+ Strong El Niño1992-93 W   W+ W- El Niño1993-94 W+   W    1994-95 W+   W W- El Niño1995-96     C-  C-  1996-97          1997-98 W+ W W+ W+ Strong El Niño1998-99 C+   C C- La Niña1999-00     C C  2000-01 C C C- C- La Niña2001-02          2002-03 W W W W El Niño2003-04          

Warmer Cooler Equator

Northern Hemisphere

Southern Hemisphere

Ocean water temperatures have a great effect on weather patterns, including creating hurricanes and providing energy for coastal storms.

Hundreds of years ago, South American fishermen observed that every year around December or Christmas, coastal waters of the Pacific became warmer as a current flowed from north to south. This change often meant a smaller catch but more rainfall inland. And that translated to more abundant crops. They called it El Niño.

El Niños can bring heavy rainfall and flooding to the West Coast of South America. Meanwhile, Australia and Southeast Asia may face a drought and high risk of wildfires. In North America, scientists have also linked unusual weather events — including ice storms, droughts and mudslides — to the arrival of an El Niño.