Transcript school presentation - Burton Fitzsimmons

“The El Nino Phenomenon”
News 8 Austin Weather
Burton Fitzsimmons
News 8 Girl Scout Day
November 1, 2008
[email protected]
Earth’s Atmosphere
Defined: a layer of
gasses surrounding
planet Earth that’s
retained by Earth’s
gravity
Nitrogen
78%
Oxygen
21%
Argon
1%
Water Vapor 1%
Satellite/Radar Loop
Satellite Loop
Satellite Loop
El Nino
Defined: a global coupled ocean-atmosphere phenomenon
In the Pacific ocean, El Nino (“the little boy”) and La Nina
(“the little girl”) – noticed off the west coast of South America
around Christmas time first in 1923.
El Nino – warming of the equatorial Pacific waters; seems to
occur once every 3 to 7 years
La Nina – cooling of the equatorial Pacific waters
What and how do we know?
El Niño as a physical occurrence is a proven
fact. The way it works is a theory.
Difficult to predict start of cycle but fairly
good skill in forecasting next 6 to 9 months
ahead
-Monitoring with satellites
-Buoys measure sea surface temps, waves, winds,
and ocean currents
-Reports from ships at sea
South Pacific Gyre
El Nino
Global SST Departures (oC)
Equatorial SSTs remained below-average in the central and east-central Pacific Ocean,
and above-average in the western Pacific, Atlantic and central Indian Ocean. Positive
anomalies covered much of the North Atlantic and western North Pacific Oceans.
Central & Eastern Pacific Upper-Ocean
(0-300 m) Weekly Heat Content
Anomalies
January 2007 to April 2008: below average
May 2008 to mid-August 2008: above average
Mid-August 2008 to Current: below-average
El Nino Oscillation since 1950
The most recent
ONI value (July–
September 2008)
is 0.0oC.
El Niño
neutral
La Niña
1997-1998 El Nino
Strongest on record, developing more rapidly than
any other El Nino in past 40 years.
July 1997: record high sea-surface temps in the
Pacific Ocean.
Fall 1997: record flooding in Chile, Marlin caught off
coast of Washington, extensive smog cloud over
Indonesia, quiet Atlantic hurricane season.
Winter 1997-98: heavy rains southern US, unusually
mild Midwest winter, record rains in California and
Florida.
Hurricane Katrina
Tropical Connections?
Historically…
El Nino yields less tropical activity in the
Atlantic and more in the Pacific.
La Nina yields more tropical activity in the
Atlantic and more in the Pacific.
Funnel Cloud Over Austin
El Niño Outlook
Forecasts indicate NEUTRAL conditions will continue through
Northern Hemisphere Summer 2009. Several dynamical models suggest
weak La Niña conditions during the Winter of 2008-09
Figure provided by the
International Research
Institute (IRI) for
Climate and Society
(updated 24 October
2008).
SST Outlook: NCEP CFS Forecast
Issued 26 October 2008
The CFS ensemble mean (heavy blue line)
indicates La Niña conditions through mid2009.
U. S. Seasonal Outlooks
November 2008 – January 2009
Temperature
Precipitation
These seasonal outlooks combine long-term trends and soil
moisture effects.
For More Information
http://news8austin.com/weather
http://weather.gov
Thank you!
Burton Fitzsimmons
Chief Meteorologist
www.news8austin.com/weather
[email protected]