Download LA Nina CONDITIONS

La Nina and El
Nino
Phenomena
http://www.youtube.com/watch?v=AEoHz56jWGY
El Nino Definition
http://edition.cnn.com/video/#/video/weather/2009/07/27/byrnes.ctw.aregenti
no.el.nino.cnn?iref=videosearch Impact
Water (Ocean) and Air
(Atmosphere)
Interactions
Source: http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html
Animation
Trade Winds
Ocean Currents
La Nina 2011 video
http://www.youtube.com/
watch?v=iWTucpsClLc&NR=
1&feature=fvwp
Air Pressure
Air and water
temperature
What do we already know?
•Density: Warm air is less dense than cool air. Warm air
rises. Cool air sinks. (convection)
•Pressure:
High temperature means low air pressure and
low temperature means high air pressure.
High pressure = fair weather. Air masses press down,
Warm air cannot rise and form clouds.
Low pressure = cloudy, rainy weather. Air masses
move apart, warm air rises and form clouds.
Air moves from an area of high to low pressure.
NORMAL CONDITIONS
Western
Pacific
(Australia)
Guide questions:
1. In what direction would the wind blow?
2. Describe the climate in the Western Pacific? Eastern Pacific? Consider
a. pressure systems (high or low)
b. ocean temperature
Eastern
Pacific
(Peru)
Western
Pacific
(Australia)
Eastern
Pacific
(Peru)
Trade winds
blowing
Guide questions:
1. Describe what is happening in the atmosphere (Walker Circulation Cell)?
2. Why is rain most likely to happen over a longer period in the Western Pacific?
LA Nina CONDITIONS
Western
Pacific
(Australia)
Eastern
Pacific
(Peru)
Trade winds
blowing
Guide questions:
1. What would happen to the water in the Eastern Pacific if the trade winds got
stronger?
2. What would be the result of cold water moving towards the West (Think about
the weather)?
Western
Pacific
(Australia)
Eastern
Pacific
(Peru)
Guide questions:
1. Why is there heavier rain observed in more countries in the western Pacific?
2. What changes in weather would occur in North America? Hint: red circle
• Trade winds weaken
Global Impact
La Nina
http://www.youtube.com/watch?v=ovDp1crqdOU
El Nino/La Nina video (with impact on fishing and US
weather)
During non-El Niño years, the southeast trade winds, drag surface water westward away
from shore. As surface water moves away, upwelling brings up colder waters from depths
of 40-80 meters or more. This deep sea water is rich in nutrients which can sustain large
fish populations.
During an El Niño event, the southeast trade winds weaken and so does the
amount upwelling in the eastern Pacific.
The deeper thermocline means that any upwelling that does occur is unable to tap
into the rich nutrients found in deeper waters. Consequently, warm nutrient-poor
water predominates the region and a decrease in the fish population is observed.
Atmospheric Consequences of El Niño
influencing weather patterns worldwide
Drought in Southern Africa, Southern India, Sri Lanka, Philippines,
Indonesia, Australia, Southern Peru, Western Bolivia, Mexico, Central
America
Heavy rain and flooding in Bolivia, Ecuador, Northern Peru, Cuba, U.S.
Gulf States
Hurricanes in Tahiti, Hawaii
Why do we care: Global climate impacts continued
Floods
Lakeport, California (1998)
Fires
Australia (1998)
SOURCES:
•http://esminfo.prenhall.com/science/geoanimations/animations/2
6_NinoNina.html
•http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/eln/home.rxml
•PAGASA-DOST