Download El Nino

El Nino
BIG IDEA: Abiotic and biotic factors
influence the environment
• Large-scale changes in
atmospheric and ocean current
patterns in which, among other
things, warms surface water in the
Pacific moves further to the east
than normal
• NORMAL: A convection cell is driven
by heat at the ocean surface
• Water from the surface evaporates and
the warm, moist water rises, pulling in
cool, dry air,and creating a loop that
transfers heat and moisture out of the
hot zone.
• El Niño: During an El Niño, the
hot spot moves east,creating two
convection cells and altering
climate around the Pacific
basin.
• The red indicates sea-surface
temperature 5 degrees C above
• A warmer ocean translates into
more humidity and clouds in the
area, thus creating global changes
in jet stream circulation.
• Since it's heat that drives the
weather -- differences in
temperature and pressure literally
move air and moisture around the
sky -- if you change the source of
heat, you change the entire weather
system.
Effects of El Nino
• More hurricanes in the Pacific
• Induced droughts in the Amazon and
Indonesia leading to fires
• Intense rains in areas that are
characteristically dry
• Major storms in the NE U.S.
• Flooding in the SE U.S.
• catches of tropical fish off the
West Coast of the United States
• Global economy losses of around 8
billion dollars
La Nina
• Large-scale changes in
atmospheric and ocean current
patterns in which, among other
things, warms surface water in the
Pacific moves further to the west
than normal
• This results in below-normal
sea surface temperatures in the
eastern equatorial Pacific
• Effects tend to be the opposite
of El Nino such as below
normal precipitation in areas of
the U.S.
Why do El Nino and La Nina
Occur?
• El Niño and La Niña result from
interaction between the surface of
the ocean and the atmosphere in
the tropical Pacific.
• Changes in the ocean impact the
atmosphere and climate patterns
around the globe.
• In turn, changes in the atmosphere
impact the ocean temperatures and
currents.
• The system oscillates between
warm (El Niño) to neutral (or cold
La Niña) conditions with an on
average every 3-4 years.