Transcript Oceans and Climate Changes

Oceans and
Climate Changes
Ocean Currents
• Movement
of water
from one
place to
another
Surface Currents
•Powered by
wind
•Move upper
few 100
meters of
seawater
• Wind forms when air in an area of
high pressure moves to an area of
lower pressure
• Equator’s warm air is pushed up by
denser, colder air
• The Pole’s cold air, sinks below less
dense air
•Due to the movement of the
earth, wind and currents DO
NOT move in straight lines
• The Coriolis Effect –
rotation of the Earth
causes moving air and
water to change
direction
– To the right north of
the equator
– To the left south of
the equator
Gulf Stream Current - Warm
• Atlantic Ocean
• Brings warm water
from the equator up
North
• Keeps N. American
East Coast Waters
warm
• Keeps Iceland mild
and ice-free all year
California Current - Cold
• Pacific Ocean
• Brings waters
from North pole
down South
• Keeps North
American West
Coast Cool
Density Currents
• More dense water sinks and pushes up
less dense water
• This moves water around globe
What makes Water Dense?
• Cold
Temperature
• High Salinity
(amount of
salt in
water)
Cold, Salty Water
• When water freezes, salts are dissolved and
left in unfrozen water
– This makes unfrozen water VERY DENSE
• When frozen water melts, it is less dense
• This causes a change in density and
movement of water…DENSITY CURRENTS
WHY IS THIS IMPORTANT?
It is important because…
•If the ice caps where to melt, then we
would have a large amount of less
dense water
•If salinity is reduced, then density
currents would WEAKEN or STOP
•This would cause major CLIMATE
SHIFTS
–Change in climate
–Change in weather
El Nino
• An occasional climatic
event in which strong
Pacific winds WEAKEN or
REVERSE
Effects of El Nino
• Ocean temperatures near Peru
HEAT UP.
• The position and strength of one of
the jet streams may be altered,
changing wind and precipitation
patterns around the world.
• Africa and Australia may
experience drought
La Nina
•The winds blowing
across the Pacific are
stronger than normal