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Current and Climate
Ch 13-4
Which is more dense?
• Hot water is red and
cold water is blue.
• Is cold water more
•
•
dense than warm
water?
How can you tell?
Explain.
Current
• A large stream of moving
•
•
water that flows through
the oceans
Can carry water from one
place to another
Because of the density
differences between
warm and cold water
some currents form on
the surface of the ocean
and others form deep in
the ocean
Surface Currents
• Are driven mainly by winds.
• Most flow east to west and then double back to
complete the circle
Coriolis Effect
• Because the Earth is
•
moving on its axis this
motion effects the
elements of the Earth
that can freely move
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Coriolis Effect
• In the Northern
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•
Hemisphere the currents
curve to the right
In the Southern
Hemisphere the currents
curve to the left
The Coriolis effect is
strongest at the poles
and weakest at the
equator.
Gulf Stream
• Most powerful surface
•
•
current in the North
Atlantic Ocean
30 km wide and 300
meters deep
Carries warm water
from the Gulf of
Mexico up the North
American coast
Gulf Stream
• This powerful current brings warm water
up from the tropics to northern countries
like Norway
• The heat exchange with the air allows
northern points to experience milder
climatic conditions despite the geography
Effects on Climate
• Currents carry warm and
•
•
cold water around the
Earth
As heat is transferred
from the water to the air
(warm currents) or from
the air to the water (cold
currents)
The exchange of heat
effects the weather
patterns
El Nino
• El Nino, an abnormal
•
•
•
warming of surface ocean
waters in the eastern
tropical Pacific
Scientists do not fully
understand
Can affect the ocean as
well as the land
Causes a shift in the
weather patterns around
the world such as a
unusually warm winter in
the Northeastern USA
Deep Currents
•
•
•
•
•
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Caused by the differences in density of ocean water
Warm water moves from the Equator to the Poles
It gradually cools
Ice forms
The ice is fresh water
The remaining water has increased salinity
The water becomes dense and sinks
The deep currents carry cold, dense, highly salinated
water from the Poles to the Equator
Upwelling
• The movement of cold
•
•
water upward from the
deep ocean and now
begins the shift to a
warm current
The winds blow away
warm water and cold
water replaces it
Brings up nutrients from
the deep ocean
• Oceans in Motion
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