Chapter 22, section 1
Currents →
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Surface currents →
Factors that affect
surface currents →
Ocean Currents
 An ocean current is a continuous flow of water in a specific direction
 There are two types of currents, surface currents and deep currents
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Surface currents move on or near the surface of the ocean
Surface currents are driven by winds (in other words wind moves the
water)
1) The wind belts- the Trade winds and the Westerlies blow across the top
of the ocean, moving the ocean water in the direction they are blowing
o The wind always moves in the same direction, and so the water
always moves in that direction as well
2) The Coriolis effect- the deflection of the earth’s ocean currents (and
winds) caused by the earth’s rotation
o Gyres- circular movement of ocean currents because of the
Coriolis effect
3) Location of the continents- when the ocean currents approach the
the continents the water is deflected and divided
o The land is a barrier, preventing the water from continuing its
original course
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Current temperature→
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Ocean currents that are created at or near the equator are warm.
Ocean currents that are created at or near the poles are cold. Warm
ocean currents make the climate on land warmer, cold water currents
make the climate on land colder
The Gulf Stream is a warm water current created near Central
America that moves towards the east coast of the United States. The
warm water current makes the climate of the Yucatan, Florida and
surrounding areas warmer
The California Current is a cold water current created near Alaska that
moves towards California along the west coast of the U.S. The cold
water current makes the climate of Washington, California, and Baja
Mexico colder
California has a very different climate than Florida, even though they
have a similar latitude
Deep ocean currents →
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Upwelling →
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Deep currents move very slowly beneath the surface of the ocean and
are caused by differences in density
Deep currents are produced in the polar regions, where the water is
cold and dense
o Cold water is more dense and sinks to the bottom of the ocean
o Polar water has more salt because glaciers leave the salt in the
ocean when they form
 The cold, dense current moves towards the warmer waters of the
equator
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The deep currents only rise when wind blows across the surface of the
ocean, pushing it aside. This process is known as upwelling
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