Ch. 22 Movements of the Oceans

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Ch. 22 Movements of the Oceans

• Ch. 22.1 Ocean Currents

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Objectives

• By the end of this unit, you should be able to
• Discuss how wind patterns affect surface
  currents.
• Explain how differences in the density of ocean
  water affect the flow of deep currents.

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• Currentsgiant streams of ocean water.
• There are Surface Currents and Deep Currents.

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Surface Currents

• Wind is the driving force of surface currents.
• Most surface currents result from global wind
  patterns.
• Surface currents are fastest near the surface,
  and are almost undetectable 100 meters below the
  surface.

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Factors Affecting Ocean Surface Currents

• 1. The wind belts
• 2. Earths rotational effects
• 3. Location of the continents

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• Huge circles of moving water, or gyres, result
  from the wind belts and Coriolis force.
• Gyres move clockwise in the northern hemisphere,
  and counterclockwise in the southern hemisphere.
• Major landmasses may deflect or divide surface
  currents.

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• Trace out surface currents. Reading pg. 428-430.

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Deep Currents

• Slow, cold, dense deep currents form when the
  cold polar water sinks and flows beneath the
  warmer ocean water toward the equator.
• The cold high-salinity dense water stays below
  the warmer lower-density water.

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Antarctic Bottom Water

• Cold, salty dense water forming near Antarctica
  sinks and moves slowly northward along the bottom
  of the ocean, far into the N. hemisphere. The
  trip can take several hundred years.

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North Atlantic Deep Water

• Cold water deep current that forms in the Arctic
  flows southward, but it rides above the denser
  Antarctic bottom water.

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• High salinity, high density water that forms in
  the Mediterranean due to evaporation sinks and
  flows outward through the Straits of Gibraltar.

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Turbidity Currents

• Caused by underwater landslides.
• Dense, sediment-laden water moves under
  less-dense, clear water.
• May cause deepening of submarine canyons.

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