The Movement of Ocean Water

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Chapter 14

• The Movementof Ocean Water

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Section 1 Currents

• Objectives
• Describe surface currents.
• List the three factors that control surface
  currents.
• Describe deep currents.
• Identify the three factors that form deep
  currents.

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Explore Currents

• Thor Heyerdahl
• Norwegian explorer
• Theory
• Inhabitants of Polynesia originally sailed from
  Peru
• Proved Theory in 1947 after spending 97 days at
  sea and traveled more then 6,000 km

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• What is Ocean Current?
• Surface current
• What is Surface Current?
• Affects only the upper few hundred meters of
  seawater

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Controlled by Three Factors

• Global winds
• Coriolis effect
• Causes currents to move in clockwise direction
• Continents deflect currents

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Global Winds

• Near the equator,
• winds blow ocean water east to west
• At the poles
• ocean water is blown west to east

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Coriolis Effect

• Apparent curving of the path of a moving object
  from an otherwise straight path due to the
  Earths rotation
• Example Ball rolled from the center of a moving
  merry-go-round

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Continental Deflections

• Continents cover 1/3 of Earths surface
• When surface currents meet continents, the
  currents deflect, or change direction.

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Taking Temperatures

• Currents can affect the climate of an area
• West coast is cold (water comes from the north)
• East coast is warm (water comes from the south)

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Deep Currents

• What are Deep Currents?
• Not directly controlled by wind
• Form in parts of the ocean where water density
  increases
• Density
• The amount of matter in a given space, or volume.
• Salinity
• Measure of the amount of dissolved salts or
  solids in a liquid

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Relationship b/w Surface Current and Deep Current
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Section 2 Currents and Climate

• Objectives
• Explain how currents affect climate.
• Describe the effects of El Niño.
• Explain how scientists study and predict the
  pattern of El Niño.

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Warm-Water Currents and Climate

• Surface currents are generally much warmer than
  deep currents
• Temperatures of surface currents do vary
• Surface currents are classified as
• warm-water currents or coldwater currents
• Warm-water currents create warmer climates in
  coastal areas that would otherwise be much
  cooler.

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Cold-Water Currents and Climate

• Cold-water currents also affect the climate of
  the land near where they flow
• Keeps the Coast climate cooler than the inland
  climate year round

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Upwelling

• Process in which cold, nutrient-rich water from
  the deep ocean rises to the surface and replaces
  warm surface water
• Occurs when cold water from deep in the ocean
  rises to the surface in an area
• Area of good nutrients and good fishing
• Process in which cold, nutrient-rich water from
  the deep ocean rises to the surface and replaces
  warm surface water

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Surface Currents and Climate

• El Niño
• Periodic change in the location of warm and cool
  surface waters in the Pacific Ocean
• Can last for a year or longer
• Changes the interaction of the ocean and the
  atmosphere
• Which in turn changes global weather patterns.
• La Niña
• periodic change in the eastern Pacific Ocean in
  which the surface-water temperature becomes
  unusually cool.
• Like El Niño, La Niña also affects weather
  patterns.

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Effects of El Niño

• Causes more then average rainfall on the Western
  edge of the Pacific Ocean
• Can cause mudslides and flashfloods
• Causes less then average rainfall on the Easter
  edge of the Pacific Ocean
• Can cause droughts if effect is prolonged for a
  long period of time
• Upwelling of nutrient-rich water does not occur
  off the coast of South America,
• Affects the organisms that depend on the
  nutrients for food.

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Studying and Predicting El Niño

• Occurs every 2 to 12 years,
• Data collected through a network of buoys
  operated by the National Oceanic and Atmospheric
  Administration (NOAA)

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Section 3

• Waves movements in which water alternately rises
  and falls
• Crest highest point
• Trough lowest point

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• Wave Height distance between crest and trough
• Wavelength distance between crest to crest

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• Energy moves forward while water particles remain
  in the same place

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• Breaker when the top of waves move faster than
  the bottoms, tall enough waves collapse

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• The height of waves depends on
• 1) wind speed
• 2) distance wind blows
• 3) time of blowing

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• Tides long waves that result in a periodic
  change in the surface level of the oceans due to
  the gravitational pull of the moon

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• Tidal range difference between high and low tide

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