Current and Climate

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Current and Climate

• Ch 13-4

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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.

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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

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Surface Currents

• Are driven mainly by winds.
• Most flow east to west and then double back to
  complete the circle

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Coriolis Effect

• Because the Earth is moving on its axis this
  motion effects the elements of the Earth that can
  freely move
• http//www.youtube.com/watch?vE8gsH_XsE8A

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Coriolis Effect

• In the Northern 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.

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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

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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

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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

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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

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Deep Currents

• 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

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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

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• Oceans in Motion
• Safari Montage