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Ch. 22 Ocean Currents

Ch. 22 Ocean Currents. Ocean Currents. Movements of the ocean’s waters in giant “streams” 2 Major Currents : Surface Currents Deep Currents. Surface Currents. Move on or near the surface Driven by winds Factors affecting Surface Currents: Wind Belts Rotational Effects

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Ch. 22 Ocean Currents

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  1. Ch. 22 Ocean Currents

  2. Ocean Currents • Movements of the ocean’s waters in giant “streams” 2 Major Currents: • Surface Currents • Deep Currents

  3. Surface Currents • Move on or near the surface • Driven by winds Factors affecting Surface Currents: • Wind Belts • Rotational Effects • Location of Continents

  4. How do wind belts affect surface ocean currents? • Energy from the movement of both the trade winds and westerlies is transferred to the surface of the ocean.

  5. What are rotational effects and how do they affect ocean surface currents? • Coriolis effect: the twisting or deflection of the ocean’s currents due to Earth’s rotation. • creates Gyres: large circles of moving water

  6. Deep Currents • Cold, dense currents that flow very slowly, deep beneath the surface.

  7. How do deep Currents form? • As cold dense water of the polar regions sinks, it flows beneath warmer ocean waters towards the equators. • Movement is caused by density differences

  8. Turbidity Currents • A strong current caused by an underwater land slide.

  9. 22.2 Ocean Waves • Waves: periodic up and down movement of water

  10. Wave period: time it takes for one complete wavelength to pass a given point Wave Speed = wavelength Period

  11. Wave energy • Waves are caused by a transfer of wind energy to the water If there were no wind, what would happen to the waves???? So no wind = no wave energy Add wind = more wave energy

  12. Water Movement in a Wave • The individual water molecules themselves are moving very little!!!

  13. Wave Size Three Factors that affect wave size: • Speed of wind • Amount of time the wind blows • Fetch: distance that the wind blows

  14. Waves and the Shore • Breakers • Refraction

  15. Waves and the Shore • Undertows • Rip Currents

  16. Longshore Currents • Tsunamis

  17. 22.3 Tides • The daily changes in the levels of the ocean What causes tides??? The gravitional interactions between the Earth and the Moon!!!

  18. Tidal Range

  19. Behavior of Tides • When the earth, moon, and sun are aligned • The combined gravitational pull causes the range in tides.

  20. When the sun and moon are at right angles relative to the earth • The gravitational pulls do not act together and the daily tidal range is small

  21. Tidal Variations • Influenced by the Ocean Basin’s: • Size • Shape • Depth • Location

  22. Tidal Currents • Flow of oceans towards and away from coasts as the tides rise and fall. • Most influential closer to coastlines • Tidal Bore: a surge of water due to tidal currents in a long bay.

  23. The End • Ocean Currents Activity

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