ch. 22 movements of the oceans ch. 22.1 ocean currents

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  • Ch. 22 Movements of the OceansCh. 22.1 Ocean Currents

  • ObjectivesBy 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.

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

  • Surface CurrentsWind 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.

  • Factors Affecting Ocean Surface Currents1. The wind belts2. Earths rotational effects3. Location of the continents

  • 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.

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

  • Deep CurrentsSlow, 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.

  • Antarctic Bottom WaterCold, 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.

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

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

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