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Ocean Currents

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Presentation on theme: "Ocean Currents"— Presentation transcript:

1 Ocean Currents

2 Ocean Currents Warm currents flow away from the equator.
Cold currents flow toward the equator.

3 Factors Influencing Currents
Sun Wind Coriolis Gravity

4 Sun Energy from the Sun heats the water.
Warm water is less dense than cold water. Warm water rises, and cold water sinks. As warm water rises, cold water moves in to replace it.

5 Wind

6 Wind Water moves from high pressure to low pressure areas (just like wind). Winds blow across the surface of the water, causing friction. The water piles up because the surface currents flow slower than the winds.

7 Gravity As water piles up and flows from high to low pressure, gravity will pull down on the water. This forms dunes or mounds of water. The Coriolis Effect causes the water to curve.

8 The Coriolis Effect Causes water to:
Curves to the right in the Northern Hemisphere Curves to the left in the Southern Hemisphere

9 The Coriolis Effect (draw this)

10 Surface Currents Affects 10% of oceans’ water Maximum depth of 400 m
Caused by the surface wind patterns.

11 Surface Currents

12 Gulf Stream A strong surface current Begins at the tip of Florida
Flows up the eastern coastline of the U.S. Crosses the Atlantic Ocean Causes warmer climate in NW Europe

13 Gyres Dunes or mounds of water at the surface and they flow in circles
Produce enormous circular currents Five major locations: North Pacific – clockwise-cw South Pacific – counterclockwise-ccw Indian Ocean – ccw (counterclockwise) South Atlantic – ccw (counterclockwise) North Atlantic – cw (clockwise)

14 Gyres

15 Climate Interaction Both Galveston, Texas, and San Francisco, California, are adjacent to bodies of water. Galveston typically has warm humid weather, while San Francisco Is usually cool. Why is this?

16 Climate Interaction The Pacific Ocean currents in this area are colder causing the air mass to take on the same characteristics (mP).

17 Climate Interaction The Gulf of Mexico is warm and humid, so the air mass originating there would be warmer.

18 Upwelling Surface waters blown by the wind.
Less dense surface water moves off shore and cold, deep, denser waters come to the surface to replace them.

19 Upwelling

20 Upwelling lab demo
NASA animation Bill Nye 2 minutes

21 The Great Ocean Conveyor: Helps maintain Earth’s Balance

22 Deep Water Currents Make up about 90% of oceans’ water
Differences in density cause them to move. Differences in density are related to temperature and salinity. (salty) At high latitudes, they sink deep into the ocean basins. Temperatures are so cold, they cause the density to increase.

23 Reflective Question- How are ocean currents produced?
Wind pushing surface water allowing denser water to surface, causing a convection current. Denser water sinking (cold from polar region) and less dense water rising (equatorial region).

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