1. Ocean Circulation

2. Global Surface Currents
zations/es2401/es2401page01.cfm?chapter_no=visualization

3. What causes surface currents?
Surface currents are driven by wind
Coriolis effect is in place due to Earth’s rotation
Surface currents in the Northern Hemisphere move to the right of wind direction
Surface currents in the Southern Hemisphere move to the left of wind direction
If no rotation, ocean currents would move the same direction as wind
At the equator, Coriolis force is zero (neither left or right)
Ekman transport (or Ekman spiral) (
Movement of water layers below the water surface rotates 45 degrees
Depth of movement is determined by total depth of water body (less in lakes than in ocean)

4. Global Circulation

5. Simplified Global Circulation
Five major ocean gyres

6. Ekman Spiral

7. What about tides?
Tidal currents are the rise and fall of water caused by gravitational pull from moon on our planet
Flood current is the movement of water toward the shore
Ebb current is the flow of water away from shore
However, water doesn’t actually go anywhere, it is just pulled higher of lower in elevation

8. Are there other types of currents?
Currents can be caused by ocean topography, rain, and runoff from land
The majority of sub-surface currents are caused by differences in water densities and have a BIG affect on global temperatures
This can include interaction of hot and cold water (thermocline) OR
Interaction of saltier water and fresher water (halocline)
Usually a combination of both (thermohalocline)

9. Thermohaline Circulation
Great Ocean Conveyor Belt

10. Gulf Stream and North Atlantic Drift
Gulf Stream is one of the strongest currents known.
It brings warm air from the Gulf of Mexico, up the coast of the Eastern U.S., to Newfoundland (Canada), then across to Northern Europe
Without this current of warm water (and subsequently air temperature), England and other places in Europe would be as cold as Canada
AND the Gulf Stream is the reason palm trees grow in Ireland (which is at the same latitude as Labrador in Canada)

11. NOAA: Motion in the Ocean

12. Upwelling

13. Curt Ebbesmeyer
Article:

14. Movement of Objects in Ocean

15. Collapse of Atlantic Ocean Current
Article:

16. Bill Nye: Ocean Currents