1. Surface Currents

2. Currents
Current: A horizontal movement of water in a well- defined pattern.
In the ocean, there are surface currents and deep currents.

3. Surface Currents What do you think causes surface currents?
Answer: WIND.
What do you think affects the direction surface currents flow?
Answer: Controlled by 3 factors: Air currents (such as major wind belts), Earth’s rotation (Coriolis Effect), and the location of the continents (deflect and divide currents).

4. Atmospheric Circulation
Drives Surface Currents
Drives El Nino, La Nina (we will look at this next class).
Drives Monsoons and Hurricanes (we will also look a these in more detail).

5. Layers of the Atmosphere

6. Label the wind belts, pressure zones, and calm winds on your sheet.

8. Global Winds over the Pacific

9. Atmospheric Circulation Cells
Hadley Cells: degrees (tropics). Brings warm, moist air from equator towards the poles.
Ferrel Cells: degrees (mid-latitude). Cold air moves from the poles toward the equator.
Polar Cells: degrees. Cold air ascends and moves toward the poles.

10. Global Winds and Surface Currents affected by Coriolis Effect.
Coriolis Effect: The bending of winds due to Earth’s rotation.
Winds and Currents bend to the right (Clockwise) in Northern Hemisphere.
Winds and Currents bend to the Left (Counterclockwise) in Southern Hemisphere.

11. Doldrums and Horse Latitudes
Doldrums: Zone of calm equatorial winds where two Hadley cells meet. The word doldrums means gloomy, perhaps because sailors felt that way when they were stuck here. Horse Latitudes: Zone of high pressure where Hadley Cells and Ferrel Cells meet. Called this because sailors would get stuck and have to either throw their horses overboard or eat them.

12. World Surface Currents

13. Gyres: Circular flow around an ocean basin
Gyres: Circular flow around an ocean basin. Made of multiple, connected currents.

14. Heat transfer by surface currents
What do you notice about how surface currents transfer heat?
Answer: Warm water is brought from equator towards poles. Cold water from poles to the equator.
What causes England to be fairly warm even though it is the same latitude as Canada?
Answer: Warm water from Gulf Stream.

15. Western and Eastern Boundary Currents
Western Boundary
Eastern Boundary
Fastest (2 m/s) and deepest (up to 1500 feet)
Western boundary of ocean basins or eastern boundary of continents
Move warm water from equator towards the poles
Includes the Gulf Stream and the East Australian Current (EAC).
Shallow and slower
Eastern boundary of ocean basins or western boundary of continents
Move cold water from the poles towards the equator
Includes the Canary current off the coast of Europe and the Humboldt Current off the coast of Peru.

16. World Surface Currents

17. Eddies:Turbulent rings of circulating water on the edge of a current.
Formed by abrupt changes
in water temperature,
speed, and direction.
Only form along western
boundary currents.
Gulf Stream
Eddies