1. Ocean Currents

2. Two Types of Currents Density Driven (deep water) Currents
Wind Driven (surface) Currents

3. Density Driven Currents
Move water vertically through the ocean
Density differences cause deep water currents
Dense water sinks at the poles
Less dense water rises
at the equator
This process creates
circulation throughout
the oceans of the world

4. Surface Currents Winds are primary energy source for surface currents.
Winds blow across the ocean surface
friction between the wind and the ocean surface drags the water along

5. Which way does the water flow?
Rotation of the earth changes path of air and water (Coriolis Effect)
Water flows to the right (clockwise) in Northern Hemisphere

6. Northern Pacific Surface Currents
California Current
Kuroshio Current
North Equatorial Current
Equator
South Equatorial Current
East Australian Current
Peru Current
West Wind Drift

7. Global Surface Currents
Most ocean currents have a dramatic impact on local weather and continental climate patterns
Ex: Mediterranean climate zones

8. Surface Currents in the US
The California Current is cold and comes from Alaska
The Gulf Stream is warm and comes from the equator/ Gulf of Mexico
San Francisco
Washington, DC

9. What is a gyre? A roughly circular pattern of ocean surface currents
Caused by the Coriolis Effect

10. North Pacific Gyre
Equator

11. Why are gyres/ currents important?
Warm currents move heat from the equator to middle and high latitudes
Gyres influence air temperature, weather and climate of every continent