1. Ocean Circulation Winds and Currents

2. The atmosphere and the oceans interact The ocean and atmosphere transport heat from the equatorial regions to the poles Winds create daily, short-term weather changes, while the oceans have a slower, more long-lasting effect on climate

3. Currents move much more slowly than winds and retain more heat than the atmosphere While winds affect ocean currents, oceans also influence the winds, helping to determine their direction and speed

4. Current Patterns

5. Global Wind Patterns Winds are caused by uneven heating and cooling of the atmosphere.

7. At this animated image you can see the seasonal variations of wind over the World Ocean averaged during several decades of observations

8. Warm, humid air rises at the equator and moves towards the poles, where it cools. The cold, dry air sinks (some moves towards the equator forming trade winds, and some moves towards the poles forming westerly winds) resulting in a circulation pattern of prevailing winds.

9. The prevailing winds blow clockwise in the Northern Hemisphere and counter clockwise in the Southern Hemisphere.

10. The equatorial region is known as the doldrums: hot moist air rises and cools resulting in thunder clouds. The world’s rain forests are here.

11. 30° N and S are known as the horse latitudes, where cold, dry air sinks toward Earth’s surface. The world’s great desert regions are found here. 60° N and S is where the cold, dry air is flowing south, warming and rising, forming Easterly winds. The poles are actually cold deserts.

14. Global Current Patterns Current: a large mass of continuously moving ocean water There are two types: –Surface Currents –Deep Currents

15. Surface currents: –10% of currents and are mostly wind driven –Horizontal water movement –Follow pattern of prevailing winds –Usually in the top 400 m of water Even though the currents are all connected, we give them different names based on where they are

16. Surface Current Pattern

17. Deep currents: –density driven (depend exclusively on salinity and temperature) –mainly vertical water movement –90% of all currents –called thermohaline circulation

18. Deep Currents

19. Unique Currents Equatorial Countercurrent (Cromwell Current): –Lies between the North and South Equatorial Currents –It is several hundred meters wide –It flows in the opposite direction from the currents next to it and we do not have a reason/explanation for this

21. Antarctic Current (West Wind Drift): –It’s the world’s largest current –It could fill the Great Lakes in 2 days

22. Gulf Stream: –Can reach depths of over 450 m –Can move at a rate of 2 m/s = ~160 km/day which makes it the fastest surface current –It is ~70 km wide –Goes from Florida to NFLD