Ocean Currents 101:

1. Ocean Currents 101: The Good, The Bad and ! The Ugly

2. The Power of Ocean Currents • Impacts Earth’s Weather Systems • Vital to Maintaining Life on Earth!

3. A review of the terminology… High/Low Latitude Convection cell Albedo Coriolis Effect Pycnocline/Density

4. A review of the terminology… High/Low Latitude Convection cell Albedo Coriolis Effect Pycnocline/Density

5. A review of the terminology… High/Low Latitude Convection cell Albedo Coriolis Effect Pycnocline/Density

6. 0% 50% 100% Albedo –the percentage of radiation reflected back to space A review of the terminology… High/Low Latitude Convection cell Albedo Coriolis Effect Pycnocline/Density

7. If Earth was covered in ice • 84% • If Earth was completely covered by a dark green forest canopy • 14% • A drop of as little as 1% • warming influence on climate • roughly equal to the effect of doubling the amount of CO2 in the atmosphere Extreme Albedo: 0% 50% 100%

8. BUT—is Earth’s Albedo Changing? YouTube - Amount of Arctic Sea Ice is Dropping Each Decade (2008.09.17) Remember for later: An indication of warming surface waters and fresh-water input.

9. A review of the terminology… High/Low Latitude Convection cell Albedo Coriolis Effect Pycnocline/Density

10. Earth’s Big Picture—we live on a spinning planet • Coriolis Effect changes the intended path of all moving bodies • Affects both atmospheric and oceanic circulation processes

11. The Coriolis Effect—What is it? • Caused by Earth’s rotation toward the east and its decrease in velocity with increasing latitude • Motions are deflected to the right in northern hemisphere and left in southern hemisphere

12. A review of the terminology… High/Low Latitude Convection cell Albedo Coriolis Effect Pycnocline/Density

13. T (Thermocline) + H (Halocline) = P (Pycnocline) Low Latitudes

14. Let’s begin… • Ocean Circulation • Consists of • Wind-driven Surface Currents • Density-driven Deep Currents

15. Wind-driven Surface Currents • Atmospheric Winds • Created from uneven solar heating • Earth’s Albedo • Latitude

16. Variations in Solar Absorption/Reflection Create Convection Cells • Atmospheric Low (L) occurs when warm, moist air (less dense) rises • Atmospheric High (H) occurs when cool, dry air (more dense) sinks

17. Creates Earth’s Major Surface Winds • Tradewinds • Low Latitudes • Westerlies • Mid Latitudes • Polar Easterlies • High Latitudes • The Coriolis Effect gives it a ‘twist’ to the right in the northern hemisphere and a ‘twist’ to the left in the southern hemisphere

18. Example of Important Surface Current Created by Winds… • Trade Winds form the Equatorial Currents • Travel westward until they reach the western portion of ocean basin (hit land) This image shows cold water (purple) upwelling near the coast of Peru and joining the South Equatorial Current, which flows westward across the Pacific Ocean

19. The Power of the Ocean: Impacts Earth’s Weather Systems Western Intensification and El Niño A similar Western Intensification occurs in the Atlantic Ocean

21. 2009 Hurricane Season • More in the Pacific • Note Atlantic Pattern

22. Jet Stream Saturday, January 9, 2010

23. Brazil Current Surface Currents Combine to create another remarkable system … • Westward-moving Equatorial Current • ‘Hitting land’ and Coriolis Effect results in theWestern Boundary Currents • e.g., the Gulf Stream and Brazil Current in the Atlantic ocean

24. And then… • Prevailing Westerlies (Mid latitude) form Eastward Surface Currents that are, again, deflected off the continents creating the Eastern Boundary Currents

25. …Together They Form an Ocean Gyre • Combination of the Equatorial, Western Boundary, Prevailing Westerlies and Eastern Boundary Currents create a circular flow called a Gyre

26. AND HERE’S THE UGLY!! Click here: Synthetic Sea - Plastic in the open Ocean

28. Density-driven Deep Currents T + H = P Low Latitude

29. Average Ocean Depths Atlantic ~3500 m Indian ~3900 m Pacific ~4300 m Changing ocean depths influence the direction of flow.

30. Now—Let’s Connect the Ocean’s Surface Currents to its Deep Currents…via Downwelling and Upwelling

31. T + H = P Remember our Pycnocline at Low Latitudes? Low Latitude

32. How does it look in the Higher Latitudes?

33. High Latitudes: Important Areas of Ocean Downwelling…

34. IMPORTANT REGION OF OCEAN UPWELLING

35. Remember this?

36. Putting it all together—The Conveyor Belt Circulation • A current that connects the Ocean’s Surface Waters to Deep waters via Upwelling and Downwelling • Also called Thermohaline Circulation

37. Putting it all together—The Conveyor Belt Circulation • THE GOOD… • Mixes waters within and throughout all oceans • Oxygen flows down • Nutrients flow up

38. Putting it all together—The Conveyor Belt Circulation • THE BAD… • It’s demise can result in global devastation!! The Power of the Ocean: Vital to Maintaining Life on Earth!!

39. Putting it all together—The Conveyor Belt Circulation • Due to • Less-dense surface waters in High Latitudes • Less-salty • Warmer

40. Putting it all together—The Conveyor Belt Circulation • Due to • Less-dense surface waters • Less-salty • Warmer

41. YouTube - GLOBAL WARNING - The Great Ocean Conveyor and Potential Mass Extinctions

42. Vast majority of land was desert interior • Increased volcanic activity • Increased CO2 production • Increased ocean acidification

43. The Power of Ocean Currents

44. Questions?