1. Ocean Circulation Currents

2. Horizontally Vertically

3. The Forces That Drive Currents Primary forces –Starts water movement and determine its velocity Stress of wind Secondary forces –Influence the direction and nature of flow Coriolis effect gravity friction shape of ocean basins

4. Surface currents Wind Surface currents – rapid with well defined boundaries –slow and diffuse –horizontal or vertical Gyre

5. Bottom Currents Driven by the force of gravity - dense water sinks and less dense water rises

6. Flow within a Gyre North Atlantic gyre –Four inter connected currents

7. Eckman spiral Eckman transport

8. Geostrophic Gyres Geostrophic Gyre –5 Geostrophic gyre North Atlantic gyre South Atlantic gyre North Pacific gyre South Pacific gyre Indian Ocean gyre – Geostrophic gyres independent of each other in each hemisphere Geostrophic currents 6 current circuits in the world ocean –2 in Northern hemisphere 4 in southern hemisphere

9. Currents within Gyres Western boundary Currents Eastern Boundary Currents Transverse currents

10. Western Boundary Currents Fastest and deepest Found at the western boundaries of the Ocean basins Narrow Move warm water poleward in each gyre

11. Western boundary currents Five western boundary currents –Gulf stream –Japan or Kuroshio current –Brazil current –Agulhas current –East Australian current Sverdrup Eddies –Cold core eddies –Warm core eddies

12. Eastern Boundary Currents The Canary Current The Benguela Current California Current West Australian Current The Peru or Humboldt Current

13. Eastern Boundary Currents Carry cold water equatorward Shallow and broad Boundaries not well defined Eddies tend not to form

14. Westward Intensification The converging flow of the trade winds on either side of equator The rotation of the earth

15. Transverse Currents Currents that flow from east to west –Linking the eastern and western boundary currents Counter Currents Under Currents

16. Exceptional Surface Currents Monsoon Currents High Latitude Currents

17. Effects of Surface Currents on Climate Distribute tropical heat Influences climate and weather

18. Wind-Induced Vertical Circulation Upwelling –Equatorial upwelling –Coastal upwelling Downwelling

19. Langmuir Circulation (page 222 fig 9.16) Langmuir Circulation

20. El Nino

21. Thermohaline Circulation Density driven

22. Water Masses Five common water masses –Surface water –Central water –Intermediate water –Deep water –Bottom water

23. Formation and downwelling of Deep water Antarctic bottom water North Atlantic deep water

24. Thermohaline Circulation Patterns Low and mid latitudes Caballing Contour currents

25. Studying Currents Float method Flow method Acoustical Tomography