Oceans

1. Oceans

2. Name the oceans

3. Name the oceans Just joking. There is only one ocean.

4. Name the parts of the ocean • North Atlantic • South Atlantic • North Pacific • South Pacific • Indian • Antarctic • Arctic?

5. Name the parts of the ocean • North Atlantic • South Atlantic • North Pacific • South Pacific • Indian • Antarctic • Arctic?

6. Name the parts of the ocean Arctic? North Pacific North Atlantic Antarctic South Atlantic Indian South Pacific

7. Name the parts of the ocean

8. Statistics • Area—~ 340 million km2 (71% of surface) • Average Depth—3800m • Salinity—35g salt/kg of ocean water (varies) • Average Temperature--Surface: 17oC (63oF) Deep: 3oC (37oF)

9. Temperature • Where would you find warmer surface water?

10. Temperature • Where would you find warmer surface water? Cooler Warmer Cooler

11. Temperature • Surface water is warmer than deep water • From 200 m to 1000 m deep, temperature drops sharply. • This region is called the thermocline

13. Density • Surface water is less dense than deeper water • From 100 m to 1200 m, the density rises sharply • This region is called the pycnocline

15. What causes density differences?

16. What causes density differences? Temperature and salinity

17. What causes density differences? Temperature and salinity Cooler water is more dense Saltier water is more dense

18. Where will you find the saltiest surface water?

19. Where will you find the saltiest surface water? Surface water in the tropics. Evaporation is the highest there. …but it’s warm water Surface water near the poles. Freezing sea water freezes the water and leaves the salt.

20. Why does ocean water move?

21. Why does ocean water move? • Wind • Density differences • Coriolis effect

22. Why does ocean water move? • Wind—surface water moves in the direction of the wind • Density differences • Coriolis effect

23. Why does ocean water move? • Wind—surface water moves in the direction of the wind • Density differences—more dense water sinks under less dense water • Coriolis effect

24. Why does ocean water move? • Wind—surface water moves in the direction of the wind • Density differences—more dense water sinks under less dense water • Coriolis effect—water flowing north or south bends to the right in the northern hemisphere.

25. Why does deep ocean water move?

26. Why does deep ocean water move? • Density differences, mainly. • Masses of water sink near the poles, traveling thousands of kilometers before mixing with other layers • The tides also affect deep water.

27. The thermohaline current (deep)

28. Surface currents

29. Surface currents Currents have to turn when they hit a continent

30. Surface currents Cold currents come from polar waters

31. Surface currents Warm currents come from equatorial waters

32. Surface currents Currents heading towards the poles bend east

33. Surface currents Currents heading away from the poles bend west

34. Surface currents Currents circle clockwise in the northern hemisphere

35. Surface currents Currents circle counterclockwise in the southern hemisphere

36. Warm currents include:

37. Warm currents include: The Gulf Stream, Alaska, Brazil and East Australia Currents

38. Cold currents include:

39. Cold currents include: The California, Peru, Canary and West Australia Currents

40. http://www.montereyinstitute.org/noaa/lesson08.html

41. Ekman Drift • Winds blow east or west in bands by latitude (PS: winds are named by where they come from)

42. Ekman Drift • The water below the surface pulls to the right in the northern hemisphere

43. Ekman Drift • Ekman drift causes a mound of water to pile up between the bands of wind.

44. Geostrophic Currents • Coriolis forces and Ekman drift force water to move in a circle • These currents are called geostrophic currents

45. Why does ocean water move? • Wind • Density differences • Geostrophic forces • Tides

46. Gyres The circular pattern formed is called a gyre. There are about 5 major gyres, and 10 minor ones

47. Gyres Gyres carry heat around. Trash collects in the center of a gyre

48. The speed of the water depends on the width of the current It takes several years for water (and floating objects) to be carried around a gyre. Gyres

49. Upwelling and downwelling • Ekman drift near a continent can movewater away from shore. Water comes up from below to replace it.

50. Upwelling and downwelling • Ekman drift near a continent can movewater away from shore. Water comes up from below to replace it. Reverse the wind, or place the continent on the other side to force downwelling