1. Ocean Currents “There are rivers in the oceans”
-- Matthew Maury, Father of Oceanography

2. The Earth is not evenly Heated!
At the poles: incoming radiation travels through more atmosphere, is spread across more surface area, and is reflected by ice.
The Earth is not evenly
Heated!
Net radiative
heat gain in
the tropics
Net radiative
heat loss at
the poles

3. The equator gets more concentrated solar energy.

4. Seasons: because of the tilt, NOT getting closer/farther to the sun

5. Earth’s Rotation and Wind
Earth rotates west to east – surface at the equator moves faster than at poles
Atmosphere also rotates at the same speed as surface
Wind gets deflected – coriolis effect
Coriolis effect – due to earth’s rotation, objects in northern hemi deflect right, objects in the southern hemi deflect left.

6. Coriolis effect on moving things
An object moving across a rotating surface keeps the same direction and speed, but it appears to curve if you are on the rotating surface.
In the fixed frame of reference, the black ball moves in a straight line.
However, the observer (red dot) standing in the rotating frame of reference sees the object as following a curved path.

7. Deflection

8. Earth is consistently warmer at the equator; convection causes air at the equator to rise, air at the poles to sink, forming large planetary winds.

9. Convection + Coriolis
cause winds blowing at these angles across the planet
these are “planetary winds” that blow nearly all the time!

10. Planetary winds are disrupted and modified over land on a daily basis but are nearly constant over the oceans since they are “flat” and uniform.

11. “Westerlies” “Trade winds” brought the Europeans over to the Americas,
sent them back

12. If the winds are blowing like this, what direction do you predict the ocean surface currents will be moving at the equator?

13. Basic Wind-Driven Currents

14. Western vs. Eastern boundary vocabulary to know

15. Try the Pacific

16. Which Currents Are Western Boundary Currents?

17. Why Are Some Red and Some Blue?

18. Which Side of all the continents have warm currents
Which Side of all the continents have warm currents? What direction do all of the warm currents flow?

19. Which Side of all the continents have cold currents
Which Side of all the continents have cold currents? What direction do all of the cold currents flow?

20. Western vs. Eastern currents
WESTERN BOUNDARY: EASTERN BOUNDARY:
HOT and FLOWS TOWARD POLE COLD and FLOWS TOWARD EQUATOR

21. The Primary Sources of Water Movement
1. Solar Heating
2. Winds
3. Gravity
4. Coriolis

22. Two types of Currents: Surface Currents:
These waters make up about 10% of all the water in the ocean.
These waters are the upper 400 meters of the ocean.
Deep Water Currents: Thermohaline Currents
These waters make up the other 90% of the ocean
These waters move around the ocean basins by density driven forces and gravity.
The density difference is a function of different temperatures and salinity
These deep waters sink into the deep ocean basins at high latitudes where the temperatures are cold enough to cause the density to increase.

23. Surface Ocean Currents
Broad, slow drifts; never cross equator
Wind generated; circular gyres

24. IMPORTANCE OF SURF. CURRENTS
NAVIGATION
MIGRATION
WEATHER

25. Localized Surface Currents
Longshore Current.
Flows parallel to shore; move sediment

26. RIP CURRENT
- Caused by converging longshore currents
- Very dangerous ; Red Flag
- DO NOT fight rip current; swim parallel to shore to get out of channel

28. Deep Ocean Currents Flow beneath surface; cross equator
Separated from surface currents by boundary called a “Thermohaline” (diff in densities)
Move North to South

30. Upwelling brings cold water from deeper regions to surface
Cold, nutrient-rich water rises to replace the surface water (good for fishing- Peru)
process is dominant when winds are parallel to coastline

31. Currents to know by name
California Current
North Equatorial current
Gulf Stream
North Atlantic drift
Canary Current
And in general be able to use these terms:
“Western boundary current”
“Eastern boundary current”

32. Do you see any patterns?
The Gulf Stream is a good example of a Western Boundary Current

33. Gulf Stream

34. What direction do north oceans spin
What direction do north oceans spin? What direction do south oceans spin? Clockwise or counter clockwise?

35. These spins are called Gyres there are 5 major gyres

37. Big Picture Things To Know About
Unequal heating of the Earth, convection and Coriolis work together to set up predictable planetary wind patterns
These constant winds in turn set up constant ocean currents – know the currents mentioned by name and location
The ocean currents bring warm water to the west side of all the oceans, cold water to the east side of all the oceans – know which side and what temperature a “western boundary current” would be on in an ocean
Currents account for about 40% of global heat transport