1. PHYSICAL OCEANOGRAPHY Part 3: Heat Budget & Ocean Currents
GEOL 1033
(Lessons 27-28, 33, & 34)
Ppt file

2. EARTH'S HEAT BUDGET
About half of solar radiation, mostly as visible light, reaches Earth's surface
Re-radiated energy is in the form of infrared radiation
Carbon dioxide and water vapour temporarily absorb some of this infrared (=greenhouse effect & global warming)
half
Infrared radiation = heat

3. LATITUDINAL VARIATIONS IN SOLAR RADIATION
High latitudes receive less solar energy per unit of surface area

4. LATITUDINAL VARIATION IN HEAT GAINS AND LOSSES
Heat gains are greatest at lower latitudes
Heat losses are relatively greater at higher latitudes
Heat is redistributed by air & ocean currents

5. Global Air Circulation Cells
Wet
Dry
Wet
Dry
Wet

6. Major Surface Wind Patterns
Simplify this model & look at surface winds
Winds are mainly responsible for surface ocean currents

7. Coriolis Effect in Northern Hemisphere
Shifts winds & ocean currents to the right
Related to faster surface rotation rates near the equator in comparison to those at higher latitudes

8. Influences on Oceanic Gyre Formation
Winds cause currents
Currents redistribute heat from Sun
Coriolis effect shifts current directions to right in N. Hemi. & left in So. Hemi.
Continents block pure E-W flow, creating boundary currents
Some gravitational influence
Northern
Subtropical
gyre

9. North Atlantic Gyre System
Know these currents
Western boundary currents (e. g., Gulf Stream) are deeper, narrower, and faster than eastern boundary currents (e. g., Canary Current)
Review Lessons 33 & 34

10. Major Ocean Surface Currents & Climatic Zones
Review Exercise #15 (Completed answer sheet on page 235 is due next Thursday, Dec. 2nd.)

11. Circum-Antarctic Surface Circulation
Less interference from north-south oriented continental masses

12. REMEMBER THE PYCNOCLINE
Halocline refers to the salinity increase coinciding with the thermocline
Pycnocline is the density change associated with the thermocline and halocline

13. Surface zone Pycnocline Deep zone
REMEMBER LATITUDINAL VARIATIONS IN AVERAGE DEPTH OF VERTICAL DENSITY ZONES
Surface zone
Pycnocline
Deep zone

14. PACIFIC OCEAN Salinity/Temperature Structure

15. ATLANTIC OCEAN Salinity/Temperature Structure

16. Circulation of Atlantic Ocean Water Layers
Note Antarctic Intermediate and Bottom Waters
Find the North Atlantic Deep Waters
AC = ? AD = ?

17. Antarctic Ocean Upwelling and Downwelling
North Atlantic Deep Waters

18. Stopped Here

19. Ekman Spiral
Due to Coriolis effect, can get a weak countercurrent at depth

20. Northern Hemisphere Coastal Upwelling and Downwelling
Coriolis right shift of surface waters (Ekman spiral effect)
Onshore to produce downwelling
Offshore to produce upwelling

21. Southern Hemisphere Coastal Upwelling and Downwelling
Coriolis left shift of surface waters (Ekman spiral effect)
Onshore to produce downwelling
Offshore to produce upwelling
El Nino off NW coast of So. Am.

22. Circulation of Atlantic Ocean Water Layers
Note Antarctic Intermediate and Bottom Waters
Find the North Atlantic Deep Waters
Note Med. Salty, warm water AC = ? AD = ?

23. The Oceanic “Conveyor Belt”
Thermohaline surface to deep planetary circulation system.
A disruption may bring on another Ice Age!

24. END OF FILE