1. Oceans II
Surface Currents

2. Heat Variations Latitude
Depends on angle sunlight hits surface
Sunlight at polar latitudes covers wider area; therefore, less heat
At equator, sunlight covers less area; more heat

3. Heat Transfer Heat is transferred from equator to poles
Air Circulation
Ocean currents

4. Origin of Currents Ocean surface currents are wind driven
Air movement due to less dense air rising and more dense air sinking
Horizontal air flow along Earth’s surface is wind
Air circulating in this manner is convection currents

5. Wind Movement Non-rotating Earth
Simple wind pattern
Warm air rises at equator, flows toward poles
Air cools at poles, sinks, and flows toward equator
Winds named by direction from which they blow
North-blowing winds = southerly winds
South-blowing winds = northerly winds

6. Wind Movement Rotating Earth
At equator, warm air rises
Zone of low pressure
Clouds and precipitation
Reaches troposphere and moves poleward
As it spreads, it cools
30° N&S, cool air sinks
Area of high pressure
Dry conditions
Location of world deserts
60° N&S, air masses meet
Form Polar Front
Air masses rise, diverge and 90° and 30° N&S

7. Wind Movement At equator, warm air rises, condenses and precipitates
At 30° and 90°, cool air sinks
Air that sinks does not flow back in a straight north-south path – it curves (Coriolis Effect)

8. Rotation on a Globe
Buffalo and Quito located on same line of longitude (79ºW)
Both cities circles the globe in one day (360º/24 hours = 15º/1 hour)
Quito has larger circumference; thus, travels farther
Quito needs to travel faster than Buffalo

9. Apparent Deflection Hypothetical war game
If a cannonball is shot north from Quito
It will travel a straight path
But, because Earth is rotating east to west
The cannonball appears to veer to the right in Northern Hemisphere
This is the Coriolis Effect

10. Wind Movement Coriolis Effect
Deflected winds due to movement over spinning object
Produce wind bands
In Northern Hemisphere:
Winds are deflected to the right
Travel clockwise around high P
In Southern Hemisphere:
Winds are deflected to the left
Travel counter-clockwise around high P
Assume water-covered Earth

11. Surface Current Circulation

12. Waves
Transport energy over a body of water

13. Wave Terminology
Height
Still water line
Still water line – level of ocean if it were flat w/o waves
Crest – highest part of wave
Trough – lowest part of wave
Ocean waves have distinct parts. When describing a wave its easier if the parts have names. The steeper the wave, the more likely it will break.
Wave height (H) – vertical distance between crest and trough
Amplitude – distance between crest and still water line
½ the wave height
Wavelength (L) – horizontal distance from each crest or each trough
Or any point with the same successive point
Steepness = Height (H)/length (L)

14. Wave Parameters
Beach T = 10 seconds; whereas, a tsunami T = 20 min (up to an hour).
Period (T) – the time it takes for two successive waves to pass a particular point
Frequency (f) – the # of waves that pass a particular point in any given time period

15. Deep Water Wave Motion Waves transmit energy, not water mass
Water particles move in orbits
Diameter of orbits decrease with depth
Particle motion ceases at ½ wavelength

16. Shallow Water Waves 1. Swell feels bottom at depth < ½ wavelength
2. Wave crest peaks and wave slows
3. Orbits progressively flatten at depth
4. Wave height (H) increases and wavelength (L) decreases
5. Wave breaks when H/L ratio > 1/7
6. Just above seafloor particles move in back-and-forth motion

17. Breaking Waves

18. Tsunami Characteristics
Energy passes through entire water column
Long periods (T)
T = min.
Small Height (H)
H = 1-2 m
long wavelengths (L)
L = km
Shallow water wave
Deep wave base
Travel at great speeds
c = 200 m/s

19. Tsunami Crest and Trough