1. Aquatic Science Fall Final Review

2. Tides The rhythmic/periodic rise and fall of the ocean’s water
High tide = rising, incoming tide, flow
Low tide = receding, outgoing tide, ebb
Tides are very long, slow waves

3. What Causes Tides? 1. Gravitational pull of sun & moon on Earth
Moon closer, therefore > effect
Like a magnet, pulls water away from surface = TIDAL BULGE

4. Types of Tides Spring Tide
Moon and sun are in direct line with one another
Results in unusually high tidal range
2x’s/month

5. Neap Tide sun and moon are at right angles
Pulls cancel each other out – causes a weak pull
unusually low tidal range
2 x’s / month

6. Spring vs. Neap Tides

7. Waves A complex mix of water and energy.
Mostly caused by winds (i.e. surface waves)
-Also earthquakes, volcanoes, gravitational pull

8. Wave Characteristics Parts of a Wave Crest = high point
Trough = low point
Height = vertical distance from crest to trough
Wavelength = Horizontal distance between crest to crest or trough to trough

9. Tsunami vs Surface Waves
Out on the open ocean, Tsunami waves are:
Fast (hundreds of mph)
Not tall (up to 3 ft)
Out on the open ocean, surface waves are:
Relatively slow (5-65 mph)
Much taller than tsunami waves (up to 45 feet)

10. Coriolis Effect
The apparent deflection of the path of air, due to the rotation of the earth

11. Upwelling
Cold, nutrient-rich water rises to replace the surface water (good for fishing- Peru)
process is dominant when winds are parallel to coastline

12. Convection + Coriolis
cause winds blowing at these angles across the planet
“planetary winds” blow constantly

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

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

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

16. This is because they are Basic Wind-Driven Currents

17. 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

18. Which side of the continent are there warm currents. Cold
Which side of the continent are there warm currents? Cold? What direction do each of these currents flow?

19. Western vs. Eastern boundary vocabulary to know

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

21. What is ENSO? ENSO stands for El Nino Southern Oscillation
An irregular, periodic climate change caused by variations in sea surface temperatures over the tropical eastern Pacific Ocean
On average, occurs every 2-7 years
Use of SST anomalies and SOI values to predict these events

22. Southern Oscillation Index
Southern Oscillation Index (SOI) values are calculated using the pressure differences between Tahiti and Darwin.
Sustained negative values of the SOI below -8 indicate an El Nino episode.
Sustained positive values of the SOI above +8 indicate a La Nina episode.

23. Normal conditions vs. El Nino
Eastern Pacific = colder, cools off with depth much faster
Western Pacific = pool of warm water, extending hundreds of meters down
El Nino:
Warm water extends from the west to the east of the Pacific (across the equator), at the surface and several hundred meters down.

24. Normal conditions vs. El Nino
Weather in Indonesia, Australia, Southwest Asia = wet
Weather in CA, Central America, Ecuador, Peru = dry
El Nino:
Weather in eastern Pacific = warmer, increased rainfall
Weather in western Pacific = cool, dry (some drought)

25. Under El Nino
Trade winds and the Equatorial currents are weaker than normal.
Warm water builds up in the eastern Pacific.
Upwelling decreases in the eastern Pacific because of weakening trade winds.
Rainfall increases in the eastern Pacific, and becomes drier in the western Pacific.

26. ENSO impact on hurricane and severe weather frequency
El Nino:
Fewer than normal hurricanes
More tornadoes and thunderstorms in the southern US
La Nina:
Higher than normal hurricanes
Warm weather for most of US, but drought in southwest

27. THE END