Waves 4 Flashcards
In the open ocean, waves become unstable when
H/L > 1/7
the wave becomes too high for it’s wavelength
Waves approaching shore will turn into ___ waves
shallow water
Shallow water waves will break when ___
H/L > 1/7
OR
H/d ~ 3/4
Whichever occurs first
A breaker is where
waves start to break
The shape and size of breakers is determined by ___
slope of ocean floor
Name the three types of breakers
- Plunging
- Spilling
- Surging
What are spilling breakers? How is energy released?
Flat bottom
- small, gentle
- wave energy released slowly over wide area
- usually not hazardous
What are plunging breakers? How is energy released?
Steep bottom, forms pipeline/tube for surfers
- large, violent
- sudden release of energy
- potentially violent
What are surging breakers? How is energy released?
Very steep slope (narrow surf zone)
- very large, powerful
- fast release of energy over limited area
- waves don’t break, but surge and collapse onto shore
- can be deadly
Wave refraction
the change in direction of wave motion as wave slows down
As waves approach the shore, they ___
bend towards the shore
Why do waves refract as they approach the shore?
Speed of shallow water waves depends on depth, so shallower water means waves slow down
How do waves affect coastlines?
- shore straightening because
- bays fill in
- headlands erode - sediment transport
longshore drift
net movement of sand along shoreline
longshore current
moves suspended sand in surf zone
