Ocean Waves and Tides (Study Guide)

The size of wind-generated waves depends on what three factors?

- Wind speed - Duration of wind - Fetch: Distance wind blows in the same direction

For deep-water waves, the depth of no wave motion (wave-base) is approximately equal to __ the wavelength.

1/2

(Waves break when the height to wavelength ratio is) Waves break when the height to wavelength ratio is ___.

1:7

Shallow water waves develop when the water depth is approximately equal to or less than _______ the wavelength.

20 times

What is a seiche and how does it differ from wind-driven ocean waves?

A seiche is a rhythmic oscillation of water in an enclosed basin. During a seiche water level in a basin rises at one end and falls on the other. The water height in the center doesn't change.

According to the Equilibrium Theory of the Tides, how many high tides and how many low tides should each location on Earth experience in a day?

According to the Equilibrium Theory of the Tides, there should be two high and two low tides in each day.

As waves enter shallow water, what happens to the wavelength? What about the wave height?

As waves enter shallow water the wavelength decreases and the wave height increases. Breakers develop in some cases when the water particles near the crest don't slow as much.

Do astronomical tides behave as shallow or deep water waves? Explain.

Astronomical tides behave as shallow-water waves. An average ocean depth of 4000m has tidal celerity of 200 m/s.

Distinguish between diurnal, semi-diurnal, and mixed tides.

Diurnal- One high and one low in 24 hours Semi-diurnal- Two highs and two lows in 24 hours of the same height Mixed tides- Two highs and two lows in 24 hours of different heights

A rising tide and accompanying currents directed toward the land, into a harbor, or upriver are called _____. .

Flood tides

For the same wind speed, are higher sea waves generated with increasing or decreasing fetch?

Higher sea waves would be generated with increasing fetch.

For a seiche, where are the wave heights the highest?

In a seiche, the wave height is the highest at the antinodes.

What is a rogue wave, and how are rogue waves created?

Rouge waves are unusually high waves created by constructive interference. Waves are considered rouge when they are 2.2 or more times the significant wave height.

What is significant about the tidal range during spring vs. neap tides?

Spring tides have a greater variation than neap tides. Spring tides- new moon and full moon Neap tides- When the sun and moon are at a 90-degree angle.

What location on Earth has the largest tidal range and why?

The Bay of Fundy has the largest tidal range because it is mostly an enclosed basin and has a high resonance.

Where specifically is the development of internal waves most likely to occur in the ocean water column?

The development of internal waves occurs in the base of the mixed layer, between distinct water masses, and in estuaries along the pycnocline.

What non-astronomical factors are not taken into account in the Equilibrium Theory of the Tides?

The presence of continents, Coriolis, water depth, and coastal configuration all affect ocean tides.

Compare the restoring force for capillary waves versus longer wavelength ocean waves.

The restoring force for capillary waves is surface tension. The restoring force for longer wavelength ocean waves is gravity.

What astronomical factors are not taken into account in the Equilibrium Theory of the Tides?

The rotation of the moon occurs in lunar months. The plane of the moon is inclined by 5 degrees. The sun also produces bulges.

How do tides relate to the position of the moon?

Tides are produced by the gravitational attraction of the moon and shift in position and strength as the moon moves.

Why are tsunamis classified as shallow-water waves?

Tsunamis are classified as shallow-water waves because they have extremely long wavelengths, and the depth is less than 20 times the wavelength.

What causes most waves on the ocean surface?

Waves on the ocean surface are caused by wind, seismic activity, and tidal forces.

For deep-water waves, the diameter of the orbit of a water particle at the ocean surface is equivalent to the _________.

wave height