Oceanography Chapter 8

What ratio is important to wave steepness? What happens if this ratio is exceeded?

1/7. the wave will break if it exceeds the steepness.

What happens when wave trains collide?

An interference pattern is produced when two or more wave systems collide.

How does water move as a wave passes through it? Is there a point below the surface where this motion disappears? What happens to the motion of water as you approach this depth?

As a wave travels, the water passes energy along by moving in a circle (this is circular orbital motion). The water itself does NOT travel, but the waveform does. Only once a wave is breaking does it transport water. This At some point below the surface, the circular orbits become so small that movement is barely measurable. This depth is called the wave base.

What is the difference between deep-water and shallow-water waves? Can you give an example of each?

Deep-Water Waves: If water depth is greater than the wave base, the waves are called deep-water waves. Deep-water waves have no interference with the ocean bottom Shallow-Water Waves: Shallow-water waves touch the bottom of the ocean floor which interferes with their orbital motion.

What happens to waves as they approach a shore in regards to their: Speed? Wavelength? Height? Steepness?

If they encounter any shallowly submerged obstacle (like a coral reef, sunken ship, or sand bar) waves will release some energy. Wave speed decreases - because the ocean floor interferes w/ movement. Wavelength decreases - because waves begin to "pile up". Wave height increases - because wavelength has decreased. Wave steepness increases - and once the 1:7 ratio is breached, the wave breaks and releases its energy.

Where are waves are generated in the open ocean by wind? What are the characteristics of this area? What is: A sea? Fetch? Breakers? A fully developed sea? Swell?

Origin is in a windy region of the ocean. Movement is across great expanses of open water (no longer driven by wind). Waves terminate when they break and release their energy, either in the open ocean or against the shore. Area where wind-driven waves are generated is called the "sea". The sea is characterized by choppiness and waves moving in many directions. Fetch - the distance over which the wind blows in one direction. open ocean breakers called whitecaps form. When wave speed becomes equal to the speed of the wind, a fully developed sea has been achieved. Swells are uniform, symmetrical waves that have traveled out of their area of origination (

What types of waves are the result of: a gently sloping ocean bottom? A moderately steep sloping ocean bottom? An abruptly steep ocean floor?

Spilling Breakers - Result from a gently sloping ocean bottom which causes water to spill or run down the front slope of the wave. Plunging Breakers - Form on moderately steep beach slopes and are considered the best waves for surfing. Surging Breakers - Created when the ocean bottom has an abrupt slope and wave energy is compressed into a shorter distance causing the wave to surge forward.

What are the typical characteristics of swell?

Swell: Toward the outside margins of a sea, wind speeds diminish and waves eventually move faster than the wind. Wave steepness decreases and waves become long-crested called swells. Swells are uniform, symmetrical waves that have traveled out of their area of origination (out of the "sea" where it formed). Swells lose little energy as they travel across the ocean, transporting large amounts of energy from one area to another. The movement of swells is why there can be waves at a shoreline even though there is no wind.

How are most ocean waves generated?

The majority of waves in the ocean are generated by wind. Wind causes waves to radiate out in all directions. The movement of fluids with different densities can also create waves

What types of waves are tsunamis? What causes them? How high are they typically? How do they arrive at a coastline? Where are they most common and why?

Tsunami originate from sudden changes in the topography of the sea floor.The majority of tsunami are caused by fault movement that displaces Earth's crust seismic sea waves. Much less common events like underwater volcanic eruptions create the largest type of tsunami. a tsunami is a shallow-water wave everywhere in the ocean In the open ocean, tsunami move as fast as a jet plan - over 430mph - yet they have wave heights of only about 0.5 meters.

Be sure to know the difference between: wave height, wavelength, wave period, and frequency.

Wave Period: The time it takes one full wave (one wavelength) to pass a fixed position (like a pier piling). Frequency: The number of wave crests passing a fixed location per unit of time. Wave Speed: The rate at which a wave travels.

What is wave refraction? What is wave reflection? What happens to the energy in a wave in both circumstances?

Wave Refraction: Waves rarely approach a shore at a perfect right angle. Usually, some segments of a wave will touch bottom first and will slow before the rest of the wave, causing refraction. Refraction is the bending of each wave crest it can be reflected back into the ocean with little loss of energy. This is called wave reflection.

What causes waves to form? Where do they occur?

a disturbing force causes waves to form. atmospheric waves internal waves ocean waves

What types of waves exist?

atmospheric waves oceanic waves internal waves

Can wave energy be harnessed?

harnessing wave energy is seen as a promising possibility, especially in higher latitudes where high winds produce major waves.

What are waves? What are they doing? How are they moving?

ocean surface waves are orbital, waves transmit energy. they move in a circle

Are there waves that don't break (or show) along the surface?

progressive waves