Exam 3 - Chapters 7,8,9

When deep-water waves approach the shore, the water depth decreases and the wave base starts to intersect the sea floor. At this point the wave starts to change. (Label the image)

-Wave Base (depth = 1/2 wavelength) -Velocity decreases (wave height increases) -Approaching shore, waves begin to "feel bottom" (wavelength shortens) -Deep-water waves with constant wavelength -Surf Zone (wave pitch forward and break)

The wavelength of a tsunami exceeds _______ kilometers, therefore the wave base exceeds the depth of the ocean, so the wave "feels" the bottom during its travels throughout the entire ocean basin.

11

The length of gravity waves are ________ to ________ times the wave height.

15 to 30

In deep water, a wave with a wavelength of 60 meters and a wave height of 6 meters will have orbital motion down to a depth of ___________________ meters (500 ft.)

150

When wave steepness exceeds a ___________ ratio, the waves become unstable and ________________.

1:7, break

Theoretic maximum height of a wind-generated wave is __________ feet and is known as the '_________________________.'

60, 60 foot rule

Be able to label the following: swell, storm, sea, fetch, wind

A = fetch, B = limits of storm (red line), Under cloud = sea

______________________ waves are the first waves that form when the wind begins to blow across the ocean's surface. These waves form as wind pushes down on and parallel to the surface, causing water to pile up into ripples.

Capillary

___________________ a property that results from the surface tension of water.

Capillary waves

List the three wave Interference types:

Constructive Interference, Destructive Interference, Mixed Interference

____________________ interference occurs when wave trains having the same wavelength come together In Phase, meaning crest to crest and trough to trough. The interference pattern results in a wave with the same wavelength, but an ________________ wave height.

Constructive, unchanged

___________________ interference occurs when wave trains having the same wavelength come together Out of Phase, meaning the crest of one wave coincides with the trough of a second wave. If the waves have identical heights the result is a canceling of wave _________________, creating a smooth ocean surface.

Destructive, energies

Wave _________________ is the separation of waves as they leave the sea area first, to be followed by progressively _____________waves.

Dispersion, shorter

All waves begin as a disturbance, ocean waves form as the result of a ______________ Force.

Disturbing

Wind ______________ is the length of time during which the wind blows in one direction.

Duration

The ______________ is the distance over which the wind blows in one direction.

Fetch

An __________________________ Pattern is produced when two or more wave systems collide is the sum of the disturbance that each would have produced individually. Results in a larger or smaller wave trough or crest.

Interference

The gravitational force is derived from _______________ Law of Universal Gravitation which states that every object that has mass in the universe is attracted to every other object.

Newton's

What are the three types of ocean waves?

Ocean Tides, Tsunami, Wind-generated waves

__________________________ are used to help determine how energy is distributed along the shoreline by breaking waves. (white lines)

Orthogonal Lines

___________________ Breaker has a curling crest that moves over an air pocket. They form on moderately steep beach slopes and are the Best waves for surfing.

Plunging

_____________________ is a massive, solitary, spontaneous ocean wave that occurs amid normal ocean waves of smaller size. Also known as super wave, monster wave, sleeper wave.

Rogue Wave

__________________ Breakers is a turbulent mass of air and water that runs down the front slope of the wave as it breaks. Results from gently sloped ocean bottoms, which gradually extract energy from the wave over an extended distance and produces breakers with low overall energy.

Spilling

Name the three types of Wave Breakers:

Spilling Breaker, Plunging Breaker, Surging Breaker

_________________________ is an irregular wave pattern caused by mixed interference that results in a varied sequence of larger and smaller waves. This is typically the wave patter observed at the beach.

Surf Beat

____________________ Breakers forms when the ocean bottom has an abrupt slope and abruptly extracts energy from the wave. These breakers form when the waves build up and break right at the shoreline. Board surfers tend to Avoid these type of breakers.

Surging

Which type of ocean wave has the longest wave period and which has the shortest?

Tidal, Wind-generated

_______________ are the periodic raising and lowering of sea level that occurs daily throughout the ocean.

Tides

__________________ waves are intermediate waves that are traveling from deep-water to shallow-water with wavelengths between 2 and 20 times the water depth. Particle orbits are beginning to be influenced by the ocean ________________.

Transitional, floor

___________________ are shallow-water waves generated by sudden changed in the topography of the ocean bottom caused by slippage along underwater faults or the collapse of oceanic volcanoes.

Tsunamis

Not all wave energy is expended as waves rush onto the shore. _____________________________ is when a wave hits a solid object such as a seawall, jetty, island or some other solid structure, the wave is reflected off the object in the opposite direction with little loss of wave ________________.

Wave Reflection, energy

Calculating: You can calculate the speed of the wave with the wave length and the wave period.

Wave length (m)/Period(s) = Wave Speed (m/s)

Wave __________ is the depth at which circular motion becomes negligible. It exists at a depth of one-half wave length (L/2), measured vertically from still-water level.

base

As a wave approaches the shoreline from deep water, the circular orbit of water molecules within the wave begins to interact with the ocean _____________.

bottom

Shallow-water waves ______________________ or feel bottom. The lower wave orbitals interact with the shallow seafloor and are slowed as their orbital paths are _______________________.

bottom (hit the bottom?), interfered

What is the principle cause and wave period of a Tsunami?

cause: earthquakes, volcanoes, and landslides period: 5 minutes-1 hour

What is the principle cause and wave period of Ocean Tides?

cause: the moon and sun period: 12-24 hours (max. 2 per day)

What is the principle cause and wave period of Wind-generated waves?

cause: wind period: 0.1 second-5 minutes

Water particles in a wave travel in a _________________ (orbital) motion.

circular

The water itself does not travel the entire distance across the ocean, but the waveform does. As the wave travels, the water passes the energy along by moving in circles. This movement is called: _________________________________________________.

circular orbital motion

The (grey in this image) arrows represent the paths of incoming waves along an irregular shoreline. As the waves approach the shore and refract, some waves ____________ on the headlands and others ____________________ in the bays.

converge, diverge

An idealized wave passes a permanent marker, such as a pier pilling, a succession of high parts of the waves, called __________ alternate with low parts called _______________.

crests, troughs

The distance over which waves change from choppy "sea" to uniform swell is called the _____________ distance, which can be up to several ________________________ kilometers.

decay, hundred

As waves approaching the shore and begin to "feel the bottom" the following occurs: wave speed ________________, wavelength ____________________ and wave height __________________.

decreases, decreases, increases

Internal waves travel along boundary between waters of different __________________. Internal waves can be much larger than surface waves, with heights exceeding ______________ meters (330 ft).

densities, 100

Waves can also be created by the movement of fluids with different _______________. These waves travel along the ____________________ (boundary) between the two different fluids. Air and ocean fluids.

densities, interface

The speed of a tsunami is determined by the ocean _____________. Speed of a tsunami is ________________ km/hr.

depth, 700

Gravitational force (Fg) is ______________ proportional to the product of the masses of the two bodies (m1, m2) and is ________________ proportional to the square of the distance between the two masses (r2). _________ is the gravitational constant, which does not change.

directly, inversely

Ocean waves are caused by a transfer of __________. Examples: wind, earthquakes, landslides, gravity, etc.

energy

Waves are moving __________ traveling along the interface between ocean and atmosphere.

energy

Waves transfer _________ from a storm far out at sea over distances of several thousand kilometers.

energy

Wave height is directly related to the ___________________ in a wave. Wave heights in a sea area are usually less than _________ meters, but can have heights up to ____________ meters and periods of ____________ seconds.

energy, 2, 10, 12

Wave refraction affects the distribution of wave ________________ along the shore, influencing where and to what degree ________________, sediment transport and __________________ will occur.

energy, erosion, deposition

Swells move with little loss of ___________________ over large stretches of the ocean surface, transporting energy away from one sea and depositing it in another. The far reaches of swells beyond their origination is the reason there are waves at a shoreline even though there is no _______________ blowing locally.

energy, wind

When wave speed _____________ wind speed, neither wave height nor wavelength can change because there is no net energy exchange and the wave has reached its ____________________ size.

equals, maximum

Deep-water waves travel __________________ than shallow-water waves because the orbital motion of deep-water waves is not affected by the seafloor.

faster

This means that the top portion of the wave is traveling _____________ than the bottom portion of the wave. Water piles up and when the height of the wave is __________ times the wavelength, then the water plunges forwards, creating breaking "_____________."

faster, 7, waves

The majority of tsunamis are caused by vertical fault movements. Underwater ________________ movement displaced the Earth's crust, generating ____________________, rupturing of the seafloor, producing a sudden change in water level at the ocean basin, which displaces the entire water column generating a ___________________.

fault, earthquakes, tsunami

A fully developed sea is the maximum size a wave can develop for a given wind speed when it has blown in the same direction for a minimum duration over a minimum _____________________.

fetch

Wave ___________ (f) is the number of waves that pass a fixed point in a unit of time.

frequency

Waves cannot grow larger in size once they reach an equilibrium condition called a _____________________.

fully developed sea

Waves loose as much energy as whitecaps under the force of __________________ as they receive from the wind.

gravity

A deep-water wave is a wave in which the water depth is greater than _________________ of the wavelength. At this depth, the water is deep enough so that water travels in a circular motion without interface with the ocean ___________________.

half, bottom

The wave ____________ (H) is the vertical distance between a crest and a through.

height

Additionally energy transfered to the water results in the ___________________ in wave height more rapidly than in the increase in wavelength.

increase

As wind speed increases (from left to right), wave height and wavelength __________________.

increases

As "sea" waves gain energy, their steepness _________________. When wave steepness reaches a critical value of 1/7, open ocean breakers called ________________________ form.

increases, whitecaps

Deep-water waves - the longer the wave ________________, the faster a wave travels. A fast wave does not necessarily have a large wave height - wave speed depends only on wavelength.

length

Capillary waves are _________ than 1.74 cm. Gravity waves are __________ than 1.74 cm.

less, greater

In most ocean areas, it is likely that two or more swells of different heights and lengths will collide and result in a mixture of constructive and deconstructive interference producing a _____________ interference.

mixed

The main cause of a rogue wave is theorized to be an extraordinary case of ___________________ interference where multiple waves overlap In-Phase to produce an extremely large wave.

mixed

Along an air-air interface, the movement of different air masses creates _____________ waves. Atmospheric waves are common when ______________ fronts, high density air, move into the area.

ocean, cold

The portion of the wave still in deep water is traveling faster, as it feels the bottom, it too slows. Waves coming towards a straight shoreline are refracted and align themselves nearly ___________________ to the shore.

parallel

Wave ____________ (T) the elapsed time between the passage of two successive wave crests (or troughs) passed a fixed point.

period

Over a long period of time, wave refraction will result in the erosion of the headlands and deposition in the bay and eventually ____________________ an irregular shoreline.

refract

The slowing and bending of waves crest in shallow water is wave ___________________. As deep-ocean waves approach the shore, a portion of the waves will "feel bottom" and __________________ down.

refraction, slow

The area where wind-driven waves are generated is called the ________. It is characterized by choppiness with _____________ traveling in all directions. The waves vary in periods and _______________.

sea, waves, wavelengths

The __________________ of transitional waves depend partially on water depth and partially on wavelength.

speed

Wave ___________ (S) is the rate at which a wave travels. It can be calculated by dividing a wave's length (L) by its period (T).

speed

Wave _____________ is the ratio of wave height (H) to wavelength (L).

steepness

Halfway between the wave crest and trough is the ______________ level, or zero energy level. This is the level of the water is there are no ____________________.

still water, waves

Most waves generated in the sea are by storm winds moving across the ocean as a swell. These waves then release their energy along the margins of continents in the ______________________, zone of breaking waves.

surf zone

As wind blows across a body of water, the wind's energy is transferred to the surface of the water as a result of ________________________ between air and water.

surface tension

Tsunamis do NOT form breaking waves at the shoreline. They runup on shore as a _______________ of water. A tsumani resembles a sudden, extremely high tide. It takes many minutes for the crest of a tsunami to arrive on shore during which time, the sea level at the shoreline can rise up to __________ meters above normal.

surge, 40

As waves generated in the sea area travel out of their area of ordination, wind speeds diminish and the waves eventually move __________________ than wind. During this process, wave steepness decreases and waves become long-crested, uniform, symmetrical waves called ___________________.

swells

Many people mistakenly call them "tidal waves," but tsunamis are unrelated to the _______________.

tides

The Japanese term for the large, destructive waves that occasionally roll into harbors are called _______________.

tsunami (tsu = harbor, nami = waves)

Shallow-water waves occur when the water depth is less than 1/20 of the _______________ length.

wave

The decrease of orbital motion with depth has practical applications. Floating bridges and floating oilrigs are constructed with most of their mass below wave base, so they are unaffected by ____________ motion.

wave

Waves with longer wavelengths travel faster and thus leave the sea area first. The faster waves are followed by slower, shorter groups of waves called a ______________ train.

wave

As a group of waves leaves a sea area and become a swell ______________ train. The number of waves in a group remains the same as the group travels outward, a result of the disappearing __________________ wave, being replaced by a new wave created at the ____________ of the group.

wave, leading, back

The __________________ (L) is the horizontal distance between any two corresponding points on successive waveforms, such as from crest to crest or from trough to trough.

wavelength

Wind blowing across the surface of the ocean generates most ocean ____________. The ocean ___________ radiate out in all directions, just as when a rock is thrown into a pond, but on a larger scale.

waves

Most waves are driven by the ________ and relatively small, so they release low wave energy onto the shoreline.

wind

The height, length and period of a wave depend on three factors:

wind speed, duration, the fetch

As capillary wave development increases, the sea surface takes on a rougher appearance. The water "catches" more of the _______________, allowing more energy from the wind to be transferred to the ocean surface, leading to the development of ____________________ waves.

wind, gravity

The life history of a wind-generated wave includes its origin in a _________________ region of the ocean, the wave's movement across the ocean's deep-water without subsequent aid wind and terminating when it breaks and releases its ___________ energy in either the open ocean or against the shore.

windy, energy

The tide-generating forces create two simultaneous bulges: one on the side of Earth directed towards the Moon (the _______________) and the other on the other side directed away from the Moon (the ____________).

zenith, nadir