# Shared Flashcard Set

## Details

Oceanography Exam 3
Waves and Water Dynamics, Tides, & The Coast
31
Other
03/25/2010

Term
 Define wavelength.
Definition
 The length from crest to crest.
Term
 Define wave period.
Definition
 The amount of time that passes between each successive wave break.
Term
 Define wave height.
Definition
 The height of a wave from crest - trough.
Term
 Define wave base.
Definition
 The depth in the ocean at which the wave energy dies out.
Term
 How does wavelength relate to the celerity (speed) of the wave?
Definition
 The bigger the wavelength, the faster the speed.
Term
 Describe the movement of water molecule as a wave passes by in deep water.
Definition
 Circular.
Term
 How does this movement differ when a wave is in shallow water?
Definition
 It slows down.
Term
 How deep can this energy be felt?
Definition
 As deep as the wave base.
Term
 How are "deep-water" and "shallow-water" waves defined?
Definition
 "Deep-water" waves = the depth of the ocean is greater than 1/2 of the wavelength."Shallow-water" waves = the depth of the ocean is less than 1/2 of the wavelength.
Term
 Explain how wind speed, wind duration, and fetch determine the height of a wave.
Definition
 The faster the wind, the longer the wind lasts, and the bigger the fetch, the bigger the wave.
Term
 What is a "fully-developed sea"?
Definition
 When it has reached its maximum wave height.
Term
 Are waves affected by the Coriolis force? Why or why not?
Definition
 No. The Coriolis force only affects moving mass. The ENERGY is what is moving, which is not a mass.
Term
 Define constructive wave interference.
Definition
 When two wave crests meet and combine their heights.
Term
 Define destructive wave interference.
Definition
 When two waves meet crest to trough. This results in no waves.
Term
 How does a rogue wave develop?
Definition
 In a low pressure region where there is wave interference.
Term
 What happens to wavelength, height, speed and period when a wave approaches a shoreline? Why does this happen.
Definition
 They all decrease, except for the period. This happens because of wave refraction.
Term
 If there were no land masses on Earth, how many high and low tides would there be at any given time?
Definition
 Two of each. (12 hours apart)
Term
 How does gravitational attraction between two objects vary with changes in mass and distance?
Definition
 The greater the mass, the stronger the attraction, but the further the distance, the weaker the attraction.
Term
 Are tides deep-water or shallow-water waves? Explain.
Definition
 Shallow-water, because the depth is less than 1/2 of the wavelength. (The wavelength = 12,000 mi. , and the average depth of the ocean is only 4 mi.)
Term
 Define tidal range.
Definition
 The difference between the high tide and the low tide.
Term
 Describe differences between the daily tidal patterns. (Diurnal, Semidiurnal, and mixed)
Definition
 Diurnal = one high tide and one low tide per day.Semidiurnal = 2 high tides and 2 low tides per day with the same range.Mixed = 2 high tides and 2 low tides per day with different ranges. (*Most common)
Term
 How does tidal range vary with spring and neap tides?
Definition
 Spring = highest highs, lowest lows, so Greatest tidal range.Neap = lowest highs, highest lows, so Smallest tidal range.
Term
 How are Moon phases related to monthly tidal patterns?
Definition
 It involves the relative positions of the moon, Earth, AND sun. If they all line up, the sun's and the moon's gravitational forces combine (high tides). If they do not line up, their gravitational forces work against each other (low tides).
Term
 What is longshore transport?
Definition
 The movement of water (and sediment) along the coastline.
Term
 Explain how and why a summer beach profile is different from a winter beach profile.
Definition
 A summer beach is wider than in the winter because the sand is carried into the water during winter storms, and washes back onto the beach in the summer.
Term
 What are the common features of an erosional shoreline?
Definition
 (Rocky.) Sea cliffs, sea caves, sea arches, sea stacks, and uplifted marine terraces. (Because the waves carve away at sand)
Term
 What are the common features of a depositional shoreline?
Definition
 (Sandy.) Beach, spits, bay barrier, barrier islands.
Term
 What evidence is there that barrier islands are being moved by wave activity?
Definition
 Houses at the edge about to tip and fall into oceans!
Term
 How can a seawall actually accelerate shoreline erosion?
Definition
 The waves bounce off the wall with the same energy, eroding the beach.
Term
 What does beach nourishment/replenishment mean? How does it differ from other shoreline protection methods?
Definition
 Pump sand from the ocean floor onto the beach. It is more "natural" - no hardened constructed structures.
Term
 What is the main long-term driving force that causes shoreline erosion?
Definition
 Global warming, which causes changing sea level (rising), causing extra erosion.
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