GEO 110 Lecture 9: CGEO Final Exam Notes
15 Jun 2018
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Coastal Process
Wave Actions
• Waves: are caused by the frictional drag of wind over the water.
1.) Waves of Oscillation
o Water particles move in near-circular orbits which decrease in diameter with depth
o Wave crest: The highest part of a wave or the peak of the wave
o Wave trough: The lowest part of a wave
o Wave height: The vertical distance between the trough and the crest of a wave. The longest
wave.
o Wavelength: the horizontal distance between the successive crests of a wave
o Wave period: the time for two consecutive crest to pass a point.
o The wavelength, or horizontal size of the wave, is determined by the horizontal distance
between two crests or two troughs.
2.) Wave of Translation
o Water particles actually move forward
o Wave of oscillation change energy and mass moves in the same direction (horizontally)
▪ As waves roll into shallow water, wave motion is affected by frictional drag on sea
bottom
▪ Waves are slowed and bunched together; wavelength DECREASES & wave height
INCREASES.
o Swash: Wave that advances. When wave breaks, water is washed up the beach.
o Retreating: Then when the water runs back down the beach it is called the backwash waves.
3.) Wave Refraction
o When waves approach a straight shoreline at an oblique/acute angle
o One part of the wave advances faster and touch the shoreline and reduce speed/velocity.
o Wave change direction as they approach shore
o Friction with the sea bed as waves approach the shore cause the wave front to become
distorted or refracted as velocity is reduced.
4) Longshore drift
o The transport or movement of material (sand or pebbles) in the sea, in the direction of the
shoreline, in regions close to the shore by tidal forces.
o Moving significant amounts of sediment along the coast. This usually occurs in one direction as
dictated by the prevailing wind.
o Waves are formed by wind action and when they reach the shore they are not necessarily
parallel to the shoreline.
o Surf: Run parallel to the shoreline
Thermohaline conveyor
• Moves a massive current of water around the globe, from northern oceans to southern
oceans, and back again. Currents slowly turn over water in the entire ocean, from top to
bottom. It is somewhat like a giant conveyor belt, moving warm surface waters downward and
forcing cold, nutrient-rich waters upward.
• Cold water is denser than warm water and moves beneath (move from polar regions to equator)
• Warmer ocean current is fresher and moves above (move from the equator to polar regions)
Ocean Current
• To occur it depends on the curvature or morphology of the ocean basin (depth of the ocean) and the
temperature of the ocean
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Document Summary
Wave actions: waves: are caused by the frictional drag of wind over the water. When wave breaks, water is washed up the beach: retreating: then when the water runs back down the beach it is called the backwash waves. This usually occurs in one direction as dictated by the prevailing wind: waves are formed by wind action and when they reach the shore they are not necessarily parallel to the shoreline, surf: run parallel to the shoreline. Thermohaline conveyor: moves a massive current of water around the globe, from northern oceans to southern oceans, and back again. Currents slowly turn over water in the entire ocean, from top to bottom. Ocean current: to occur it depends on the curvature or morphology of the ocean basin (depth of the ocean) and the temperature of the ocean. It is more or less permanent or continuous directed movement of ocean water that flows in one of the.
