Title: The Dynamic Ocean
1 Lecture 15 The Dynamic Ocean
2 (1.) Ocean Currents
(2.) Ocean Waves
(3.) Wave Erosion
(4.) Coastal Features
(5.) Tides
3 (1.) Ocean Currents
(2.) Ocean Waves
(3.) Wave Erosion
(4.) Coastal Features
(5.) Tides
4Ocean Currents
- Ocean Surface Currents
- Ocean surface water that flows from one place to
another - Develop from friction between ocean water and
the wind that blows across the surface
Wind
Surface Current
5Ocean Currents
- Gyres
- Large circular surface current patterns found in
the oceans
6Ocean Currents
Map of Ocean Surface Currents
Warm Surface Current
Cold Surface Current
7Ocean Currents
Map of Ocean Surface Currents
Main Gyres
8Ocean Currents
- Deep-Ocean Circulation
- Movement of ocean water caused by density
differences due to variations in water
temperature and salinity - Cold and/or high salinity water is denser so it
sinks, which creates ocean circulation
9Ocean Currents
Map of Deep-Ocean Circulation
Warm Surface Flow
Cool Subsurface Flow
10 (1.) Ocean Currents
(2.) Ocean Waves
(3.) Wave Erosion
(4.) Coastal Features
(5.) Tides
11Wave Terminology
12Wave Terminology
- Wave Crests
- Tops of the waves
13Wave Terminology
- Wave Troughs
- Low points of the waves
14Wave Terminology
- Wave Height
- Vertical distance between between trough and
crest of a wave
15Wave Terminology
- Wavelength
- Horizontal distance between crest and crest
16Wave Motion
17Wave Motion
- Circular Orbital Motion
- As a water wave travels, it passes along the
energy of the wave by moving water in a circle
18Wave Motion
- Note that water particles only move in small
circles they do not travel with the wave - Wave energy is what is actually traveling
19Breaking Waves on Shore
20Breaking Waves on Shore
Deep Water Waves (i.) constant wave speed(ii.)
constant wavelength (iii.) constant wave height
21Breaking Waves on Shore
Waves Approaching Shore (i.) waves slow
down(ii.) wavelength decreases (iii.) wave
height increases
22Breaking Waves on Shore
Waves at Shore (i.) waves slow down(ii.)
wavelength decreases (iii.) wave height collapses
23Wave Refraction
24Wave Refraction
- Wave Refraction
- The process where the portion of a wave in
shallow water slows, causing the wave to bend - Tends to align waves with the contours of the
shore line
25Wave Refraction
Wave refraction causes waves to violently
converge on headlands (land that sticks out into
the ocean)
26Wave Refraction
Wave refraction causes waves to gently
diverge in bays
27 (1.) Ocean Currents
(2.) Ocean Waves
(3.) Wave Erosion
(4.) Coastal Features
(5.) Tides
28Wave Erosion
- Abrasion
- The grinding and scraping of a rock surface by
the friction and impact of rock particles carried
by water, wind, or ice
29Wave Erosion
- Impact Erosion
- Rock erosion due to waves
- compressing water into rock cracks, which causes
the cracks to grow larger until the rock breaks
30 (1.) Ocean Currents
(2.) Ocean Waves
(3.) Wave Erosion
(4.) Coastal Features
(5.) Tides
31Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Beach
- An accumulation of sediment found along the
landward margin of an ocean or lake
32Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Wave-cut cliff
- A seaward facing cliff along a steep shoreline
formed by wave erosion at its base and mass
wasting
33Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Wave-cut Platform
- A bench or shelf in the bedrock at sea level,
cut by wave erosion
34Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Marine Terrace
- A wave-cut platform that has been exposed above
sea level
35Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Headland
- A high, narrow strip of land that extends out
into the ocean
36Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Sea Arch
- An arch formed by wave erosion of a headland
37Coastal Features (a.) Beach (b.) Wave-cut
Cliff (c.) Wave-cut Platform (d.) Marine
Terrace (e.) Headland (f.) Sea Arch (g.) Sea
Stack
- Sea Stack
- An isolated mass of rock standing just offshore,
produced by wave erosion of a headland
38 (1.) Ocean Currents
(2.) Ocean Waves
(3.) Wave Erosion
(4.) Coastal Features
(5.) Tides
39Tides
- The Moon gravitationally stretches the Earth and
its Oceans to create Tides
40Tides
- The Moon gravitationally stretches the Earth and
its Oceans to create Tides
( Actual change in ocean height is only about 2
meters )
41Tides