Earth Science, Tarbuck Chapter 15 Flashcards
How is Ocean Circulation Determined
pattern of surface-ocean circulation closely matches the
pattern of global winds but is also strongly influenced by
the distribution of major landmasses and by the spinning
of Earth on its axis.
What are Gyres
large whirls of water within an ocean basin
What are the 5 main Gyres
the North Pacific Gyre, the South Pacific Gyre, the North
Atlantic Gyre, the South Atlantic Gyre, and the Indian
Ocean Gyre
At which latitude do the main 5 Gyres form
the center of each gyre coincides with the subtropics at about 30° north or south latitude
What is the Coriolis effect that affects Both wind and Water currents
Due to Earth’s rotation, currents are deflected
to the right in the Northern Hemisphere and to the left in
the Southern Hemisphere
What is the Only water current that completely circulates around the earth
West Wind Drift
What is Upwelling
the rising of cold water from deeper layers to replace warmer surface water
What causes upwelling
Wind
What is Thermohaline Circulation
Also known as deep-ocean circulation, thermohaline circulation is caused by differences in density of Seawater
What causes most waves in the ocean
Storms and Wind
As waves get closer to the shore what happens to them
Wavelength gets shorter
Waves are usually _______ to the shore
Parallel
Where does most coastal upwelling occur
West Coast of Continents
How does Deep-Ocean Circulation occur
When water gets denser at the surface, it sinks and spreads out
What is the Shoreline
The area where the land touches the sea
What is the shore
Area between Lowest tide level and highest land affected by Ocean waves
Where is the Coastline found
The landward edge of the shore
What is the foreshore
the area between Low tide and High tide water levels
What is the backshore
The area between the foreshore and the coastline
What is a berm
flat sandy platforms near dunes, and the beach face, the wet sloping area to the shoreline.
What are beaches made up of
material nearby that is readily available
What are beaches mostly composed of
Quartz grains
What aree waves technically
energy traveling through water
What are Whitecaps
when waves grow tall enough to break, forming white foam
What is circular orbital motion
The idea that water moves in circles and returns to its original place in waves, while objects on top of the wave move slightly forward and backward while on the wave
What is swash
the rush of seawater up the beach after the breaking of a wave.
What is Beach Drift
zigzag movement of sediment along the beach caused by the angular motion of swash and the straight motion of backwash
What is backwash
As swash recedes back into the ocean, it is called backwash
What are rip currents
strong flows of water that move away from the shore, opposite to breaking waves
What are wavecut hills
a flat, gently sloping rock surface formed at the base of a cliff by the erosive action of waves, essentially creating a “platform” where the cliff has retreated over time due to wave action
what is ocean wave refraction
the bending of ocean waves as they approach a coastline at an angle, happening because the part of the wave closer to the shore slows down due to friction with the seabed, causing the wave to bend and align more parallel with the coastline
What is a sea cave
an opening in the headlands caused by surf selectively eroding softer rocks
What is a sea arch
When two sea caves on opposite sides of a headland unite, a sea arch is formed
What is a sea stack
When a sea arch falls in, it causes isolated rock structures to form
Where is sediment transported along the shore tend to be deposited
areas where wave energy is low
Where are spits and tombolos formed
areas where beach drift and longshore currents are active
What are longshore currents
ocean currents that flow parallel to the shoreline, caused by waves that approach the beach at an angle
What is a spit
long ridge of sand that extends into a bay, often curving landward
What is a baymouth bar
sandbar that completely crosses a bay.
What is a sandbar
ridge of sand or coarse sediment that is built by waves offshore from a beach
What is a tombolo
ridge of sand or gravel that connects an island to the mainland.
What are barrier islands
long, narrow, sandy landforms that are separated from the mainland by bays or lagoons
Difference between east and west coasts of america
Difference is plate tectonics, as there is active uplift on the west coast, while the east coast is mostly quiet
Coasts are usually classified as
emergent or submergent
What are emergent coasts
coasts that are a result of uplift or sea level drop
What are submergent coasts
sea level rises or land sinks
What is a headland
raised area of land that extends into a body of water, such as an ocean or lake, and is characterized by a steep cliff on one side
What are jetties
structures that extend into the water from the shore to protect coastlines and help ships navigate
What are groins
structures that are built perpendicular to the shoreline to protect beaches from erosion
What are the different types of hard stabilization
Groins, Jetties, breakwaters, and seawalls.
What is a breakwater
a structure built parallel to the shore to reduce the impact of waves on the coast
What is a seawall
a wall erected to prevent the sea from encroaching on or eroding an area of land.
What is beach nourishment
adding large amounts of sand to the beach
How does the Moon’s gravitational pull affect the tides
the moon pulls the water on the side of the earth it is closest to, causing a tidal bulge, which also occurs on the direct opposite side of the earth
What does the tidal bulge caused by the gravitational pull of the moon cause on earth
two high and two low tides per day, as the tidal bulge stays in place while the earth rotates, as the moon only moves moderately
The sun also exhibits control on the earths tides but are much weaker than the moons due to what
Greater distance from earth
When are the gravitational forces of the sun and moon combined, producing larger tidal bulges
New and Full moons
What does the combination of the gravitational forces of the sun and moon cause
higher high tides and lower low tides
What are spring tides
When the gravitational forces of the sun and moon combine, they form tides with larger range
How often do spring tides occur
Twice a month
When do the gravitational forces of the sun and the moon offset each other
1st and 3rd quarters of the lunar cycle, as they act on each other at right angles
What are neap tides
during the first and third quarters of a lunar cycle, the gravitational forces of the sun and moon offset each other
What are the 3 main tidal patterns that exist world wide
Diurnal, Semidiurnal, and Mixed
What is a diurnal tidal pattern
a single high tide and a single low tide each tidal day
What is a semidiurnal tidal pattern
exhibits two high tides and two low tides each tidal
day, with the two highs about the same height and the
two lows about the same height
What is a mixed tidal pattern
2 high tides and 2 low tides each tidal day, but heights are unequal
Where do diurnal tidal patterns occur in america
northern shore of the Gulf of Mexico
Where do semidiurnal tidal patterns occur in america
Atlantic Coast
of the United States
Where do mixed tidal patterns occur in america
Pacific Coast of the United States
