chapter 16 earth scinece Flashcards
what are ocean currents
masses of ocean water that flow form one place to another.
what are surface currents
they are movements of waters that flow horizontally in the upper part of the oceans surface
what are gyres
Huge circular moving currents that move within an ocean basin.
what is the coriolis effect
it is when currents dont go their original direction because the earth is moving.
ocean currents and climates
when currents from low latitude regions move into higher latitude regions they transfer heat form warmer to cooler areas on earth. and vice versa.
what are upwellings
The rising of cold water to replace warmer surface water that has been displaced by wind.
deep ocean circulation
density currents are caused by differences in density of ocean water. it creates vertical motion.
what does evaporation do
Causes an increase in salinity in dryer warmer areas.
What is sea ice
most water involved in density currents begin near poles
A conveyor belt
The circulation map can be simplified to a conveyor belt that travels throughout the world oceans
waves and tides
currents are not visible to the eye while waves and tides and waves change shorelines over time.
what are waves
they are rhythmic movement that carries energy through water or space.
wave characteristics
Crest-highest point
trough-lowest point
wavelength-horizontal distance between the crests of two waves
what is frequency
the number of waves that pass a point in a certain amount of time.
what is amplitude of waves
is the half distance of the wave height
what is wave motion
water can travel a great distanec. It looks like it moves forward but it stays in about the same place
breaking waves
as wave approach shore they change.
long low waves in deep water are called swells.
what are tides
tides are regular changes in the elevation of the ocean surface due to the moon.
what causes tides
the moon and the earth are relatively close together in space so the moons gravity exerts a strong pull on earth.
what are some factors that effect the height of a wave
landforms can interrupt the waters movement
a basin at the mouth of a river can increase the tidal range
the spread and depth increases as it flows into a narrower channel.
what are spring tides
are when the moon earth and sun are lined up during ht new moon.
what are neap tides
are when the sun earth and moon form a right angle at 1st quarter.
what are tidal patterns
ocean basins vary in size and shape and depth so coastal locations may have different tidal patterns.
shoreline processes and features
beaches and shorlines are always undergoing changes as the force of the waves and currents act on them
wave impact
waves along the shoreline are constantly eroding, transporting and depositing sediments, as a result many shoreline features develop
what is abrasion
when waves move sediments back and forth across the shore zone.
as the wave hits land the sediments wear away rock like sandpaper.
what is wave refraction
as waves reach shallow water the waves crests refracs(bends)
whats longshore transport
longshore currents run parallel to the coastline that carry a lot of sediments
what’s wave cut cliffs and platforms
a wave cut cliff may result if the base of a steep area that has softer rock at the base
this softer rock erodes and the rock above collapses
sea arches and sea stacks
remember how headlands extend into the sea and are vigorously eroded by waves because of wave refraction.
usually the softer rock at the base erodes forming a sea cave on both sides.
eventually the erosion is deep that the two caves meet resulting in an arch.
what is a spit
a spit is a beach that projects like a finger out into the water at a result of longshore drift deposits.
what is a tombolo
is a ridge of sand that connects an island (or a sea stack) to the mainland
whats a barrier island
they are sand deposits that are parallel the shore but are separated from the mainland by 3 to 30km.
they form along coastal plains that slope gently seaward
what are sand dunes
they are hills of windblown sand making beaches more stable and lessens erosion
whats protective structures
they are built to protect a coast from erosion or to prevent the movement of sand along a beach
what is beach nourishment
artificially adding large quantities of sand to a beach system.
