Studied by 2 peopleel nino
The trade winds decrease, air pressure patterns in the South Pacific are reversed, flow of water away from South America decreases and warmer temperature.
Surface currents
are caused by the influence of prevailing winds blowing steadily across the sea
Upwelling currents
where the ocean currents move cold water, rich in nutrients, from the ocean floor to the surface
Hurricanes
Low-pressure systems that bring heavy rainfall, strong winds, and high waves and cause other hazards such as floods and mudslides
3 conditions for hurricane
warm water, damp air, winds that meet
Geological structure
the disposition and nature of the materials on the coast
Processes affecting coastline
erosion & deposition
Sea level changes
interact with erosional or depositional processes to produce advancing or retreating coastlines
Waves
the movement of water molecules within the ocean, and are restricted to the surface layers of our oceans and seas
Why do waves break?
a critical point is reached where the top of the wave (the CREST) curves over and creates a breaking wave
swash
The movement of water and sediment up a beach, determined by the prevailing wind
backwash
The movement of water back down the beach, determined by the slope of the beach
longshore drift
moves sediment in one general direction along the coastline in a zig-zag fashion, governed by the prevailing wind and interaction between swash and backwash
Constructive waves
swash is stronger than bakwash
Destructive waves
backwash stronger than swash
Spilling breakers
Break slowly as they approach the shore, and wave energy is spread over a large area of the beach.
plunging breaker
Breaks quickly with substantial force and wave energy is concentrated over a small area of the beach.
Surging breakers
Rush up a very steep beach without dissipating much energy in the beach layer known as swash.
What causes headlands and bays
Differentiated rates of erosion due to different levels of resistance in the geology
How are beached formed
Beaches form in sheltered environments, such as bays. When the swash is stronger than the backwash, deposition occurs.
Spits
A spit is a landform of coastal deposition, an extended stretch of beach material that sticks out to sea and is joined to the mainland at one end. Caused by longshore drift.
The formation of a spit
Longshore drift transports material along the coast, and spit forms when material is deposited due to reduced energy when the sea meets a river.
tombolo
spit joining the mainland to an island
Sand dunes formation
Sand dunes are small ridges or hills of sand found at the top of a beach, above the reach of the waves, sand is deposited by the wind around an object such as a rock, forming embryo dunes
la nina
The trade winds increase, increasing upwelling off South America, lower-than-normal sea surface temperatures
oceanic conveyor belt
a constantly moving system of deep ocean circulation driven by temperature.
Upwelling
deep cold nutrient water rising on the surface
Thermohaline circulation
the conveyor belt- transfer of energy by deep sea currents, cold water sink and moves towards the equator
thermocline
layer between surface warm water and deep cold water.
halocline
change in water salinity levels as the depth change
EEZ
exclusive economic zones- prescribed by UN that a state has speacial rights regarding exploration and use of marine resources
Subaerial weathering
weathering of caves and large sedinments caused due to waves.
isostatic
local sea level change- the height of the land rises or falls depending on pressure out on by ice.
fetch
the stretch of ocean water over which wind was blown
coral reefs
underwater ecosystem characterised by reef building corals
Mangroves
shrub that grow in costal saline water
concordant coast
ocean infiltration and erosion of soft material
discordant coast
when the bands of different rock types run perpendicular to the coast
gabion
wire meshcages filled with pebbles
groyne
wooden barriers constructed at right angles
revetments
traditionally been wooden slatted barriers constructed towards the rear of beaches to protect the base of cliffs
sea walls
built in front of cliffs to protect against waves
downwelling
occurs when surface water becomes more dense and sinks to the bottom
onceanic carbon cycle
photosynthesis, turns carbon dioxide into organic material, this carbon sinks to the bottom causing upper part to have low carbon concentration.
Note
Flashcard