Coastal Landscapes Flashcards
(204 cards)
The size and energy of a wave can be influenced by:
- how long the wind has been blowing
- the strength of the wind
- the length of the fetch
what is a closed system?
a system where there is no transfer of energy or matter across the system boundary, eg. the earth as a whole
what is an open system?
where there are transfers of energy and matter across a system boundary, eg. the body
what is dynamic equilibrium?
when your inputs and outputs mean that the system stays in balance
what is feedback?
changes in the system almost always leading to a further change
what is positive feedback?
amplifying change in a system almost like a snow borne effect, making it more unstable
what is an example of positive feedback?
through the greenhouse effect, radiations heats up our earth, co2 traps the heat, leads to global warming as the planet continues to heat up, leading to increasing temperatures
what is negative feedback?
when the system changes and this dampens the initial change, positive, holds the system in a more stable equilibrium
what is an example of negative feedback?
more global warming means temps will rise, more carbon trapped in the atmosphere, leading to carbon fertilisation which can increase forest cover, carbon levels to decrease
what is carbon fertilisation?
when the carbon is absorbed by the trees, thus lowering the levels
Give three inputs on the coast (what are the three areas)
Marine- ocean currents, waves, sediment (erosion of rocks and cliffs)
Atmosphere- wind speed, sun
Humans- settlement, defences
give three outputs on the coast
- sediment transfer
- ocean currents
- dissipation of wave energy
give three transfers/flows on the coast
- erosion
- transportation
- deposition
give three stores/sinks (coastal landforms)
- beaches
- headlands and bays
- wave-cut platforms
how are waves created?
by the transfer of energy from the wind to the sea, blowing over the surface. the wind creates ripples that grow into waves as the frictional drag increases
what are swell waves?
waves formed by winds blowing over large distances
what is the fetch?
the length of open sea over which the wind blows to generate waves
what is a wave period?
time take for a wave to travel through one wavelength. it can be calculated by timing 11 waves and dividing them by 10.
what is a wavelength?
the distance between two crests
what is wave velocity?
speed of movement of a crest in a period of time
what is wave steepness?
the ratio of the waveheight to the wavelength
what is wave breaking?
it breaks when the ratio is 1:7. The upper part accelerates and the lower part slows down due to friction. This causes the upper part to spil over- causing it to break. the wave height increases but the wavelength and wave velocity both decrease which causes it to break.
what is deep water?
the depth of the water is greater than half the wavelength
explain the process of orbital motion
winds move across the surface of the water, causing a frictional drag which creates small ripples and waves. this leads to a circular orbital motion of water particles in the ocean