Physical - Coasts Flashcards
What are inputs (in terms of systems)?
Energy and matter which are added into the system
What are outputs (in terms of systems)?
The end result of a system and the aspects of energy and matter that leave. Includes:
- Sediment removed beyond local sediment cells
- Depositional landforms
- Erosion landforms
- Dissipation of wave energy
- Accumilation of sediment above the tide line
What is a system?
An assemblage of interrelated parts that work together by way of process
What is an open system? Give a geographical example.
Matter and energy can be transferred.
Eg. Coastal systems
What is closed system?
Only energy can be transferred. Eg Planet Earth
What is an isolated system?
Neither energy or matter can be transferred
What is positive feedback?
When the effects of an action are amplified or multiplied by subsequent knock-on or secondary effects. (usually bad)
What is dynamic equilibrium?
When inputs and outputs of a system are in balance with use of feedback loops
What is negative feedback?
The effects of an action are nullified by its subsequent knock-on effects (usually good)
What sort of system are coasts?
An open system whereby matter and energy can be transferred
What is aeolian transportation?
Transportation with (suspended in) wind
What is the energy source of waves?
Wind as a result of low pressure rising under high temperatures
What is fetch?
The distance wind travels across the sea (or flat expanses of land)
From what points do you measure wavelength?
From crest to crest (OR trough to trough)
What is wave frequency?
How often a wave passes
What is wave height?
The distance (height) from crest to trough
What is swash?
The movement and deposition of sediment onto a beach
What is backwash?
The erosion (including removal) of sediment from the beach into the sea.
What is wave refraction?
The slowing down of waves in one location due to shallower water causing them to curve round into areas of faster current (in deeper water)
More erosion of headlands, forming arch, stack and stump
Give some characteristics of constructive waves.
- More elliptical orbital motion
- Long wavelength
- Short wave height
- Low energy
- More swash, less backwash
Give some characteristics of destructive waves.
- Short wavelength
- Long wave height
- High frequency
- High energy
- More backwash, less swash
Give a feedback loop for waves.
- Constructive waves build up a beach (with swash), steeper profile
- Steeper beach causes waves to become more destructive
- Destructive waves have more backwash, so beach is eroded and becomes shallow
RESTARTS
What is a spring tide?
Extremely high or low tides
Under what conditions do spring tides occur?
Sun and moon are parallel, causes larger ‘bulges’ of water due to more gravitational pull