Coasts Flashcards
What type of system is the coastal system? Why?
Open system because there are inputs from outside the system into the system and outputs to other natural systems
How many sediment cells are there in England and Wales?
11
Define input and give example
Material or energy moving into the system from outside
Eg. Precipitation and Wind
Define output, give an example
Material or energy moving from the system to the outside
Eg. Ocean currents, rip tides, sediment transfer and evaporation
What is the dominant wind in the UK?
South west
Air moves from subtropical high pressure belt at about 30N to the sub polar low pressure belt
What 3 factors affect wave energy?
The strength of the wind
Duration of the wind
Fetch
Describe how a wave forms
1) water becomes shallower and the circular orbit of the water particles change to an elliptical shape
2) wavelength and velocity decrease and wave height increases causing water to back up from behind causing it topple over
3) water rushes up beach as awash
What are the two main types of wave?
Constructive and destructive
When are constructive waves form?
Distant weather systems generate waves in open ocean
What is the wave form of a constructive wave?
Low, surfing waves with a long wavelength
Describe the wave break of a constructive wave
Strong swash, weak backwash
Does the beach gain size/ lose size from constructive waves?
Beach gain
What beach profile is seen with constructive waves?
Gentle beach profile
When are destructive waves formed?
Local storms
What is the wave form of a destructive wave?
High pressure plunging waves with W short wavelength
Describe the wave break of a destructive wave
Weak swash, strong backwash
What beach profile is associated with destructive waves?
Steeper beach profile
What are tides?
Changes in the water level of seas and oceans caused by gravitational pull of the moon and to a certain extent the sun.
What is the tidal range?
The difference between the high tide and the low tide
When is the highest tidal range?
Spring tide
When is the lowest tidal range?
Neap tides
What is the effect of a high tidal range?
Powerful tidal currents especially in estuaries and river channels
What are rip currents?
Strong localised underwater currents in certain parts of a beach
Give 2 examples of high energy coastlines in the UK
Stretches of the Atlantic facing coast
Where rates of erosion exceed rates of deposition
What indicates a low energy environment?
Sandy and estuarine coasts
What is wave refraction?
The distortion of wave fronts as they approach and indented shoreline
