Coasts - Systems and processes Flashcards
What are some of the sources of energy in the coastal system?
- Wind - strengthen, create and moves waves, e.g. fetch
- Waves - transfer energy, could deposit or erode
- Currents - transportation of sediment and erosion
- Tides - determine where waves hit + where beaches form
How does the wind provide energy?
- Strong winds move the water surface and create waves
- Winds with large fetches can transfer more energy
How is wind energy formed?
By air moving between areas of different pressure
How does wind strength impact waves?
The stronger the wind, the more power and energy the waves have and so the more powerful and potentially destructive they are
How do waves provide energy?
- Waves have powerful erosive energy, can destroy features
- Moves sediment around, creates as well as destroys
How do currents provide energy?
- Can move sediment on the sea floor
- Move material on and off coastline regularly, great force
How do tides provide energy?
- Moves sediment up the beach and down again, carries material
- Dictates where waves can get to, location of the energy
How does the sun provide energy?
It causes differences in air pressure due to different rates of heating, when then creates wind
How are powerful winds created?
The greater the difference in air pressure gradient, the faster the wind speed and the more powerful
What are the factors impacting the size of waves?
- Strength of the wind
- The fetch
- Duration of the wind
How are waves formed?
By energy passing through the water, causing it to move in a circular motion
What do waves transmit?
Energy, not water
What are wind driven waves caused by?
Frictional drag between the wind and the surface water
How do waves change as they approach the shore?
Disturbance to the circular motion beneath the surface leads to a more horizontal movement and the wave breaks
What terrestrial (land) factors influence the coastline?
- Supply of sediment
- Tectonics
- Fluvial processes
What marine (sea) processes influence the coastline?
- Wave (type) shape/size
- Wave direction
- Tides
- Sea level change
- Biotic features (e.g. reefs)
What human intervention factors influence the coastline?
- Industrial and residential intervention - development
- Pollution
- Conservation
- Global warming
- Tourism and recreation
- Sea defences
What atmospheric factors influence the coastline?
- Winds
- Sub-aerial processes (above sea level) e.g. weathering + mass movement
- Solar energy
- Temperature
- Fetch
- Glaciations
- Precipitation
Outline ways the coastal system interacts with other Earth systems
- Plants growing on sand dunes links to the carbon and nitrogen cycle - plants are a source of carbon
- Cliff erosion links to the rock cycle because erosion moves the rocks
What are the features of constructive waves?
- Add material to coastline
- Low wave with long wavelength
- Strong swash
What are the features of destructive waves?
- Tall in relation to length
- Remove material from coastline
- Common in winter
- Strong backwash
- Never reach the backshore
- Causes cliff face erosion
What are orthogonals?
Lines of wave energy
What are high energy coastlines like?
Rocky, ocean facing coasts where waves are powerful
What types of landforms tend to be on high energy coasts?
Wave cut platforms and headlands
What are low energy coastlines like?
Sandy, estuarine and where waves are less powerful as the coast is sheltered
How do rates of deposition and erosion compare at high energy stretches of coast?
Rate of erosion exceeds rate of deposition
How do rates of deposition and erosion compare at low energy stretches of coast?
Rate of deposition exceeds rate of erosion
