The Coastal System Flashcards
Give examples of inputs in coasts
Sediment
Energy = Wind, waves, tides, currents
Give examples of flows in coasts
Erosion, weathering, transportation, deposition
Give examples of stores in coasts
Beaches, dunes, spits
Give an example of positive feedback in coasts
Beach builds = slows waves = more desposition = beach builds
Give an example of negative feedback in coasts
As a beach erodes, the cliff behind it are exposed to wave attack. Sediment eroded from the cliffs is deposited on the beach, causing it to grow in size.
What are the 4 sources of energy in coasts?
Winds, waves, tides, currents
How are winds formed?
Created by air moving from high pressure to low pressure
What is prevailing wind? What is the result of it?
Wind constantly blowing over one direction - creates high energy waves
How are waves formed?
By wind blowing over the ocean’s surface
What causes waves to move in a circular motion?
Friction between wind and ocean
What is wave height affected by?
Wind speed and fetch
Define fetch
Maximum distance of ocean over which wind has blown
What causes waves to become elliptical as they approach the shore?
Friction with seabed
What are the characteristics of constructive waves?
- Long wavelength
- Stronger swash than backwash
- Longer wave period (time taken to complete one wave cycle)
- Low height
- Lower frequency, 6-8/min
What are the characteristics of destructive waves?
- High frequency
- 10-14/min
- Stronger backwash than swash
- Steep height
