Waves and beaches Flashcards
How do Ocean waves form?
They form when wind blows over the water creating frictional drag
What makes waves larger?
When the wind speed is higher for a longer time over a longer fetch (distance it blows over the water)
What are the two main types of waves?
Constructive and Destructive
What are the characteristics of constructive waves?
- Low energy
- Low, surging waves with a long wavelength
- Strong swash, weak backwash
- Beach gain
What are the characteristics of destructive waves?
- High energy
- High plunging waves with short wavelength
- Weak swash, strong backwash
- Beach loss
How do waves affect beach morphology as a result of seasonal changes in the summer in the UK?
The UK summer has calmer weather producing more constructive waves where sediment from offshore bars is pushed onto the beach by swash resulting in a steeper beach profile
What is a berm?
A ridge at the top of a beach
What further weakens backwash?
Berms that often consist of shingle, the swash drains into this porous berm weakening backwash
How do waves affect beach morphology as a result of seasonal changes in the winter in the UK?
Stormier weather results in more destructive waves and sediment being pulled off the beach by backwash and deposited at offshore bars resulting in a flatter beach
Where might larger pebbles be found on a beach?
They may be found on the backshore where they may have recently been eroded from a cliff by storm waves or due to weathering / mass movement
Why are pebbles on the foreshore often smaller?
This is due to constant wave movement causing attrition
