3.2 - Coastal systems Flashcards
What created wind?
High and low pressure
How is energy transferred from wind to sea?
Wind blows over surface - frictional drag - energy transfers to water - ripples - wind increases strength and ripples get bigger
Why do waves break?
Circular orbit - approach shore so friction
Elliptical orbit - top breaks (translatory wave)
What influences energy of waves? (3)
Strength - determined by pressure gradient
Duration – longer = powerful
Fetch
Define prevailing winds
Most common wind direction
3 characteristics of high energy coasts
Strong waves
Headland, cliff, WCP
High rate of erosion and transportation
3 characteristics of low energy coasts
High rate of deposition
Beach, spit
Sheltered area
What causes tides?
The gravitational pull of the sun and moon
What causes a high tide?
The beach is directly facing / away from the moon. The tidal force is strongest on the side facing the moon, causing the Earth to bulge
What causes a spring tide?
What is it?
A new or full moon. Has the highest and lowest tides
What causes a neap tide?
What is it?
Moon is at a right angle to Earth so the pull of the sun / moon is weak. Causes low low and high high tides
What is the case study for a storm surge?
2013 UK - Yorkshire
Stats for the 2013 UK storm surge
2 deaths
100mph + winds
£100 million in damage
19ft above sea level in Hull
What type of tides caused the 2013 storm surge?
Spring tides
What causes storm surges
An intense area of low pressure is over the sea, causing the tide to be higher. This creates a pressure wave and travels inland due to strong winds
