Coastal Energy

Question 1

The driver

Answer 1

. The initial energy input for the coastal system is from the sun
. The sun’s energy causes different air pressures (due to different rates of heating) which creates wind
. This wind then generates waves, the main form of energy at the coast.

Question 2

Wind energy

Answer 2

. Wind is formed by air moving between areas of different pressure (from high to low) along a pressure gradient
. The steeper the gradient the faster the wind moves
. So areas with large pressure gradients experience strongest winds

Question 3

Fetch

Answer 3

. Area of ocean or lake surface area which the wind blows in an essentially constant direction
. Fetch determines wave size
. The longer the fetch the longer the wave

Question 4

Wind strength

Answer 4

. The stronger the winds, the larger the force and therefore a bigger wave and greater friction on sea surface
. Wind gives waves energy

Question 5

Direction of the wind

Answer 5

. The greater the wind velocity the longer the fetch and the greater duration the wind blows, then more energy is converted to waves and the bigger the waves
. Longer the wind blows the larger the wave
. If wind speed is slow the resulting waves will be small regardless of fetch or duration
. Strength = biggest energy supply

Question 6

Constructive waves

Answer 6

. Strong swash
. Weak backwash
. Low wave in proportion to length
. Adds material to coastline 
. Formed by distant weather systems

Question 7

Destructive waves

Answer 7

. Common during winter storms
. Strong backwash
. Weak swash
. High wave in proportion to length 
, tall breaks which breaks downwards with great force
. Removes material from the coastline
. Generally steep beach profile

Question 8

Formation of waves

Answer 8

. Waves are created by energy passing through water, causing it to move in a circular motion
. However, water does not actually travel in waves
. Waves transmit energy, not water, across the ocean and if not obstructed by anything, they have the potential to travel across an entire ocean basin
. Waves are most commonly caused by wind
. Wind-driven waves, are created by the frictional drag between wind and surface water
. As wind blows across the surface of the ocean, the continual disturbance creates a wave crest
. As the wave approaches the shore disturbance to the circular motion beneath the surface leads to more
horizontal wave movement and the wave breaks.