Sources of Energy at the Coast Flashcards
What causes waves to form?
wind moving across the surface of the water and causing water to ripple due to drag
How do waves break?
- offshore, waves are not impacted by the sea bed
- as they approach the shoreline, the water gets shallower
- friction between the seabed and the water causes a more elliptical orbit
- as the rest becomes unstable, the waves break
What factors impact the energy of waves?
- size of the fetch
- strength of the wind
- duration of the wind
How do constructive waves impact the characteristics of the shore?
they usually lead to deposition, which causes a more gently sloped beach and depositional landforms
How do destructive waves impact the characteristics of the shore?
they usually erode material, resulting in more steep beaches and erosional landforms
How might storms affect wave type?
create more destructive waves because of stronger winds
What is responsible for tides?
gravity, from the moon and sun
What is a spring tide and when does it occur?
largest tidal range, when sun and moon are in alignment (equinox)
What is a neap tide and when do they occur?
smallest tidal range, when sun and moon are perpendicular
What forms ripcurrents?
large amounts of water from destructuve waves is forced away from the coast through a specific area
What are high energy coastlines associated with?
powerful waves, typically more destructive. rate of erosion> rate of deposition
What are low energy coastlines associated with?
less powerful, typically constructive waves in sheltered areas. rate of deposition> rate of erosion
What is wave refraction?
process by which wave fronts are distorted as they approach the shoreline
How might refraction impact landform development?
energy is focused on landforms out to sea, causing erosional landforms to form, whereas in sheltered areas such as bays, the waves lose energy and depositional landforms will form
Compare the formation of destructive and constructive waves
destructive: form as a result local storms
constructive: form as a result of distant weather systems in open ocean
How might wave type impact beach profile?
destructive: make profile more steep, over time will flatten it
constructive: make profile more gentle, over time will build up the beach
How might tides affect coastal processes?
smaller tidal range means concentrated erosion which results in the formation of WCP and WCN
Where are rocky coasts normally found?
high energy coastlines, where there are high rates of erosion
Where are sandy/estuarine environments normally found?
low energy coastlines, where there are higher rates of deposition
How might bays be considered negative feedback?
as the more concentrated erosion at headlands prevents the erosion of softer rock (which was the initial change in the system)
How does upwelling occur?
- wind blows across water in a certain direction
- allows space for water from the deep ocean to move upwards
What are tides?
the periodic rise and fall of the level of the sea
Why do neap tides occur?
- sun and moon perpendicular
- so water pulled in different directions
- so sun reduces effect of the moon, leading to a smaller tidal range
How do tides link to energy at the coast?
tidal range impacts the area that wave energy is concentrated over
