15 terms

Sources of energy in coastal environments

STUDY
PLAY
Wind
Primary source of energy for other processes including erosion, deposition and transport
Fetch
Refers to the distance of open water over which a wind blows uninterrupted by major land obstacles
Wave height
The height difference between a wave crest and the neighboring trough
Wavelength
The distance between two successive wave crests
Wave frequency
The time for one wave to travel the distance of one wavelength
Backwash
The action of water receding back down the beach towards the sea
Constructive waves
Waves with low wave height, long wavelength and low frequency. Their swash tends to be more powerful than their backwash, as a consequence beach material builds up
Destructive waves
Waves with a high wave height, a steep form and a high frequency. Their backwash is stronger than their swash so more sediment is removed than added.
Swash
The rush of water up the beach after a wave breaks
Longshore currents
occur as waves hit beach at an angle, generates a current running parallel to the shore, this transports sediment along the shore
Rip currents
Strong currents moving away from the shore, initially running parallel as water is trapped between the incoming waves and the land. After running parallel it goes out to sea beyond the breaker zone, extremely hazardous to swimmers
Upwelling
Movement of cold water from deep in the ocean towards the surface. Replaces warm surface water and creates nutrient rich cold ocean currents.
Tides
Periodic rise and fall of the level of the sea in response to the gravitational pull of the sun and moon
Spring tides
Where the Earth, moon and sun are all in line and causes large bulges of water, it has the highest monthly tidal range, occurs twice a month
Neap tides
Where the Earth, moon and sun are perpendicular, it has the lowest monthly tidal range, occurs twice a month