coastal systems and processes

Question 1

are coats open or closed systems

Answer 1

open systems as it receives inputs from outside the system and transfers outputs away

Question 2

what are the inputs, outputs and stores of coasts

Answer 2

INPUTS- waves, wind,tide,sea currents, sediment, geology of coastline and sea levels rising
STORES- wind and water transport
OUTPUTS- dissipation of wave energy, accumulation of sediment above tidal limit

Question 3

features of wind

Answer 3

• spatial variations in energy result from variations in the strength and duration of the wind
• fetch helps determine the magnitude and energy of the waves reaching the coast
• wind plays a vital role in wave formation as they are created from the transfer of the wind blowing over the sea surface (frictional drag)
• wind acts as an agent of erosion

Question 4

fetch=

Answer 4

refers to the distance of the open water over which the wind blows uninterrupted by major land obstacles

Question 5

formation of waves

Answer 5

• wind moves across the surface causing frictional drag which creates small ripples
• this leads to a circular orbital motion of water particles
• as seabeds are shallower towards the coastline it causes the wave height to increase but the wavelength to decrease
• this causes water to back up from behind the wave until it breaks and surges up the beach

Question 6

constructive wave

Answer 6

-low wave height
-long wavelength
-low frequency
-powerful swash, weak backwash
they build up the beach

Question 7

destructive wave

Answer 7

• high wave energy
• high frequency
• powerful backwash, weak swash
• they cause the beach to be steep

Question 8

seasonal changes to the waves

EXAMPLE OF NEGATIVE FEEDBACK

Answer 8

• beaches are subject to alternating cycles
• in summer they are more constructive whereas in the winter they are destructive
• constructive waves build up the beach resulting in a steeper beach profile-this then encourages them to be destructive and overtime the waves move the material back to the sea so they become constructive= NEGATIVE FEEDBACK

Question 9

current=

Answer 9

refers to the permanent or seasonal movement of surface water in oceans

Question 10

3 types of current:

Answer 10

LITTORAL DRIFT= occurs as waves hit the coastline at an angle-this generates a current running parallel to the shoreline
RIP CURRENT= strong currents moving away from the shoreline. they develop when the sea water is piled up along the coastline by incoming waves. they move out to sea
UPWELLING= the movement of cold water from deep oceans to the surface. the denser colder water replaces the warmer water to form currents

Question 11

tide=

Answer 11

the periodic rise and fall of the level of the sea due to the gravitational pull of the sun and moon

Question 12

types of tides:

Answer 12

SPRING TIDE: when the moon and sun are in alignment causes the highest high tide and lowest low tide. the gravitational forces combine to pull the oceans towards them=LARGEST possible tidal range
NEAP TIDE: when the sun and moon are perpendicular and the gravitational forces act against each other so the pull is minimised at high tide but creates higher low tide=LOWEST possible tidal range

Question 13

difference between high and low energy coastlines

Answer 13

LOW ENERGY=rate of deposition exceeds rate of erosion
occurs in more sheltered areas
constructive waves
depositional landforms(beaches and spits)
HIGH ENERGY= a coastline where strong steady winds cause more erosion than deposition
more powerful waves so larger fetch
rocky headlands, cliffs
destructive waves