Systems and processes Flashcards
(46 cards)
What are the sources of energy into a coastal environment ?
Wind, waves (constructive and destructive), currents and tides
What are the 2 types of coast ?
High and low energy
What are the geomorphological processes ?
Erosion, transportation and deposition
What are the distinctively coastal processes ?
-Marine erosion: hydraulic action, wave quarrying, corrasion/abrasion, cavitation, solution, attrition
-Transportation: traction, suspension, longshore/littoral drift
-Deposition
-Sub aerial weathering
-Mass movement
-Run off
What are the drivers behind wind patterns
Primary source is energy from the sun which forms a high pressure zone and when air moves from lower to higher pressure zone due to differential heating form the sun it is wind. Coreolis effect deflects wind direction to form global wind belts such as trade winds in coastal zones
What’s an AO2 for what winds and waves can be generated by other than the sun ?
Tectonic activity
What significantly increases wave energy in the UK ?
High energy transfer of prevailing winds from the South West in the UK as air moves from subtropical high pressure belt to subpolar low pressure belt
What does the enhanced greenhouse effect mean interms of the formation of pressure zones ?
Increase in formation of low pressure zones which increases pressure gradients around the world leading to stronger winds adn more intense storms (affects global climate and global atmospheric circulation)
Give the factors affecting wave energy
-Strength of wind
-Duration of wind
-Fetch
Give the statistic for the UKs longest fetch
3000+ miles over the Atlantic ocean to Brazil which accounts for high energy waves which affect the South West facing coast
What is the main process which forms waves ?
Frictional drag
What is the frequency of constructive waves ?
6-8/m
What is the frequency of destructive waves ?
10-14/m
What type of system generate constructive waves ?
Distant weather systems in the open ocean
What type of system generated destructive waves ?
Localised storms
What causes variations in wind ?
Spatial variations in energy (strength duration affected) and local weather patterns influence short term changes in wind speed
Give an example of a high energy coastline
Stretches of Atlantic facing coast such as Cornwall in UK
Give an example of a section of a low energy coast
Estuaries and bays of Lincolnshire
Give an example of cliff erosion as an example of a sediment source
Till cliffs along Holderness coast made of sand have erosion rated up to 10m a year vs igneous granite in Cornwall has very slow erosion rates
Give the statistic for sea level rise and sediment sources
UK sea levels rose at end of last glacial period 10,000 years ago resulting in coarse sediment deposition on South coast of England which formed barrier beaches such as Chesil beach in Dorset
Define wind
Movement of air from one place to another
Define high energy coast
Coastline where strong prevailing winds create high energy waves and rates of erosion are greater than rates of deposition
Define low energy coast
Coastline where wave energy is low and the rate of deposition of sediment exceeds erosion rates
Define sediment budget
The balance between the losses and gains of sediment within a sediment cell
