1.b. coastal landscape systems are influenced by a range of physical factors

Question 1

what are storm surges?

Answer 1

extremely high onshore wind speed, very low atmospheric pressure.

High wind speeds are usually associated with the passage of tropical storms

When air in the lower atmosphere rises, there is lower pressure on the sea surface so sea level rises.

Question 2

give an example of a storm surge

Answer 2

Example: 5th December 2013 a storm surge affected coastlines surrounding the north sea and through into the channel:

• two successive high tides
• highest In 60 years
  Evacuation of thousands people living in low lying location in England, Belgium, Netherlands and France
• Resulted in severe erosion

Question 3

what are seismic sea waves / tsunamis?

Answer 3

triggered when vast quantities of water are suddenly displaced , can be due to earthquake affecting sea bed or large scale underwater mass movement. e.g. underwater steep slope collapsing

Question 4

give an example of a tsunami

Answer 4

Example: Sumatra December 2004
- delivered an estimated 1000 tonnes of water per metre of shoreline.

Question 5

physiscal factors affecting landscape

Answer 5

1. Lithology - physical and chemical composition of rocks
2. Geological structure - concerns the properties of individual rock types
   E.g. jointing, bedding, faulting, permeability etc
3. Rock outcrops with run parallel to the coastline are called concordant coastlines
   Rock outcrops which are at right angles to the coastline cause discordant coastlines

Question 6

global patters of ocean currents

Answer 6

Ocean currents:

Warm ocean currents transfer heat energy from low altitudes toward the poles. Particularly affect Western facing areas and are driven by onshore winds.

Cold ocean currents move cold water from polar regions toward the equator, usually driven by offshore winds , therefore tend to have less of an impact on coastal landscape systems.

Question 7

3 types of breaking wave

Answer 7

1. Spilling - steep, Gently sloping sea bed, Break at some distance from the shore, Foam forms at wave crest and becomes a line of surf as wave approaches shore.
2. Plunging - steep, moderately or suddenly changing sea bed shape, steep fronted, tend to curl over and plunge down on shore producing lots of foam.
3. Surging - gentle, steep angled shore gradient, tend not to break completely, top of wave breaks close to shore, water slides up and down the shore.

Question 8

descripe constructive and destructive waves

Answer 8

Constructive breakers:
- lower wave height
- Long wave length
- Low frequency 6-8/min
- Swash > back wash

Destructive breakers:
- higher wave height
- Short wavelength
- High frequency 12-14/min
- Swash energy < backwash energy

Question 9

what is tidal range?

Answer 9

the difference in height between high and low tide

Question 10

what is a neap tide?

Answer 10

twice a month the sun and moon are at right angle to eachother. gravitational pull is at its weakest. low range

Question 11

what is a spring tide

Answer 11

twice a month the sun and moon are aligned with the earth.gravitational pull is at its strongest. high range

Question 12

describe the role of wind in influencing coastal landscape systems

Answer 12

• source of energy [for both trasportation and erosion]
• carries sediment
• responsible for many aoelian processes
• creates waves [higher wind speed = longer fetch]
• oblique wind = oblique waves = LSD

Question 13

how do waves form and break

Answer 13

1. water molecule orbits in a circular motion in the trough
2. as waves flow the molecule slides up to the wave front
3. then back into a new wave trough as the wave anvances
   4.as the wave reaches water of 1/2 its wavelength the bottom molecules have friction with the sea bed.
4. this causes the bottom of the wave to slow whilst the top keeps moving forward with momentum
5. the wave begins to steepen as the water gets shallower and eventually topples over swaching up the beach and back down as backwash.

Question 14

how are rip currents formed? what role do they have?

Answer 14

1.by tidal motion or waves breaking perpendicular to the shore. Cellular circulation is caused by differing wave heights parallel to shore. Water from taller waves travels further than smaller.

2. they play an important role in the transport of sediment.

Question 15

what landform do rip currents form? and how?

Answer 15

they create cusps:
-small-circular depressions that are a temporary feature.
- formed by a collection of waves with the same strength swash and backwash meeting at the same place. The sides channel incoming waves into the middle creating a strong back wash [mini rip]