Waves and Tides

Nota:

• http://www.s-cool.co.uk/a-level/geography/coastal-processes/revise-it/wave-processes

1. Constructive waves

   Nota:

   • Also known as Swell or Surging waves
   1. Depsitional
   2. Long wave length

      Nota:

      • Up to 100m
   3. Low Frequency

      Nota:

      • 6-8 waves per minute
   4. Elliptical orbit
   5. Swash is larger than Backwash
   6. Low Gradient
   7. Caused by distant storms
   8. Create Berms
2. Destructive waves

   Nota:

   • Also known as surfing, storm, or plunging
   1. Erosional
   2. Short wave length

      Nota:

      • smaller than 20m
   3. High Frequency

      Nota:

      • 10-12 waves per minutes
   4. Circular orbit
   5. Larger backwash than Swash
   6. Steep graident
   7. Caused by local winds/storms
3. Caused by:
   1. The surface of the sea exerting frictional drag on the lowest layer of wind
   2. The distance (fetch) travelled before the wave reaches the shoreline
   3. How long the wind had blown for
   4. How strong the wind is
4. Wave refraction
   1. Occurs when waves approches a waveline
      1. Which is a irregular coastline
   2. As waves approach a coast they are refracted so that their energy is concentrated around headlands but reduced around bays.
   3. Waves then tend to approach coastline parallel to it, and their energy decreases as water depth decreases.

1. Caused by
   1. Controlled by the gravitational pull of the moon (and to a lesser extent the sun)
2. High Tide
   1. The Moon pulls the water of the earth towards it, creating a bulge (High tide)
   2. The Moon pulls the Earth towards it, creating a bulge of water on the otherside of the earth to the high tide
3. Spring tide
   1. Twice a month, the Earth, Moon and Sun align
      1. Puts an extra gravitational pull on the earth
         1. Producing an extra high tide
4. Neap tide
   1. Lowest tidal range
   2. Occur when the Sun and Moon are at right angles to each other