EOS110 Mid-Final

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EOS110 Mid-Final
2013-04-13 01:32:56

From Midterm to Final....Begining with Lecture 10 waves
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  1. Basic features of surface water waves (7 items)
    • Crest- High point
    • Trought- low point
    • wave length L distance between crests
    • frequency f number of crest per second
    • Period T time between crests
    • wave height h vertical distance from trough to crest
    • speed C horizontal rate of travel 
  2. Two wave speed formulas...relations between speed period and lenght
    • f  frequency
    • L lenght
    • T period
    • C speed
  3. the motion of water in surface wave
    the water in a surface wave doesnt move, rather the wave crest and trough pass through

    if the wave is going to the right the orbital motion is clockwise. 

    These orbital motions are as deep as half the wave lenght

    The wave begins to stand and break when the orbitals feel the bottom
  4. charectoristics of waves
    free vs forced
    deep water vs shallow water
    free wave - opperates independent of its driving force i.e. storm swell or tsunamii keeps going after the force disipated

    Forced - will only contiue as long as the drving mechinism pertains. i.e. tidal wave is force dependent on gravity

    Deep water wave the depth of the water is greater then 1/2 the wavelengh

    for this reason tides are shallow water waves as the wavelengh can be up to 1/2 the diameter of earth
  5. Wave restoring force
    either surface tension and or gravity and in large scale coriolis

    • surface tension stops small capilary waves
    • gravity is the restoring force of most other waves
    • coriolis effect and gravity aare the restoring force of large waves like tides.
  6. process of wave break
    • 1. wave feels the bottom depth=1/2L
    • 2. wave stands as the energy is compresed into smaller area (due to shallow bottom)
    • 3. the bottom of wave slows while top continues at spped (same principal as refraction)
    • 4. wave aproaches the critical ratio of 1:7 height:lengh
  7. What forces create tides? (2)
    Gravity from the sun and moon tends to pull water towards thems

    centrifugal force tends to pull water away
  8. why is high tide not the same time/height every day
    because the tidal day is 24 hours and 50 minutes due to the rotation of earth and moon

    not the same height because the moon/sun not always in the same place and due to their relitive location paired with local geography tidal waves may be restricted
  9. 3 tide types and descriptions
    • Diurnal - 1 high and one low
    • semi-diurnal - two highs and two lows of same size
    • mixed - two highs and two lows of differing size
  10. what is an amphidronic point?
    • a no-tide point in the center of ocean basin.
    • as a tidal wave moves north
    • it trends to the right due to coreolis, 
    • it is bounded to the right by the continent 
    • results in counter clockwise rotation around the amphridonic point
  11. spring tides vs neap tides
    spring tides - when moon and sun are in-line results in greater high/low tides

    neap tides - moon and sun at right angles
  12. why do some bays have very large tidal ranges
    • 1. tides are greates at the boundries of the largest bodys of water.
    • 2. in a narrower bay there is no amphridonic point for it to rotate around so it all comes in then out. no circulation 
    • *3 in some locations the water in the bay may resonate or sieche at the same frequency as the tide creating an extremly large tide
  13. two main techniques for capturing tidal energy
    in line turbines in deep water

    barrage in bays
  14. what is and cuase eustatic sea level rise
    • eustatic means world wide
    • it rises due to-

    • warming= more precipitation
    • melting= land ice melting into sea water
    • *note that ice berg melting doesnt effect this as the iceberg is already dispacing its amount of water
  15. errosiaonal vs depositional coast
    errosional marked by tectonic uplift, storm activity, high wave energy volcanism

    passive marked by low energy, tectonicly passive areas lots of sandy features

    **typically the west coast is a more errosional active coast then the east
  16. river deltas wave dominated vs tide dominated
    tide dominated tend to have many chanels

    river dominated is one main channel with more deposition in a fan like shape.
  17. what creates el nino?
    the pressure systems near the equator change up, (typically low pressure in the east) spreads out along equator, disrupts the northeasterly trade winds which create the equatorial upwellings