wave height h vertical distance from trough to crest
speed C horizontal rate of travel
Two wave speed formulas...relations between speed period and lenght
f frequency
L lenght
T period
C speed
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
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
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.
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
What forces create tides? (2)
Gravity from the sun and moon tends to pull water towards thems
centrifugal force tends to pull water away
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
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
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
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
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
two main techniques for capturing tidal energy
in line turbines in deep water
barrage in bays
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
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
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.
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
Author
spb83
ID
213141
Card Set
EOS110 Mid-Final
Description
From Midterm to Final....Begining with Lecture 10 waves