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2013-02-14 00:34:25

Midterm 1
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  1. What is a gyre?
    current flow around the periphery of ocean basins.

    subdivided into currents by flow characteristic and temperature
  2. Surface Currents-
    make up about 10% of total ocean water

    0-400m depth

    Wind driven by friction but divert due to coreolis effect  (to the right in NH)
  3. Ekman Transport-
    In NH surface current is deflected to the right of wind direction due to Coriolis effect.

    2nd layer of water below it has friction from the upper water and moves to the right of that but slower speed

     3rd layer down moves to the right of the 2nd layer and slower

    4th to the right of the 3rd and slower

    **theoretical net flow is 90d to the right of wind direction

    ***actual barely reaches 45d due to 'hills' and down pressure gradient.

    ****is effective down to 100m
  4. water hills
    ekamn transport and continues right deflection of water due to coriolis pushes water into in a hill.

    water slides down hill due to gravity, cant turn left due to coreiolis so it continues right

    this creates the conection of currents- gyres

    the hill of water also dreates a greature pressure which depress the pycnocline much further below
  5. 6 major gyres of the world

    geostrophic gyers
    • N-atlantic...to the right-clockwise
    • N-pacific....."                "

    • S. Pacific
    • S. atlantic
    • Indian ocean........all to the left-counter clockwise

    • antartic circumpolar current...west wind drift...alll the way around the pole frow west to east.
    • ***tech not a gyre as iot doesnt flow around the pheripheral of a basin
  6. types of currents within a gyre
    • western boundry current -
    • *fastest and deepest of gyre currents
    • *west edge of ocean=east coast of land
    • *move warm water poleward
    • *ex: the gulf stream

    • Eastern Boundry current-
    • *east edge of basin=west edge of land
    • *basicly the opp of western
    • *cold water equataord
    • *shallow and broad and slow

    • transverse currents-
    • *both eastern and western boundry tend to hug the shore.
    • *transverse are the ones that cross the ocean.
    • *broad and slow
  7. ocean eddies
    caused when warm or cold water splits off a current.

    in NH warm water goes right-anticyclonic

    cold water goes to the left-cyclonic

    • **eddies can be huge, up to 1,000km
    • and retain their identity for 3 years!!!
  8. why are the hills centers to the west?
    why westward intensification?
    the coriolis is stronger towards the poles. so east bound water in the N.Atlantic turns to the right (eqautor bound) faster.

    this creates a wide broad mass of water moving southward which shoves the hill center to the west.

    thus the westward current has less room forcing it faster and deeper.(same reason small narrow inlets have a faster tidal current)
  9. counter currents and under currents-
    equatorial current are accompanied by counter currents/undercurrents

    • flow in opposite direction of main current
    • due to lack of winds at the meteriological equator (5-8d north of geo).
  10. thermohaline circulation

    the movement of water due to density

    density is determined either by presure or salinity
  11. where is density stratifaction highest?
    near temperate/tropical areas because the temp difference between warm surface and cold bottom is the most extreme

    at the poles both depp and surface water is closer in temp thus easier to mix.
  12. what is caballing?
    mixing of two massses of water with equal density but opposite temperature and salinity.

    creates a denser mass of water that sinks
  13. antartic formation of deep water/downdwelling
    most significant is at antartica

    ice production and cold temp produces densist  water in the world. 

    it sinks, moves out along the continetal shelf and creeps northward

    1000 years to travel along bottom to eqautor.
  14. north artic formation of deep water/downwelling
    similar to antartic however the basin of north atlantic restricts movement.

    only place it can really get out is in the deep submarine canyons between scotland and green land

    cold nnorth atlantic water plus the warm gulfstream and cold canadian wind releases heat making the warm temp. of n. europe
  15. other deep waters
    caused by extreme evaporation

    mediteranian and enters through the straight of gibralter.

    water is more salty then either artic but much warmer so it floats above the artic bottoms
  16. Sun is the driving force of weather...
    what effects how much  is accepted into earth?
    • Daily by rotation of the planet
    • seasonaly by the tilt

    • the angle at which the light hits the earth
    • *90 degress more intense
    • **>90 surface area is increased this not as direct.
    • ***also amount of atmosphere it goes throught
  17. what is the noon sun angle...how does it change?
    The angle at which the sun hits earth at noone for a specific latitude

    nsa=90d-latitude+declination angle

    • sin(nsa)*100 = % intensity
    • 90d..................1.00...........100%
    • 45d...................0.70..........70%
    • 30d...................0.50..........50%
  18. what is the solar constant?
    • the rate that energy from sun reaches earth
    • 1388 watts/sq.meter
  19. difference between weather and climate?
    weather describes short period of time and is constantly changing.

    Climate long term generalized statistics of weather
  20. composition of the atmoshpere (4 main)
    • N2   78%
    • O2   21.5%
    • Ar    1%
    • CO2  .5%
    • *all others trace elemets
  21. where is ozone (the good ozone)
    • in stratospher (2nd up )
    • ~10-50km above surface
  22. pressure decreases with altitude name two interesting facts about its concentration
    • 1/2 atmospher is below 5.6 km
    • 9/10 atmosphere is below 16km
  23. atmosphere boundrys vs ocean water boundrys
    atmosphere upper boundry denoted pause

    •       thermosphere
    • mesopause
    •        mesosphere
    • stratopause
    •        stratusphere
    • tropopause
    •         troposphere

    • ocean water denoted -clyne
    • pycnocline
    • thermoclyne
    • haloclyne
  24. mean temp of earth without green houses gasses
    -18d C