Physical Oceanography

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					 Physical Oceanography
            Chap. 15

The Oceans
Sea Water
Ocean Movements
     The Oceans – 15.1
Objectives
• identify methods
used by scientists to
study Earth’s oceans
• discuss the origin
and composition of
the oceans.
• describe the
distribution of
oceans and major
seas
I. Introduction
I. Introduction
   A. Uses




 What are some useful features of oceans?
I. Introduction
  A. Uses
     1. travel
     2. fishing/food
     3. recreation
I. Introduction
  A. Uses
  B. Studying
I. Introduction
     A. Uses
     B. Studying
          1. H.M.S. Challenger




Measured depth, water temperature, fauna, current,
and other data. First measured Mariana trench
(26,890 ft.)
I. Introduction
     A. Uses
     B. Studying
          1. H.M.S. Challenger
          2. Meteor




Used sonar to map undersea topography
    Example Calculation
A sonar signal travels about
1500 m/s in ocean water. If
it takes 6 seconds for a
signal to return to the ship
after it is emitted what is
the distance to the ocean
floor?
I. Introduction
     A. Uses
     B. Studying
          1. H.M.S. Challenger
          2. Meteor
          3. TOPEX-Poseidon




NASA satellite that measures ocean data
           TOPEX/Poseidon




• tracks ocean tides
• measures sea levels (to 5 cm accuracy)
• monitors climates by measuring ocean temperatures.
II. Ocean origins
II. Ocean origins
   A. Oceans are as old as Earth’s rocks
II. Ocean origins
   A. Oceans are as old as Earth’s rocks
       1. Lava flows have been dated at 4.6 b.y.
II. Ocean origins
   A. Oceans are as old as Earth’s rocks
       1. Lava flows have been dated at 4.6 b.y.
       2. These formed rocks by cooling quickly
          (in water)
II. Ocean origins
   A. Oceans are as old as Earth’s rocks
   B. Source of water
II. Ocean origins
   A. Oceans are as old as Earth’s rocks
   B. Source of water
      1. Comets (dirty snow
         balls)
II. Ocean origins
   A. Oceans are as old as Earth’s rocks
   B. Source of water
      1. Comets (dirty snow balls)
      2. Water was trapped in
         Earth when it formed.
         Volcanoes released this
         into the atmosphere.
III. Earth’s Water




This is also called the hydrosphere
III. Earth’s Water
     A. Location




Where is the Earth’s water found?
       The Hydrosphere
Type        Percentage   Volume Used in
                             Model
Total         100 %         2000 mL
             The Hydrosphere
      Type            Percentage   Volume Used in
                                       Model
      Total             100 %         2000 mL

Salt Water (oceans)     97.2%
              The Hydrosphere
      Type            Percentage   Volume Used in
                                       Model
      Total             100 %         2000 mL

Salt Water (oceans)     97.2%         1941 mL

   Fresh Water          2.8%

        Ice

   Underground

     Surface

    Soil & Air
              The Hydrosphere
      Type            Percentage   Volume Used in
                                       Model
      Total             100 %         2000 mL

Salt Water (oceans)     97.2%         1941 mL

   Fresh Water          2.8%           56 mL

        Ice             2.3%

   Underground

     Surface

    Soil & Air
              The Hydrosphere
      Type            Percentage   Volume Used in
                                       Model
      Total             100 %         2000 mL

Salt Water (oceans)     97.2%         1941 mL

   Fresh Water          2.8%           56 mL

        Ice             2.3%           46 mL

   Underground          0.4%

     Surface

    Soil & Air
              The Hydrosphere
      Type            Percentage   Volume Used in
                                       Model
      Total             100 %         2000 mL

Salt Water (oceans)     97.2%         1941 mL

   Fresh Water          2.8%           56 mL

        Ice             2.3%           46 mL

   Underground          0.4%           8 mL

     Surface           ~ 0.05%         1 mL

    Soil & Air         ~ 0.01%        0.2 mL
III. Earth’s Water
   A. Location
   B. Amount of frozen water has varied
III. Earth’s Water
   A. Location
   B. Amount of frozen water has varied
     1. During ice ages as much as 10% of
        hydrosphere was frozen.
III. Earth’s Water
     A. Location
     B. Amount of frozen water has varied
         1. During ice ages as much as 10% of
            hydrosphere was frozen.
         2. Sea level varied by hundreds of
            meters.



Due to melting of glaciers and tectonic forces altering
sea floor.
III. Earth’s Water
   C. Most of Earth’s surface is covered
      by water (71%)
III. Earth’s Water
   C. Most of Earth’s surface is covered
      by water (71%)
      1. The          hemisphere contains
         higher percentage of water.
III. Earth’s Water
   C. Most of Earth’s surface is covered
      by water (71%)
      1. The southern hemisphere contains
         higher percentage of water.
      2. All oceans are connected.
III. Earth’s Water
   C. Most of Earth’s surface is covered
      by water (71%)
      1. The southern hemisphere contains
         higher percentage of water.
      2. All oceans are connected.
      3. Pacific, Atlantic, and Indian oceans
         are main oceans.
III. Earth’s Water
   C. Most of Earth’s surface is covered
      by water (71%)
      1. The southern hemisphere contains
         higher percentage of water.
      2. All oceans are connected.
      3. Pacific, Atlantic, and Indian oceans
         are main oceans.
      4. Seas are partly or mostly surrounded
         by land.
III. Earth’s Water
   C. Most of Earth’s surface is covered
      by water (71%)
      1. The southern hemisphere contains
         higher percentage of water.
      2. All oceans are connected.
      3. Pacific, Atlantic, and Indian oceans
         are main oceans.
      4. Seas are partly or mostly surrounded
         by land.
      5. Sea ice forms in the Arctic and
         Antarctic seas.
The End
          Seawater - 15.2
Objectives
• compare &
contrast physical and
chemical properties of
seawater
• explain ocean
layering
• describe the
formation of deep-
water masses
I. Chemical Properties
I. Chemical Properties
     A. Salinity




A measure of the dissolved salts in water.
I. Chemical Properties
  A. Salinity
      1. Sea water is about 35 parts per
         thousand (ppt) salts
I. Chemical Properties
  A. Salinity
      1. Sea water is about 35 parts per
         thousand (ppt) salts
      2. Salts include Na+, Cl- , SO42-, Mg2+,
         Ca2+, K+, HCO3-, and others
I. Chemical Properties
  A. Salinity
      3. The salinity varies and is lower
         where there is . . .
I. Chemical Properties
  A. Salinity
      3. The salinity varies and is lower
         where there is . . .
         a. a lot of precipitation
I. Chemical Properties
  A. Salinity
      3. The salinity varies and is lower
         where there is . . .
         a. a lot of precipitation
         b. an estuary/river delta
I. Chemical Properties
  A. Salinity
      3. The salinity varies and is lower
         where there is . . .
         a. a lot of precipitation
         b. an estuary/river delta
         c. melting of glaciers
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
         a. the atmosphere (Cl- and SO42-)
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
         a. the atmosphere (Cl- and SO42-)
         b. weathering rocks (Na+, K+, Ca2+
            from feldspar)
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
      5. Removing sea salt
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
      5. Removing sea salt
         a. deposited when water evaporates
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
      5. Removing sea salt
         a. deposited when water evaporates
         b. carried via sea spray
I. Chemical Properties
  A. Salinity
      4. Source of sea salt
      5. Removing sea salt
         a. deposited when water evaporates
         b. carried via sea spray
         c. marine organisms use it in
            building shells, bones, and teeth
II. Physical Properties
II. Physical Properties
    A. Density is greater than 1.00 g/cm3




Density of fresh water is 1.00 g/cm3
II. Physical Properties
   A. Density is greater than 1.00 g/cm3
   B. Freezing point is less than 0ºC




Can be as low as -2ºC
II. Physical Properties
   A. Density is greater than 1.00 g/cm3
   B. Freezing point is less than 0ºC
   C. Light absorption
II. Physical Properties
   A. Density is greater than 1.00 g/cm3
   B. Freezing point is less than 0ºC
   C. Light absorption
         1. Water absorbs light




The ocean is completely dark at depths > 100 m
II. Physical Properties
   A. Density is greater than 1.00 g/cm3
   B. Freezing point is less than 0ºC
   C. Light absorption
       1. Water absorbs light
       2. Some colors penetrate
          further than others
II. Physical Properties
   D. Layers
II. Physical Properties
   D. Layers
      1. The deeper you go the _____ the temp.
II. Physical Properties
   D. Layers
      1. The deeper you go the cooler the temp.
      2. Temperature profiles show water
         depth/temperature relationship
II. Physical Properties
   D. Layers
      1. The deeper you go the cooler the temp.
      2. Temperature profiles show water
         depth/temperature relationship
      3. The thermocline is a layer in which the
         temperature decreases linearly with
         depth
II. Physical Properties
   D. Layers
      1. The deeper you go the cooler the temp.
      2. Temperature profiles show water
         depth/temperature relationship
      3. The thermocline is a layer in which the
         temperature decreases linearly with
         depth
      4. There is no thermocline for polar seas
II. Physical Properties
   E. Water masses
II. Physical Properties
   E. Water masses
      1. Cold water comes from polar seas
II. Physical Properties
   E. Water masses
      1. Cold water comes from polar seas
      2. Surface water sinks as salinity
         increases due to sea ice formation
II. Physical Properties
   E. Water masses
      1. Cold water comes from polar seas
      2. Surface water sinks as salinity
         increases due to sea ice formation
      3. Deep currents carry water to the
         equator
The End
  Ocean Movements – 15.3
Objectives
• describe the
  physical properties
  of waves
• explain how tides
  form
• compare and
  contrast various
  ocean currents
                        http://tv-antenna.com/heavy-seas/3/
I. Waves




Periodic movement that carries energy from one
place to another.
I. Waves
  A. Wave characteristics
I. Waves
   A. Wave characteristics
        1. Crest




                      http://ans.hsh.no/home/bji/Fys01/week8/nasa/


The peak of a wave
I. Waves
   A. Wave characteristics
         1. Crest
         2. Trough




                        http://ans.hsh.no/home/bji/Fys01/week8/nasa/


Lowest part of a wave
I. Waves
   A. Wave characteristics
         1. Crest
         2. Trough
         3. Wavelength




                             http://ans.hsh.no/home/bji/Fys01/week8/nasa/


Distance between successive wave crests (or troughs)
I. Waves
   A. Wave characteristics
        1. Crest
        2. Trough
        3. Wavelength
        4. Wave height




Depends on wind speed, wind duration, and fetch.
I. Waves
   A. Wave characteristics
        5. Breakers




Collapsing waves
I. Waves
   A. Wave characteristics
         5. Breakers
            a. Waves slow
               down




More friction with ocean bottom causes waves to
slow.
I. Waves
   A. Wave characteristics
         5. Breakers
            a. Waves slow
               down
           b. Waves
              become
              unstable



The tops of the waves collapse forward because the
bottoms are being slowed
I. Waves
    B. Tides




Periodic rise and fall of sea level.
I. Waves
    B. Tides
         1. High tide




Highest level to which water rises (a bulge of water)
I. Waves
     B. Tides
          1. High tide
          2. Low tide




Lowest level water rises (caused by lack of water)
I. Waves
    B. Tides
         3. Types of daily cycles




Caused by topography and latitude
I. Waves
    B. Tides
          3. Types of daily cycles
             a. Semidiurnal




Characterized by __ high tides each day
 I. Waves
      B. Tides
           3. Types of daily cycles
              a. Semidiurnal
              b. Mixed




Have one pronounced high tide and one _____ high tide
I. Waves
    B. Tides
         3. Types of daily cycles
            a. Semidiurnal
            b. Mixed
            c. Diurnal




Characterized by one ____ ____ each day
I. Waves
  B. Tides
     4. Cause of tides   tutorial
I. Waves
  B. Tides
     4. Cause of tides
       a. Gravity from the moon pulls on
          earth/oceans
I. Waves
  B. Tides
     4. Cause of tides
       a. Gravity from the moon pulls on
          earth/oceans
       b. Centrifugal motion moves the
          water away from Earth
I. Waves
  B. Tides
     4. Cause of tides
        c. During spring tide (unrelated to
           the season) high tides are highest
I. Waves
  B. Tides
     4. Cause of tides
        c. During spring tide (unrelated to
           the season) high tides are highest
       d. During neap tide high tides are
          lower and low tides are higher than
          normal
I. Waves
      B. Tides
           4. Cause of tides
              e. The sun influences tides to a
                 smaller degree




This is because of the greater distance between Earth
and the sun (compared to Earth and the moon)
II. Ocean Currents
   A. Density currents




Move bottom water according to temperature and
salinity differences
II. Ocean Currents
   A. Density currents
   B. Surface currents




Driven by surface wind.
II. Ocean Currents
    A. Density currents
    B. Surface currents
         1. Follow global wind patterns




Trade winds, prevailing westerlies, polar easterly
winds. Coriolis effect alters directions
II. Ocean Currents
  A. Density currents
  B. Surface currents
      1. Follow global wind patterns
      2. Currents from the poles bring
         colder water, while currents from
         equator bring warmer water
II. Ocean Currents
   A. Density currents
   B. Surface currents
         1. Follow global wind patterns
         2. Currents from the poles bring
            colder water, while currents from
            equator bring warmer water
         3. Gyres develop due to landmasses
            interacting with current flow


Circular surface ocean currents
Major Ocean Currents
II. Ocean Currents
   C. Upwelling brings nutrient-rich
      water.




Movement of cold water upward as surface water is
blown by offshore winds
The End

				
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posted:11/26/2011
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