Transcript Physical Oceanography

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 deepwater 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