Transcript Circulation of the Air and Oceans - GMCbiology

Circulation of the Air and
Oceans
I. Air Circulation
A. Uneven heating of earth’s
surface
B. Seasonal changes in
temperature & precipitation
C. Rotation of the earth on its
axis

Coriolis Effect—because the
earth is rotating anything that
moves over its surface tends
to turn to one side rather than
moving in a straight line.
• deflection of winds to right in
N and left in S
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https://www.youtube.com/w
atch?v=i2mec3vgeaI
II. Chemical Make-up of
Atmosphere
A. Greenhouse Gases

Traps energy from
escaping atmosphere
warming air
B. Greenhouse Effect
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Natural warming of
atmosphere
Necessary for Earth
C. Global Warming
 Unnatural
warming of the Earth
 Caused by human activity; ie burning of
fossil fuels
 Increase greenhouse gases in atmosphere
to unnatural levels
 Heavily debated as to rate of occurence
D. Ozone Layer
 Oxygen(O2)
conversion to Ozone
(O3)
 Prevents 95% of UV
radiation from
reaching earth’s
surface
E. Depletion of Ozone Layer
 CFCs
in atmosphere due to human activity
 C,F, Cl break apart bonds between
oxygen molecules
 Result in new compounds; less ozone
 UV radiation allowed to reach earth’s
surface
 DNA mutations
III. Ocean Currents
A. Large scale currents
1. Gyre – large circular
systems of surface currents;
redistribution of heat &
moisture; warm the western
sides of oceans; ex. Gulf
Stream along eastern US coast
2. Upwelling —cold, nutrient
rich bottom water move to the
surface along steep coastlines
Ocean Currents,
cont.
3. Thermohaline – changes in density from
temperature & salinity changes; vertical
movement; downwelling = sinking of more
dense water; upwelling = rising of less dense
water
a. North Atlantic Deep Water
b. Antarctic Bottom Water – denser, moves
under NADW, causes upwellings
4. Thermocline – changes in temperature
cause circular currents in the water column
Ocean Currents, cont.
B. Smaller scale currents
1. Longshore current – travels north to south,
causes sand to move from north end of islands to south
end - “River of Sand” (barrier islands erode on N and
grow on S), caused by swash and backwash, creates a
spit on the island (hook shape on S end); people attempt
to stop the erosion by building jetties/seawalls, moving
the sand, etc
Ocean currents, cont.
Waves
2.
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caused by wind energy
wind transfers some of its energy to the water through friction
between the air molecules and the water molecules
size depends on velocity of wind, length of time wind blows,
fetch (distance the wind blows)
water molecules move in circular pattern
energy transferred from molecule to molecule as wave moves;
upon breaking, energy is transferred to the beach (erosion and
sediment deposition)
Tides
Tides are periodic rises and falls of large
bodies of water
Causes for Tides
 Tides
are caused by the gravitational
interaction between the Earth, the Moon,
and the sun.
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The gravitational attraction of the moon
causes the oceans to move out in the
direction of the moon
On the opposite side of the earth the ocean
moves out as well due to the fact that the
moon’s gravitational pull is at its weakest and
the earth itself is also being pulled in the
direction of the moon
Sun’s Interaction with Tides
1.
Spring Tides (they do not have anything to do with the season Spring)

are especially strong tides
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Occur when the Earth, Sun, and the Moon are in
a line.
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The gravitational forces of the Moon and the Sun
both contribute to the tides.

Spring Tides occur during the full and new moon
Proxigean Spring Tides
2.
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Rare and unusually high tide
Occurs when the moon is both unusually
close (proxigee) to the Earth and in the new
moon phase (when moon is between the
sun and the earth)
Occurs at most once every 1.5 years
Neap Tides
3.
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Very weak tides
Occur when the gravitational forces of the
moon and the sun are perpendicular to one
another (with respect to the Earth)
Neap Tides occur during quarter moons
Types of Tides
Diurnal Tides
 These
tides have 1 high and 1 low tide per
tidal day
 Found in parts of the northern Gulf of
Mexico and Southeast Asia
Semi-diurnal Tides
 These
tides have 2 high and 2 low tides
per tidal day
 Found on the Atlantic coasts of the United
States and Europe
Mixed Tides
 These
tides have a high high tide, a low
high tide, a high low tide, and a low low
tide
 Found around the west coast of Canada
and the United States