Lutgens & Tarbuk “The Atmosphere” chp1
CollegeNow Meteorology 31 March 11 2008
http://www.globalsecurity.org/wmd/library/
policy/army/fm/3-6/3-6apc.htm
Elements of climate and weather
Elements
Measurements
 Air temperature
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 Humidity
 Type & amount of
cloudiness
 Type &a mount of
precipitation
 Pressure exerted by air
 Wind speed and direction
Thermometers
Barometers
Pschycrometers
Radiosondes
Balloons
Stations
Satellites
Rockets
Planes
Buoys
The Structure of the
Atmosphere
Layers of gases that extent into
space.
Variations in temperature,
humidity, pressure, and
composition.
Components include water vapour,
ozone, aerosols, Nitrogen, Oxygen,
Ar, CO2, and other gases.
•Troposphere
•Stratosphere
•Mesosphere
•Thermosphere
The Structure of the
Atmosphere
Temperature varies vertically
throughout the atmosphere
The Structure of the
Atmosphere
Temperature variation is used to
define the different layers of the
atmosphere
•Troposphere
•Stratosphere
•Mesosphere
•Thermosphere
The upper end of a layer is a
‘pause’, thus there is a tropopause ,
a stratopause, etc. These are zones
where temperature is invariant.
The Structure of the
Atmosphere
Temperature variation is used to
define the different layers of the
atmosphere
•Troposphere
•Stratosphere
•Mesosphere
•Thermosphere
The upper end of a layer is a
‘pause’, thus there is a tropopause ,
a stratopause, etc. These are zones
where temperature is invariant.
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
The Structure of the
Atmosphere
Some phenomena are correlated
with specific layers of the
atmosphere
Troposphere: Layer of mixing of
gases, also the Sphere of Weather
Stratosphere: Residence of Ozone
layer
Thermosphere: Site of Aurorae
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
What causes vertical variation in
Temperature?
What causes vertical variation in
Temperature?
Temperature is decreasing with height, the further away from the warm, radiating
surface of the earth, the lower the temperature of the air mass.
In the Troposphere, for every kilometer of increase in altitude, there is a 6.5°C drop
in temperature (called the “normal lapse rate)
But Temperature
increases
Temperature increases in a few
layers of the atmosphere.
What layers?
Image after: http://wpos12.physik.uni-wuppertal.de
But Temperature
increases
Temperature increases in a few
layers of the atmosphere.
What layers?
•Stratosphere
•Thermosphere
Image after: http://wpos12.physik.uni-wuppertal.de
But Temperature
increases
Temperature increases in a few
layers of the atmosphere.
What layers?
•Stratosphere
•Thermosphere
Temperature increases for different
reasons in the two spheres.
Image after: http://wpos12.physik.uni-wuppertal.de
Stratosphere
Temperature increase
The air mass needs to receive heat
in order to be wamed. Closer to the
earth’s surface, it is the heat that is
radiating from the earth that
warms the air.
In the stratosphere, the energy to
heat the air comes chemical
reactions, ultimately through UV
radiation, in the ozone-oxygen
cycle
Image after: http://wpos12.physik.uni-wuppertal.de
Stratosphere
Temperature increase
Step 1
The air mass needs to receive heat
in order to be wamed. Closer to the
earth’s surface, it is the heat that is
radiating from the earth that
warms the air.
In the stratosphere, the energy to
heat the air comes chemical
reactions, ultimately through UV
radiation.
Step 2
Ozone is present in high
concentrations in the
stratosphere. It is created and
destroyed in the ozoneoxygen cycle.
Image after: http://science.howstuffworks.com/earth5.htm
Stratosphere
Temperature increase
Step 1: Oxygen Molecule absorbs UV light and splits
The air mass needs to receive heat
in order to be wamed. Closer to the
earth’s surface, it is the heat that is
radiating from the earth that
warms the air.
In the stratosphere, the energy to
heat the air comes chemical
reactions, ultimately through UV
radiation, in the ozone-oxygen
cycle
Step 2: Oxygen atom reacts with molecular oxygen creating ozone
Image after: http://science.howstuffworks.com/earth5.htm
Stratosphere
Temperature increase
Step 1: Oxygen Molecule absorbs UV light and splits
The air mass needs to receive heat
in order to be wamed. Closer to the
earth’s surface, it is the heat that is
radiating from the earth that
warms the air.
In the stratosphere, the energy to
heat the air comes chemical
reactions, ultimately through UV
radiation, in the ozone-oxygen
cycle
Step 2: Oxygen atom reacts with molecular oxygen creating ozone
When Step 2 is run backwards, Ozone absorbs UV
radiation, splits into molecular and atomic oxygen, and
heat is added to the stratosphere
Image after: http://science.howstuffworks.com/earth5.htm
Ever hear of Ozone
Depletion?
The Ozone molecule, as we have
seen, is absording solar radiation.
The Ozone layer is created by the
sun, and it protects the earth
beneath it from the sun.
It is the result of a chemical
process. Like any other chemical
process, it can be interfered with.
Chlorofluorocarbons can react
with ozone in the atmosphere, and
prevent the formation of ozone.
Image after: http://www.safety-devices.com/what_is_ozone.htm
Ever hear of Ozone
Depletion?
Chlorine and Ozone react
CFCs are normally stable
compounds. They get into the air,
are pushed up into the
stratosphere by wind currents, and
there are exposed to UV rays.
The UV rays break the bonds that
hold the CFCs together, releasing
free Chlorine.
Chlorine is liberated to react again with Ozone
That cholorine reacts with ozone,
stripping off one of its oxygens.
Other free oxygen in the
atmosphere can react with the
Chloro-oxide, creating molecular
oxygen, leaving the Chlorine free to
rip apart other ozone molecules.
Image after: http://www.safety-devices.com/what_is_ozone.htm
Ever hear of Ozone
Depletion?
Chlorine and Ozone react
Chlorine is liberated to react again with Ozone
CFCs can destroy ozone molecules, this competes again
the action of UV rays creating ozone.
Image after: http://www.safety-devices.com/what_is_ozone.htm
The Ozone “Hole”
Image after: http://www.theozonehole.com
The Ozone “Hole”
Image after: http://www.theozonehole.com
What about the Thermosphere
temperature increase?
So we can explain the temperature
increase in the stratosphere as a
result of energy input from the
sun.
In the Thermosphere, there is a
similar effect. Oxygen and
Nitrogen in the layer are
bombarded by high energy solar
radiation (short wave, think like
how ‘microwaves’ can heat things).
This causes an increase in
temperature within the
Thermosphere.
To what temps?
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
What about the Thermosphere
temperature increase?
To what temps?
Here we see up to 50°C,
but temperatures
actually get up to
1,ooo°C
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
What about the Thermosphere
temperature increase?
Up
to 1,ooo°C
However:
HEAT IS NOT THE SAME
AS TEMPERATURE
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
Heat is not the Same as Temperature
Temperature: A statistical property of objects, a measure of the movement of its
component molecules. Fast moving particles mean an object has a high temperature.
Heat: A measure of energy
So what does that mean about the Thermosphere????
Heat is not the Same as Temperature
Temperature: A statistical property of objects, a measure of the movement of its
component molecules. Fast moving particles mean an object has a high temperature.
Heat: A measure of energy
So what does that mean about the Thermosphere????
The air molecules are very ,very fast moving. A sample
of it has low heat energy.
If an astronaut put their hand out into the thermosphere, it sure wouldn’t feel hot.
Variation in vertical Structure
What is the altitude of
the Tropopause?
10 km?
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
Variation in vertical Structure
Tropopause position varies
with latitude.
At the Poles, it can be as
shallow as 8 km. This is
because air at the poles is in
fact sinking.
At the equator, it can reside at
an altitude of 18 km. This is
because the warm, moist air of
the equator is rising through
the atmosphere.
In the Middle Latitudes, the
Tropopause is higher in the
summer and lower in the
winter.
After: http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html
So….
The atmosphere is divided into
layers on the basis of temperature,
the Troposphere, the
Stratosphere, the Mesosphere,
and the Thermosphere.
The Troposphere is where most
weather and clouds occur.
Normally, the further away from
the surface of the earth, the cooler
the air. But in the Stratosphere,
the absorption of UV radiation
by the ozone layer heats up the
Stratosphere. And in the
Thermosphere, absorption of
shortwave radiation by Oxygen
and Nitrogen molecules heat
the Thermosphere.
After Lutgens and Tarbuk, “The Atmosphere” Figure 1-25
We can also divide the atmosphere into layers based air composition.
Variations other than Temperature
 Homosphere: Zone within which the ratio of components (Oxygen, Nitrogen,
CO2, etc) does not vary much. Up to 80 km
 Heterosphere: Zone within which the ratio of components varies greatly. The
lowermost layer is dominated by N2, then a layer of atomic Oxygen, then a layer
dominated by Helium (He), and then the highest layer, dominated by atomic Hydrogen
(H). Notice, the heaviest elements are lowest, and the lightest elements ‘float’ in a layer
above that. Earth actually looses H and He to space at the outer edge of this sphere,
gravity is insufficient to hold those gases to Earth. Also, the density of gases becomes
extremely low in this layer. Said to occur from 80-10,000 km
Variations other than Temperature
 Ionosphere: Region where N2 and Oxygen atoms are ionized; high
energy rays strip off some of their electrons (iow, they become Ions). b/t
80-400 km
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D & E Layer: Ephemeral. At night, when there is no influx of solar radiation, the ions disappear, reappearing during
daylight
F Layer: Constant, but very weak. Low density of atoms and molecules prevents ions from disappearing, so they last
throughout the night.
Aurora: borealis and australis
Interaction between electromagnetic
‘solar wind’ and the earth’s magnetic
field. The solar particles are directed to
the poles, where they interact with
molecules in the atmosphere,
energizing them, creating lights.
Variations other than Temperature
Aerosols: Particulate matter
suspended in the atmosphere,
smoke, dust, etc.
After: http://namma.nsstc.nasa.gov/reporting/large/
Atmospheric
Structure
After: http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html
Atmospheric
Structure
After: http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html
Titan’s Atmosphere
Earth’s atmosphere is not,
clearly, the same as other
planets, neither in
composition nor strucuture.
Jupiter’s
Atmosphere
Earth’s atmosphere is not,
clearly, the same as other
planets, neither in
composition nor strucuture.
After: http://cseligman.com/text/planets/jupiteratmostruct.jpg
Jupiter’s
Atmosphere
Jupiter has Aurora also,
however they result from
interactions between
Jupiter’s magnetic field and
its moons. This is a UV
image.
After: http://cseligman.com/text/planets/jupiteratmostruct.jpg
Jupiter’s
Atmosphere
Jupiter, and other planets, have
weather. But it is wildly different
than on earth. The Great Red
Spot is a storm that has been
observed ever since Jupiter has
been telescopically observed
(iow, +300 years), and is as big
as the entire surface area of
the earth. The smaller red spot
below it has a diameter as large
as that of earth. The red storms
are thought to have stirred up
material from deeper within
jupiter, while the white storms
aren’t strong enough to reach
below its atmosphere.
Notice the banding of the
atmosphere in this image, this is
‘zonal banding’, it occurs on
earth too.
After: http://cseligman.com/text/planets/jupiteratmostruct.jpg
More on structure:
Atmospheric Circulation Cells: Convecting cells of rising and sinking air
that carry moisture and heat with them across earth
Afterhttp://www.climateprediction.net/science/cl-intro.php
More on structure:
Atmospheric Circulation Cells: Convecting cells of rising and sinking air
that carry moisture and heat with them across earth
Afterhttp://www.climateprediction.net/science/cl-intro.php
More on structure:
Atmospheric Circulation Cells: Convecting cells of rising and sinking air
that carry moisture and heat with them across earth
Afterhttp://www.climateprediction.net/science/cl-intro.php
The altitudes at which the
boundaries for the layers (the
pauses) occur is not the same
throughout the world. There is
variation in all directions.
The rate of temperature change is
not the same within the layers
throughout the world, it varies too,
largely with changes in latitude.
In fact, all characteristics can vary
between different locations on the
earth, with respect to latitude and
longitude. We will find that
latitudinal variation is often
related to Insolation.
The atmosphere can be divided into four
layers based on temperature, the Troposphere,
Stratosphere, Mesosphere, and
Thermosphere.
There is vertical variation of temperature
within those layers, and you can explain that
variation
The atmosphere can also be divided into layers
based on their composition, such as the
Homosphere and Heterosphere or the
Ionosphere
Some components, like Ozone, can have their
atmospheric concentrations changed by
biological activities (human or otherwise)