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Chapters 11 and 12
 Are weather and climate the same thing?????
So what's the difference
 Weather is constantly changing, and it
refers to the state of the atmosphere at any
given time and place.
 Climate is based on observations of
weather that has been collected over many
years. Climate helps describe a place or
region.
What Makes Up Our
Atmosphere
 Nitrogen
 Oxygen
 Carbon Dioxide
 Water Vapor
 Argon
 Methane, Neon, Helium, Krypton, Xenon, Oxone,
Hydrogen
*Please draw diagram in your notes*
Gases in the Atmosphere
 Nitrogen-78%
 Oxygen-21%
 Carbon Dioxide
 Water Vapor
 Argon
 Trace Gases-Neon, Helium, Methane, Krypton, Xenon,
Oxone, Hydrogen
Water Vapor
 The source of all clouds and
precipitation.
Ozone Layer
 Ozone absorbs most of the UV light
from the sun.
 UV light is very harmful because it can
damage the genetic material in living cells.
*Skin cancer
Ozone Eaters
 CFCs (chloroflourocarbons) are man-made
chemicals found in spray cans and
refrigerator coolants.
The Ozone Hole
 In 1985, a study showed that the ozone layer
above the South Pole had thinned.
 As ozone decreases, more UV light hits the
Earth.
 UV light can kill or damage skin cells.
Stopping the Thinning
 In 1987, many nations agreed to stop
producing CFCs. This meeting was called
the Montreal Protocol.
 It appears that the thinning of the ozone
layer has slowed.
Human Influence
 Emissions from transportation vehicles
account for nearly half the primary pollutants
by weight.
Height and Structure of the Atmosphere
 The atmosphere can be divided vertically
into four layers based on composition and
temperature.
 Troposphere
 Stratosphere
 Mesosphere
 Thermosphere
 Exosphere
 Troposphere is the bottom layer of the
atmosphere
 Stratosphere-contains ozone layer
 Mesosphere
 Thermosphere
Troposphere
 Contains most of the mass of the atmosphere (water
vapor)
 Weather takes place here
 Air pollution is collected here
 10 km
Stratosphere
 Where the Ozone (O₃) is located
 Ozone absorbs the UV Radiation
 This layer is heated
 Increases in temp. as you travel up the stratosphere
 50 km
Mesophere and Thermosphere
 Mesosphere= Temperature decreases (no Ozone)
-80 Km
 Thermosphere= Temperature increases, thin air
-120 Km
Ionosphere and Exosphere
 Ionosphere is made up electrically charged particles
and layers of light gases
 Exosphere is the outermost layer of the Earth’s
atmosphere
-helium and hydrogen are found here (light gases)
-above the exosphere lies OUTER SPACE
-there is no clear boundary between the Exosphere and
Outer Space
Atmoshere Videos
 https://www.youtube.com/watch?v=Z8RRkMsHOMU
 http://www.youtube.com/watch?v=Qw8OJJQ_hgk
 http://www.youtube.com/watch?v=YIj9XGLTGH8
Earths Motion and Orientation
 Earth has two principal motions:
 Rotation
 Revolution
 Seasonal changes occur because Earth’s
position relative to the sun continually
changes as it travels along its orbit.
Why do we have seasons?
 The Earth's seasons are not caused by the
differences in the distance from the Sun
throughout the year.
 The seasons are the result of the tilt of the
Earth's axis.
Earths Axis: 23.5 degrees
WHY??
 Summer is warmer than winter (in each
hemisphere) because the Sun's rays hit the
Earth at a more direct angle during
summer than during winter and also
because the days are much longer than the
nights during the summer.
Why are summer days longer than
winter days
Energy Transfer
 Heat is the energy transferred from one
object to another because of a difference in
the objects’ temperature
 Temperature is a measure of the average
kinetic energy of the individual atoms or
molecules in a substance
 Three mechanisms of energy transfer as
heat are:
 conduction
 convection
 radiation.
 Conduction is the transfer of heat through
matter by molecular activity.
 Convection is the transfer of heat by mass
movement or circulation within a substance
 Radiation is the transfer of heat through space
by electromagnetic waves that travel out in all
directions.
What happens to solar radiation?
 Some energy is absorbed by the object
 Some energy is reflected
 Some energy is scattered
 Reflection occurs when light bounces off
an object. Reflection radiation has the
same intensity as incident radiation.
 Scattering produces a larger number of
weaker rays that travel in different
directions.
Cloud coverage and temperature .
 Did you know cloud cover can greatly
impact how the temperature of an area
changes.
 http://ww2010.atmos.uiuc.edu/(Gh)/guides
/mtr/fcst/tmps/cld.rxml
 Albedo is the fraction of total radiation that is
reflected by any surface.
 Many clouds have a high albedo and therefore
reflect back to space a significant portion of the
sunlight that strikes them.
 At night they can hold heat and during the day they
can reflect it.
Air Masses
 http://video.about.com/weather/Types-of-Air-
Masses.htm
 An air mass is a large volume of air in the atmosphere that is mostly
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uniform in temperature and moisture.
Air masses can extend thousands of kilometers across the surface of
the Earth
Air masses form over large surfaces with uniform temperatures
and humidity, called source regions.
Low wind speeds let air remain stationary long enough to take on the
features of the source region, such as heat or cold.
When winds move air masses, they carry their weather conditions
(heat or cold, dry or moist) from the source region to a new
region..
Air Masses
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When the air mass reaches a new region, it might
clash with another air mass that has a different
temperature and humidity. This can create a severe
storm
How are air masses classified?
 Air masses are classified on weather maps using two or three letters.
 A lowercase letter describes the amount of moisture in the air mass: m
for maritime (moist) and c for continental (dry).
 An uppercase letter describes the heat of the air mass: E for equatorial,
T for tropical, M for monsoon, P for polar, A for Arctic or Antarctic, and
S for superior—a unique situation with dry air formed by a powerful
downward motion of the atmosphere.
 A lowercase letter describes the relationship between the air mass and
the earth: k signifies that the air mass is colder than the ground below
it, while w describes an air mass that is warmer than the ground below
it
Example: mT= maritime tropical
North American Air Masses
North American Air Masses
Isotherms
 Isotherms are lines on a weather map that
connect points where the temperature is the
same.
 They are typically placed at intervals of 10 degrees
Fahrenheit.