Transcript Chapter 11 Atmosphere

Chapter 11
Atmosphere
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I. Atmospheric Basics
1. The atmosphere is combined with several
gasses.
2. About 99% of the atmosphere is composed of
nitrogen and oxygen, the remaining 1% small
amounts of argon, hydrogen, carbon dioxide,
water vapor and other gasses.
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3. The amount of water vapor in the atmosphere at any
given time or place changes constantly. It can be as
much as 4% of the atmosphere or as little as almost
zero.
4. The level of both carbon dioxide and water vapor are
critical because they play an important role in regulating
the amount of energy the atmosphere absorbs.
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5. Water vapor is the source of clouds, rain and
snow.
6. The atmosphere also contains solids in the
form of tiny particles of dust and salt. Dust is
carried into the atmosphere by wind.
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B. Ozone
1. Another component of the
atmosphere, ozone, (O3) is a
gas formed by the addition of
a third oxygen atom to an
oxygen molecule.
2. It is important because it
absorbs ultraviolet radiation
from the Sun.
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C. Structure of the atmosphere
1. The atmosphere is made up of several
different layers.
2. The layer closest to Earth’s surface, the
troposphere, contains most of the mass of the
atmosphere, including water vapor. This is the
layer in which most weather takes place and
most air pollution collects.
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3. Above the tropopause is the stratosphere, a
layer made up primarily of concentrated ozone.
4. Above the stratopause is the mesosphere.
There is no concentrated ozone in the
mesosphere, so the temperature decreases
once again
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5. The thermosphere contains only a minute
portion of the atmosphere’s mass.
6. The ionosphere is part of the thermosphere. It
is made up of electrically charged particles and
layers of progressively lighter gasses.
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7. The exosphere is the
outer layer of Earth’s
atmosphere. Light gases
such as helium and
hydrogen are found in
this layer.
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D. Solar Fundamentals
1. Radiation is the transfer of energy through
space by visible light, ultraviolet radiation, and
other forms of electromagnetic waves.
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2. Conduction is the transfer of energy that occurs
when molecules collide, energy is transferred
from the bottom of the point into the lowest part
of the water. (Water on a burner)
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3.
Convection is the
transfer of energy by the
flow of heated
substance.
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II. States of atmosphere
A.
Temperature verse heat.
1. Temperature is a measurement of how
rapidly or slowly molecules move around.
More molecules are faster-moving molecules
in a given area generate a higher temperature.
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2. Heat is the transfer of energy that occurs
because of a difference in temperature between
substances.
3. Temperature can be measured in degrees
Fahrenheit or degrees Celsius or in Kelvin’s.
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4. Another atmospheric measurement is the
dew point. The dew point is the temperature to
which air must be cooled at constant pressure to
reach saturation.
5. Saturation is the point at which the air holds
as much water vapor as it possibly can.
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6. Condensation occurs when matter changes
state from a gas to a liquid.
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B. Vertical Temperature changes
1. The height at which condensation occurs is
called lifted condensation level (LCL)
2. Above the LCL, air becomes saturated and
cools more slowly.
3. The rate at which saturated air-cools is called
the moist adiabatic lapse rate.
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C. Air pressures
1. The density of air is proportional to the number
of particles of air occupying a particular space.
2. In the atmosphere, the relationship between
temperature and pressure is not always fixed.
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3. A temperature inversion is an increase in
temperature with height in an atmospheric layer.
4. The amount of water vapor in air is referred to
as humidity.
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5. The ratio of water vapor in a volume of air
relative to how much water vapor that volume of
air is capable of holding is called relative
humidity.
6. Relative humidity is expressed as a
percentage.
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III. Moisture in the atmosphere
A.
Cloud formation.
1. Clouds form when warm, moist air rises,
expands and cools in a convection current. As
the air reaches its dew point, the water vapor
in the air condense around condensation
nuclei.
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2. Condensation nuclei are small particles in the
atmosphere around which cloud droplets can form.
3. Clouds can also form when wind encounters a
mountain and the air has no place to go but up.
4. This method of cloud formation is called orographic
lifting.
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5. How rapidly any given mass of air cools
determines its stability. Stability is the ability of
an air mass to resist rising.
6. Stored energy is called latent heat.
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B. Types of clouds
1. Clouds are generally classified according to a
system originally developed by English naturalist
Luke Howard in 1803.
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Cirro
2. Cirro- high clouds
above 6000m wispy,
stringy clouds
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Alto
3. Alto- middle clouds
2000m pile or heat,
puffy, lumpy looking.
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Strato
4. Low clouds below
2000m low, gray
rain clouds.
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5. When cloud droplets collide, they join
together to form a large droplet in a process
called coalescence.
6. As the process continues, the droplet
becomes too heavy to be held. Gravity takes
over and the droplet fall to earth- precipitation.
Either liquid or a solid.
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C. The water cycle
1. The process of water changing from liquid to gas is
called evaporation.
2. The first step- water evaporates from lakes and
streams.
3. As the water vapor rises, it cools and changes back
into liquid.
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THE END
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