Layers of the Atmosphere
Basis for Layers
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Layers are based on TEMPERATURE CHANGE
within the layer.
As you move up through the troposphere,
temperature decreases.
As you move up through stratosphere,
temperature increases.
As you move up through the mesosphere,
temperature decreases
As you move up through the thermosphere,
temperature increases.
As you move up through the exosphere,
temperature increases.
These are the layers in order
from the Earth upwards
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Troposphere
Stratosphere
Mesosphere
Thermosphere
Exosphere
The Troposphere
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Lowest and thinnest
layer.
7.5 miles/12.5km above
earth’s surface.
90% of the atmosphere’s
mass
Densest layer.
“Tropo” means turning
or changing conditions.
Weather occurs here
and therefore clouds.
The Troposphere
We live in it.
 Temperature is warmer
at the surface and
decreases with altitude.
the
air
temperature begins to
decrease up to -52°C
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Temperature of the Troposphere
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temperature
at
surface is warmed
by
the
earth
absorbing energy
from the sun.
Convection
currents carry the
heat upward, so
the air cools as it
rises.
Heat moves throughout (within) our
atmosphere in CONVECTION
CURRENTS
The Stratosphere
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“Strato” means layer or spreading
out.
-52°C to -3°C
30mi above earth’s suface.
Contains the ozone layer which
absorbs energy and causes the
temperature to rise.
The ozone layer protects the surface
from dangerous UV rays (ultraviolet
radiation from the Sun).
Temperature and the
Stratosphere
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Ozone, made of
oxygen, absorbs
ultraviolet
radiation
from
the sun, causing
the temperature
to increase.
The Mesosphere
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“Meso” means middle
31 - 50mi above earth’s
suface.
Coldest layer down to 1480 F (-1000C)
Not enough oxygen to
breathe
Most meteors burn up
here
Temperature and the
Mesosphere
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This layer does
not
absorb
energy from the
sun, so it starts
to cool again.
The Thermosphere
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“Thermo” means heat
Very hot (over 1000°C), but
since air is so thin (not very
dense) it would not feel warm at
all.
So even though it is very hot
(over 1000°C), it would feel cold
because there are so few
particles to transfer heat to
you.
least dense
absorbs solar radiation
The space shuttle orbits here.
reflects radio waves
It takes special instruments to
measure the temperature.
Temperature and the
Thermosphere
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Solar radiation first hits
this layer, so the few
particles that are here can
gain lots of energy. They
move rapidly, so they have a
very high temperature.
But the air is so thin here
that it takes special
instruments to measure the
temperature accurately.
The Exosphere
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“Exo” means outer
Extends for 1000’s of
miles
the
interface
between Earth and
space
No definite edge
Molecules gradually
escape out into space
Air is extremely thin.
Satellites travel here
because there is very
little friction with air.
Altitude and Density
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As the air pressure
decreases, the density of
the air decreases. The
air particles are not
squashed together as
tightly the higher one
goes. This is caused by
gravity!
The air at sea level and
at 6km has the same 21%
oxygen, but at 6km there
are fewer molecules, so
you take in less oxygen
with each breath.