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• Atmosphere Layers
• Atmosphere
Pg. 76
Pg. 77
Atmosphere
• Atmosphere – layer of gases that protect Earth.
The Atmosphere is Called ‘Thin Blue
Line’
Picture from International Space Station
Our fragile biosphere's only protection from the solar wind's full
onslaught is provided by the Earth's atmosphere (the thin blue
layer in the photograph) and its magnetic field (which acts as a
shield against the sun's radiation and magnetic fields).
Atmophere composition:78% Nitrogen, 21% Oxygen,
1% H2O, CO2 and others
MIR SPACECRAFT
Layers of the Atmosphere:
1. Troposphere – we live here!
Weather happens here.
Air pressure decreases with altitude increase.
At the top it is 10% of sea level pressure.
Temperature decreases with altitude(not in all layers)
Boundary with the next layer is called the tropopause.
2. Stratosphere
• Jet stream – bands of high-speed winds in
upper tropo. and lower strato.
• Ozone exists in this layer.
– Absorbing the UV from the sun.
– Causes this layer to heat up as altitude increases.
• Boundary is called the stratopause.
3. Mesosphere
• Coldest layer - but this is where meteors burn up.
• Boundary called the mesopause.
4. Thermosphere – 2 parts
• UPPER LIMITS
EXTENDS INTO THE
VACUUM OF SPACE
A. Ionosphere
A. Ionosphere
• Temperature increases steadily here.
• Area ionized by solar radiation.
– Solar radiation absorbed by gases cause the atoms
of the gases to lose electrons and produce ions
and free electrons.
• This causes auroras to happen.
Alaska
• Auroras that occur in
the northern
hemisphere are called
‘Aurora Borealis’ or
‘northern lights’ and
auroras that occur in
the southern
hempishere are called
‘Aurora Australis’ or
‘southern lights’.
• Both Aurora’s can be seen in the northern or southern
hemisphere, in an irregularly shaped oval centered
over each magnetic pole. Scientists have learned that
in most instances northern and southern auroras are
mirror-like images that occur at the same time, with
similar shapes and colors. Auroral displays can appear
in many vivid colors, although green is the most
common. Colors such as red, yellow, green, blue and
violet are also seen occasionally. The auroras can
appear in many forms, from small patches of light that
appear out of nowhere to streamers, arcs, rippling
curtains or shooting rays that light up the sky with an
incredible glow.
B. Exosphere
• Region where atoms and molecules escape into space.
• Satellites orbit here.
The Jason-2 satellite orbits Earth.
It carries tools and sensors to help
scientists study the oceans.
Image Credit: NASA
Construct layers of the atmosphere