Transcript Courtesy LPI/NASA
Modern Atmosphere and Air
Sunrise from space over the South China Sea. An astronaut would see something like this; clearly
defined bands of color through the atmosphere as the sun rises. High-peaking cumulus clouds,
topping out in anvil-head cirrus can be seen as black shadows against the sunlit horizon. The
brightness of the colors in the atmosphere in this photograph is due to the amount of dust in the
atmosphere. More dust is found in near the equator. There are various sources for such upper leve
dust. Many dust storms in Africa and ash clouds from major volcanic eruptions are two reasons.
Earth viewed from the Moon
Why is the Sky Blue?
The atmosphere protects Earth
Cosmic rays are very
the Solar System.
They may produce
that penetrate and
impact the Earth's
reach the surface.
protons and atomic
nuclei, they are of
Pressure vs. Altitude
Air density vs. Altitude
( h ) 0 exp
0 1.2 kg/m
H 0 7.99 km
The gases are mixed
The gases are not
Stable Components of the
• Troposphere – the region of principal weather
activity, 90% of the atmosphere. The upper
limit defined by temperature of -57C.
• The upper layer is called tropopause, 18 km at
the equator and 12 km at middle latitude; 8
km at the poles.
The temperature profile of the
• Normal lapse rate ,
decrease of 6.4C per km
and it is only an average;
• The actual lapse rate is
• Extends from 18 to 50 km from the Earth’s
• Temperatures increase with altitude up to 0C
at 50 km
• The stratosphere is layered in temperature
because ozone (O3) here absorbs high energy
UVB and UVC energy waves from the Sun and
is broken down into atomic oxygen (O) and
diatomic oxygen (O2).
• Between 50 to 80 km
• The upper limit the
mesopause is the coldest
portion of the atmosphere
• This is due to decreasing
• Temperatures are rise sharply in the
• Thermospheric temperatures increase with
altitude due to absorption of highly
energetic solar radiation.
• Radiation causes the atmosphere particles in
this layer to become electrically charged (the
Atmospheric Function Criterion
• The Ionosphere absorbs
cosmic rays, gamma rays, Xrays and shorter ultra violet
atoms to positively charged
• Extends from 85 to 600 km
Ionosphere and broadcast
Profile of the Atmosphere
These two photos show the aurora borealis (Northern Lights) over Alaska
in March 2001. The green color of this aurora tells us something about it.
The green glow comes from oxygen atoms in Earth's upper atmosphere.
Images courtesy of Jan Curtis.
• The portion of the stratosphere that contains t
an increase level of Ozone.
• Ozone is a highly reactive oxygen and absovs
UV 100-300 nm and reradiates this energy in
• Today it is in situation of continues change
• ClO+O3 --->Cl+2O2
• Cl+O3 --->Cl0+O2
Chemical evidence of ozone damage
Vertical profile of the temperature
The big jump in History
Speed of the Jump