Atmosphere Basics:
The atmosphere makes life on Earth possible. It shields us from harmful extra-planetary ra-
diation; it moderates the surface temperature of the planet and insulates us from the diurnal
solar cycle; it allows for a common, well mixed reservoir of gasses from which organisms can
cycle necessary chemical compounds; and it provides a medium for the long range transport
and circulation of water.  It is important to study the atmosphere in order to understand our weather and climate.

Temperature:
The atmosphere can be divided into different zones based on the way that the temperature changes.

[US Standard Atmosphere - A.J. Krueger]
The troposphere is the lowest region extending from the surface of the planet up to nominally
10 km altitude and it is characterized by decreasing temperature with height, convective and turbulent mixing,
and an abundance of water vapour. It is also the region of the atmosphere that we associate withour day-to-day weather.

The stratosphere is the region directly above the tropopause and extends to roughly 50 km
altitude. The region gets its name from the stably stratified (layered) nature of the temperature profile.
Whereas the troposphere got colder with height, the stratospheric temperature profile
increases with increasing altitude due to the presence of ozone. This happens beause the
ozone molecule, O3 , absorbs incoming ultraviolet solar radiation and redistributes a portion of
the energy as increased temperature.