Parameter Tree:
EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC CHEMISTRY > OXYGEN COMPOUNDS

Definition:
Oxygen (O) (and molecular oxygen (O2)) is the second most abundant species in
the atmosphere. The abundance of O2 remains fairly constant in the atmosphere
up to about 80km where it photodissociates to atomic oxygen. Atomic oxygen is
formed from the photolysis of molecular oxygen (O2), ozone (O3), or nitrogen
dioxide (NO2) in the atmosphere. Below about 40 km, atomic oxygen recombines
with O2 to form ozone. Above 40 km, oxygen can participate in other chemical
reactions that cause the destruction of ozone.


Reference:
American Meteorological Society. 2000. Glossary of Meteorology, Second Edition.
Boston, MA: American Meteorological Society.