Geology Reference
In-Depth Information
(vi) The removal of nitric acid (and other oxides of nitrogen), by slow,
gravitational settling means that the reservoir species cannot be
regenerated. The HNO
3
is liberated within the particle.
In more recent times, there have been discoveries of ozone depletion in
the Arctic that occur by similar mechanisms as the ones described here
(see Figure 28). The Arctic equivalent does not tend to be as dramatic
owing to the fact the Artic stratosphere does not get as cold as the
Antarctic, mainly owing to a less well-formed vortex, largely owing to
northern hemisphere topography.
52
2.11 SUMMARY
The chemistry of the atmosphere is diverse, driven in the main by the
interaction of light with a few molecules that drives a complex array of
chemistry. The type and impact of atmospheric chemistry varies in
concert with the physical and biological change throughout the atmos-
phere. An integral understanding of atmospheric chemistry within the
earth system context underpins many contemporary global environmen-
tal problems and is therefore vital to sustainable development.
This chapter has outlined the main features of the chemistry of the
troposphere and stratosphere. In some senses it must be remembered
that our understanding of atmospheric chemistry is still evolving, but the
science expressed gives entry into the rich and changing world of
atmospheric science. In the coming years we need to understand the
interaction of atmospheric chemistry with climate as well as better
understand the multi-phase impacts of the chemistry. There is still much
to discover, rationalise and understand in atmospheric chemistry.
QUESTIONS
(i) The earth system is made up of the atmosphere, hydrosphere,
lithosphere and biosphere. Describe, with examples, the chem-
ical interactions between these different elements of the earth
system.
(ii) The amount of any chemical substance in the atmosphere is
dependent on the source-transport-sink relationship for that
compound. Describe the different types of sources of trace gases
in the atmosphere.
(iii) Discuss the following statement: ''The atmosphere can be split
into different regions according to different physical or chemical
properties''.
