Glossary of Terms
- The North Polar region.
- The South Polar region.
- Chapman reactions
- So called after S. Chapman who is famous for his paper 'A theory of
upper-atmosphere ozone, Mem. Roy. Meteorol. Soc.' in 1930 which set out
the first theoretical explanation of the ozone layer in the stratosphere.
- ChloroFluroCarbons (CFC's)
- A common industrial product, used in refrigeration systems, air
conditioners, aerosols, solvents and in the production of some types of
packaging. Although chemically inert in the lower atmosphere (troposphere), they
are taken to very high altitudes where they are broken down into their components by
the stronger sunlight (UV) at these altitudes. It is the chlorine formed in this
process that causes the damage to ozone. The manufacture and use of CFCs in industry
has been severely curtailed following the Montrol Protocol and subsequent amendments.
See also halocarbons.
- Dobson Unit
- The unit of `Column (or Total) Ozone' - the amount of ozone directly
above a point on the Earth's surface. More Information.
- European Arctic Stratospheric Ozone Experiment (EASOE)
- A major European campaign, during winter 1991/92.
More information. See also SESAME.
- The layer of the atmosphere lying above 400 km altitude.
- A class of halide (i.e. containing Chlorine, Bromine or Iodine) compounds,
including CFC's. These can break down to form various
- The layer of the atmosphere lying between 50 - 100 km altitude.
- Montreal Protocol
- The crucial first step in limiting further damage to the ozone layer in the stratosphere.
The Montreal Protocol was a convention signed in 1987 by many countries to greatly reduce the
production and use of CFCs which had been shown to be responsible for damage to the ozone layer.
Since 1987, further amendments to the protocol have imposed even greater restrictions of the
production and use of potentially damaging compounds.
- A naturally occuring trace gas, chemical formula O3.
In the stratosphere, it serves to absorb many harmful solar UV
rays. More Information.
- Polar Stratospheric Clouds (PSC's)
- The medium in which reservior chlorine comounds are converted into
ozone-destroying chlorine radicals. They are clouds of ice/water particles,
typically found at frost point in the stratosphere. More Information.
- Polar Vortex
- A distinct column of cold air contained over the poles (esp. South) by
meterological effects. Develops during the polar winter when the polar regions are in
polar night (sunlight does not reach the poles). Wind speeds around the vortex may
reach 100 metres per second. The vortex establishes itself in the middle to lower
stratosphere. It's important because it isolates the very cold air within it.
- Potential Temperature
- The temperature that a dry air parcel would have if transported
adiabatically from its ambient temperature and pressure to a pressure of 1000 mb
- Potential Vorticity
- The vorticity (curl of the wind field) that an air parcel would have if
moved to a reference latitude and altitude. The entire dynamical behaviour of
the atmosphere can be obtained from the knowledge of the entire PV field at all
- Reservoir species
- The reservoir species are those that hold ozone destroying chemicals in inactive forms.
For example, HCl and ClONO2, are reservoir species for chlorine. BrCl and
BrONO2 are reservoir species for bromine (Br). The reservoir species are important
because their concentration tells us how many chlorine atoms are potentially available to
destroy ozone in the perturbed chemical conditions of polar winters
(see Part II: Chemical reactions leading to ozone loss for more details).
- Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME)
- A major European campaign, during 1994 and 1995.
More information. See also
- The layer of the atmosphere lying between 10 - 50 km altitude.
- The layer of the atmosphere lying between 100 - 400 km altitude.
More information here.
- Third European Stratospheric Experiment on Ozone. See also SESAME and EASOE.
THESEO runs from 1997-1999. More information can be found on the
European Ozone Research Coordinating Unit website.
- The narrow region separating the troposphere and the stratosphere.
More information here..
- The layer of the atmosphere lying below 10 km altitude.
More information here.
Centre for Atmospheric Science, Cambridge University, UK.
No text or graphics can be used or reproduced without explicit written permission.
This version designed and maintained by
Dr. Glenn Carver.
Original concept and design Owen Garrett.