London scoping - ukcip

GLOSSARY
Final Report
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Terms in italics are found elsewhere in this Glossary.
Aerosols Airborne solid or liquid particles, with a typical size between
0.01 and 10mm that reside in the atmosphere for at least several
hours. Aerosols influence the climate directly through scattering
and absorbing radiation, and indirectly through the formation and
optical properties of clouds.
ALG Association of London Government
Anthropogenic Resulting from, or produced by, human beings.
Aquifer Layer of permeable rock, sand or gravel which allows water to
pass through it and which if underlain by impermeable material,
holds water to form a saturated layer or water table.
Atmosphere The gaseous envelope surrounding the Earth, comprising almost
entirely of nitrogen (78.1%) and oxygen (20.9%), together with
several trace gases, such as argon (0.93%) and greenhouse gases
such as carbon dioxide.
Black box Describes a system or model for which the inputs and outputs are
known, but intermediate processes are either unknown or
unprescribed. See regression.
Climate The ‘average weather’ described in terms of the mean and
variability of relevant quantities over a period of time ranging
from months to thousands or millions of years. The classical
period is 30 years, as defined by the World Meteorological
Organisation (WMO).
Climate change Statistically significant variation in either the mean state of the
climate, or in its variability, persisting for an extended period
(typically decades or longer). Climate change may be due to
natural internal processes or to external forcings, or to persistent
anthropogenic changes in the composition of the atmosphere or
in land use.
Climate model A numerical representation of the climate system based on the
physical, chemical and biological properties of its components,
their interactions and feedback processes, and accounting for all
or some its known properties.