Glossary 339into other forms of energy or which only delivers the heat energy to another
reservoir at a different temperature. The Law further provides a formula for the
maximum efficiency of a heat engine which takes heat from a cooler body and
delivers it to a hotter one
Thermohaline Circulation (THC) Large-scale density driven circulation in the
ocean caused by differences in temperature and salinity
Transpiration The transfer of water from plants to theatmosphere
Tritium Radioactiveisotopeof hydrogen, used to trace the spread of radioactivity
in the ocean after atomic bomb tests, and hence to map ocean currents
Tropical cyclone A storm or wind system rotating around a central area of low
atmospheric pressureand occurring in tropical regions. They can be of great
strength and are also called hurricanes and typhoons. Tornadoes are much
smaller storms of similar violence
Troposphere The region of the loweratmosphereup to a height of about 10 km
where the temperature falls with height and where convection is the dominant
process for transfer of heat in the vertical
UNCED United Nations Conference on Environment and Development, held at
Rio de Janeiro in June 1992, after which the United Nations Framework
Convention on Climate Change was signed by 160 participating countries
UNEP United Nations Environmental Programme – one of the bodies that set up
theIPCC
UV Ultra-violet radiation
Watt Unit of power
WEC World Energy Council – an international body with a broad membership of
both energy users and the energy industry
Wind farm Grouping of wind turbines for generating electric power
WMO World Meteorological Organization – one of the bodies that set up the
IPCC
Younger Dryas event Cold climatic event that occurred for a period of about
1500 years, interrupting the warming of the Earth after the last ice age (so
called because it was marked by the spread of an Arctic flower,Dryas
octopetala). It was discovered by a study of paleoclimatic data
Zooplankton Minute forms of animal life in the ocean