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Definitions
A directory of terms associated with tropical cyclones. (Sources: Australian Bureau of Meteorology, Cambridge Dictionary, the IPCC Fourth Assessment Reports and Wikipedia).
A
Adaptation
Adjustment of natural or human systems in response to actual or expected climate change, or its effects, that lessens damage or exploits beneficial opportunities.
C
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.
Cyclone intensity
The maximum mean wind speed over open flat land or water. Also called the maximum sustained wind, it is found near the eyewall of the cyclone.
D
Downscaling
A method that derives local- to regional-scale (10 to 100km) weather and climate information from larger-scale (200–300km resolution) climate models or data analyses.
E
Eye
A roughly circular area of low pressure at the centre of a tropical cyclone that usually has relatively light winds and fair weather.
Eyewall
A ring of deep convection that surrounds a cyclone's eye, where the heaviest rain, strongest winds and worst turbulence are normally found.
F
Forecast
A model-based estimate of the weather or climate's actual evolution in the future.
H
Hurricane
A tropical cyclone, with wind speeds over 32 metres per second, accompanied by heavy rainfall, especially found in the west Atlantic Ocean.
R
Risk management
A structured approach to managing uncertainty related to threats from extreme weather events or climate change involving: risk assessment, planning and implementation of adaptation responses.
S
Storm surge
Also called a tidal wave, this is a temporary rise above normal tidal level due to the action of wind stress and atmospheric pressure reduction on the ocean surface.
T
Tropical cyclone
A storm originating over tropical or subtropical waters, characterised by strong rainstorms and high-velocity winds that circulate around a central area of very low pressure.
Tropical depression
A frequent type of tropical cyclone, characterised by wind speeds of less than 8 metres per second.
Tropical low
The most frequent type of tropical cyclone, characterised by wind speeds of 8–17 metres per second.
Typhoon
A violent wind, accompanied by heavy rainfall, which has a circular movement around an area of low pressure, found in the west Pacific Ocean.
U
Uncertainty
An expression of the degree to which a value (such as the future state of the climate system) is unknown. Uncertainty can result from lack of information or from disagreement about what is known or even knowable.
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