Radiative forcing:

net change in irradiance (in watts per meter squared, Wm-2) at the tropopause after allowing for stratospheric temperatures to readjust to equilibrium.


or free radical; an atom or molecule that has one unpaired electron.


research, deployment, test, and evaluation.


installation of new or updated systems in existing platforms.



Significant New Alternatives Program.


that region of the atmosphere lying above the tropopause in which, in contrast to adjoining regions, temperature does not increase with increasing height. The stratosphere extends from the tropopause to a height of about 50 km, where the temperature reaches a maximum.

Streaming agent:

a fire suppression agent (typically liquid) applied in a stream, often from hand-held extinguishers, directly on an unobstructed fire.



1 million million (1012) floating point operations per second.


trifluoroacetic acid (CF3COOH).


the atmospheric shell extending from the top of the mesosphere to outer space. It is a region of more or less steadily increasing temperature with increasing altitude, starting at about 80 to 95 km.

Total flooding agent:

an easily dispersed fire suppression agent (typically gaseous) for use in obstructed spaces.


tending to degrade, or break down into constituent elements, in the lower atmosphere (troposphere). Tropodegradable compounds emitted at the surface are not likely to be transported to the stratosphere.


the atmospheric boundary between the troposphere and the stratosphere, defined as the level at which the decrease in temperature with height becomes 2°C/km or less, over at least 2 km.


the lowest layer of the atmosphere below the tropopause extending from Earth's surface to about 8 km at the poles and 16 km at the equator.



space above fuel inside a partially filled fuel tank.

Ultraviolet (UV) radiation:

electromagnetic radiation lying beyond the violet end of the visible spectrum with wavelength less than 400 nm.


United Nations Environment Programme.

UV-B radiation:

electromagnetic radiation with wavelength in the range of 280 to 320 nm, which affects plants and animals.



"Osprey"; a vertical takeoff and landing tilt-rotor aircraft currently under development.

Volume mixing ratio:

the ratio of the number of molecules of a species in air to the total number of gas molecules in a sample.


Water mist systems:

fire suppression systems that dispense water in the form of finely aerosolized droplets. The fine water mist behaves, in some instances, like a gaseous agent and is able to be dispersed effectively in obstructed spaces.

Window region:

a region in the infrared portion of the electromagnetic spectrum with wavelengths in the range of 8 to 12 µm. The atmosphere is relatively transparent to radiation in this spectral region.


World Meteorological Organization.

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