A measure of luminous flux remaining in a light beam after it has passed through a specified distance of the atmosphere.

Read Only Memory. A memory that cannot be altered in normal use of a computer, Usually used to store information permanently, such as firmware programs.

Electromagnetic radiation lying in the wavelength interval between 0.8 micron and I millimeter. At the lower limit of this interval, the infrared radiation spectrum is bounded by visible radiation, while on its upper limit it is bounded by microwave radia ...

meter-An instrument for measuring the transmissivity of the atmosphere; a type of transmissometer. It consists of a constant- intensity collimated light source located at a suitable distance from a photoelectric cell. Variation in the turbidity of the atm ...

Wind with a speed between 17 and 21 knots (19 and 24 mph); Beaufort scale number 5.

An instrument for measuring the frost point of the atmosphere.

General term for any device that measures precipitation: principally a rain gauge or snow gauge.

The temperature at which the liquid and solid forms of a substance may exist in equilibrium at a given pressure (usually one standard atmosphere). The true freezing point of water is known as the ice point.

An accumulation of granular ice tufts on the windward sides of exposed objects that is formed from supercooled fog or cloud and built out directly against the wind.

A strong wind characterized by a sudden onset, a duration on the order of minutes, and a rather sudden decrease in speed.

A standard interface between a computer input/output port and a peripheral device. Signal properties including time duration, voltage. and current, are specified by the Electronic Industries Association.

Thermometer used for measuring the lowest temperature attained during a given interval of time, for example, a day.

Same as Aeolian.

That portion of the record of a microbarograph between any two (or a specified small number) of successive crossings of the average pressure level (in the same direction). Analogous to microseism.

The outer, solid portion of the earth: the crust of the earth.

A set of weekly colored rainbow arcs sometimes discernable inside a primary rainbow.

For a given location, a measure of the long-range effectiveness of precipitation in promoting plant growth. Also called precipitation-evaporation index.

Erasable Programmable Read Only Memory. Programable read-only memory which can be erased, usually by ultraviolet light, and re-programmed.

The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

A hygrometer based upon the diffusion of water vapor through a porous membrane.