The attenuation of light.

The visibility along an identified runway, determined from a specified point on the runway with the observer facing in the same direction as a pilot using the runway. Compare to runway visible range.

The change in the measured transducer output caused by changes in ambient temperature. Usually expressed a percentage of full scale.

See gain.

The total of direct solar radiation and diffuse sky radiation received by a unit horizontal surface. Global radiation is measured by pyranometers.

Facing away from the wind.

An instrument used to reveal but not necessarily measure the presence of an electrical quantity. It is used to display the output of a sensing element after suitable amplification and modification. Sometimes called display.

The depth of water that would result from the melting of snow or ice, assuming measurement on a horizontal surface and no infiltration or evaporation.

A self-recording thermometer.

A plastic molding component formed by the reaction of phenol and formaldehyde. It can be heavily reinforced or "filled" with glass fibers or other materials. Phenolics are known for their high impact strength, excellent wear characteristics, and dimension ...

The ratio of the output of an instrument to the input value, i.e. a rain gauge with a sensitivity of 1 tip per 0.01"

The measuring, transmitting, receiving, and indicating apparatus for obtaining the value of a quantity at a distance.

The officially designated elevation of an airport above mean sea level, taken as the highest point on any of the runways of the airport. Same as airport elevation.

The depth below which the ground is saturated with water. No water table exists if the ground water is confined by an overlying impermeable stratum, as in the case of artesian ground water.

A type of instrument shelter. It is a wooden box painted white with double louvered sides and mounted on a stand four feet above the ground.

A refraction phenomenon similar to a parahelion, but occurring generally at a distance of 120

A temperature-sensing element which converts thermal energy directly into electrical energy. In its basic form it consists of two dissimilar metallic conductors connected in a closed loop. Each junction forms a thermocouple. If one thermocouple is maintai ...

Same as instrument shelter.

Wind with a speed between 22 and 27 knots (25 and 31 mph); Beaufort scale number 6.

The water volume within a specified portion of a stream channel.