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 ...

The total of all deviations of a transducer's output from a specified straight line in a constant environment.

See radiation shield.

A vector term which includes both wind speed and wind direction.

A nephoscope in which the motion of the cloud is observed by its reflection in a mirror.

The value of the quantity measured, as indicated or otherwise provided by a measuring instrument.

Board that holds graph paper on which is plotted information obtained from a pilot-balloon observation.

A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates. Usually has a very slight downward motion and may fall from a cloudless sky.

A self-recording instrument used on aircraft for the simultaneous recording of atmospheric pressure, temperature, and humidity.

A device for computing certain psychrometric data, usually the dew point and the relative humidity, from known values of the dry-bulb and wet-bulb temperatures and the atmospheric pressure. One type is the circular slide-rule form and, like the psychromet ...

The range of operating conditions within which a device is designed to operate and for which operating influences are stated. See operating conditions, reference operating conditions.

A balloon having a detachable tail which is released when the balloon has undergone a predetermined expansion. It thus serves to measure approximately the density of the atmosphere at the point of release.

Force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

Same as pitot tube.

A measure of the relative power, or of the relative values of two flux densities, especially of sound intensities and radar power densities. The decibel is derived from the less frequently used unit, the bel, named in honor of Alexander Graham Bell.

Solar radiation scattered by particles in the atmosphere.

Rate of flow of water past a point in a stream, expressed as volume per unit time, i.e. cubic feet per second.

Same as parhelion.

Physical equipment used in data processing. Compare to firmware, software.

A method of winds aloft observation in which the elevation and azimuth angles of a theodolite are read while visually tracking a pilot balloon. Balloon height data is estimated from assumed balloon ascension rates.