An instrument of the aspiration condenser type which measures the concentration and mobility of small ions.

Anemometer which measures wind speed by the speed of rotation of 3 or 4 hemispherical or conical cups, each fixed to the end of a horizontal arm projecting from a vertical axis. See condenser-discharge anemometer, contact anemometer. Compare to bridled-cu ...

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

Cathode Ray Tube. A display element, consisting of a vacuum tube and screen, used with computers.

A recording variometer.

A system of physical units based on the use of the centimeter, gram. and the second as elementary quantities of length. mass. and time.

An optical instrument which consists of a sighting telescope mounted so that it is free to rotate around horizontal and vertical axes, with graduated scales so that the angles of rotation may be measured. Used to observe the motion of a pilot balloon.

Reduction of visibility by strong winds blowing across dry ground with little or no vegetation. Visibilities of 1/8 mile or less over a widespread area are criteria for a Blowing Dust Advisory.

Readily taking up and retaining moisture.

The effect upon the measurement of rainfall caused by the presence of the rain gauge.

The maximum distance along the runway at which the runway lights are visible to a pilot at touchdown. Runway visual range may be determined by an observer located at the end of the runway, facing in the direction of landing, or by means of a transmissomet ...

The correction applied to an instrument to account for the effect of temperature upon its response characteristics.

A balloon designed to float at a constant pressure level. This may be accomplished by a pressure valve which controls the release of ballast so as to maintain flight above a selected pressure level until the supply of ballast is exhausted. See Moby Dick b ...

Temperature of equilibrium between the liquid and vapor phases of a substance at a given pressure.

A Sunshine recorder of the type in which the time scale is supplied by the motion of the sun. The instrument, which is pointed at the celestial pole, consists of a hemispherical mirror mounted externally on the optical axis of a camera. The lens of the ca ...

Instrument for measuring the intensity of radiant energy. Its principle is based on the variation of electrical resistance, with the incoming radiation, of one or both the metallic strips which the instrument comprises.

A radar term for a single pulse of radio energy.

A relatively small-scale, upward moving current of air.

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

A thin metal disc partially evacuated of air used to measure atmospheric pressure by measuring its expansion and contraction.