ceilometer

/see lom"i teuhr, si-/, n.
an automatic device for measuring and recording the height of clouds by projecting a modulated beam of light onto a cloud base, receiving the reflection of light through a photoelectric apparatus, and computing the height by triangulation.
[1940-45; CEIL(ING) + -O- + -METER]

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▪ measurement instrument
 device for measuring the height of cloud bases. One important use of the ceilometer is to determine cloud ceilings at airports. The device works day or night by shining an intense beam of light (often ultraviolet), modulated at an audio frequency, at overhead clouds. Reflections of this light from the base of the clouds are detected by a photocell in the receiver of the ceilometer.

      There are two basic types of ceilometers: the scanning receiver and the rotating transmitter. The scanning-receiver ceilometer has its separate light transmitter fixed to direct its beam vertically. The receiver is stationed a known distance away. The parabolic collector of the receiver continuously scans up and down the vertical beam, searching for the point where the light intersects a cloud base. When a reflection is detected, the ceilometer measures the vertical angle to the spot; a simple trigonometric calculation then yields the height of the cloud ceiling.

      The rotating-transmitter ceilometer has its separate receiver fixed to direct reflections only from directly overhead while the transmitter sweeps the sky. When the modulated beam intersects a cloud base directly over the receiver, light is reflected downward and detected.

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Universalium. 2010.

Look at other dictionaries:

  • Ceilometer — Der Laser Wolkenhöhenmesser, auch Laser Ceilograph (ceiling = Wolkenuntergrenze), misst die Laufzeit eines vom Boden senkrecht nach oben ausgesandten Lichtpuls eines Lasers zur Wolkendecke und zurück. Aus der Laufzeit und der Lichtgeschwindigkeit …   Deutsch Wikipedia

  • Ceilometer —   [silo...; zu englisch ceiling »Wolkenhöhe«] das, s/ , Gerät zur Messung und Registrierung von Wolkenhöhen durch Bestimmung der Laufzeit eines an der Wolkenbasis reflektierten Licht oder Radarimpulses. * * * Cei|lo|me|ter [tsailo...] …   Universal-Lexikon

  • ceilometer — ☆ ceilometer [sē läm′ət ər ] n. [< CEILING + O + METER] an automatic device used to determine the height of a cloud ceiling, as by means of a reflected light beam …   English World dictionary

  • Ceilometer — A ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere.Optical Drum Ceilometer* An optical drum ceilometer… …   Wikipedia

  • ceilometer — An instrument to measure the heights of clouds during the day. The ceilometer beams a light at the cloud base, which it detects by a photoelectric cell. A process of triangulation then determines the height of the cloud. Cloud ceilometer …   Aviation dictionary

  • ceilometer — noun Etymology: ceiling + o + meter Date: 1943 a photoelectric instrument for determining by triangulation the height of the cloud ceiling above the earth …   New Collegiate Dictionary

  • ceilometer — noun A device that measures the altitude of the cloud base, especially above an airfield …   Wiktionary

  • Ceilometer — Cei|lo|me|ter [ts...] das; s, <zu engl. ceiling »Wolkenhöhe« u. 1↑...meter> Wolkenhöhenmesser …   Das große Fremdwörterbuch

  • ceilometer — instrument for measuring height of cloud ceiling above earth Scientific Instruments …   Phrontistery dictionary

  • ceilometer — ceil·om·e·ter …   English syllables

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