An instrument which automatically records the voltage applied to it, as a function of time.

A synoptic code approved by the World Meteorological Organization in which the observable meteorological elements are encoded and transmitted in "words" of five numerical digits length. Often abbreviated synoptic code.

A curve showing the variation of temperature with height in the free air. See lapse rate.

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

The maximum distance, usually horizontally, at which a given object or light source is just visible under particular conditions of transmittance and background luminance.

Same as atmospheric pressure.

A rain gauge which is placed under trees or foliage to determine the rainfall in that location. By comparing this catch with that from a rain gauge set in the open. the amount of rainfall which has been intercepted by foliage can be determined.

An instrument which measures evaporation by measuring the loss of water from a burette reservoir through a ceramic disc.

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

A device that allows a terminal or computer at one location to communicate with a terminal or computer at a distant location via wire or phone lines.

The probability distribution of random errors, typically a normal distribution with a zero mean.

An instrument used for measuring geometric angles. See radio direction-finder.

Dihydrogen oxide, molecular formula H2O.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

In nautical terminology, a contraction for "weather glass" (a mercury barometer).

A device, similar to a phytometer, for measuring transpiration. It consists of a small vessel containing water and sealed so that the only escape of moisture is by transpiration from a leaf, twig, or small plant with its cut end inserted in the water.

Same as instrument shelter.

A system in which radar techniques are used to determine the range, elevation, and azimuth of a radar target carried a!oft by a radiosonde, so that wind data may be obtained along with the other meteorological data.

In meteorology, a deflecting force acting on a body in motion and resulting from the earth's rotation. It deflects air currents to the right in the northern hemisphere and to the left in the southern hemisphere, thus having an effect on wind direction.

A set of regulations set down by the U.S. Civil Aeronautics Board to govern the operational control of aircraft on instrument flight. The abbreviation of this term is seldom used to denote the rules themselves, but is in popular use to describe the weathe ...