A common unit used in measurement of atmospheric pressure. Defined as that pressure exerted by a one-inch column of mercury at standard gravity and a temperature of 0'C.

An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves.

The distance or length of flow of the air past a point during a given interval of time.

A thermometer with a muslin-covered bulb which is moistened. used to measure wet-bulb temperature.

A cup anemometer with its shaft mechanically coupled to a magneto.

Upwarddirected solar radiation, reflected by the earth's surface and the atmosphere.

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

Generic term for rapid variations in apparent position, brightness, or color of a distant luminous. object viewed through the atmosphere.

A special type of radar target, usually a comer reflector, tied beneath a free balloon and designed to be an efficient reflector of radio energy.

Sir Napier Shaw's name for the approximate absolute temperature scale,

A device, similar to a potometer, for measuring transpiration, consisting of a vessel containing soil in which one or more plants are rooted and sealed so that water can escape only by transpiration from the plant.

An instrument used for the determination of the electrical conductivity of the atmosphere.

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 ...

Apparatus consisting of (a) standard radiosonde and radiosonde ground equipment to obtain upper-air data on pressure, temperature, and humidity, and (b) a self-tracking radio direction-finder to provide the elevation and azimuth angles of the radiosonde s ...

Not a linear function of the relevant variables.

A liquid-in-glass or liquid-in-metal thermometer using mercury as the liquid.

Random Access Memory. The memory of a computer which can be read and written into at any location without passing through preceding locations.

A thermometer which uses a transducing element whose element proper-ties are a function of its thermal state. Common meteorological examples of such thermometers are the resistance thermometer and the thermoelectric thermometer.

A power supply which achieves its output regulation by means of one or more active power handling devices which are alternately placed in the "off" or "on" states. It is more efficient than linear supplies which vary the conduction of power devices to ach ...

A conductor or system of conductors for radiating and/or receiving radio energy. Also called aerial.