An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

Operation mode of a communication circuit in which each end can transmit and receive, but not simultaneously.

A device attached to a meteorological instrument to provide ventilation; usually a suction fan.

Transmitted energy which is modulated in order to carry information. Usually, it is in the form of a radio- frequency sine wave, modulated either in amplitude or in frequency.

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.

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

Thermometer used for measuring the highest temperature attained during a given interval of time, for example, a day.

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

A modification of the dew cell used in radiosonde equipment.

Same as instrument shelter.

A method of streamflow routing which assumes that storage is a linear function of the weighted flow in the reach and is adaptable to a simple mathematical solution.

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

The quantity to be measured (or modulated, or detected, or operated upon) which is received by an instrument. Thus, for a thermometer. temperature is the input quantity.

The change in the measured transducer output caused by changes in ambient temperature. Usually expressed a percentage of full scale.

A cone-tipped metal rod designed to be driven downward into deposited snow or firn. The measured amount of force required to drive the rod a given distance is an indication of the physical properties of the snow or firn.

A generic term for any machine that enables a human being to communicate with a computer.

An instrument for the measurement of the radon content of the atmosphere.

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 ...

An instrument which automatically determines the size distribution of raindrops.

The average temperature of the air as indicated by a properly exposed thermometer for a given time period, usually a day, a month, or a year.