Central Processing Unit. The part of a computer which controls and directs all functions.

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

The general term for dry atmospheric suspensoids, including dust, haze, smoke. and sand. Compare to hydrometeor.

A type of rain gauge shield consisting of freely hanging, evenly spaced slats arranged circularly around the gauge. The advantage of this shield is that the slats do not easily accumulate snow, permitting its use on unattended gauges. See rain gauge shiel ...

A cover which fits over a large inflated balloon to facilitate handling in high or gusty winds.

Board that holds graph paper on which is plotted information obtained from a pilot-balloon observation.

Programmable Read-Only Memory. Read-only memory which can be programmed by the user using a special hardware programmer.

A type of modulation in which the frequency of a continuous radio carrier wave is varied in accordance with the properties of a second (modulating) wave.

A barometer which measures atmospheric pressure using one or a series of aneroid capsules. Also called holosteric barometer.

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

The portion of the precipitation on the land which ultimately reaches the streams. especially the water from rain or melted snow that flows over the surface.

In a radiosonde observation, a level (other than a standard level) for which values of pressure, temperature, and humidity are reported because temperature and/or humidity data at that level is sufficiently important or unusual to warrant the attention of ...

The process by which events in the real world are translated into machine-readable signals.

Name applied to a class of instruments which measure the liquid content of the atmosphere.

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

A unit of pressure which directly expresses the force exerted by the atmosphere. Equal to 1000 dynes/cm2 or 100 pascals.

Same as aneroid barometer. Holostelic means wholly made of solids, while aneroid means devoid of liquid.

The temperature to which a sample of air must be cooled, while the mixing ratio and barometric pressure remain constant, in order to attain saturation by water vapor. When this temperature is below O

A nephoscope in which the motion of the cloud is observed by its reflection in a mirror.

A graphical representation of a frequency distribution. The range of the variable is divided into class intervals for which the frequency of occurrence is represented by a rectangular column. The height of the column is proportional to the frequency of ob ...