A unit of luminous flux. The lumen is equal to the luminous flux radiated into a unit solid angle (steradian) from a small source having a luminous intensity of one candle. An ideal source possessing an intensity of one candle in every direction would rad ...

Graduated fixed stake used in regions of abundant snowfall to facilitate the measurement of snow depth.

A thermometer, invented by James Six in 1782, which simultaneously indicates the maximum and minimum temperatures attained during a given interval of time. A U-tube min/max thermometer

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.

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.

The addition of one or more redundant bits to information to verify its accuracy.

A chronograph used to make a time-record of certain measured meteorological elements. The most common type, the triple register, records wind direction and speed, duration of sunshine, and amount of rainfall (sensed respectively by a contact anemometer, M ...

See ceilometer.

See Koschmieder's law.

Similar to the spectroheliograph, but used for visual instead of photographic purposes.

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

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

A form of data transmission in which the bits of each character are sent one at a time along a single communication path. Compare to parallel data transmission.

Same as ceiling light.

An effect noted primarily in wet snow conditions when snow clings to the sides of a precipitation gauge and gradually accumulates until the gauge orifice is capped with accumulated snow. This effect can be minimized by using large collectors, and wind scr ...

The pressure exerted by the atmosphere as a consequence of gravitational attraction exerted upon the "column" of air lying directly above the point in question.

The volume of water required to cover one acre to a depth of one foot: 43,560 cubic feet.

An instrument which measures the effective terrestrial radiation. See Angstrom pyrgeometer.

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

Having a specific relationship to a time base or clock. In synchronous communications, data characters are sent according to a timing signal which synchronizes the two communicating devices.