A instrument designed to study small fluctuations of some quantity. The microbarograph is an example of a recording pressure variometer.

Automated Local Evaluation in Real Time. Network of automatic rain gauges that transmit via VHF radio link when precipitation occurs. Some sites are also equipped with other sensors such as temperature, wind, pressure, river stage or tide level. More info ...

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

Abbreviation for visual flight rules, but commonly used to refer to the relatively favorable weather and/or flight conditions to which these rules apply.

An instrument, located at the surface observing station, which is used to record the data presented by a radiosonde aloft.

Wind with a speed between 48 and 55 knots (55 and 63 mph), Beaufort scale number 10.

The size of the area comprising a watershed or river basin. Also called catchment area.

A graphical representation of stage or discharge at a point on a stream as a function of time.

An instrument for the measurement of the rate of ice accretion on an unheated body.

Solar radiation scattered by particles in the atmosphere.

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

A set of electrical conductors, often on a backplane, that carry data and power signals among the various components of a computer.

A halo phenomenon consisting of a horizontal circle passing through the moon, corresponding to the parhelic circle through the sun. Produced by reflection of moonlight from ice crystals.

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.

Snow shower, particularly of a very light and brief nature.

Same as ombrometer.

A general term for instruments designed to measure the amount of cloudiness.

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.

An addition to a rawinsonde system which allows determination of the slant range to the radiosonde.

A balloon designed to float at a constant pressure level. This may be accomplished by a pressure valve which controls the release of ballast so as to maintain flight above a selected pressure level until the supply of ballast is exhausted. See Moby Dick b ...