An instrument for measuring the extinction coefficient in water.

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.

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 ...

An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

A hydrometeor consisting of a visible aggregate of minute water droplets suspended in the atmosphere near the earth's surface. Fog differs from cloud only in that the base of fog is at the earth's surface while clouds are above the surface.

The visibility along an identified runway, determined from a specified point on the runway with the observer facing in the same direction as a pilot using the runway. Compare to runway visible range.

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

Same as rain-intensity gauge.

A unit of energy defined as the heat required to raise the temperature of one pound of water one degree Fahrenheit. It is equal to 252.1 calories or to 1055 joules.

Liquid water at temperatures colder than freezing.

National Centers for Environmental Prediction. Central computer and communications facility of the National Weather Service; located in Washington, DC.

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

The statement that the viscosity of air is independent of the density of air.

The water portion of the earth as distinguished from the solid part, called the lithosphere, and from the gaseous outer envelope, called the atmosphere.

Any sudden and heavy rain, almost always of the shower type.

Particle on which the freezing of water occurs.

Same as geostrophic wind level.

Growth of a cloud or precipitation particle by the collision and union of a frozen particle with a super-cooled water drop.

Name sometimes used in place of pyranometer as a generic term.

Binary Coded Decimal. A coding system in which each decimal digit from 0 to 9 is represented by a 4-digit binary number.