A rain gauge or array of rain gauges designed to measure the inclination and direction of falling rain.

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

In meteorology, a deflecting force acting on a body in motion and resulting from the earth's rotation. It deflects air currents to the right in the northern hemisphere and to the left in the southern hemisphere, thus having an effect on wind direction.

A hygrometer which uses a transducing element whose electrical properties are a function of atmospheric water vapor content. The humidity strip and carbon-film hygrometer element are examples of such a transducer.

Any quantity, such as force velocity, or acceleration, which has both magnitude and direction at each point in space, as opposed to scalar which has magnitude only. Such a quantity may be represented geometrically by an arrow of length proportional to its ...

An evaluation, according to set procedures, of those weather elements which are most important for aircraft operations. Always includes cloud height or vertical visibility, sky cover, visibility, obstructions to vision, certain atmospheric phenomena, and ...

An absolute pyhrliometer, developed by C.G. Abbott, in which the radiation-sensing element is a blackened water-calorimeter.

The true freezing point of water. The temperature at which a mixture of air-saturated pure water and pure ice may exist in equilibrium at a pressure of one standard atmosphere.

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

Temperature of equilibrium between the liquid and vapor phases of a substance at a given pressure.

See evaporation pan.

A general name for instruments which detect the presence of (but do not necessarily measure) small electrical charges by electrostatic means. Compare to electrometer.

Situated on the side from which the wind blows.

The maximum distance along the runway at which the runway lights are visible to a pilot at touchdown. Runway visual range may be determined by an observer located at the end of the runway, facing in the direction of landing, or by means of a transmissomet ...

National Weather Service. Administered by the U.S. Department of Commerce.

Any one of numerous devices for the measurement of either speed alone or of both direction and speed (set and drift) in flowing water.

Ragged low clouds, usually stratus fractus. Most often applied when such clouds are moving rapidly beneath a layer of nimbostratus.

The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

The unit of force in the centimeter-gram-second system of physical units, i.e. one gm cm per sec2, equal to 7.233 x 10-5 poundal.

A measure of the attenuation due to scattering, of light as it traverses a medium containing scattering particles.