An instrument which measures the transmissivity of the atmosphere between two points for the determination of visual range.

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

A semiconductor which exhibits rapid and extremely large changes in resistance for relatively small changes in temperature.

The distance that an observer can see vertically into a surface-based obscuring phenomenon such as fog, rain, or snow. The distance estimate must be based upon ceiling balloon ascensions or ceiling light projector measurements.

A medium-sized instrument shelter. It is a white louvered box with a flat double to of and is mounted four feet above the ground on a four-legged stand.

The lowest value of a measured quality at which a sensor meets its accuracy specification.

A scale of yellows, greens, and blues for recording the color of sea water, as seen against the white background of a Secchi disk.

A basic equation in night visual range theory, relating the illuminance of a point source of light to distance and the transmissivity of the atmosphere.

A unit of power equal to one joule per second or 10' ergs per second.

General name for an instrument designed to measure the vertical component of the wind speed. See anemoclinometer.

Same as marine rainbow.

Wind with a speed between 22 and 27 knots (25 and 31 mph); Beaufort scale number 6.

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

Instrument for measuring the mean intensity of glo global solar radiation (direct and diffuse) near the earth's surface in a specified time interval.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

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

A line drawn through points of equal humidity on given surface.

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

The energy of any type of electromagnetic radiation. Also called radiation.

Defect in the action of an aneroid barometer resulting in a sluggish adjustment of the index toward the correct reading when the barometer is subjected to a large and rapid change in pressure.