A unit of pressure used principally in oceanography. One decibar (10' dynes/cm2) equals 0.1 bar. In the ocean, hydrostatic pressure in decibars very nearly equals the corresponding depth in meters.

Transmitted energy which is modulated in order to carry information. Usually, it is in the form of a radio- frequency sine wave, modulated either in amplitude or in frequency.

A fixed-length group of bits representing the large data element handled as a unit by a computer. Word length is determined by the capacity of the CPU registers.

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.

The group of bits which a computer processes as a unit; often, 8 bits.

A unit of pressure equal to 10' dyne per cm-' (101 barye), 1000 millibars. 29.53 inches of mercury.

Area of a computer or other device where various logic and control elements are interconnected. Often a printed circuit board into which other circuit boards plug at right angles.

Same as luminous intensity.

An instrument which indicates the presence of dust particles in the atmosphere. Also spelled coniscope.

The range through which the input may be varied without initiating a response. Usually expressed as a percentage of full-scale range.

A method of streamflow routing which assumes that storage is a linear function of the weighted flow in the reach and is adaptable to a simple mathematical solution.

A hygrometer in which the sensitive element is a strand or strands of human hair, the length of which is a function of the relative humidity of the air.

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.

A river gauge in which a weight suspended on a wire is lowered to the water surface from a bridge or other overhead structure to measure the distance from a point of known elevation to the water surface.

Same as atmospheric pressure.

A special form of the aspiration psychrometer. developed by Assmann, in which the thermometric elements are well shielded from radiation. Psychrometric measurements may be taken with the instrument in the presence of direct solar radiation.

See river basin.

An instrument for determining the dust content of a sample of air. Also spelled conimeter.

An instrument for rapidly obtaining samples of airborne dust; a type of dust counter. Particles pass through a cylindrical chamber, are drawn at high velocity through a narrow slit, and then impinge upon a microscope cover glass located a short distance f ...

A forecast of weather elements of particular interest to aviation; including ceiling, visibility, upper winds, icing, turbulence, precipitation types, and storms.