Generally, an instrument designed to measure or estimate the blueness of the sky. See Linke-scale.

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

Electromagnetic radiation lying within the wavelength interval to which the human eye is sensitive, the spectral interval from approximately 0.4 to 0.7 microns (4000 to 7000 angstroms). Bounded on the short-wavelength end by ultraviolet radiation and on t ...

Name given to the unit of pressure in the International System of Units (SI). Equal to 1 newton/meter2 or 0.01 millibar.

An instrument for recording global solar radiation.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

The level at which ice crystals and snowflakes melt as they descend through the atmosphere.

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

The interval between the lower and upper measuring limits of an instrument, i.e. a thermometer with a range of -35 to 50

Part of a computer word that has meaning in itself, often, a byte.

Same as instrument shelter.

Wind with a speed between 7 and 10 knots (8 and 12 mph), Beaufort scale number 3.

An instrument for measuring the pressure of gases and vapors. A mercury barometer is a type of manometer.

A Sunshine recorder of the type in which the time scale is supplied by the motion of the sun. The instrument, which is pointed at the celestial pole, consists of a hemispherical mirror mounted externally on the optical axis of a camera. The lens of the ca ...

An old nautical term for mercury barometer.

See calorie.

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.

Conditions to which a device is subjected, not including the variable measured by the device. See normal operating conditions, reference operating conditions.

In thermodynamics, the integrating factor of the differential equation referred to as the first law of thermodynamics, In statistical mechanics, a measure of translational molecular kinetic energy (with three degrees of freedom). In general, the degree of ...

Generic term for rapid variations in apparent position, brightness, or color of a distant luminous. object viewed through the atmosphere.