A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

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.

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

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.

An instrument for recording global solar radiation.

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.

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

Same as instrument shelter.

An old nautical term for mercury barometer.

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

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.

The atmospheric pressure at mean sea level either directly measured by stations at sea level or empirically determined from the station pressure and temperature by stations not at sea level. Used as a common reference for analyses of surface pressure patt ...

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