Physical equipment used in data processing. Compare to firmware, software.

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

The greatest distance at which it is just possible to see and recognize with the unaided eye (1) in the daytime, a prominent dark object against the sky at the horizon, and (2) at night, a known, preferably unfocused, moderately intense light source.

The envelope of air surrounding the earth and bound to it more or less permanently by virtue of the earth's gravitational attraction. The system whose chemical Properties. dynamic motions, and physical processes constitute the subject matter of meteorolog ...

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 instrument, for the recording of two or more meteorological parameters, in which the ventilation is provided by a suction fan.

Same as freezing point.

A thin metal disc partially evacuated of air used to measure atmospheric pressure by measuring its expansion and contraction.

A rotation anemometer in which the axis of rotation is horizontal. The instrument has either flat vanes (as in the air meter) or helicoidal vanes (as in the propeller anemometer). The relation between wind speed and angular rotation is almost linear.

Name sometimes given to a transmissometer.

An instrument resulting from the combination of a thermograph and a hygrograph and furnishing, on the same chart, simultaneous time recording of ambient temperature and humidity.

A reflecting type telescope with a 45

A set of electrical conductors, often on a backplane, that carry data and power signals among the various components of a computer.

An instrument used for the measurement of the reflecting, power (the albedo) of a surface. A pyranometer adapted for the measurement of radiation reflected from the earth's surface is sometimes employed as an albedometer.

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 ...

An instrument developed by K. Angstrom for measuring the effective terrestrial radiation. It consists of four manganin strips, of which two are blackened and two are polished. The blackened strips are allowed to radiate to the atmosphere while the polishe ...

The older name for the Celsius temperature scale. Officially abandoned by international agreement in 1948, but still in common use.

The total of all deviations of a transducer's output from a specified straight line in a constant environment.

A combination cup anemometer and pressure-plate anemometer, consisting of an array of cups about a vertical axis of rotation, the free rotation of which is restricted by a suitable spring arrangement.

Wind with a speed between 4 and 6 knots (4 and 7 mph), Beaufort scale number 2.