Same as freezing point.

A colloquial term in western Australia for a squall, associated with thunder, on the northwest coast in summer.

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.

A unit of energy equal to 101 ergs or to 0.2389 calories.

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

Infrared radiation emitted by or being propagated through the atmosphere.

General term for an instrument which records the vertical electric current in the atmosphere.

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

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 ...

A temperature scale with the ice point at 273 degrees and boiling point of water at 373 degrees. It is intended to approximate the Kelvin temperature scale with sufficient accuracy for many sciences, notably meteorology.

See evaporation pan.

Name sometimes given to a transmissometer.

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 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.

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.

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

The ratio of the amount of electromagnetic radiation reflected by a body to the amount incipient upon it, commonly expressed as a percentage. The albedo is to be distinguished from the reflectivity, which refers to one specific wavelength.

Interational thermometric scale on which the freezing point of water equals 0

Turbulence encountered by aircraft when flying through air space devoid of clouds. Thermals and wind shear are the main causes.

A thermoelectric thermometer used for measuring air temperature. The name is derived from the fact that the reference thermocouple is placed in an insulated bottle.