Infrared radiation emitted by or being propagated through the atmosphere.

Same as atmometer.

An instrument for the measurement of the rate of ice accretion on an unheated body.

A measure, proposed by Angstrom, of the precipitation effectiveness of a region.

Name sometimes used in place of pyranometer as a generic term.

In aviation terminology, route or terminal weather conditions of sufficiently low visibility to require the operation of aircraft under instrument flight rules.

Same as Aeolian.

A system of estimating and reporting wind speed, originally based on the effect of various wind speeds on the amount of canvas that a full-rigged nineteenth century frigate could carry.

Any twelve-month period, usually selected to begin and end during a relative dry season. Used a basis for processing streamflow and other hydrologic data. The period from October 1 to September 30 is widely used in the U.S.

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

Instrument for measuring the depth to which the soil is frozen.

A sudden brief increase in the speed of the wind, followed by a lull or slackening. Compare to peak gust.

Same as parhelion.

The rate of decrease of pressure per unit distance at a fixed time.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

A recording hair hygrometer.

The physical exposure of an instrument. The effect of immediate environment upon the representativeness of the measurements obtained by meteorological instruments is considerable and not always correctable. The purpose of the instrument shelter is to prov ...

A nephoscope in which the motion of the cloud is observed by its reflection in a mirror.

Sustained winds greater than or equal to 40 mph or gust greater than or equal to 58 mph.

Anemometer which measures wind speed by measuring the degree of cooling of a metal film heated by an electric current. A type of cooling-power anemometer.