See mote.

Precipitation composed of white or translucent ice crystals, chiefly in complex branched hexagonal forms.

Radiation with wavelengths greater than 4 microns. (In meteorology, same as infrared radiation.)

(1) The ratio of the speeds of a chemical reaction at two temperatures differing by 10

The general term for anemometers operating on the principle that the heat transfer to air from an object at an elevated temperature is a function of the air speed. Examples are the hot-wire anemometer and the katathermometer.

A barometer which measures atmospheric pressure using one or a series of aneroid capsules. Also called holosteric barometer.

Same as precipitation-evaporation ratio.

A device, similar to a potometer, for measuring transpiration, consisting of a vessel containing soil in which one or more plants are rooted and sealed so that water can escape only by transpiration from the plant.

The range of operating conditions within which a device is designed to operate and for which operating influences are stated. See operating conditions, reference operating conditions.

Any meteorological instrument, such as a radiosonde, in which the recording apparatus is located at some distance from the measuring apparatus.

A photometric unit of illuminance or illumination equal to one lumen per square centimeter.

Apparatus designed to measure the amount of precipitation falling in the form of snow. The device determines the weight of the snow or the volume of water after the snow melts.

The transducer of any hygrometer, i.e. that part of a hygrometer that quantitatively "senses" atmospheric water vapor.

Precipitation composed of balls or irregular lumps of ice with diameters between 5 and 50 mm.

A cover which fits over a large inflated balloon to facilitate handling in high or gusty winds.

An element that can control current without moving parts, heated filaments, or vacuum gaps.

An aneroid barometer arranged so that the deflection of the aneroid capsule actuates a pen which graphs a record on a rotating drum. Sometimes called aneroidograph.

Snow shower, particularly of a very light and brief nature.

A pressure-plate anemometer consisting of a plate which is free to swing about a horizontal axis in its own plane above its center of gravity. The angular deflection of the plate is a function of the wind speed. This instrument is not used for station mea ...

The difference between downward and upward (total) radiation; net flux of all radiation.