A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

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.

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

Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

Any one of six gases, helium, neon, argon, krypton, xenon, and radon, all of whose shells of planetary electrons contain stable numbers of electrons such that the atoms are chemically inactive.

An instrument for recording global solar radiation.

Particle on which the freezing of water occurs.

The combined processes by which water is transferred from the earth's surface to the atmosphere: evaporation of liquid or solid water plus transpiration from plants.

The frequency of a carrier wave.

The state of the atmosphere, mainly with respect to its effects upon life and human activities. As distinguished from climate, weather consists of the short-term (minutes to months) variations of the atmosphere.

The number of cycles per second between the limits of a frequency band.

Integrated Flood Observing and Warning System. National Weather Service flood warning program.

Line drawn through geographical points recording equal amounts of precipitation during a given time period or for a particular storm.

A psychrometer in which the ventilation is provided by a suction fan.

The total area drained by a river and its tributaries. Same as river basin.

Same as freezing point.

Sir Napier Shaw's name for the approximate absolute temperature scale,

An instrument for measuring the extinction coefficient in water.

The total infrared radiation emitted from the earth's surface. To be carefully distinguished from atmospheric radiation, effective terrestrial radiation, and insolation.

See sea-water thermometer, reversing thermometer.