A rotation anemometer which has a horizontal axis upon which helicoidal shaped vanes are mounted. See windmill anemometer.

A rainbow of angular radius of about 50

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

See hook gauge.

An anemometer which measures wind speed by means of the properties of wind-borne sound waves. It operates on the principle that the propagation velocity of a sound wave in a moving medium is equal to the velocity of sound with respect to the medium plus t ...

A clockwise change in wind direction. Veering winds with height are indicative of warm air advection (WAA).

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

A clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

A type of electrical thermometer consisting of two thermocouples which are series-connected with a potentiometer and a constant-temperature bath. One couple, called the reference junction, is placed in a constant-temperature bath, while the other is used ...

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 type of pressure-tube anemometer, named after the inventor.

Same as luminous intensity.

The processing of the form or mode of a signal so as to make it intelligible to, or compatible with, a given device.

The mean difference between the readings of a given instrument and those of a standard instrument.

A severe weather condition characterized by low temperatures and strong winds bearing a great amount of snow, either falling or picked up from the ground.

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

A rain gauge which indicates but does not record the amount of precipitation captured.

Same as balloon cover.

A device used to switch electrical current at a selectable setpoint temperature.

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.