Same as instrument shelter.

An instrument used to measure the amount of dew formed on a given surface.

A direct-vision nephoscope which is constructed in the following manner: a comb consisting of a crosspiece containing equispaced vertical rods is attached to one end of a column eight to ten feet long and is supported on a mounting that is free to rotate ...

Same as atmospheric pressure.

February 2nd. In American folklore, a day that is popularly supposed to provide the key to the weather for the remainder of the winter. Specifically, if the ground-hog upon emerging from its hole casts a shadow, it will return underground, thereby forebod ...

A hygrometer which determines the amount of precipitable moisture in a given region of the atmosphere by measuring attenuation of radiant energy caused by the absorption bands of water vapor.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

See radiosonde commutator.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

That portion of the record of a microbarograph between any two (or a specified small number) of successive crossings of the average pressure level (in the same direction). Analogous to microseism.

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 navigational aid used to facilitate the landing of an aircraft at an airport in instrument weather, i.e. low visibility.

The most common of the principal rainbow phenomena, which appears as an arc of about 42

Hygrometer in which the dew (frost) point is determined by observing the temperature of an artificially cooled surface at the moment at which dew (frost) first appears on it.

A hydrometeor consisting of a visible aggregate of minute water droplets suspended in the atmosphere near the earth's surface. Fog differs from cloud only in that the base of fog is at the earth's surface while clouds are above the surface.

As used by the U.S. Army Corps of Engineers, the departure (in

A type of atmometer. It is a pan used in the measurement of the evaporation of water into the atmosphere. The NWS Class A pan is a cylindrical container 48 inches in diameter and 10 inches deep.

A device that combines several separate communications signals into one and outputs them on a single line.

Operation mode of a communication circuit in which one end can only transmit and the other end can only receive.

Liquid water at temperatures colder than freezing.