An instrument for taking photographs of an image of the sun in monochromatic light.

A fixed-length group of bits representing the large data element handled as a unit by a computer. Word length is determined by the capacity of the CPU registers.

An instrument used to measure the water vapor content of the air.

A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates. Usually has a very slight downward motion and may fall from a cloudless sky.

Temperature assumed by an unsaturated air parcel when brought adiabatically to a standard pressure (1,000 mb).

An instrument used to measure changes in the level of the water in an evaporation pan. The gauge is normally placed in a Stillwell and adjusted so that the point of the hook just breaks the water surface. The change in water level is read on the attached ...

Particle on which the freezing of water occurs.

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

A hygrometer using goldbeater's skin as the sensitive element. Variations of the physical dimensions of the skin caused by its hygroscopic character indicate relative humidity. (Note: Goldbeater's skin is the prepared outside membrane of the large intesti ...

An instrument, for the recording of two or more meteorological parameters, in which the ventilation is provided by a suction fan.

Frequency Shift Keying. A form of frequency modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

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

A wave resulting from the action of wind on a water surface.

Same as river gauge.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

A series of Nansen-bottle water samples and associated temperature observations resulting from one release of a messenger.

Downward scattered and reflected solar radiation, coming from the whole hemisphere with the exception of the solid angle of the sun's disc on a surface perpendicular to the axis of this cone.

A mercury barometer arranged so that the position of the upper or lower meniscus may be measured photographically. In one design the image of the meniscus is formed on a rotating drum covered with sensitized paper so that a continuous record of pressure a ...

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.