A liquid-in-glass or liquid-in-metal thermometer using mercury as the liquid.

An instrument that shows changes in humidity.

A coating of ice, generally clear and smooth. formed by the freezing of supercooled water on a surface.

Facing away from the wind.

See standard atmosphere.

The distance that an observer can see vertically into a surface-based obscuring phenomenon such as fog, rain, or snow. The distance estimate must be based upon ceiling balloon ascensions or ceiling light projector measurements.

The water volume within a specified portion of a stream channel.

Occupational Safety and Health Administration. A regulatory office of the U.S. Department of Labor.

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

Emission or transfer of energy in the form of electromagnetic waves or particles.

Random Access Memory. The memory of a computer which can be read and written into at any location without passing through preceding locations.

That part of an audio-modulated radiosonde consisting of the baroswitch, the sensing elements, the reference elements, and the relay.

In nautical terminology, a contraction for "weather glass" (a mercury barometer).

The transmission of data collected at a remote location over communications channels to a central station.

An instrument used to measure and record earthquake vibrations and other earth tremors.

Same as dropsonde.

A type of photoelectric photometer used to measure high-altitude winds on the assumption that stellar scintillation is caused by atmospheric inhomogeneities being carried along by wind near the tropopause level.

Routine broadcast of meteorological information for aircraft in flight.

The lowest level at which the wind becomes geostrophic in the theory of the Ekman spiral. Also called gradient wind level.

The process by which small particles suspended in a medium of a different refractive index diffuse a portion of the incident radiation in all directions. In scattering no energy transformation results, only a change in the spatial distribution of the radi ...