See standard atmosphere.

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

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.

Facing away from the wind.

An instrument that shows changes in humidity.

The change in the measured transducer output caused by changes in ambient temperature. Usually expressed a percentage of full scale.

A special type of radar target, usually a comer reflector, tied beneath a free balloon and designed to be an efficient reflector of radio energy.

The array of indicating marks and figure in relation to which the position of an index is observed, i.e. a scale plate on a recorder.

Same as dropsonde.

Routine broadcast of meteorological information for aircraft in flight.

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

Not a linear function of the relevant variables.

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

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.

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 ...

A power supply which achieves its output regulation by means of one or more active power handling devices which are alternately placed in the "off" or "on" states. It is more efficient than linear supplies which vary the conduction of power devices to ach ...

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

Any meteorological instrument, such as a radiosonde, in which the recording apparatus is located at some distance from the measuring apparatus.

Apparatus consisting of (a) standard radiosonde and radiosonde ground equipment to obtain upper-air data on pressure, temperature, and humidity, and (b) a self-tracking radio direction-finder to provide the elevation and azimuth angles of the radiosonde s ...

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