Programs or instructions which are stored in readonly memory.

An evaluation of upper air temperature, pressure, and humidity from radio signals received from a balloon- borne radiosonde.

A systematic observational error due to the characteristics of the observer. The uncertainty in a reading made by an observer may be acertained by a statistical analysis of his or her readings.

The addition of one or more redundant bits to information to verify its accuracy.

A rainbow formed by light rays which have been reflected from an extended water surface. Not to be confused with a reflected rainbow whose image may be seen in a still body of water. The center of a reflection rainbow is at the same elevation as the sun b ...

Small particle on which water vapor condenses.

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

An instrument for measuring radiant energy. See actinometer, Dines radiometer, photometer, Tulipian radiometer.

A photometric unit of illuminance or illumination equal to one lumen per square meter

An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

An instrument for measuring the extinction coefficient in water.

National Centers for Environmental Prediction. Central computer and communications facility of the National Weather Service; located in Washington, DC.

Abbreviation for mean sea level.

Navy Operational Global Atmospheric Prediction System. A global meteorological model operated by the Department of Defense.

Same as wave pole.

A semiconductor which exhibits rapid and extremely large changes in resistance for relatively small changes in temperature.

A transducer for converting thermal energy directly into electrical energy. It is composed of pairs of thermocouples which are connected either in series or in parallel. Thermopiles are used in thermoelectric radiation instruments when the output of a sin ...

A measure of the intensity of gusts given by the ratio of the total range of wind speed between gusts and the intermediate periods of lighter wind to the mean wind speed, averaged over both gusts and lulls.

Having a specific relationship to a time base or clock. In synchronous communications, data characters are sent according to a timing signal which synchronizes the two communicating devices.

A device used on certain types of instruments to prevent unwanted radiation from affecting the measurement of a quantity. Also called solar radiation shield.