Programs or instructions which are stored in readonly memory.

The maximum positive and negative deviation observed in testing a device under specified conditions and by a specified procedure. It is usually measured as an inaccuracy and expressed as accuracy, typically in terms of the measured variable, percent of sp ...

A type of electrical thermometer consisting of two thermocouples which are series-connected with a potentiometer and a constant-temperature bath. One couple, called the reference junction, is placed in a constant-temperature bath, while the other is used ...

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

Same as humidity strip.

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 ...

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.

Same as wave pole.

Barometer in which pressure is determined by balancing air pressure against the weight of a column of mercury in an evacuated glass tube.

A device which automatically records the water equivalent of snow on a given surface as a function of time. A small sample of a radioactive salt is placed in the ground in a shielded collimator which directs a beam of radioactive particles upwards. A Geig ...

An instrument for measuring the extinction coefficient in water.

Small particle on which water vapor condenses.

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

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

An instrument which measures the spectral distribution of the intensity of direct solar radiation.

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

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.

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

A rainbow of angular radius of about 50

A pyranometer developed by M. Robitzsch. Its design utilizes three bimetallic strips which are exposed horizontally at the center of a hemispherical glass bowl. The outer strips are white reflectors and the center strip is a blackened absorber. The bimeta ...