A small balloon, loaded with ballast and inflated so that it will explode at a predetermined altitude, which is attached to a larger balloon.

A point (or line) on a scale used for reference or comparison purposes. In calibration of meteorological thermometers, for example, the fiducial points are 100

That part of snow melt that reaches stream channels as runoff.

Name sometimes given to a transmissometer.

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

Generally, a measure of the departure of the mean daily temperature from a given standard, one degree day for each degree (

The record of an aneroid barograph.

The effect upon the measurement of rainfall caused by the presence of the rain gauge.

The inaccuracy that the manufacturer permits when the unit is calibrated in the factory.

A rain gauge which is placed under trees or foliage to determine the rainfall in that location. By comparing this catch with that from a rain gauge set in the open. the amount of rainfall which has been intercepted by foliage can be determined.

A refraction phenomenon similar to a parahelion, but occurring generally at a distance of 120

Difference between the instantaneous wind velocity at a point and the mean wind velocity taken over a given time interval. Also called fluctuation velocity.

A large plastic constant-level balloon for duration flying at very high altitudes.

A set of electrical conductors, often on a backplane, that carry data and power signals among the various components of a computer.

A feeble oscillatory disturbance of the earth's crust, detectable only by very sensitive seismographs. Certain types of microseisms seem to be closely correlated with pressure disturbances. See microbarm.

Not a linear function of the relevant variables.

The process whereby a position on the scale of an instrument is identified with the magnitude of the signal (or input force) actuating the instrument.

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

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

Physical equipment used in data processing. Compare to firmware, software.