A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

The elevation of the water surface in a stream as measured by a river gauge with reference to some arbitrarily selected zero datum.

A clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

Name sometimes used in place of pyranometer as a generic term.

General name for an instrument which measures the earth's magnetic field intensity.

A term used to describe a sensor (or sensors), the associated transducer(s), and the data readout or recording device.

A cover which fits over a large inflated balloon to facilitate handling in high or gusty winds.

A thermodynamic change of state in a system in which there is no transfer of heat or mass across the boundaries of the system. In an adiabatic process, compression always results in warming, expansion in cooling. Compare to diabatic process.

A hygrometer in which the rotation of the hygrometric element is a function of humidity.

Downward-facing pyranometer used for measuring reflected solar radiation.

Wind with a speed between 17 and 21 knots (19 and 24 mph); Beaufort scale number 5.

Operation mode of a communication circuit in which each end can transmit and receive, but not simultaneously.

The standard deviation (positive square-root of the variation) of the errors associated with physical measurements of an unknown quantity, or statistical estimates of an unknown parameter or of a random variable.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

Same as ombrometer.

A river gauge in which a weight suspended on a wire is lowered to the water surface from a bridge or other overhead structure to measure the distance from a point of known elevation to the water surface.

A sunshine recorder of the type in which the time scale is supplied by the motion of the sun. It consists essentially of a spherical lens which bums an image of the sun upon a specialty prepared card.

In the direction from which the wind is blowing.

The lowest value of a measured quality at which a sensor meets its accuracy specification.

A line drawn through points of equal humidity on given surface.