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

In folklore, a name for wind.

A type of hygrometer which measures the water vapor content of the atmosphere by means of the absorption of vapor by a hygroscopic chemical.

Any twelve-month period, usually selected to begin and end during a relative dry season. Used a basis for processing streamflow and other hydrologic data. The period from October 1 to September 30 is widely used in the U.S.

An old nautical term for mercury barometer.

An instrument whose calibration can be determined by means of simple physical measurements on the instrument. Compare to secondary instrument.

A line drawn through geographical points having the same duration of sunshine (or other function of solar radiation) during a given interval of time.

A faintly-colored circular arc similar to a rainbow but formed on fog layers containing drops whose diameters are 100 microns or less. Also called mistbow, white rainbow.

A device for measuring the height of tide. It may be simply a graduated staff in a sheltered location where visual observations can be made, or it may consist of an elaborate recording instrument (sometimes called a marigraph) making a continuous graphic ...

A recording variometer.

A common type of terrestrial scintillation; shimmering over a hot surface (such as a roadway) on a quiet, cloudless. summer day.

Frequency Shift Keying. A form of frequency modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

A subtle, diumal component of the wind velocity leading to a diumal shift of the wind or turning of the wind with the sun, produced bv the east-to-west progression of daytime surface heating.

Readily taking up and retaining moisture.

A device used to switch electrical current at a selectable setpoint temperature.

The distance or length of flow of the air past a point during a given interval of time.

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

A series of Nansen-bottle water samples and associated temperature observations resulting from one release of a messenger.

A small, moveable graduated scale adjacent and parallel to the main scale of an instrument. It provides a means for interpolating between the graduations of the main scale.

Wind with a speed between 28 and 33 knots (32 and 38 mph); Beaufort scale number 7.