film hygrometer element-An electrical hygrometer element constructed of a plastic strip coated with a film of carbon black dispersed in a hygroscopic binder. Variations in atmospheric moisture content vary the volume of the binder and thus change the resi ...

A standard interface between a computer input/output port and a peripheral device. Signal properties including time duration, voltage. and current, are specified by the Electronic Industries Association.

The water volume within a specified portion of a stream channel.

The atmospheric pressure at mean sea level either directly measured by stations at sea level or empirically determined from the station pressure and temperature by stations not at sea level. Used as a common reference for analyses of surface pressure patt ...

An instrument used for measuring geometric angles. See radio direction-finder.

A line drawn through geographical points having the same pluvial index.

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water in streams, lakes, and on or below the land surface. In terms of the hydrologic cycle, the ...

A radiosonde whose carrier wave is modulated by audio-frequency signals whose frequency is controlled by the sensing elements of the instrument.

See aneroid capsule.

A small pointer extending downward from the top of the cistern of a Fortin barometer. The level of the mercury in the cistern is adjusted so that it just comes in contact with the end of the pointer, thus setting the zero of the barometric scale.

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

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.

Root Mean Square. This notation is used frequently with error analysis. In that context, it is the square root of the arithmetic mean of the squares of the deviations of the individual calibration points from the theoretical or ideal response.

Moisture contained in the soil above the water table, including water vapor which is present in the soil pores. In some cases this term refers strictly to the humidity contained in the root zone of plants.

Readily taking up and retaining moisture.

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.

The atmospheric pressure at the level of the barometer. May or may not be the same as station pressure.

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

See calorie.

The gravity flow of water within soil.