An empirical curve relating stream discharge or stage at a point on a stream to discharge or stage at one or more upstream points and, possibly. to other parameters. Also called stage relation.

A relatively small-scale, downward moving current of air.

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

A thermopile used in some types of radiation instruments. See solarimeter.

See aneroid capsule.

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 ...

The quantity to be measured (or modulated, or detected, or operated upon) which is received by an instrument. Thus, for a thermometer. temperature is the input quantity.

An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves. T ...

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

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

A combination cup anemometer and pressure-plate anemometer, consisting of an array of cups about a vertical axis of rotation, the free rotation of which is restricted by a suitable spring arrangement.

Wind with a speed between 28 and 55 knots (32 and 63 mph); Beaufort scale numbers 7 through 10.

Same as ombrometer.

Not a linear function of the relevant variables.

The play or loose motion in an instrument due to the clearance existing between mechanically contacting parts.

Any horizontal wind velocity tangent to the contour line of a constant pressure surface (or to the isobar of a geopotential surface) at the point in question.

A thermometer. the sensitive element of which consists of two metal strips which have different coefficients of expansion and are brazed together. The distortions of the system in response to temperature variations are used as a measure of temperature. It ...

A recording hair hygrometer.

The length of fluid flow (gas or liquid) past a sensor required for the sensor to respond to 63.2% of a step change in speed. Expressed in feet or meters. For anemometers, this value is calculated from time constant times wind tunnel speed.

Same as fogbow.