A hygrometer using goldbeater's skin as the sensitive element. Variations of the physical dimensions of the skin caused by its hygroscopic character indicate relative humidity. (Note: Goldbeater's skin is the prepared outside membrane of the large intesti ...

The number of cycles per second between the limits of a frequency band.

An instrument which measures evaporation by measuring the loss of water from a burette reservoir through a ceramic disc.

The amount of precipitation captured by a rain gauge.

Very generally, any moving- stream of air. It has no particular technical connotation.

A measure of the relative power, or of the relative values of two flux densities, especially of sound intensities and radar power densities. The decibel is derived from the less frequently used unit, the bel, named in honor of Alexander Graham Bell.

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

A wind blowing in the same direction as the heading of a moving object. thus assisting the object's intended progress. The opposite of a head wind.

An up slope wind due to local surface heating. Opposite of katabatic wind.

An automatic, recording cloud height indicator.

A small anemometer with flat vanes which indicates the number of linear feet or meters of air which have passed the instrument during its exposure.

Old snow that has become granular and compacted as a result of melting and refreezing.

Pertaining to measurements or devices in which the output varies continuously, i.e. voltage or rotation signals. Compare to digital.

The height at which the maximum wind speed occurs, determined in a winds-aloft observation.

See aneroid capsule.

Instrument for measuring the depth to which the soil is frozen.

A device for obtaining a continuous record of stage at a point on a stream. The most common recorders consist of a float-actuated pen which traces a record on a clock driven chart.

The pressure exerted by the atmosphere as a consequence of gravitational attraction exerted upon the "column" of air lying directly above the point in question.

An ice coating with a consistency intermediate between glaze and rime.

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