See Koschmieder's law.

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

The amount of precipitation captured by a rain gauge.

An instrument which records the duration of sunshine and gives a quantitative measure of the amount of sunshine by the action of the sun's rays upon blueprint paper. A type of sunshine recorder.

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

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.

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

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

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

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.

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.

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

An automatic, recording cloud height indicator.

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.

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

The indicating part of an instrument. For example, the hand of a watch or the meniscus of a mercury column.

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.