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

See Koschmieder's law.

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.

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

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.

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

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 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.

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.

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

See aneroid capsule.

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

An automatic, recording cloud height indicator.

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

Formation of a single water drop by the union of two or more colliding drops.

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

The height ascribed to the lowest layer of clouds or obscuring phenomena when it is reported as broken, overcast, or obscuration and not classified as "thin" or "partial." The ceiling is termed unlimited when these conditions are not satisfied. ...