The pressure unit of the meter-ton-second system of physical units. equal to 10 millibars or 101 dynes per cm2.

A description or explanation of the manner in which the height of the ceiling is determined, i.e. aircraft ceiling, balloon ceiling. estimated ceiling, indefinite ceiling, measured ceiling, precipitation ceiling.

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

The limiting values of ceiling, visibility, and wind, or runway visual range, established as safety minimum for aircraft landings and take-offs.

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.

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

See Koschmieder's law.

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

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

See aneroid capsule.

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

The amount of precipitation captured by a rain gauge.

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

See bimetallic thermometer.

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.

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 automatic, recording cloud height indicator.

A mercury barometer in which the lower mercury surface is larger in area than the upper surface. The basic construction of a cistern barometer is as follows: A glass tube one meter in length, sealed at one end is filled with mercury, and then inverted. Th ...

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