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

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

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

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.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

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

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

See Koschmieder's law.

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

The amount of precipitation captured by a rain gauge.

See aneroid capsule.

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.

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

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 ...

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.

See bimetallic thermometer.