A buoyant balloon kept from rising freely by means of a line secured to a point on the ground, as opposed to a free balloon. See kytoon.

An instrument that automatically records pressure and temperature.

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

A hypothetical body which absorbs some constant fraction, between zero and one, of all electromagnetic radiation incident upon it, which fraction is the absorptivity and is independent of wavelength. Compare to black body, white body.

The water volume within a specified portion of a stream channel.

See photometer.

A standard interface between a computer input/output port and a peripheral device. Signal properties including time duration, voltage. and current, are specified by the Electronic Industries Association.

The lowest value of a measured quality at which a sensor meets its accuracy specification.

Snow shower, particularly of a very light and brief nature.

The succession of stages through which water passes on the ground and in the atmosphere: evaporation from land or bodies of water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.

The frequency of a carrier wave.

The programs and instructions which direct a computer.

A polariscope consisting of a specially constructed double plate polarizer and a tourmaline plate analyzer. Polarized light passing through the instrument is indicated by the presence of parallel colored fringes, while unpolarized light results in a unifo ...

The portion of the strearnflow during any month or year derived from precipitation in previous months or years.

The distance or length of flow of the air past a point during a given interval of time.

See bimetallic thermometer.

A photoelectric spectrophotometer which is used in the determination of the ozone content of the atmosphere.

The true freezing point of water. The temperature at which a mixture of air-saturated pure water and pure ice may exist in equilibrium at a pressure of one standard atmosphere.

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.

See radiation shield.