Instrument for measuring the intensity of radiant energy. Its principle is based on the variation of electrical resistance, with the incoming radiation, of one or both the metallic strips which the instrument comprises.

The effect upon the measurement of rainfall caused by the presence of the rain gauge.

Same as ombrometer.

The size of the area comprising a watershed or river basin. Also called catchment area.

An anemometer which measures wind speed in terms of the drag which the wind exerts on a solid body. See bridled-cup anemometer, normal-plate anemometer, pendulum anemometer.

A type of rain gauge shield consisting of freely hanging, evenly spaced slats arranged circularly around the gauge. The advantage of this shield is that the slats do not easily accumulate snow, permitting its use on unattended gauges. See rain gauge shiel ...

The unit of acceleration in the centimeter-gram-second system of units, equal to one cm per sec2. Commonly used in gravimetry.

The source of illumination for an antenna reflector. Also called antenna feed.

Same as humidity strip.

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

A photometer which measures the intensity of radiation as a function of the frequency (or wavelength) of the radiation.

Wind with a speed between 4 and 6 knots (4 and 7 mph), Beaufort scale number 2.

See river basin.

An instrument used to indicate wind direction.

An estimate of the temperature of an incandescent body, determined by observing the wavelength at which it is emitting with peak intensity (its color) and using that wavelength in Wien's law.

An instrument designed to record the duration of sunshine at a given location without regard to intensity. See Campbell- Stokes recorder, Jordan sunshine recorder, Marvin sunshine recorder, Pers sunshine recorder.

The level at which ice crystals and snowflakes melt as they descend through the atmosphere.

Area of a computer or other device where various logic and control elements are interconnected. Often a printed circuit board into which other circuit boards plug at right angles.

Temperature assumed by an unsaturated air parcel when brought adiabatically to a standard pressure (1,000 mb).

Contraction for pilot balloon observation.