Electromagnetic radiation lying within the wavelength interval to which the human eye is sensitive, the spectral interval from approximately 0.4 to 0.7 microns (4000 to 7000 angstroms). Bounded on the short-wavelength end by ultraviolet radiation and on t ...

The total area drained by a river and its tributaries. Same as river basin.

One of the radiation laws which states that the wavelength of maximum radiation intensity for a black body is inversely proportional to the absolute temperature of the radiating black body.

Same as rain-intensity gauge.

An instrument designed to measure the effect of sunlight on evaporation from plant foliage. It consists of a porous clay atmometer whose surface has been blackened so that it absorbs radiant energy.

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.

Any and all forms of water particles, liquid or solid, that fall from the atmosphere and reach the ground.

Generally, a measure of the departure of the mean daily temperature from a given standard, one degree day for each degree (

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

A numbering system using a base number of 16 and including the ten decimal digits (0 to 9) along with six alpha digits (A to F). Thus. a digit is available to represent each of the possible values of a 4-bit binary digit.

A barometer which measures atmospheric pressure using one or a series of aneroid capsules. Also called holosteric barometer.

A box-like structure designed to protect certain meteorological instruments from exposure to direct sunlight, precipitation, and condensation, while at the same time providing adequate ventilation. Instrument shelters are painted white, have louvered side ...

(1) The initial component or the sensing element of a measuring system. For example, the receiver of a rain gauge is the funnel which captures the rain and the receiver of a thermoelectric thermometer is the measuring thermocouple. (2) An instrument used ...

Contraction for pilot balloon observation.

The study of waters (including oceans, lakes, and rivers) embracing either: (a) their physical characteristics, from the standpoint of the oceanographer or limnologist; or (b) the elements affecting safe navigation, from the point of view of the mariner. ...

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

Instrument for measuring the mean intensity of glo global solar radiation (direct and diffuse) near the earth's surface in a specified time interval.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

Same as atmometer.

Complementary Metal-Oxide Semiconductor. A method of making silicon chips that results in low power consumption by the circuits.