Electromagnetic radiation of shorter wavelength than visible radiation but longer than x-rays, between 0.02 and 0.4 micron (200 and 4000 angstrom).

(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 ...

A thermoelectric thermometer used for measuring air temperature. The name is derived from the fact that the reference thermocouple is placed in an insulated bottle.

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

A special type of radar target, usually a comer reflector, tied beneath a free balloon and designed to be an efficient reflector of radio energy.

See standard atmosphere.

A thermometer consisting of a clock mechanism the speed of which is a function of temperature.

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

A large body of air having similar horizontal temperature and moisture characteristics.

Same as contact anemometer.

Difference between the temperatures of the dry-bulb and the wet-bulb thermometers of a psychrometer.

Generic term for rapid variations in apparent position, brightness, or color of a distant luminous. object viewed through the atmosphere.

See radiosonde commutator.

An instrument for measuring the pressure of gases and vapors. A mercury barometer is a type of manometer.

The lowest temperature that can be obtained on a wet-bulb thermometer in any given sample of air. Obtained by evaporation of water (or ice) from the muslin wick. Used in computing dew point and relative humidity.

In physics, any process in which the flux density (or power, amplitude, intensity, illuminance, etc.) of a "parallel beam" of energy decreases with increasing distance from the source. Attenuation is always due to the action of the transmitting medium its ...

Temperature to which absolutely dry air would have to be brought in order for it to have the same density as moist air, considered at the same pressure.

An inert gas. A colorless, monatomic element which is found to occur in dry air to the extent of only 0.000524 percent by volume. Helium is very light, having a molecular weight of only 4.003 and specific gravity referred to air of 0.138. Because helium i ...

An instrument which measures the effective terrestrial radiation. See Angstrom pyrgeometer.

A device for measuring the frequency of occurrence of atmospherics whose intensity is greater than a predetermined level.