Transmitted energy which is modulated in order to carry information. Usually, it is in the form of a radio- frequency sine wave, modulated either in amplitude or in frequency.

The energy of any type of electromagnetic radiation. Also called radiation.

An instrument of the aspiration condenser type which measures the concentration and mobility of small ions.

The value of the quantity measured, as indicated or otherwise provided by a measuring instrument.

A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

A graphical aid used in fire weather forecasting to calculate the degree of forest-fire danger (or burning index). Commonly in the form of a circular slide rule, the firedanger meter relates numerical indices of (a) the seasonal stage of foliage, (b) the ...

An instrument used for the determination of the electrical conductivity of the atmosphere.

Solar radiation of selected wavelengths.

A local variation in the wind direction or speed. This condition can present danger to aircraft, especially at landing, when a sudden shift from headwind to tailwind can cause a rapid loss of airspeed and lift.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

A pyrheliometer of the bimetallic type used to measure the intensity of direct solar radiation.

A photometric unit of illuminance or illumination equal to one lumen per square centimeter.

Precipitation from a cumuliform cloud. Characterized by the suddenness of beginning and ending, by the rapid change in intensity, and usually by a rapid change in the condition of the sky. The solid or liquid water particles are usually bigger than the co ...

See feed.

The temperature at which an object gives out as much radiation as it receives from its surroundings.

An instrument used for the measurement of the reflecting, power (the albedo) of a surface. A pyranometer adapted for the measurement of radiation reflected from the earth's surface is sometimes employed as an albedometer.

The difference between the outgoing infrared terrestrial radiation of the earth's surface and the downcoming infrared counterradiation from the atmosphere.

An instrument for the measurement of both solar and terrestrial radiation.

Thermodynamic change of state of a system in which there is transfer of heat across the boundaries of the system. Compare to adiabatic process.

A unit of signaling speed representing the number of code elements sent per second; often, bits per second.