A pyranometer developed by M. Robitzsch. Its design utilizes three bimetallic strips which are exposed horizontally at the center of a hemispherical glass bowl. The outer strips are white reflectors and the center strip is a blackened absorber. The bimeta ...

An instrument used to measure the water vapor content of the air.

Pyrheliometer based on the comparison of the heating of two identical metal strips, one exposed to radiation, the other to a joule effect.

The transducer's output when the maximum sensed value is applied to the transducer's input. For example, the F.S. output of a 4-20 mA transmitter is 20 mA, whereas its span is only 16mA.

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 hygrometer in which the sensitive element is a strand or strands of human hair, the length of which is a function of the relative humidity of the air.

The sum of solar and terrestrial radiation.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

Any source of radiant energy, especially electromagnetic energy.

An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

The statement that the viscosity of air is independent of the density of air.

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.

The temperature at which all three phases of a substance can exist in equilibrium. This temperature occurs at only one pressure. The triple-point of water is 273.16 K and is the basis of the Kelvin scale.

(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 ...

The inaccuracy that the manufacturer permits when the unit is calibrated in the factory.

See wind vane.

Readily taking up and retaining moisture.

A device used on certain types of instruments to prevent unwanted radiation from affecting the measurement of a quantity. Also called solar radiation shield.

A river gauge in which a weight suspended on a wire is lowered to the water surface from a bridge or other overhead structure to measure the distance from a point of known elevation to the water surface.

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