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 ...

Lacking a relationship to a time base or clock. In asynchronous communications, individual data characters are sent at an arbitrary rate.

A hypothetical body which absorbs some constant fraction, between zero and one, of all electromagnetic radiation incident upon it, which fraction is the absorptivity and is independent of wavelength. Compare to black body, white body.

Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

The component of the radiosonde which includes the modulating blocking oscillator and the radiofrequency carrier oscillator.

See instrument error, observational error. random error, standard error, systematic error.

A radiosonde whose carrier wave is switched on and off in such a manner that the interval of time between the transmission of signals if a function of the magnitude of the meteorological elements being measured.

A direct-vision nephoscope constructed in the following manner: A grid-work of bars is mounted horizontally on the end of a vertical column and made free to rotate about the vertical axis. The observer rotates the grid and adjusts his or her position unti ...

The total amount of water transferred to the atmosphere by evapotranspiration.

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

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 ...

Solar and terrestrial radiation directed downwards (towards the earth's surface); incoming radiation.

Graduated fixed stake used in regions of abundant snowfall to facilitate the measurement of snow depth.

Automated Surface Observing System. A network of instrumented weather stations deployed primarily by the National Weather Service to make weather observations without operator involvement.

A type of modulation in which the frequency of a continuous radio carrier wave is varied in accordance with the properties of a second (modulating) wave.

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

Cathode Ray Tube. A display element, consisting of a vacuum tube and screen, used with computers.

In meteorology, an area of low pressure; a low or trough.

That stage, on a fixed river gauge, at which overflow of the natural banks of the stream begins to cause damage in any portion of the reach for which the gauge is used as an index.

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 ...