The true freezing point of water. The temperature at which a mixture of air-saturated pure water and pure ice may exist in equilibrium at a pressure of one standard atmosphere.

The height of the cloud base above the local terrain.

Ragged low clouds, usually stratus fractus. Most often applied when such clouds are moving rapidly beneath a layer of nimbostratus.

A general name for instruments which detect the presence of (but do not necessarily measure) small electrical charges by electrostatic means. Compare to electrometer.

Turbulence encountered by aircraft when flying through air space devoid of clouds. Thermals and wind shear are the main causes.

A definite portion of a stream channel, commonly taken between two gauging stations, but may be taken between any two specified points.

National Weather Service. Administered by the U.S. Department of Commerce.

The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

A general term for instruments designed to measure the amount of cloudiness.

The part of a measuring instrument which responds directly to changes in the environment.

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

Air in motion relative to the surface of the earth. Almost exclusively used to denote the horizontal component.

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

A set of electrical conductors, often on a backplane, that carry data and power signals among the various components of a computer.

An instrument which determines the black-body temperature of a substance by measuring its thermal radiation.

A measure of the attenuation due to scattering, of light as it traverses a medium containing scattering particles.

A hypothetical "body" whose surface absorbs no electromagnetic radiation of any wavelength. An idealization exactly opposite to that of the black body. In nature, no true white bodies are known. Moist white pigments exhibiting high reflectivity for visibl ...

A wave resulting from the action of wind on a water surface.

A radiosonde which transmits the indication of the meteorological sensing elements in the form of a code consisting of combinations of dots and dashes.

Same as mirror nephoscope.