An old nautical term for mercury barometer.

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 ...

A radiosonde whose carrier wave is modulated by audio-frequency signals whose frequency is controlled by the sensing elements of the instrument.

A unit of power equal to one joule per second or 10' ergs per second.

See hydrologic accounting.

An increase in the central pressure of a pressure system; opposite of a deepening. More commonly applied to a low rather than a high.

A graphical device used for the determination of the speed of the geostrophic wind from the isobar or contour-line spacing on a synoptic chart.

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

A scale with the ice point at zero degrees and the boiling point of water at 80 degrees, with pressure of one atmosphere.

Nested Grid Model generated every 12 hours by NCEP.

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

The gravity flow of water within soil.

The condition of the atmosphere when the amount of water vapor present is the maximum possible at the existing temperature.

A flower-like diagram indicating the relative frequencies of different wind directions for a given station and period of time.

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.

In general, any object that reflects incident energy. Usually it is a device designed for specific reflection characteristics.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

In thermodynamics, the integrating factor of the differential equation referred to as the first law of thermodynamics, In statistical mechanics, a measure of translational molecular kinetic energy (with three degrees of freedom). In general, the degree of ...

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

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