Any and all forms of water particles, liquid or solid, that fall from the atmosphere and reach the ground.

Having a specific relationship to a time base or clock. In synchronous communications, data characters are sent according to a timing signal which synchronizes the two communicating devices.

An aneroid barograph designed to record atmospheric pressure variations of very small magnitude.

A hygrometer which determines the amount of precipitable moisture in a given region of the atmosphere by measuring attenuation of radiant energy caused by the absorption bands of water vapor.

Force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

The atmospheric pressure computed using station elevation as the reference datum level. Station pressure is usually the base value from which sea level pressure and altimeter setting are determined.

Winds from the four cardinal points of the compass; that is, north, east, south, and west winds.

bucket rain gauge-A rain gauge where the precipitation collected by the receiver empties into one side of a chamber which is partioned transversely at its center and is balanced bistably upon a horizontal axis. When a predetermined amount of water has bee ...

Frequency Shift Keying. A form of frequency modulation of a data signal performed by a modem for transmission over dedicated wire or phone lines.

Rate of wind movement in distance per unit time.

The height at which the maximum wind speed occurs, determined in a winds-aloft observation.

The average temperature of the air as indicated by a properly exposed thermometer for a given time period, usually a day, a month, or a year.

A hydrostatic principle that pressure supplied to an enclosed fluid is transmitted undiminished to every portion of the fluid and to the walls of the containing vessel.

A device used by oceanographers to obtain subsurface samples of sea water. The "bottle" is lowered by wire, its valves open at both ends. It is then closed in situ by allowing a weight (called a messenger) to slide down the wire and strike the reversing m ...

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.

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

A unit of luminance or brightness equal to 1/d candles per foot'.

A local variation of the wind vector or any of its components in a given direction.

An instrument for measuring the ultraviolet in solar and sky radiation.

A wind scale adapted by the U.S. Forest Service for use in the forested areas of the northern Rocky Mountains (NRM). It is an adaptation of the Beaufort wind scale. The difference between these two scales lies in the specification of the visual effects of ...