Any conventional barometer fitted with an extended scale so that atmospheric pressure measurements may be made at both high and low altitudes.

A mercury barometer of the fixed cistern type in which a moveable scale terminating in an ivory point is used to compensate for the variations in the height of the mercury in the cistern

Abbreviation for mean sea level.

A chronograph used to make a time-record of certain measured meteorological elements. The most common type, the triple register, records wind direction and speed, duration of sunshine, and amount of rainfall (sensed respectively by a contact anemometer, M ...

A device that combines several separate communications signals into one and outputs them on a single line.

A method of streamflow routing which assumes that storage is a linear function of the weighted flow in the reach and is adaptable to a simple mathematical solution.

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 ...

A series of Nansen-bottle water samples and associated temperature observations resulting from one release of a messenger.

The nautical mile is closely related to the geographical mile which is defined as the length of one minute of arc on the earth's equator. By international agreement, the nautical mile is now defined as 1852 meters.

National Centers for Environmental Prediction. Central computer and communications facility of the National Weather Service; located in Washington, DC.

An instrument which measures the scattering function of particles suspended in a medium in order to determine the visual range through the medium. See visibility meter.

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

An instrument for determining the direction of cloud motion. There are two basic designs of nephoscope, the directvision nephoscope and the mirror nephoscope.

An instrument for measuring the difference of the solar radiation falling on both sides of a horizontal surface from the whole hemisphere.

An instrument for measuring the difference between incoming and outgoing terrestrial radiation.

The difference between downward and upward (total) radiation; net flux of all radiation.

An instrument for the measurement of the net flux of downward and upward total (solar and terrestrial) radiation through a horizontal surface.

The difference between the solar radiation directed downward and upward; net flux of solar radiation.

A reflecting type telescope with a 45

NEXt Generation RADar. A NWS network of about 140 Doppler radars operating nationwide.