That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

Same as river gauge.

As used by the U.S. Army Corps of Engineers, the departure (in

A transducer which converts electromagnetic radiation in the infrared, visible, and ultraviolet regions into electrical quantities such as voltage, current, or resistance. Also called photo cell.

Situated on the side from which the wind blows.

A basic equation in night visual range theory, relating the illuminance of a point source of light to distance and the transmissivity of the atmosphere.

A defective maximum thermometer of the liquid-inglass type in which the mercury flows too freely through the constriction. Such a thermometer will indicate a maximum temperature that is too low.

A method of winds aloft observation essentially the same as a pilot balloon observation except the height data is derived from the radiosonde observation rather than from assumed ascension rates.

A wind vane used to obtain the horizontal and vertical components of the wind.

The ratios, to the mean wind speed, of the average magnitudes of the component fluctuations of the wind along three mutually perpendicular axes.

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

The scientific study of the waters of the earth, especially with relation to the effects of precipitation and evaporation upon the occurrence and character of water in streams, lakes, and on or below the land surface. In terms of the hydrologic cycle, the ...

Same as precipitation-evaporation ratio.

Nested Grid Model generated every 12 hours by NCEP.

Forecasting weather by the use of numerical models, run on high speed computers. Most of the NWP for the National Weather Service is done at the National Centers for Environmental Prediction (NCEP).

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

Anemometer which measures wind speed by the speed of rotation of 3 or 4 hemispherical or conical cups, each fixed to the end of a horizontal arm projecting from a vertical axis. See condenser-discharge anemometer, contact anemometer. Compare to bridled-cu ...

The difference between amounts of precipitation and runoff for a given storm. It is that portion of the precipitation that remains in the basin as soil moisture, surface storage, ground water, etc.

The difference between the outgoing infrared terrestrial radiation of the earth's surface and the downcoming infrared counterradiation from the atmosphere.

An instrument used for measuring the specific gravity of a liquid.