The succession of stages through which water passes on the ground and in the atmosphere: evaporation from land or bodies of water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.

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.

An instrument for measuring the pressure of gases and vapors. A mercury barometer is a type of manometer.

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 ...

A clay atmometer consisting of a hollow ceramic sphere through which evaporation occurs. Evaporation is measured by the loss of water from the reservoir which feeds the sphere.

A method of winds aloft observation accomplished by tracking a balloon-borne radar target or radiosonde with either radar or a radio theodolite.

A common type of liquid-inglass thermometer, used, in meteorology, in psychrometers and as a maximum thermometer.

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 fabric cone attached to a metal ring and used to indicate wind direction. often at airfields.

A unit of luminance (or brightness) equal to 1/6 candles per square centimeter.

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.

The difference between the input quantity applied to a measuring instrument and the output quantity indicated by the instrument. The inaccuracy of an instrument is equal to the sum of its instrument error and its uncertainty.

Electromagnetic radiation of shorter wavelength than visible radiation but longer than x-rays, between 0.02 and 0.4 micron (200 and 4000 angstrom).

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).

Programmable Read-Only Memory. Read-only memory which can be programmed by the user using a special hardware programmer.

Lacking a relationship to a time base or clock. In asynchronous communications, individual data characters are sent at an arbitrary rate.

A momentary decrease in the speed of the wind.

Navy Operational Global Atmospheric Prediction System. A global meteorological model operated by the Department of Defense.

Barometer in which pressure is determined by balancing air pressure against the weight of a column of mercury in an evacuated glass tube.

Same as wave pole.