An instrument for determining the direction from which radio waves approach a receiver. It may consist of a manually operated direction indicator, or it may use a servo system to position the antenna automatically in the direction of the incident waves.

Random Access Memory. The memory of a computer which can be read and written into at any location without passing through preceding locations.

Routine broadcast of meteorological information for aircraft in flight.

A wooden enclosure about sixteen feet square and eight feet high with a precipitation gauge at its center. The function of the fence is to minimize eddies around the gauge and thus insure a catch that is representative of the actual rainfall or snowfall.

The change in the measured transducer output caused by changes in ambient temperature. Usually expressed a percentage of full scale.

The lowest level at which the wind becomes geostrophic in the theory of the Ekman spiral. Also called gradient wind level.

Integrated Flood Observing and Warning System. National Weather Service flood warning program.

Same as dropsonde.

The correctable part of the inaccuracy of an instrument.

Extended Binary Coded Decimal Interchange Code. A standard code used to represent data using 8 bits per character.

The temperature at which a solid substance undergoes fusion, i.e. melts, changes from solid to liquid form. All substances have their characteristic melting points. For very pure substances the temperature range over which the process of fusion occurs is ...

Solar radiation scattered by particles in the atmosphere.

Same as marine rainbow.

Occupational Safety and Health Administration. A regulatory office of the U.S. Department of Labor.

A vector term which includes both wind speed and wind direction.

A thermometer which uses a transducing element whose element proper-ties are a function of its thermal state. Common meteorological examples of such thermometers are the resistance thermometer and the thermoelectric thermometer.

A point (or line) on a scale used for reference or comparison purposes. In calibration of meteorological thermometers, for example, the fiducial points are 100

A conically shaped, copper rain gauge shield.

An instrument used to reveal but not necessarily measure the presence of an electrical quantity. It is used to display the output of a sensing element after suitable amplification and modification. Sometimes called display.

A recording weight barometer.