A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

A unit of distance equal to 5280 feet. It is sometimes referred to as a land mile.

A diagram showing the intensity of the radiation field in all directions from a transmitting radio or radar antenna at a given distance from the antenna.

A unit of pressure used principally in oceanography. One decibar (10' dynes/cm2) equals 0.1 bar. In the ocean, hydrostatic pressure in decibars very nearly equals the corresponding depth in meters.

The officially designated elevation of an airport above mean sea level, taken as the highest point on any of the runways of the airport. Same as airport elevation.

Same as precipitation- effectiveness index.

The older name for the Celsius temperature scale. Officially abandoned by international agreement in 1948, but still in common use.

The distance or length of flow of the air past a point during a given interval of time.

Wind with a speed between 28 and 55 knots (32 and 63 mph); Beaufort scale numbers 7 through 10.

A self-recording psychrometer.

Pertaining to measurements or devices in which the output vanes in discrete steps, i.e. on-off or pulse signals. Compare to analog.

A thermopile used in some types of radiation instruments. See solarimeter.

The processing of the form or mode of a signal so as to make it intelligible to, or compatible with, a given device.

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

The length of fluid flow (gas or liquid) past a sensor required for the sensor to respond to 63.2% of a step change in speed. Expressed in feet or meters. For anemometers, this value is calculated from time constant times wind tunnel speed.

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

The direction, with respect to magnetic north, from which the wind is blowing. Distinguish from true wind direction.

An instrument designed to record the duration of sunshine at a given location without regard to intensity. See Campbell- Stokes recorder, Jordan sunshine recorder, Marvin sunshine recorder, Pers sunshine recorder.

The standard deviation of a sufficiently large number of measurements of the same quantity by the same instrument or method. The non-correctable part of the inaccuracy of an instrument, it represents the limit of measurement precision. The uncertainty of ...

A radar term for a single pulse of radio energy.