A unit of luminance or brightness equal to 1/d candles per foot'.

A pressure tube anemometer, consisting of a pitot tube mounted on the windward end of a wind vane and a suitable manometer to measure the developed pressure and calibrated in units of wind.

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

Generally, the relative states of inflow, outflow, and storage of moisture over a given area of earth's surface.

An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

The line-of-sight distance between two objects.

modulated radiosonde-A radiosonde which transmits the indications of the meteorological sensing elements in the form of pulses spaced in time. The meteorological data are evaluated from the intervals between the pulses. Also called timeinterval radiosonde ...

An instrument for determining the degree of polarization of light. See photopolarimeter.

A unit of illuminance or illumination equal to one lumen per foot'. This is the illuminance provided by a light source of one candle at a distance of one foot.

A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

Moisture contained in the soil above the water table, including water vapor which is present in the soil pores. In some cases this term refers strictly to the humidity contained in the root zone of plants.

A local variation in the wind direction or speed. This condition can present danger to aircraft, especially at landing, when a sudden shift from headwind to tailwind can cause a rapid loss of airspeed and lift.

A recording siphon barometer.

A set of rules or conventions used to standardize data transfer between devices.

Snow shower, particularly of a very light and brief nature.

Same as rain gauge.

Same as pitot tube.

A sudden, significant increase in station pressure.

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

Atmospheric layer throughout which there is no change of temperature with height, i.e. a zero lapse rate.