A unit of energy defined as the heat required to raise the temperature of one pound of water one degree Fahrenheit. It is equal to 252.1 calories or to 1055 joules.

The transmission of data collected at a remote location over communications channels to a central station.

Same as dropsonde.

Defect in the action of an aneroid barometer resulting in a sluggish adjustment of the index toward the correct reading when the barometer is subjected to a large and rapid change in pressure.

The gravity flow of water within soil.

A type of cloud height indicator which uses a searchlight to project vertically a narrow beam of light onto the cloud base. The height of the cloud is determined using a clinometer, located at a known distance from the ceiling light, to measure the angle ...

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

The wind speed and direction at various levels in the atmosphere above the level reached by surface weather observations.

A curve showing the variation of temperature with height in the free air. See lapse rate.

in United States weather observing practice, the highest "instantaneous" wind speed recorded at a station during a specified period, usually the 24-hour observation day. Therefore, a peak gust need not be a true gust of wind.

A wind blowing in a direction perpendicular to the course of a moving object.

Routine broadcast of meteorological information for aircraft in flight.

That part of an audio-modulated radiosonde consisting of the baroswitch, the sensing elements, the reference elements, and the relay.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

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

An estimate of the temperature of an incandescent body, determined by observing the wavelength at which it is emitting with peak intensity (its color) and using that wavelength in Wien's law.

A rotation anemometer in which the axis of rotation is horizontal. The instrument has either flat vanes (as in the air meter) or helicoidal vanes (as in the propeller anemometer). The relation between wind speed and angular rotation is almost linear.

A tube designed to measure the rate of flow of fluids. It consists of a tube having a constriction or throat at its midsection. The difference between the pressure measured at the inlet and at the throat is a function of the fluid velocity. Compare to Pit ...

The condition of the atmosphere when the amount of water vapor present is the maximum possible at the existing temperature.

A conductor or system of conductors for radiating and/or receiving radio energy. Also called aerial.