One of the radiation laws which states that the wavelength of maximum radiation intensity for a black body is inversely proportional to the absolute temperature of the radiating black body.

Precipitation composed of liquid water drops more than 0.5 mm in diameter, failing in relatively straight, but not necessarily vertical, paths. Compare to drizzle.

Force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

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 sudden, significant increase in station pressure.

Readily taking up and retaining moisture.

Operation mode of a communication circuit in which one end can only transmit and the other end can only receive.

A continuous-recording barometer.

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

A temperature scale on which the freezing point of water equals 32

An instrument used to measure changes in the level of the water in an evaporation pan. The gauge is normally placed in a Stillwell and adjusted so that the point of the hook just breaks the water surface. The change in water level is read on the attached ...

An instrument which automatically records the voltage applied to it, as a function of time.

Old snow that has become granular and compacted as a result of melting and refreezing.

The unit of acceleration in the centimeter-gram-second system of units, equal to one cm per sec2. Commonly used in gravimetry.

An instrument for determining the dust content of a sample of air. Also spelled conimeter.

A hydrometeor consisting of a visible aggregate of minute water and/or ice particles in the atmosphere above the earth's surface. Cloud differs from fog only in that the latter is, by definition, in contact with the earth's surface.

A modification of the dew cell used in radiosonde equipment.

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

An instrument for measuring snow hardness in terms of the resistance of snow to the pressure exerted by a disk attached to a spring-loaded rod, a gauge calibrated in pounds per square inch registers the amount of resistance. See Canadian hardness gauge.

variable audio-modulated radiosonde developed at the Bureau of Standards and used by the United States weather services.