Central Processing Unit. The part of a computer which controls and directs all functions.

A wind blowing in a direction opposite to the heading of a moving object, thus opposing the object's intended progress; the opposite of a tailwind.

A line drawn through geographical points where a given seasonal biological event occurs on the same date.

A high-altitude sounding system consisting of a small solid- propellant research rocket carried aloft by a large plastic balloon. The rocket is fired near the maximum altitude of the balloon flight.

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.

The maximum rate at which precipitation can pass through the surface into the soil, for a given soil in a given condition.

Instrument for measuring the depth to which the soil is frozen.

Sustained winds greater than or equal to 40 mph or gust greater than or equal to 58 mph.

Automated Local Evaluation in Real Time. Network of automatic rain gauges that transmit via VHF radio link when precipitation occurs. Some sites are also equipped with other sensors such as temperature, wind, pressure, river stage or tide level. More info ...

Solar and terrestrial radiation directed upward (away From the earth's surface); outgoing radiation.

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

Same as aneroid barometer. Holostelic means wholly made of solids, while aneroid means devoid of liquid.

The gravity flow of water within soil.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

An instrument used to indicate wind direction.

Winds from the four cardinal points of the compass; that is, north, east, south, and west winds.

A type of photoelectric photometer used to measure high-altitude winds on the assumption that stellar scintillation is caused by atmospheric inhomogeneities being carried along by wind near the tropopause level.

See foehn.

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 ...

Same as atmospheric pressure.