Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

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

Same as precipitation- effectiveness index.

Same as mercury barometer.

Lacking a relationship to a time base or clock. In asynchronous communications, individual data characters are sent at an arbitrary rate.

Board that holds graph paper on which is plotted information obtained from a pilot-balloon observation.

Wind with a speed between 7 and 10 knots (8 and 12 mph), Beaufort scale number 3.

Wind with a speed between 48 and 55 knots (55 and 63 mph), Beaufort scale number 10.

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

An instrument used for the determination of the electrical conductivity of the atmosphere.

A hypothetical body which absorbs some constant fraction, between zero and one, of all electromagnetic radiation incident upon it, which fraction is the absorptivity and is independent of wavelength. Compare to black body, white body.

The record of an aneroid barograph.

Same as photometer.

A thermometer which utilizes the thermal properties of gas. There are two forms of this instrument: (a) a type in which the gas is kept at constant volume, and pressure is the thermometric property, and (b) a type in which the gas is kept at constant pres ...

An elongated area of relatively low atmospheric pressure. Usually associated with and most clearly identified as an area of maximum cyclonic curvature of the wind flow. The opposite of a ridge.

A small anemometer with flat vanes which indicates the number of linear feet or meters of air which have passed the instrument during its exposure.

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 clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

A photoelectric spectrophotometer which is used in the determination of the ozone content of the atmosphere.

See photometer.