The gravity flow of water within soil.

Same as water year.

An instrument resulting from the combination of a thermograph and a hygrograph and furnishing, on the same chart, simultaneous time recording of ambient temperature and humidity.

A line drawn through geographical points having the same pluvial index.

Of or pertaining to the air, atmosphere, or aviation. Also, same as antenna.

A series of Nansen-bottle water samples and associated temperature observations resulting from one release of a messenger.

Clouds which cover between 6/10 and 9/10 of the sky. See Sky Terminology.

A technique for making winds aloft observations in which two theodolites located at either end of a baseline follow the ascent of a pilot balloon. Synchronous measurements of the elevation and azimuth angles of the balloon. taken at periodic intervals, pe ...

In Jeffreys' classification, a wind for which the pressure force exactly balances the viscous force, in which the vertical transfers of momentum predominate.

Precipitation caused by the ascent of moist air over an orographic barrier such as a Mountain range.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifth contact of the commutator up to a number determined by the design of the commutator. It then signals every contact except the fifth, which is ...

The total of direct solar radiation and diffuse sky radiation received by a unit horizontal surface. Global radiation is measured by pyranometers.

An apparatus, used in studying soil temperatures, for measuring the total supply of heat during a given period.

Abbreviation for mean sea level.

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

A unit of pressure which directly expresses the force exerted by the atmosphere. Equal to 1000 dynes/cm2 or 100 pascals.

Abbreviation for Instrument Flight Rules, but commonly used to refer to the weather and/or flight conditions to which these rules apply, i.e. low visibility.

The amount of moisture which, if available, would be removed from a given land area by evapotranspiration. Expressed in units of water depth.

A measure of the intensity of gusts given by the ratio of the total range of wind speed between gusts and the intermediate periods of lighter wind to the mean wind speed, averaged over both gusts and lulls.

Particle on which the freezing of water occurs.