A graphical aid used in the reduction of data from a winds aloft observation.

A wind blowing in the same direction as the heading of a moving object. thus assisting the object's intended progress. The opposite of a head wind.

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

The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

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

Downward-facing pyranometer used for measuring reflected solar radiation.

An instrument of the aspiration condenser type which measures the concentration and mobility of small ions.

An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

The atmospheric pressure at mean sea level either directly measured by stations at sea level or empirically determined from the station pressure and temperature by stations not at sea level. Used as a common reference for analyses of surface pressure patt ...

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

A continuous-recording barometer.

A system in which radar techniques are used to determine the range, elevation, and azimuth of a radar target carried a!oft by a radiosonde, so that wind data may be obtained along with the other meteorological data.

See foehn.

The stage, on a fixed river gauge, corresponding to the top of the lowest banks within the reach for which the gauge is used as an index. Compare to flood stage.

A description or explanation of the manner in which the height of the ceiling is determined, i.e. aircraft ceiling, balloon ceiling. estimated ceiling, indefinite ceiling, measured ceiling, precipitation ceiling.

The cardinal points of the compass, i.e. north, south, east, west.

Abbreviation for mean sea level.

Anemometer which generates an electrical contact output with a frequency proportional to wind speed.

An element that can control current without moving parts, heated filaments, or vacuum gaps.

Amount of solar radiation incident, per unit area and time, on a surface which is perpendicular to the radiation and is situated at the outer limit of the atmosphere, the earth being at its mean distance from the sun. It equals approximately 2.00 ly/ min ...