Same as fogbow.

An absolute temperature scale with the ice point of pure water defined as 273.16 K. The size of the degree is the same as on the Celsius scale, and the zero point is absolute zero.

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.

See calorie.

A type of instrument shelter. It is a wooden box painted white with double louvered sides and mounted on a stand four feet above the ground.

A line of equal or constant temperature.

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.

Precipitation from a cumuliform cloud. Characterized by the suddenness of beginning and ending, by the rapid change in intensity, and usually by a rapid change in the condition of the sky. The solid or liquid water particles are usually bigger than the co ...

A medium-sized instrument shelter. It is a white louvered box with a flat double to of and is mounted four feet above the ground on a four-legged stand.

The record made by a hygrograph.

A fabric cone attached to a metal ring and used to indicate wind direction. often at airfields.

A contact anemometer connected to an electrical circuit which is so arranged that the average wind speed is indicated.

A type of cooling-power anemometer based upon the principle that the time constant of a thermometer is a function of its ventilation.

A common type of liquid-inglass thermometer, used, in meteorology, in psychrometers and as a maximum thermometer.

Wind with a speed between 17 and 21 knots (19 and 24 mph); Beaufort scale number 5.

Anemometer which measures wind speed by the speed of rotation of 3 or 4 hemispherical or conical cups, each fixed to the end of a horizontal arm projecting from a vertical axis. See condenser-discharge anemometer, contact anemometer. Compare to bridled-cu ...

The older name for the Celsius temperature scale. Officially abandoned by international agreement in 1948, but still in common use.

The change in barometric pressure within a specified period of time (typically 3 hours for meteorological observations).

A recording pressure-tube anemometer in which the wind scale of the float manometer has been made linear by the use of springs, i.e. Dines anemometer.

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