A type of anemometer in which the rotation of an element serves to measure the wind. Rotation anemometers are divided into two classes; those in which the axis of rotation is horizontal, such as the windmill anemometer, and those in which the axis of rota ...

An increase in the central pressure of a pressure system; opposite of a deepening. More commonly applied to a low rather than a high.

The closeness of agreement among measurements of the same value of the same quantity where the individual measurements are made under different defined conditions, i.e. by different methods or with different measuring instruments.

The height of the cloud base above the local terrain.

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

Wind with a speed between 34 and 40 knots (39 and 46 mph); Beaufort scale number 8.

Same as windsock.

An aneroid barometer arranged so that the deflection of the aneroid capsule actuates a pen which graphs a record on a rotating drum. Sometimes called aneroidograph.

An instrument for measuring the difference of the solar radiation falling on both sides of a horizontal surface from the whole hemisphere.

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

The height ascribed to the lowest layer of clouds or obscuring phenomena when it is reported as broken, overcast, or obscuration and not classified as "thin" or "partial." The ceiling is termed unlimited when these conditions are not satisfied. ...

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

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 ...

Same as atmometer.

A system of estimating and reporting wind speed, originally based on the effect of various wind speeds on the amount of canvas that a full-rigged nineteenth century frigate could carry.

The part of a measuring instrument which responds directly to changes in the environment.

Same as atmometer.

Solar radiation of selected wavelengths.

Radiation coming from the solid angle of the sun's disc, as opposed to diffuse sky radiation, effective terrestrial radiation, or radiation from any other source. Direct solar radiation is measured by pyrheliometers.

The energy of any type of electromagnetic radiation. Also called radiation.