A rain gauge capable of measuring very small amounts of precipitation. Also called micropluviometer, trace recorder.

An instrument for measuring temperature by utilizing the variation of the physical properties of substances according to their thermal states. Thermometers may be classified into types according to their construction; deformation thermometer, electrical t ...

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.

General term for an instrument which records the vertical electric current in the atmosphere.

An instrument consisting of a series of graduated cylinders possessing selective collection efficiencies. It is used for the measurement of quantities relating to the size distribution of cloud droplets.

General name for an instrument which measures the evaporation rate of water into the atmosphere. See clay atmometer, evaporation pan, evapotranspirometer, Livingston sphere, Piche evaporimeter, radio atmometer.

Contraction for pilot balloon observation.

Physical equipment used in data processing. Compare to firmware, software.

Generally, an instrument designed to measure or estimate the blueness of the sky. See Linke-scale.

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. ...

The frequency of a carrier wave.

An instrument that shows changes in humidity.

A rotation anemometer which has a horizontal axis upon which helicoidal shaped vanes are mounted. See windmill anemometer.

Any horizontal wind velocity tangent to the contour line of a constant pressure surface (or to the isobar of a geopotential surface) at the point in question.

Downward scattered and reflected solar radiation, coming from the whole hemisphere with the exception of the solid angle of the sun's disc on a surface perpendicular to the axis of this cone.

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.

An instrument, located at the surface observing station, which is used to record the data presented by a radiosonde aloft.

Apparatus using the combined simultaneous action of a bimetallic thermometer and a hair hygrometer to move a needle in front of a divided scale. fts construction permits dew point variations to be indicated approximately.

The difference between the outgoing infrared terrestrial radiation of the earth's surface and the downcoming infrared counterradiation from the atmosphere.

An aviation weather forecast for a specific flight.