pattern barometer-Mercurial barometer with a fixed scale and cistern and which therefore requires only one adjustment before each reading.

A liquid-in-glass or liquid-in-metal thermometer using mercury as the liquid.

The height at which the maximum wind speed occurs, determined in a winds-aloft observation.

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 ...

Same as altimeter setting.

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

Situated on the side from which the wind blows.

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

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

See bimetallic thermometer.

An atmometer consisting of a porous porcelain or ceramic container connected to a calibrated reservoir filled with distilled water. Evaporation is determined by the depletion of water in the reservoir.

The portion of the strearnflow during any month or year derived from precipitation in previous months or years.

A line drawn through geographical points where a given seasonal biological event occurs on the same date.

Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas which are not normally submerged.

Automated Local Evaluation in Real Time. Network of automatic rain gauges that transmit via VHF radio link when precipitation occurs. Some sites are also equipped with other sensors such as temperature, wind, pressure, river stage or tide level. More info ...

A clock-driven instrument mounting which automatically and continuously points in the direction of the sun. It is used with a pyrheliometera,hen continuous direct solar radiation measurements are required.

The succession of stages through which water passes on the ground and in the atmosphere: evaporation from land or bodies of water, condensation to form clouds, precipitation, accumulation in the soil or in bodies of water, and re-evaporation.

A unit of energy equal to 101 ergs or to 0.2389 calories.

An instrument for measuring differences in electric potential.

An instrument which records the duration of sunshine and gives a quantitative measure of the amount of sunshine by the action of the sun's rays upon blueprint paper. A type of sunshine recorder.