The meteorological visual range, which can be estimated from the average extinction coefficient using the Koschmieder equation.

A river gauge in which a weight suspended on a wire is lowered to the water surface from a bridge or other overhead structure to measure the distance from a point of known elevation to the water surface.

The ratio of the existing amount of water vapor in the air at a given temperature to the maximum amount that could exist at that temperature. Usually expressed in percent.

A modification of the dew cell used in radiosonde equipment.

The array of indicating marks and figure in relation to which the position of an index is observed, i.e. a scale plate on a recorder.

An instrument which measures the spectral distribution of the intensity of direct solar radiation.

The record of an aneroid barograph.

The maximum rate at which precipitation can pass through the surface into the soil, for a given soil in a given condition.

A mercury barometer which measures atmospheric pressure by weighing the mercury in the column or cistern.

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

Technically, the temperature registered by the dry-bulb thermometer of a psychrometer. However, it is identical with the temperature of the air and may also be used in that sense.

One of the radiation laws which states that the wavelength of maximum radiation intensity for a black body is inversely proportional to the absolute temperature of the radiating black body.

A sounding balloon which, when operationally inflated, resembles an inverted teardrop.

See gust and peak gust.

Same as humidity strip.

The actual time during which physical events take place.

Of or pertaining to rain.

Readily taking up and retaining moisture.

The record made by a hygrograph.

The size of the area comprising a watershed or river basin. Also called catchment area.