An instrument resulting from the combination of a thermograph and a hygrograph and furnishing, on the same chart, simultaneous time recording of ambient temperature and humidity.

Routine broadcast of meteorological information for aircraft in flight.

A type of electrical thermometer in which the thermal element is a substance whose electrical resistance varies with the temperature. Such thermometers can be made with very short time constants and are capable of highly accurate measurements.

A standard interface between a computer input/output port and a peripheral device. Signal properties including time duration, voltage. and current, are specified by the Electronic Industries Association.

The depth of water that would result from the melting of snow or ice, assuming measurement on a horizontal surface and no infiltration or evaporation.

An instrument for measuring the relative speed of a fluid. It consists of a concentric pipe arrangement in which the inner pipe is open at one end and the outer pipe is perforated and closed at both ends. Each pipe is connected to a manometer. The unit is ...

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 ...

The visibility along an identified runway, determined from a specified point on the runway with the observer facing in the same direction as a pilot using the runway. Compare to runway visible range.

Precipitation of very small, white opaque particles of ice, fairly flat or elongated, with diameters less than 1 mm. The solid equivalent of drizzle.

Similar to the spectroheliograph, but used for visual instead of photographic purposes.

An instrument which measures the scattering function of particles suspended in a medium in order to determine the visual range through the medium. See visibility meter.

The gravity flow of water within soil.

In a system of moist air, the ratio of the mass of water vapor to the total volume of the system. Usually expressed as grams per cubic meter (g/m3).

Rain gauge which registers precipitation that is too light to be registered by ordinary recording of the depth of water from precipitation. Same as ombrometer.

The direction from which the wind is blowing, measured in points of the compass or in azimuth degrees.

Based upon damage patterns, classifies twisters into six categories of wind speed (F0 thru F5), ranging from 40 to 318 mph estimated wind speed.

An instrument which determines the black-body temperature of a substance by measuring its thermal radiation.

A fixed support for mounting maximum and minimum thermometers of the liquid-in-glass type. The support holds the thermometers at the correct operating attitude and also permits their rotation for resetting when desired.

A term used to describe a sensor (or sensors), the associated transducer(s), and the data readout or recording device.

The most common of the principal rainbow phenomena, which appears as an arc of about 42