Board that holds graph paper on which is plotted information obtained from a pilot-balloon observation.

Anemometer which measures wind speed by measuring the degree of cooling of a metal film heated by an electric current. A type of cooling-power anemometer.

A system in which radar techniques are used to determine the range, elevation, and azimuth of a radar target carried a!oft by a radiosonde, so that wind data may be obtained along with the other meteorological data.

A buoyant balloon rising freely in the atmosphere, as opposed to a captive balloon.

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

The officially designated elevation of an airport above mean sea level, taken as the highest point on any of the runways of the airport. Same as airport elevation.

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

Apparatus designed to measure and record the size distribution of raindrops as they occur in the atmosphere.

Snow gauge composed of a metal cylinder, closed at one end, used to obtain a sample of snow from which the water is measured after melting.

A small, limited-capacity central processing unit contained entirely on one semiconductor chip.

A graphical representation of stage or discharge at a point on a stream as a function of time.

See sea-water thermometer, reversing thermometer.

See captive balloon, ceiling balloon, constant-level balloon, free balloon, hurricane beacon, kytoon, Moby Dick balloon, pilot balloon, radiosonde balloon, rockoon, skyhook balloon, transosonde.

The limiting values of ceiling, visibility, and wind, or runway visual range, established as safety minimum for aircraft landings and take-offs.

A general term for instruments designed to measure the amount of cloudiness.

A record obtained from a meteorograph. A chart in which meteorological variables are plotted against time.

An instrument, dropped from high attitude and carried by a stable parachute. used to measure the vertical component of turbulence aloft.

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.

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.

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.