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.

A unit of luminous intensity of a light source.

See bimetallic thermometer.

Not a linear function of the relevant variables.

The audio-frequency signal transmitted by the Diamond-Hinman radiosonde when the baroswitch pen passes each fifteenth contact of the commutator, up to a number determined by the design of the commutator, and each fifth contact thereafter. This signal is t ...

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

See hydrologic accounting.

The outer, solid portion of the earth: the crust of the earth.

A unit of luminous flux. The lumen is equal to the luminous flux radiated into a unit solid angle (steradian) from a small source having a luminous intensity of one candle. An ideal source possessing an intensity of one candle in every direction would rad ...

A rocket designed primarily for routine upper air observations in the lower 250,000 feet of the atmosphere, especially that portion inaccessible to balloons (above 100,000 feet).

An instrument used to determine atmospheric pressure or elevation by observing the boiling point of water or both liquids. The sensitivity of the hypsometer increases with decreasing pressure, making it more useful for high altitude work.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

Nested Grid Model generated every 12 hours by NCEP.

Of or pertaining to rain.

That temperature at which, in a specified latitude, the reading of a particular barometer requires no temperature or latitude correction.

Instrument for measuring the intensity of radiant energy. Its principle is based on the variation of electrical resistance, with the incoming radiation, of one or both the metallic strips which the instrument comprises.

The measurement and computation of wind speeds and directions at various levels above the surface of the earth. Methods include pilot balloon observations, rabals, rawin or rawinsonde observations, radar tracking, or acoustic sounding.

The closeness of agreement among a number of consecutive output values measuring the same input value under the same operating conditions, approaching from the same direction. Usually measured as nonrepeatability but expressed as repeatability, a percenta ...

The mass density of a parcel of air expressed in units of mass per volume.

An instrument for measuring the ultraviolet in solar and sky radiation.