A balloon-borne instrument for the simultaneous measurement and transmission of meteorological data. It includes transducers for the measurement of pressure, temperature, and humidity; a modulator for the conversion of the output of the transducers to a q ...

A rainbow of angular radius of about 50

The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

The amount of precipitation captured by a rain gauge.

A sudden brief increase in the speed of the wind, followed by a lull or slackening. Compare to peak gust.

A wooden enclosure about sixteen feet square and eight feet high with a precipitation gauge at its center. The function of the fence is to minimize eddies around the gauge and thus insure a catch that is representative of the actual rainfall or snowfall.

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

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).

A barometer which measures atmospheric pressure using one or a series of aneroid capsules. Also called holosteric barometer.

A self-recording instrument used on aircraft for the simultaneous recording of atmospheric pressure, temperature, and humidity.

To free something from the binding action of ice by warming it to a temperature above the melting point of ice. Also, a warm spell when ice and snow melt.

Graduated fixed stake used in regions of abundant snowfall to facilitate the measurement of snow depth.

An instrument whose calibration can be determined by means of simple physical measurements on the instrument. Compare to secondary instrument.

Reduction of visibility by strong winds blowing across dry ground with little or no vegetation. Visibilities of 1/8 mile or less over a widespread area are criteria for a Blowing Dust Advisory.

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

The lowest level at which the wind becomes geostrophic in the theory of the Ekman spiral. Also called gradient wind level.

Hygrometer in which the dew (frost) point is determined by observing the temperature of an artificially cooled surface at the moment at which dew (frost) first appears on it.

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

General name for an instrument which measures the earth's magnetic field intensity.

Same as ceiling light.