A recording siphon barometer.

An instrument for measuring the extinction coefficient in water.

A conductor or system of conductors for radiating and/or receiving radio energy. Also called aerial.

Same as instrument shelter.

Any one of a family of circular arcs consisting of concentric colored bands, arranged from red on the inside to blue on the outside, which may be seen on a "sheet" of water drops (rain, fog, spray). The most common of the many possible is the primary rain ...

Transmitted energy which is modulated in order to carry information. Usually, it is in the form of a radio- frequency sine wave, modulated either in amplitude or in frequency.

The ratios, to the mean wind speed, of the average magnitudes of the component fluctuations of the wind along three mutually perpendicular axes.

In meteorology, an area of low pressure; a low or trough.

See sea-water thermometer, reversing thermometer.

An atmometer consisting of a porous porcelain or ceramic container connected to a calibrated reservoir filled with distilled water. Evaporation is determined by the depletion of water in the reservoir.

The portion of the precipitation on the land which ultimately reaches the streams. especially the water from rain or melted snow that flows over the surface.

An instrument, located at the surface observing station, which is used to record the data presented by a radiosonde aloft.

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

Routine broadcast of meteorological information for aircraft in flight.

A flower-like diagram indicating the relative frequencies of different wind directions for a given station and period of time.

Fine dust or salt particles dispersed through a portion of the atmosphere; a type of lithometer. The particles are so small they cannot be felt or seen with the naked eye. Many haze formations are caused by the presence of an abundance of condensation nuc ...

A basic equation in daytime visual range theory, relating the apparent luminance of a distant black object, the apparent luminance of the background sky above the horizon, and the extinction coefficient of the atmosphere, or the air layer near the ground. ...

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

A type of precipitation composed of unbranched crystals in the form of needles, columns, or plates. Usually has a very slight downward motion and may fall from a cloudless sky.

Defect in the action of an aneroid barometer resulting in a sluggish adjustment of the index toward the correct reading when the barometer is subjected to a large and rapid change in pressure.