A wind (or component thereof) directed down the slope of an incline and caused by greater air density near the slope than at the same levels some distance horizontally from the slope. Also called drainage wind and sometimes called katabatic wind.

The stage on a fixed river gauge at which it is necessary to begin issuing warnings or river forecasts if adequate precautionary measures are to be taken before flood stage is reached.

In general. the severe wind of an intense tropical cyclone (hurricane or typhoon). The term has no further technical connotation, but, unfortunately, is easily conftlsed with the strictly defined hurricane-force wind,

A sunshine recorder of the type in which the time scale is supplied by the motion of the sun. It consists of two opaque metal semi-cylinders mounted with their curved surfaces facing each other. Each of the semi-cylinders has a short narrow slit in its fl ...

Electromagnetic radiation of very short wavelength. lying within the wavelength interval of 0.1 to 1.5 angstroms (between gamma rays and ultraviolet radiation). X-rays penetrate various thicknesses of all solids, and they act on photographic plates in the ...

A class of rain gauge in which the level of the collected rain water is measured by the position of a float resting on the surface of the water.

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.

A recording anemometer.

The smallest change in the environment that causes detectable change in the indication of an instrument. Compare to sensitivity.

A hygrometer which includes an arrangement for the time recording of atmospheric humidity.

variable audio-modulated radiosonde developed at the Bureau of Standards and used by the United States weather services.

Any and all forms of water particles, liquid or solid, that fall from the atmosphere and reach the ground.

One of the radiation laws which states that the wavelength of maximum radiation intensity for a black body is inversely proportional to the absolute temperature of the radiating black body.

An elongated area of relatively high pressure. Usually associated with and most clearly identified as an area of maximum anticyclonic curvature of the wind flow. The opposite of a trough.

Any conventional barometer fitted with an extended scale so that atmospheric pressure measurements may be made at both high and low altitudes.

The unit of acceleration in the centimeter-gram-second system of units, equal to one cm per sec2. Commonly used in gravimetry.

Name sometimes given to a transmissometer.

A halo phenomenon consisting of a horizontal circle passing through the moon, corresponding to the parhelic circle through the sun. Produced by reflection of moonlight from ice crystals.

The transducer of any hygrometer, i.e. that part of a hygrometer that quantitatively "senses" atmospheric water vapor.

modulated radiosonde-A radiosonde which transmits the indications of the meteorological sensing elements in the form of pulses spaced in time. The meteorological data are evaluated from the intervals between the pulses. Also called timeinterval radiosonde ...