A standard unit of atmospheric pressure, defined as the pressure exerted by a 760 mm column of mercury at standard gravity (980.665 cm/sec2 ) at O

A cone-tipped metal rod designed to be driven downward into deposited snow or firn. The measured amount of force required to drive the rod a given distance is an indication of the physical properties of the snow or firn.

The energy of any type of electromagnetic radiation. Also called radiation.

In folklore, a name for rain.

In physics, any process in which the flux density (or power, amplitude, intensity, illuminance, etc.) of a "parallel beam" of energy decreases with increasing distance from the source. Attenuation is always due to the action of the transmitting medium its ...

Wind with a speed between 41 and 47 knots (47 and 54 mph); Beaufort scale number 9.

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

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

A balloon designed to float at a constant pressure level. This may be accomplished by a pressure valve which controls the release of ballast so as to maintain flight above a selected pressure level until the supply of ballast is exhausted. See Moby Dick b ...

An up slope wind due to local surface heating. Opposite of katabatic wind.

A measure of the amount of "spin" (or rotation) in the atmosphere.

A semiconductor which exhibits rapid and extremely large changes in resistance for relatively small changes in temperature.

A liquid-in-metal thermometer in which mercury is enclosed in a steel envelope. The change in internal pressure caused by the temperature variation is measured by a Bourdon tube which is connected to the mercury by a capillary tube. This instrument is hig ...

A temperature scale on which the freezing point of water equals 32

See instrument error, observational error. random error, standard error, systematic error.

See photometer.

Solar radiation scattered by particles in the atmosphere.

In a radiosonde observation, a level (other than a standard level) for which values of pressure, temperature, and humidity are reported because temperature and/or humidity data at that level is sufficiently important or unusual to warrant the attention of ...

A measure of long-term precipitation effectiveness. The ratio of the normal annual rainfall to the normal annual evaporation.

A measure of the relative power, or of the relative values of two flux densities, especially of sound intensities and radar power densities. The decibel is derived from the less frequently used unit, the bel, named in honor of Alexander Graham Bell.