Occupational Safety and Health Administration. A regulatory office of the U.S. Department of Labor.

An instrument for rapidly obtaining samples of airborne dust; a type of dust counter. Particles pass through a cylindrical chamber, are drawn at high velocity through a narrow slit, and then impinge upon a microscope cover glass located a short distance f ...

Abbreviation for precipitation effectiveness index.

Abbreviation for precipitation-evaporation quotient.

Abbreviation for precipitation-evaporation ratio.

Abbreviation for the pressure, temperature, and humidity data obtained by a radiosonde observation.

Same as dropsonde.

A halo consisting of a faint white circle passing through the Sun and running parallel to the horizon for as much as 360

A form of data transmission in which the bits of each character are all sent simultaneously, resulting in extremely fast communication but requiring a communication path for each bit. Compare to serial data transmission.

A refraction phenomenon similar to a parahelion, but occurring generally at a distance of 120

A weakly colored lunar halo identical in form and optical origin to the solar parhelion.

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.

Either of two colored luminous spots that appear at points 22

The addition of one or more redundant bits to information to verify its accuracy.

Name given to the unit of pressure in the International System of Units (SI). Equal to 1 newton/meter2 or 0.01 millibar.

A hydrostatic principle that pressure supplied to an enclosed fluid is transmitted undiminished to every portion of the fluid and to the walls of the containing vessel.

in United States weather observing practice, the highest "instantaneous" wind speed recorded at a station during a specified period, usually the 24-hour observation day. Therefore, a peak gust need not be a true gust of wind.

A pressure-plate anemometer consisting of a plate which is free to swing about a horizontal axis in its own plane above its center of gravity. The angular deflection of the plate is a function of the wind speed. This instrument is not used for station mea ...

A pointed device which indicates the amount of resistance encountered when it is forced into a material such as snow or soil. See ram penetrometer.

The gravity flow of water within soil.