The difference between the outgoing infrared terrestrial radiation of the earth's surface and the downcoming infrared counterradiation from the atmosphere.

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.

Sustained winds greater than or equal to 40 mph or gust greater than or equal to 58 mph.

Instrument for measuring the depth to which the soil is frozen.

The change in a performance characteristic caused by a change in a specified operating condition from reference operating condition, all other conditions being held within the limits of reference operating conditions.

The ratio of the output of an instrument to the input value, i.e. a rain gauge with a sensitivity of 1 tip per 0.01"

A very sensitive electrostatic electrometer for measuring small potential differences.

A system of physical units based upon the use of the meter, the metric ton (106 grams), and the second as elementary quantities of length, mass, and time, respectively.

The amount of moisture which, if available, would be removed from a given land area by evapotranspiration. Expressed in units of water depth.

The time required for an instrument to register a designated percentage (frequently 90%) of a step change in the variable being measured.

Same as Aeolian.

A small balloon, loaded with ballast and inflated so that it will explode at a predetermined altitude, which is attached to a larger balloon.

The height of the cloud base above the local terrain.

A relatively small-scale, upward moving current of air.

A vector term which includes both wind speed and wind direction.

Wind with a speed between 28 and 33 knots (32 and 38 mph); Beaufort scale number 7.

The difference between the input quantity applied to a measuring instrument and the output quantity indicated by the instrument. The inaccuracy of an instrument is equal to the sum of its instrument error and its uncertainty.

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 ...

Same as instrument shelter.

The volume of water required to cover one acre to a depth of one foot: 43,560 cubic feet.