A rocket designed primarily for routine upper air observations in the lower 250,000 feet of the atmosphere, especially that portion inaccessible to balloons (above 100,000 feet).

That horizontal wind velocity at which the Coriolis acceleration exactly balances the horizontal pressure force. It is directed along contour lines or isobars.

Any wind blowing down an incline. If warm, it is a foehn. If cold, it may be a fall wind or a gravity wind.

Video Display Terminal. An input and display device which includes a keyboard and a screen and allows a human to communicate with a computer.

Very small precipitation drops (diameters less than 0.5 mm) that appear to float with air currents while falling in an irregular path. Unlike fog droplets, drizzle falls to the ground.

Downward scattered and reflected solar radiation, coming from the whole hemisphere with the exception of the solid angle of the sun's disc on a surface perpendicular to the axis of this cone.

An instrument used for the determination of the electrical conductivity of the atmosphere.

A buoyant balloon kept from rising freely by means of a line secured to a point on the ground, as opposed to a free balloon. See kytoon.

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

A set of regulations set down by the U.S. Civil Aeronautics Board to govern the operational control of aircraft on instrument flight. The abbreviation of this term is seldom used to denote the rules themselves, but is in popular use to describe the weathe ...

The temperature registered by a thermometer with its bulb at the level of the tops of the grass blades in short turf.

See wind vane.

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

Complementary Metal-Oxide Semiconductor. A method of making silicon chips that results in low power consumption by the circuits.

Name sometimes given to a transmissometer.

Any emission of light at temperatures below that required for incandescence.

Wind with a speed between 7 and 10 knots (8 and 12 mph), Beaufort scale number 3.

The actual lifting force of an inflated balloon, usually expressed in grams.

A faintly-colored circular arc similar to a rainbow but formed on fog layers containing drops whose diameters are 100 microns or less. Also called mistbow, white rainbow.

The lowest value of a measured quality at which a sensor responds. Compare to tracking.