Either of two colored luminous spots that appear at points 22

A tube designed to measure the rate of flow of fluids. It consists of a tube having a constriction or throat at its midsection. The difference between the pressure measured at the inlet and at the throat is a function of the fluid velocity. Compare to Pit ...

A measurement of atmospheric conditions aloft, above the effective range of a surface weather observation. Elements evaluated include temperature, humidity, pressure, wind speed, and wind direction.

Defect in the action of an aneroid barometer resulting in a sluggish adjustment of the index toward the correct reading when the barometer is subjected to a large and rapid change in pressure.

A general term for instruments designed to measure the amount of cloudiness.

A recording hair hygrometer.

Winds which, over a small area, differ from those which would be appropriate to the general pressure distribution.

An instrument that shows changes in humidity.

An atmospheric sounding instrument which is supported by a captive balloon and used to obtain temperature and humidity data from the ground level to a height of a few thousand feet. The data is telemetered to the ground through a wire cable.

check chamber-A chamber use to check the sensing elements of radiosonde equipment.

The pressure unit of the meter-ton-second system of physical units. equal to 10 millibars or 101 dynes per cm2.

A method of winds aloft observation accomplished by tracking a balloon-borne radar target or radiosonde with either radar or a radio theodolite.

Abbreviation for visual flight rules, but commonly used to refer to the relatively favorable weather and/or flight conditions to which these rules apply.

A line drawn through all points on a map having the same amount of cloudiness.

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

The boundary between the troposphere and stratosphere, usually characterized by an abrupt change in lapse rate. Its height varies from 10 to 20 km. Regions above the tropopause have greater atmospheric stability than regions below.

Literally "not wet", containing no liquid.

A high-altitude sounding system consisting of a small solid- propellant research rocket carried aloft by a large plastic balloon. The rocket is fired near the maximum altitude of the balloon flight.

The cardinal points of the compass, i.e. north, south, east, west.

Binary Coded Decimal. A coding system in which each decimal digit from 0 to 9 is represented by a 4-digit binary number.