The upward force produced by the gas in a balloon. It is equal to the free lift plus the weight of the balloon and the attached equipment.

An ion counter of the aspiration condenser type, used for the measurement of the concentration and mobility of small ions in the atmosphere.

The inaccuracy that the manufacturer permits when the unit is calibrated in the factory.

A line drawn through points of equal humidity on given surface.

The water portion of the earth as distinguished from the solid part, called the lithosphere, and from the gaseous outer envelope, called the atmosphere.

That portion of the record of a microbarograph between any two (or a specified small number) of successive crossings of the average pressure level (in the same direction). Analogous to microseism.

An instrument which indicates the presence of dust particles in the atmosphere. Also spelled coniscope.

The sum of solar and terrestrial radiation.

The decrease of an atmospheric variable with height, the variable being temperature, unless otherwise specified.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

A large plastic constant-level balloon for duration flying at very high altitudes.

A graphical device used for the determination of the speed of the geostrophic wind from the isobar or contour-line spacing on a synoptic chart.

An instrument for measuring angles of inclination. Used in conjunction with a ceiling light to measure cloud height at night.

Same as pitot tube.

Wind with a speed between 22 and 27 knots (25 and 31 mph); Beaufort scale number 6.

A line of equal or constant pressure.

In a system of moist air, the dimensionless ratio of the mass of water vapor to the total mass of the system.

Apparatus using the combined simultaneous action of a bimetallic thermometer and a hair hygrometer to move a needle in front of a divided scale. fts construction permits dew point variations to be indicated approximately.

That part of snow melt that reaches stream channels as runoff.

The temperature to which a sample of air must be cooled, while the mixing ratio and barometric pressure remain constant, in order to attain saturation by water vapor. When this temperature is below O