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

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.

Same as evaporative power.

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

An instrument for the measurement of both solar and terrestrial radiation.

Atmospheric layer throughout which there is no change of temperature with height, i.e. a zero lapse rate.

A direct-vision nephoscope constructed in the following manner: A grid-work of bars is mounted horizontally on the end of a vertical column and made free to rotate about the vertical axis. The observer rotates the grid and adjusts his or her position unti ...

The atmospheric pressure at the level of the barometer. May or may not be the same as station pressure.

Abbreviation for precipitation-evaporation ratio.

Similar to the spectroheliograph, but used for visual instead of photographic purposes.

An early and once universal name for the mercury barometer.

Same as Aeolian.

Water vapor content of the air. See absolute humidity, dew point, mixing ratio, relative humidity, specific humidity.

Temperature to which absolutely dry air would have to be brought in order for it to have the same density as moist air, considered at the same pressure.

A counterclockwise change in wind direction. Backing winds with height are indicative of cold air advection (CAA).

A hydrometeor consisting of a visible aggregate of minute water and/or ice particles in the atmosphere above the earth's surface. Cloud differs from fog only in that the latter is, by definition, in contact with the earth's surface.

Sir Napier Shaw's name for the approximate absolute temperature scale,

The mean difference between the readings of a given instrument and those of a standard instrument.

A type of climatic diagram whose coordinates are some form of temperature vs. a form of humidity or precipitation.

Same as atmometer.