An instrument for studying, or examining substances in, polarized light. See Savant polariscope.

The programs and instructions which direct a computer.

The component of the radiosonde which includes the modulating blocking oscillator and the radiofrequency carrier oscillator.

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.

A protective coating applied to circuits.

Read Only Memory. A memory that cannot be altered in normal use of a computer, Usually used to store information permanently, such as firmware programs.

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

A type of disk hardness-gauge, especially useful in relatively soft snow. See disk hardness gauge.

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

An instrument for measuring the intensity of direct solar radiation at normal incidence. See Angstrom compensation pyrheliometer, Eppley pyrheliometer, Michaelson actinograph. silver- disc pyrheliometer, spectropyrheliometer, waterflow pyrheliometer.

A thermometer based upon the principle that the velocity of a sound wave is a function of the temperature of the medium through which it passes. Sonic thermometers possess very short time-constants and eliminate radiation error.

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

See evaporation pan.

A clockwise change in wind direction. Veering winds with height are indicative of warm air advection (WAA).

Having a specific relationship to a time base or clock. In synchronous communications, data characters are sent according to a timing signal which synchronizes the two communicating devices.

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

A sudden, significant increase in station pressure.

A very sensitive electrostatic electrometer for measuring small potential differences.

A method of winds aloft observation in which the elevation and azimuth angles of a theodolite are read while visually tracking a pilot balloon. Balloon height data is estimated from assumed balloon ascension rates.

A device used by oceanographers to obtain subsurface samples of sea water. The "bottle" is lowered by wire, its valves open at both ends. It is then closed in situ by allowing a weight (called a messenger) to slide down the wire and strike the reversing m ...