A balloon having a detachable tail which is released when the balloon has undergone a predetermined expansion. It thus serves to measure approximately the density of the atmosphere at the point of release.

Wind with a speed between 11 and 16 knots (13 and 18 mph); Beaufort scale number 4.

A type of instrument shelter. It is a wooden box painted white with double louvered sides and mounted on a stand four feet above the ground.

A line drawn through geographical points where a given seasonal biological event occurs on the same date.

A radiosonde whose carrier wave is switched on and off in such a manner that the interval of time between the transmission of signals if a function of the magnitude of the meteorological elements being measured.

For a given locality and month, an empirical expression devised for the purpose of classifying climates numerically on the basis of precipitation and evaporation.

An instrument whose calibration is determined by comparison with an absolute instrument.

Abbreviation for precipitation-evaporation quotient.

Dihydrogen oxide, molecular formula H2O.

An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

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

See evaporative opportunity.

A recording magnetometer.

A type of rain gauge shield consisting of freely hanging, evenly spaced slats arranged circularly around the gauge. The advantage of this shield is that the slats do not easily accumulate snow, permitting its use on unattended gauges. See rain gauge shiel ...

A protocol similar to RS232 which makes use of differential transmission to provide high speed data transmission over significantly longer distances.

Abbreviation for precipitation effectiveness index.

Either of two colored luminous spots that appear at points 22

Name applied to a class of instruments which measure the liquid content of the atmosphere.

General term for an instrument which records the vertical electric current in the atmosphere.

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 ...