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

The envelope of air surrounding the earth and bound to it more or less permanently by virtue of the earth's gravitational attraction. The system whose chemical Properties. dynamic motions, and physical processes constitute the subject matter of meteorolog ...

Barometer in which pressure is determined by balancing air pressure against the weight of a column of mercury in an evacuated glass tube.

By international agreement, a period during which greatly increased observation of world-wide geophysical phenomena is undertaken through the co-operative effort of participating nations. July 1957-December 1958 was the first such year. However, precedent ...

An instrument for measuring the intensity of light or the relative intensity of a pair of lights. Also called an illuminometer. If the instrument is designed to measure the intensity of light as a function of wavelength, it is called a spectrophotometer. ...

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

The energy of any type of electromagnetic radiation. Also called radiation.

force wind-Wind with a speed above 64 knots (73 mph); Beaufort scale numbers 12 through 17.

A very sensitive electrostatic electrometer for measuring small potential differences.

National Centers for Environmental Prediction. Central computer and communications facility of the National Weather Service; located in Washington, DC.

The amount of sky covered or concealed by clouds or obscuring phenomena. It is reported in tenths, so that 0.0 indicates a clear sky and 1.0 (or 10/10) indicates a completely covered sky. The following classifications are used in aviation weather observat ...

The elevation of the water surface in a stream as measured by a river gauge with reference to some arbitrarily selected zero datum.

A clock-driven device for recording the time of occurrence of an event or the time interval between the occurrence of events.

Navy Operational Global Atmospheric Prediction System. A global meteorological model operated by the Department of Defense.

A definite portion of a stream channel, commonly taken between two gauging stations, but may be taken between any two specified points.

A device, similar to a phytometer, for measuring transpiration. It consists of a small vessel containing water and sealed so that the only escape of moisture is by transpiration from a leaf, twig, or small plant with its cut end inserted in the water.

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

A graphical representation of a frequency distribution. The range of the variable is divided into class intervals for which the frequency of occurrence is represented by a rectangular column. The height of the column is proportional to the frequency of ob ...

A thermometer. the sensitive element of which consists of two metal strips which have different coefficients of expansion and are brazed together. The distortions of the system in response to temperature variations are used as a measure of temperature. It ...

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