weather balloon

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Weather balloon

The invention of the weather balloon inaugurated the age of remote sensing , the ability to collect information from unmanned sources. Use of weather balloons is now common in advanced atmospheric research. High altitude weather balloons have also been used by astronomers and cosmologists seeking to take readings of certain particle frequencies or gather light readings free of excessive disturbance from Earth's relatively thick lower atmosphere (troposphere ).

The first observation balloon was launched immediately before the first manned balloon flight by Frenchmen Jean-François de Rozier and the Marquis d'Aalandes on November 21, 1783, for a pre-flight wind reading. Later, French meteorologist Leon Teisserenc de Bort (1855-1913) pioneered the use of weather balloons, handily proving their utility. With balloon-acquired data, he determined the existence of a lower level of the atmosphere, which he termed the troposphere or "sphere of change," where weather takes place. Since the 1930s, when radio tracking systems were invented, balloons have been used as complete floating weather stations, employing such instruments as thermometers, barometers, hygrometers, cameras, and telescopes.

A variety of agencies use weather balloon flights to model the atmosphere and to make more accurate weather predictions. Weather balloons are used widely to collect such atmospheric information as temperature , pressure, and humidity that can then be plotted on weather maps. Three-dimensional atmospheric modeling is also possible using weather balloons because the instruments they carry are able to provide meteorologists and other atmospheric scientists data collected from a number of altitude points. Since their inception, the elongated bags of helium, a lighter than air element that provides the balloon lift, have been carrying aloft increasingly sophisticated observation devices, taking the science of weather observation literally to the edges of outer space .

See also Air masses and fronts; Atmospheric composition and structure; Atmospheric pressure; Atomic mass and weight; History of exploration III (Modern era); History of manned space exploration; International Council of Scientific Unions' World Data Center System; Jet stream; Stratosphere and stratopause; Weather forecasting methods

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weather balloon,balloon used in the measurement and evaluation of mostly upper atmospheric conditions (see atmosphere). Information may be gathered during the vertical ascent of the balloon through the atmosphere or during its motions once it has reached a predetermined maximum altitude. Today, atmospheric information is most often gathered by height-finding radar, remote sensing by earth-orbiting or stationary satellites, and aircraft instruments, with weather balloons augmenting the data. Helium, which is less dense than air (see buoyancy), is usually used to inflate weather balloons. A pilot balloon is a small balloon (diameter c.1 m/39 in.) whose ascent is followed visually to obtain data for the computation of the speed and direction of winds at different altitudes. A smaller ceiling balloon is used to determine the altitude of cloud bases. A much larger, teardrop-shaped balloon is used to carry a radiosonde aloft. The balloon expands as it rises, usually reaching an altitude of at least 90,000 ft (27,400 m) before it bursts. A small parachute lowers the instruments to the ground. Teardrop-shaped balloons are also used for horizontal sounding of the atmosphere. Atmospheric pressure, temperature, and humidity information may be sent by radio from a balloon; monitoring of its movement provides information about winds at its flight level. Techniques also have been developed whereby many horizontal sounding balloons can be monitored by earth-orbiting satellites that relay information to earth-based stations. The tetroon is a tetrahedral balloon used for horizontal sounding. It was developed to withstand the extremely low pressures of high-altitude flight; the straight seals joining its four triangular faces are stronger than the curved seals of the more traditionally shaped balloons. Tetroons have been used extensively in tracing low-level atmospheric currents by following their movement with radar; they have thus increased the meteorologist's understanding of atmospheric turbulence, low-level vertical motions, and air pollution dispersion.

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ceiling balloon: see weather balloon.

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pilot balloon: see weather balloon.