weather balloon

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weather balloon,

lighter-than-air craft without a propulsion system, lifted by inflation of one or more containers with a gas lighter than air or with heated air. During flight, altitude may be gained by discarding ballast (e.g.
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 used in the measurement and evaluation of mostly upper atmospheric conditions (see atmosphereatmosphere
[Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other planets and satellites are known, only the earth's atmosphere has been well studied, the science of
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). 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 buoyancybuoyancy
, upward force exerted by a fluid on any body immersed in it. Buoyant force can be explained in terms of Archimedes' principle.
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), 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 radiosonderadiosonde
, group of instruments for simultaneous measurement and radio transmission of meteorological data, including temperature, pressure, and humidity of the atmosphere.
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 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 satellitessatellite, artificial,
object constructed by humans and placed in orbit around the earth or other celestial body (see also space probe). The satellite is lifted from the earth's surface by a rocket and, once placed in orbit, maintains its motion without further rocket propulsion.
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 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.
References in periodicals archive ?
Project Mobility will assist ISON by providing transport and aiding in the design of the launch platform ground retaining mechanism, which will dock with and secure the launch platform safely to the ground, whilst its weather balloons are being inflated.
The weather balloon has been lost for only three and a half minutes.
The NWS launches approximately 75,000 weather balloons each year, the majority of which never are recovered.
Further enquiries established that the heap of mangled junk was in fact a faulty weather balloon which had fallen into the jail grounds from 10,000ft up.
Working alongside a major global player in the weather balloon industry, API's first hydrogen lift gas reactor production unit is now ready for demonstration to selected military and civil government customers next month.
A 20-foot-high, high-altitude weather balloon launched by a group of students from Irvington, N.
Even Russell Grant seems almost svelte-like compared to this useless beached whale of a man, flopping about in his presumably reinforced bed like some gross cross between a Sumo wrestler and a semi-deflated weather balloon.
Their quarry was a giant weather balloon as vast as Hampden Park and as tall as the Scott Monument.
To get around these problems, Zinke tried using a weather balloon with a plumb line but found that the line wasn't taut enough.
cartridges to generate 1,000 liters of hydrogen in 20 minutes to launch a 5-foot weather balloon.
May 5, 2015 /PRNewswire-USNewswire/ -- Approximately 125 people gathered in the Street Scene of College of DuPage's Homeland Security Education Center on the College's main campus in Glen Ellyn to see the launch of a meteorological weather balloon.
Dwynwen, a cuddly toy dragon, was attached to a weather balloon and sent nearly 112,000 feet (21 miles) above the earth's surface.