Weather balloon
Overview
 
A weather or sounding balloon is a balloon
Balloon
A balloon is an inflatable flexible bag filled with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were made of dried animal bladders, such as the pig...

 (specifically a type of high altitude balloon
High altitude balloon
High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere, generally reaching between ....

) which carries instruments aloft to send back information on atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

, temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

, humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 and wind speed by means of a small, expendable measuring device called a radiosonde
Radiosonde
A radiosonde is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz and both types may be adjusted slightly higher or lower as required...

. To obtain wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

 data, they can be tracked by radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

, radio direction finding
Direction finding
Direction finding refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication...

, or navigation systems (such as the satellite based Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 (GPS).
One of the first people to use weather balloons was Léon Teisserenc de Bort
Léon Teisserenc de Bort
Léon Philippe Teisserenc de Bort was a French meteorologist who became famous for his discovery of the stratosphere...

, the French meteorologist.
Encyclopedia
A weather or sounding balloon is a balloon
Balloon
A balloon is an inflatable flexible bag filled with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were made of dried animal bladders, such as the pig...

 (specifically a type of high altitude balloon
High altitude balloon
High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere, generally reaching between ....

) which carries instruments aloft to send back information on atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

, temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

, humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 and wind speed by means of a small, expendable measuring device called a radiosonde
Radiosonde
A radiosonde is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz and both types may be adjusted slightly higher or lower as required...

. To obtain wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

 data, they can be tracked by radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

, radio direction finding
Direction finding
Direction finding refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication...

, or navigation systems (such as the satellite based Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 (GPS).

History

One of the first people to use weather balloons was Léon Teisserenc de Bort
Léon Teisserenc de Bort
Léon Philippe Teisserenc de Bort was a French meteorologist who became famous for his discovery of the stratosphere...

, the French meteorologist. Starting in 1896 he launched hundreds of weather balloons from his observatory in Trappes
Trappes
Trappes is a commune in the Yvelines department in the Île-de-France in north-central France. It is located in the western suburbs of Paris from the center in the new town of Saint-Quentin-en-Yvelines.-Transport:...

, France. These experiments lead to his discovery of the tropopause
Tropopause
The tropopause is the atmospheric boundary between the troposphere and the stratosphere.-Definition:Going upward from the surface, it is the point where air ceases to cool with height, and becomes almost completely dry...

 and stratosphere
Stratosphere
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler...

.

Materials and equipment

The balloon itself produces the lift
Lifting gas
Because of the Archimedes' principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air . Only certain lighter than air gases are suitable as lifting gases.- Hot Air :...

, and is usually made of a highly flexible latex material, though Chloroprene
Chloroprene
Chloroprene is the common name for the organic compound 2-chlorobuta-1,3-diene, which has the formula CH2=CCl-CH=CH2. This colorless liquid is the monomer for the production of the polymer polychloroprene, a type of synthetic rubber...

 may also be used. The unit that performs the actual measurements and radio transmissions
Transmission (telecommunications)
Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...

 hangs at the lower end of the string, and is called a radiosonde
Radiosonde
A radiosonde is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz and both types may be adjusted slightly higher or lower as required...

. Specialized radiosondes are used for measuring particular parameters, such as determining the ozone
Ozone layer
The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...

 concentration.

The balloon is usually filled with hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 due to lower cost, though helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

 can also be used. The ascent rate can be controlled by the amount of gas with which the balloon is filled. Weather balloons may reach altitudes of 40 km (25 miles) or more, limited by diminishing pressures causing the balloon to expand to such a degree (typically by a 100:1 factor) that it disintegrates. In this instance the instrument package is usually lost . Above that altitude sounding rocket
Sounding rocket
A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The origin of the term comes from nautical vocabulary, where to sound is to throw a weighted line from a ship into...

s are used, and for even higher altitudes satellites are used.

Major manufacturers of balloons are Zhuzhou Research & Design Institute, Chemchina Rubber Corp (Brand: Hwoyee)[China], Totex
Totex
Totex Corporation is a Japanese manufacturer of meteorological balloons. The company began production of balloons in 1937.They currently produce three types of balloons:*TA is a rubber/latex balloon and was developed in 1940....

 and Cosmopren of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 and Pawan Rubber Products (Pawan Exports, Brand: PAWAN) of India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

,

Weather balloons are sometimes cited as the cause of unidentified flying object
Unidentified flying object
A term originally coined by the military, an unidentified flying object is an unusual apparent anomaly in the sky that is not readily identifiable to the observer as any known object...

 sightings, and are also used for cluster ballooning
Cluster ballooning
Cluster ballooning is a form of ballooning where a harness attaches a balloonist to a cluster of helium-inflated rubber balloons.Unlike traditional hot-air balloons, where a single large balloon is equipped with vents enabling altitude control, cluster balloons are multiple, small, readily...

.

Launch time, location, and uses

Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and computer models
Numerical weather prediction
Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. Though first attempted in the 1920s, it was not until the advent of computer simulation in the 1950s that numerical weather predictions produced realistic...

 for weather forecasting
Weather forecasting
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, and formally since the nineteenth century...

. About 800 locations around the globe do routine releases, twice daily, usually at 0000 UTC
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

 and 1200 UTC. Some facilities will also do occasional supplementary "special" releases when meteorologists determine there is a need for additional data between the 12 hour routine launches in which time much can change in the atmosphere. Military and civilian government meteorological agencies such as the National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...

 in the US typically launch balloons, and by international agreements almost all the data is shared with all nations.

Specialized uses also exist, such as for aviation interests, pollution monitoring, photography or videography and research. Examples include pilot balloon
Ceiling balloon
A ceiling balloon is used by meteorologists to determine the height of the base of clouds above ground level during daylight hours.The principle behind the ceiling balloon is a balloon with a known ascent rate and determining how long the balloon rises until it disappears into the cloud.Ascent...

s (Pibal). Field research programs often use mobile launchers from land vehicles as well as ships and aircraft (usually dropsonde
Dropsonde
A dropsonde is a weather reconnaissance device created by the National Center for Atmospheric Research , designed to be dropped from an aircraft at altitude to more accurately measure tropical storm conditions as the device falls to the surface...

s in this case).

See also

  • High altitude balloon
    High altitude balloon
    High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere, generally reaching between ....

  • Radiosonde
    Radiosonde
    A radiosonde is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz and both types may be adjusted slightly higher or lower as required...

  • SCR-658 radar
    SCR-658 radar
    The SCR-658 radar was developed in conjunction with the SCR-268 radar. It was preceded by the SCR-258. Its primary purpose was to track weather balloons. Prior to this it was only possible to track weather balloons with a theodolite, causing difficulty with visual tracking in poor weather conditions...

  • Timeline of hydrogen technologies
    Timeline of hydrogen technologies
    Timeline of hydrogen technologies — A timeline of the history of hydrogen technology.-1600s:* 1625 - First description of hydrogen by Johann Baptista van Helmont...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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