View source for Earth:Weather balloon

{{Short description|High-altitude balloon to which meteorological instruments are attached}}

[[File:Transosonde.png|thumb|Transosonde ready for release]]
[[File:Picture taken at aprox. 100,000 feet above Oregon by Justin Hamel and Chris Thompson.jpg|thumb|Picture taken at approximately 30 km above Oregon using a 1,500 gram weather balloon]]
[[Image:nssl0020.jpg|thumb|upright|Rawinsonde weather balloon just after launch. Notice a parachute in the center of the string and a small instrument box at the end. After release it measures many parameters. These include temperature, relative humidity, pressure, and wind speed and wind direction. This information is transmitted back to surface observers.]]

A '''weather balloon''', also known as a '''sounding balloon''', is a balloon (specifically a type of high-altitude balloon) that carries instruments to the stratosphere to send back information on [[Physics:Atmospheric pressure|atmospheric pressure]], [[Physics:Temperature|temperature]], [[Physics:Humidity|humidity]] and [[Physics:Wind speed|wind speed]] by means of a small, expendable measuring device called a [[Earth:Radiosonde|radiosonde]]. To obtain [[Earth:Wind|wind]] data, they can be tracked by [[Engineering:Radar|radar]], radio [[Direction finding|direction finding]], or navigation systems (such as the satellite-based [[Engineering:Global Positioning System|Global Positioning System]], GPS).  Balloons meant to stay at a constant altitude for long periods of time are known as ''transosondes''.  Weather balloons that do not carry an instrument pack are used to determine upper-level winds and the height of cloud layers.  For such balloons, a [[Physics:Theodolite|theodolite]] or [[Physics:Total station|total station]] is used to track the balloon's [[Azimuth|azimuth]] and elevation, which are then converted to estimated wind speed and direction and/or cloud height, as applicable.

Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and [[Earth:Numerical weather prediction|computer models]] for [[Earth:Weather forecasting|weather forecasting]]. Between 900 and 1,300 locations around the globe do routine releases, two or four times daily.<ref name=":0" /><ref name=WOUK>{{Cite web|title=Weather Facts: Radiosonde &#124; weatheronline.co.uk|url=https://www.weatheronline.co.uk/reports/wxfacts/Radiosonde.htm|access-date=2023-04-06|website=www.weatheronline.co.uk|language=en-GB}}</ref><ref name=WMO>{{Cite web|date=2015-12-01|title=Observations - Data - Modelling|url=https://public-old.wmo.int/en/our-mandate/what-we-do/observations|archive-url=https://web.archive.org/web/20231218181556/https://public-old.wmo.int/en/our-mandate/what-we-do/observations|url-status=dead|archive-date=18 December 2023|access-date=2023-04-06|website=public.wmo.int|language=en}}</ref><ref name=WeatherSTEM>{{Cite web|last=WeatherSTEM|title=Upper-Air Observations|url=https://learn.weatherstem.com/modules/learn/lessons/120/11.html|access-date=2023-04-06|website=WeatherSTEM|language=en}}</ref>

== History ==
One of the first people to use weather balloons was [[Biography:Léon Teisserenc de Bort|Léon Teisserenc de Bort]], the French [[Meteorologist|meteorologist]].  Starting in 1896 he launched hundreds of weather balloons from his observatory in Trappes, France.  These experiments led to his discovery of the [[Earth:Tropopause|tropopause]] and [[Earth:Stratosphere|stratosphere]].<ref name=eb>{{Cite EB1922|wstitle=Teisserenc de Bort, Léon Philippe}}</ref>  Transosondes, weather balloons with instrumentation meant to stay at a constant altitude for long periods of time to help diagnose radioactive debris from atomic fallout, were experimented with in 1958.<ref>{{cite web|author=Staff|url=http://docs.lib.noaa.gov/rescue/wb_topicsandpersonnel/1958.pdf|title=Chief Special Projects Section: Dr. Lester Machta|pages=39–41|publisher=United States Weather Bureau|date=February 1958|access-date=21 April 2012|archive-date=3 March 2017|archive-url=https://web.archive.org/web/20170303193131/https://docs.lib.noaa.gov/rescue/wb_topicsandpersonnel/1958.pdf|url-status=dead}}</ref> The drone technology boom has led to the development of [[Engineering:Weather drone|weather drone]]s since the late 1990s.<ref>{{Cite journal |last1=Holland |first1=G. J. |last2=Webster |first2=P. J. |last3=Curry |first3=J. A. |last4=Tyrell |first4=G. |last5=Gauntlett |first5=D. |last6=Brett |first6=G. |last7=Becker |first7=J. |last8=Hoag |first8=R. |last9=Vaglienti |first9=W. |date=2001-05-01 |title=The Aerosonde Robotic Aircraft: A New Paradigm for Environmental Observations |url=https://journals.ametsoc.org/view/journals/bams/82/5/1520-0477_2001_082_0889_taraan_2_3_co_2.xml |journal=Bulletin of the American Meteorological Society |language=en |volume=82 |issue=5 |pages=889–902 |doi=10.1175/1520-0477(2001)082<0889:TARAAN>2.3.CO;2 |bibcode=2001BAMS...82..889H |issn=0003-0007|doi-access=free }}</ref> These may begin to replace balloons as a more specific means for carrying radiosondes.<ref>{{Cite web |date=2022-06-08 |title=Drones May Replace Weather Balloons Soon |url=https://www.outlookindia.com/national/drones-may-replace-weather-balloons-soon-news-201051 |access-date=2022-11-07 |website=www.outlookindia.com/ |language=en}}</ref>

== Materials and equipment ==
The balloon itself produces the [[Physics:Lifting gas|lift]], and is usually made of a highly flexible latex material, though [[Chemistry:Chloroprene|chloroprene]] may also be used. The unit that performs the actual measurements and [[Engineering:Transmission (telecommunications)|radio transmissions]] hangs at the lower end of the string, and is called a [[Earth:Radiosonde|radiosonde]]. Specialized radiosondes are used for measuring particular parameters, such as determining the [[Physics:Ozone layer|ozone]] concentration.

The balloon is usually filled with [[Chemistry:Hydrogen|hydrogen]], though [[Chemistry:Helium|helium]] - a more expensive, but viable option nonetheless - is also frequently used.  The ascent rate can be controlled by the amount of gas with which the balloon is filled.  Weather balloons may reach altitudes of {{convert|40|km|abbr=on}} 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,<ref>{{Cite web |last1=Dabberdt |first1=W F |last2=Shellhorn |first2=R |last3=Cole |first3=H |last4=Paukkunen |first4=A |last5=Horhammer |first5=J |last6=Antikainen |first6=V |date=2003 |title=Radiosondes |url=http://www.radiopassioni.it/pdf/materialirsonde/Radiosondes.pdf |publisher=Elsevier Science Direct}}</ref> although a parachute may be employed to help in allowing retrieval of the instrument. Above that altitude [[Engineering:Sounding rocket|sounding rocket]]s are used to carry instruments aloft, and for even higher altitudes satellites are used.

== Launch time, location, and uses ==
[[Image:Hydrogen balloon at upper air.jpg|thumb|left|A hydrogen filled balloon at Cambridge Bay Upper Air station, Nunavut, Canada]]
Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and [[Earth:Numerical weather prediction|computer models]] for [[Earth:Weather forecasting|weather forecasting]]. Between 900 and 1,300 locations around the globe do routine releases, two or four times daily, usually at 0000 [[Physics:Coordinated Universal Time|UTC]] and 1200 UTC.<ref name=":0">{{cite web|url=http://www.ua.nws.noaa.gov/factsheet.htm |title=NWS factsheet|archive-url=https://web.archive.org/web/20160220121505/http://www.ua.nws.noaa.gov/factsheet.htm |archive-date=2016-02-20 }}</ref><ref name=WOUK/><ref name=WMO/><ref name=WeatherSTEM/> 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 [[Earth:National Weather Service|National Weather Service]] in the US typically launch balloons, and by international agreements almost all the data are shared with all nations.

Specialized uses also exist, such as for aviation interests, pollution monitoring, photography or videography and research. Examples include [[Engineering:Ceiling balloon|pilot balloon]]s (Pibal). Field research programs often use mobile launchers from land vehicles as well as ships and aircraft (usually [[Earth:Dropsonde|dropsonde]]s in this case). In recent years weather balloons have also been used for scattering human ashes at high-altitude.
The weather balloon was also used to create the fictional entity 'Rover' during production of the 1960s TV series ''The Prisoner'' in Portmeirion, Gwynedd, North Wales, UK in September 1966. This was retained in further scenes shot at MGM Borehamwood UK during 1966–67.<ref>{{Cite book|title=The Prisoner Handbook|last=Paul-Davies|first=Steven|publisher=Pan Books|year=2002|isbn=978-0-230-53028-7|location=London}}</ref>

== See also ==
* [[Atmospheric sounding]]
* [[Engineering:Ceiling balloon|Ceiling balloon]]
* High-altitude balloon
* [[Engineering:SCR-658 radar|SCR-658 radar]]
* Skyhook balloon
* [[Physics:Timeline of hydrogen technologies|Timeline of hydrogen technologies]]
* High-altitude platform
* UFOs

==References==
{{Reflist}}

== External links ==
{{Commons|Weather balloon}}
* [http://weather.uwyo.edu/upperair/sounding.html Atmospheric Soundings for Canada and the United States] – University of Wyoming
* [http://www.chem.hawaii.edu/uham/lift.html Balloon Lift With Lighter Than Air Gases] {{Webarchive|url=https://web.archive.org/web/20140224035221/http://www.chem.hawaii.edu/uham/lift.html |date=24 February 2014 }} – University of Hawaii
* [http://www.nssl.noaa.gov/projects/telex/videos.html Examples of Launches of Instrumented Balloons in Storms] – NSSL
* [https://web.archive.org/web/20131222081748/http://www.ofcm.gov/fmh3/text/default.htm Federal Meteorological Handbook No. 3 – Rawinsonde and Pibal Observations]
* [https://web.archive.org/web/20070704045456/http://www.ua.nws.noaa.gov/photo.htm Kites and Balloons] – NOAA Photo Library
* [http://sites.wff.nasa.gov/code820/ NASA Balloon Program Office] – Wallops Flight Facility, Virginia
* [https://web.archive.org/web/20040404125719/http://avc.comm.nsdlib.org/cgi-bin/wiki_grade_interface.pl?Weather_Balloons National Science Digital Library: Weather Balloons] – Lesson plan for middle school
* [http://www.pilotballoon.com/ Pilot Balloon Observation Theodolites] – Martin Brenner, CSULB
* [http://stratocat.com.ar/indexe.html StratoCat] – Historical recompilation project on the use of stratospheric balloons in the scientific research, the military field and the aerospace activity
* [http://www.wmo.int/pages/prog/www/ois/volume-a/vola-home.htm WMO spreadsheet of all Upper Air stations around the world (revised location September 2008)]

{{Meteorological equipment}}
{{Earth-based meteorological observation}}

[[Category:Atmospheric sounding]]
[[Category:Meteorological instrumentation and equipment]]

{{Sourceattribution|Weather balloon}}