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{{Short description|High-altitude balloon to which meteorological instruments are attached}}{{hatnote group|{{redirect-distinguish|Sounding balloon|observation balloon}}{{about|atmospheric and meteorological sounding balloons|balloon space probes|List of Solar System probes}}}}
{{Use dmy dates|date=July 2022}}

[[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 [[atmospheric pressure]], [[temperature]], [[humidity]] and [[wind speed]] by means of a small, expendable measuring device called a [[radiosonde]]. To obtain [[wind]] data, they can be tracked by [[radar]], radio [[direction finding]], or navigation systems (such as the satellite-based [[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 [[theodolite]] or [[total station]] is used to track the balloon's [[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 [[numerical weather prediction|computer models]] for [[weather forecasting]]. Between 900 and 1,300 locations around the globe do routine releases, typically two or four times daily.<ref name="NWS" /><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 the French meteorologist [[Léon Teisserenc de Bort]]. Starting in 1896 he launched hundreds of weather balloons from his observatory in [[Trappes]], France. These experiments led to his discovery of the [[tropopause]] and [[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 [[Unmanned aerial vehicle|drone]] technology boom has led to the development of [[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 |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 [[lifting gas|lift]], and is usually made of a highly flexible [[Latex (rubber)|latex]] material, though [[chloroprene]] may also be used. The unit that performs the actual measurements and [[Transmission (telecommunications)|radio transmissions]] hangs at the lower end of the string, and is called a [[radiosonde]]. Specialized radiosondes are used for measuring particular parameters, such as determining the [[ozone layer|ozone]] concentration.

The balloon is usually filled with [[hydrogen]], though [[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, usually at around {{convert|300|m/min}}.<ref name="AWH">{{cite web |title=FAA-H-8083-28A, Aviation Weather Handbook |url=https://www.faa.gov/regulationspolicies/handbooksmanuals/aviation/faa-h-8083-28a-aviation-weather-handbook |publisher=[[Federal Aviation Administration]] |access-date=27 December 2024}}</ref>{{rp|24-54}}  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 [[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]]
[[File:011 Launch of wiki payload into stratosphere MAH02425.webm|thumb|Launch of wiki payload into stratosphere]]
Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and [[numerical weather prediction|computer models]] for [[weather forecasting]]. Between 900 and 1,300 locations around the globe do routine releases, two or four times daily, usually at 0000 [[Coordinated Universal Time|UTC]] and 1200 UTC.<ref name="NWS">{{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 [[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 [[Ceiling balloon|pilot balloon]]s (Pibal). Field research programs often use mobile launchers from land vehicles as well as ships and aircraft (usually [[dropsonde]]s in this case). In recent years, weather balloons have also been used for scattering human ashes at high altitudes.
The weather balloon was also used to create the fictional entity 'Rover' during the 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>

==Potential issues==
===Aviation===
In 1970, an [[Antonov 24]] operating [[Aeroflot Flight 1661]] suffered a loss of control after striking a radiosonde in flight, resulting in the death of all 45 people on board.

On 16&nbsp;October 2025,<ref>{{cite web |title=UA 1093 |url=https://windbornesystems.com/blog/ua-1093 |website=WindBorne |access-date=23 October 2025 |language=en |date=20 October 2025}}</ref> a [[United Airlines]] flight collided with a weather balloon at cruising altitude over Utah, fracturing its windshield, releasing shards of glass into the cockpit<ref name="WCCollision">{{cite web |title=Weather Balloon Likely Hit United Plane's Windshield {{!}} Weather.com |url=https://weather.com/news/news/2025-10-22-weather-balloon-likely-cracked-united-plane-windshield |website=weather.com |publisher=The Weather Channel |access-date=23 October 2025 |language=en |date=22 October 2025}}</ref> that injured the captain's right arm, and causing an emergency descent<ref>{{cite web |title=Pilot of United flight UA1093 injured after possible 'high altitude debris' damaged the windshield |url=https://airlive.net/incident/2025/10/18/pilot-of-united-flight-ua1093-injured-after-possible-high-altitude-debris-damaged-the-windshield/?srsltid=AfmBOoozLWNb1vY1VwtAAFHgLsOQ4yf60OL9pgxefCb3T_9TjqVA5XVI |website=AIRLIVE |access-date=23 October 2025 |language=en |date=18 October 2025}}</ref> and diversion. The NTSB has begun an investigation, and the company behind the weather balloon has taken measures to reduce future risk.<ref name="WCCollision" />

There are also other ways in which weather balloons can pose a danger to aircraft, such as interfering with the [[pitot-static system]]s.<ref>{{cite web |last1=Lunnon |first1=Bob |title=Aircraft encounters with weather balloons: risks and mitigations |url=https://www.ukfsc.co.uk/files/Members%20Area/Minutes%202015/422nd%20Meeting%20Presentation%20-%20Rob%20Lunnon%20January%202015.pdf |website=United Kingdom Flight Safety Committee |access-date=23 October 2025 |page=13 |language=en |date=January 2015 |quote=Radiosonde balloons, and other similar objects, pose a threat because of the risk of affecting the determination of airspeed using pitot systems on aircraft.}}</ref>

===Environmental issues===
{{AI-generated|section=Environmental|date=September 2025}}
While weather forecasting is increasingly reliant on satellites and radar technology, it still heavily involves the use of weather balloons. These devices, launched from thousands of stations worldwide, ascend into the atmosphere to collect meteorological data. The United States, for example, releases approximately 76,600 balloons annually (an average of around 210 per day), while Canada launches 22,000.<ref name="e714">{{cite web | last=Beurteaux | first=Danielle | title=Weather Forecasting Is Deadly for Marine Wildlife | website=Hakai Magazine | date=2024-10-11 | url=https://hakaimagazine.com/news/weather-forecasting-is-deadly-for-marine-wildlife/ | access-date=2024-10-14}}</ref>

Weather balloons, after reaching an altitude of approximately 35 kilometers, burst, releasing their instruments and the latex material they are made of. While the instruments are often recovered, the latex remains in the environment, posing a significant threat to marine ecosystems. Studies have shown that a substantial portion of weather balloons eventually end up in the ocean. For instance, one Australian researcher collected over 2,460 pieces of weather balloon debris from the [[Great Barrier Reef]], estimating that up to 300 balloons per week may be released into the marine environment. This environmental impact underscores the need for sustainable alternatives in weather data collection.<ref name="e714" />

Scientists and environmentalists have raised concerns about weather balloons' environmental impact. The latex material, which can persist in the ocean for extended periods, can harm marine life, including [[sea turtles]], birds, and fish. Efforts to minimize the environmental impact of weather balloons include developing biodegradable materials and improved recovery methods. However, the continued reliance on weather balloons for meteorological data challenges balancing the need for accurate weather forecasts with environmental sustainability.<ref name="e714" />

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

==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] {{Webarchive|url=https://web.archive.org/web/20210321002919/http://www.nssl.noaa.gov/projects/telex/videos.html |date=21 March 2021 }} – 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 scientific research, the military field, and 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:Earth observation balloons]]
[[Category:Atmospheric sounding]]
[[Category:Meteorological instrumentation and equipment]]
[[Category:Scientific observation]]
[[Category:French inventions]]