Weather balloon
（重定向自Meteorological balloon）
![Transosonde ready for release](/Images/godic/202501/27/Transosonde0704.png")
![Picture taken at approximately 30 km above Oregon using a 1,500 gram weather balloon](/Images/godic/202501/27/Picture_taken_at_aprox._100,000_feet_above_Oregon_by_Justin_Hamel_and_Chris_Thompson0704.jpg")
![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.](/Images/godic/202501/27/Nssl00200705.jpg")
![A hydrogen filled balloon at Cambridge Bay Upper Air station, Nunavut, Canada](/Images/godic/202501/27/Hydrogen_balloon_at_upper_air0705.jpg")
A weather or sounding balloon is a balloon (specifically a type of high altitude balloon) which carries instruments aloft 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.