A Weather Balloon is a high altitude balloon, which carries measuring instruments aloft to send back the information on atmospheric pressure temperature & humidity by method of small expandable measuring device called as RADISONDE.
Whenever any weather balloon is launched its always necessary to continuously monitor these conditions
Weather Balloon is made up of highly flexible latex material though chloroprene may be used chloroprene is used because as it includes UV inhibitors which retards the sun ability to weaken the balloon however it is considered to be more lasting instead of latex as it is less destructible.
Weather balloons is filled with gases like hydrogen and helium but now days helium gas is more used instead of using hydrogen gas because helium gas is less hazardous though bit expensive and when balloons which are used to measure atmospheric conditions when typically released they are filled to only 10% to 20% of its original quantity of balloon because due to low atmospheric pressure helium gas expands and and exerts force on the wall of balloon and as it moves in upward direction due to low atmospheric pressure helium expands and will occupy the whole quantity of the balloon and it will burst after reaching upto 70000 ft of height.
Radiosonde is the unit, which is hanged at the lower end of the string & performs the measurement and radio transmission.
Sometimes specialized radiosondes are used for measuring particular parameters such as calculating the OZONE CONCENTRATION.
Weather Balloon is used in measurement & evaluation of most upper atmospheric conditions. Information may be gathered during the vertical ascent of the balloon during his motion we can also gather information like wind movement and its speed.
HOW IT WORKS:
Initially these balloons are filled with gases like hydrogen or helium and then at the lower end of string RADIOSONDE is attached then the balloon is released. Radiosonde can be tracked by radar so we can measure wind speed & direction as it ascends by the air.
By the time it reaches the higher altitude the balloon expands as atmospheric pressure decreases and it bursts
Then radiosonde package drifts gently down the ground, which is at the end of the parachute. When data is received from radiosondes it arrives in the series of numbers. Scientists use computers to characterize the data in form of pictures, which is called Skew T Diagram.
This is how scientist measures our important features like pressure, temperature, wind speed & direction.