A weather balloon is just one of the tools used by meteorologists to measure what is happening with the world's weather. Most people probably think of those limp sheets shown after the Roswell UFO incident when they hear the term, and weather balloons have been mistaken for UFO's. Let's take a look at exactly what a weather balloon is and how it is used.
Weather balloons are sent up twice a day all over the world. At 900 different locations, the balloons are sent up at the same time, and they are used to measure atmospheric pressures, temperature, wind speeds and humidity. They send information back via a device called a radiosonde which collects information on its upward journey and transmits it back to Earth as the device comes back down from the atmosphere.
Balloon flights usually last around two hours. Weather balloons reach heights of up to 20 miles into the atmosphere and have been known to drift for 125 miles. There is an excellent graphic here, which gives a visual representation, allowing you to see this in relation to everyday objects.
Weather balloons are made from latex or neoprene (synthetic rubber). Before inflation, the latex or rubber is around .051 mm thick but it will thin further once filled and expanded, to around .0025mm. Weather balloons are filled with either helium or hydrogen before being released. The average balloon is around six feet in diameter before being released but, as it rises, it could expand to as much as twenty feet, which is the common bursting point of weather balloons.
The information gathered by weather balloons is stored and transmitted by the radiosonde. This is a small package, which is suspended about 80 feet below the weather balloon. Sensors in the radiosonde record information and use a radio transmitter to send the information back to the ground.
The radiosonde is equipped with a small, orange parachute which prevents it hurtling back to the ground and injuring people or property after the weather balloon bursts. GPS tracking is common today, but radio tracking antennas are also used. This allows the gathering of information about wind speeds by calculating how fast the balloon is being blown along.
Very few radiosondes are recovered, relative to the 75,000 sent up every year, but people do occasionally find them. They can be returned by using the mailbag that comes with each radiosonde and given to your mail carrier who will deal with it. More information about the safe handling of a radiosonde can be found at this link, with much more information about radiosondes in general. By returning a radiosonde you will save the price of a new one because they can be repaired and reused.
Weather balloons are a vital tool for gathering information across the globe. Countries share information from these balloon flights which allows us to get a good picture of the world's weather and possible changes or storms ahead. Of course, they also keep us in UFO stories, even today.