Celebrations of all kinds require specific decorations, but the one element they all have in common is the balloon. Whether it is your child’s birthday, your parents anniversary, or even a wedding reception balloons play a large role in making the event festive. They can be regular balloons that you blow up with air or helium balloons that float in the air. I’ve had experience with blowing up those long thin balloons that you can make into all sorts of animals.
The National Weather Service has been using specialized balloons to get information in the atmosphere above us for a long time. It was a long time ago that the first weather balloons were used by Leon Teisserenc de Bort. The French Meteorologist launched his weather balloons as early as 1896. If you remember, the Montgolfier Brothers from France were the first to fly in hot air balloons. So the French were pioneers in both types of balloons.
Another pioneer in the field was Alfred Wegener, a meteorologist and geophysicist who used weather balloons to discover his Continental Drift Theory that he published in 1912. James Van Allen, of the Van Allen Belt fame, performed weather experiments with weather balloons 1n the 1950s.
The National Weather Service started using weather balloons in the late 1930s and they are still a valuable tool in weather forecasting. The balloons are made of latex or neoprene (synthetic rubber) and are filled with hydrogen or helium. The balloons don’t simply go up into the sky by themselves. Attached under them is a package of weather equipment that is called a radiosonde. It records atmospheric pressure, temperature and relative humidity. It also contains a transmitter which sends the data back to a ground station receiver every one or two seconds. The wind speed and direction can be calculated by tracking the movement of the balloon package.
The readings are taken as the balloon ascends. The balloon keeps expanding as it rises and eventually bursts (at about 100,000 ft.) and then the parachute that is attached deploys and drops the radiosonde safely back to Earth. The outer packaging contains a message and the address where it can be mailed so the Weather Service can refurbish the equipment and reuse the radiosonde. Most get lost, but they retrieve enough of them (20%) to save a significant amount of money that it would cost to keep replacing all of them with new ones. The job of weather forecasting would be much more difficult if not impossible without the balloon data received from the 92 that are released in the U.S. and its territories and a total of 900 balloons that are launched simultaneously around the world at 0:00 UTC which is 5:00 pm PDT the previous day and 12:00 UTC which is 5 AM PDT. UTC stands for Coordinated Universal Time.
Scientists have found a new use for weather balloons. You should remember the movie “Twister” which I have discussed before in this column. In that movie they devised a way to send hundreds of small sensors into a tornado to study how tornadoes actually work. Two Penn State professors Paul Markowski and Yvette Richardson sending smaller weather balloons into what are called Supercell Thunderstorms. These are thunderstorms that develop rotation that can produce tornadoes. Quoting an SFGATE.com article written by Matthew Cappuccci of the Washington Post “The tram aims to launch miniature weather balloons about 12-16 inches in diameter into the air at the periphery of the storm. Attached to each balloon is a probe that measures temperature, dew point, and relative humidity. Markowski hopes his team can use the data to recreate the near-surface temperature field of the environment surrounding and within the storm.”
According to Professor Markowski “The horizontal temperature gradient in storms has a huge role in determining buoyancy.” The buoyant air rises and that means the formation of a tornado vortex is more likely. Unlike the folks in “Twister” these scientists are not trying to send the balloons up into the tornado, but rather to better understand how the inflow of air into the region that could produce a rotating vortex.
Precipitation is the hardest thing to predict in these storms. According to Markowski “We can run storm simulations and computer models, but all of them make the same assumptions on how to handle precipitation.” “We know there’s a finite amount of water that enters the storm. But what that water ends up as – whether it be big hailstones or tiny drops of mist – is is extremely important in terms of the physics.” They had to have just the right amount of the proper gas in each balloon so they would rise, but not too fast and so that rain drops wouldn’t send them back down to the ground.
They have been asked why they didn’t use drones instead of balloons. First of all the FAA restricts drones anywhere where they can’t be directly viewed. The second and maybe more important reason is that drones are not expendable and they are so much more expensive than balloons.
It will be interesting to see the results of their next deployment of balloons into those storm clouds.
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