MEMPHIS, Tenn. (WMC) - NOAA’s National Weather Service has launched balloons since the 1930s to collect temperature, humidity and other data in the upper atmosphere. These balloons are launched from the ground and they sail through the troposphere and stratosphere.
According to the National Weather Service, twice a day every day of the year, weather balloons are released simultaneously from nearly 900 locations worldwide. This includes the 92 released by the National Weather Service in the U.S. and its territories.
A typical flight of a balloon lasts around two hours and can drift as far away as 125 miles from the launch point; it can also rise over 100,000 ft or 20 miles into the Earth’s atmosphere.
The National Weather Service explains that the balloons are made of latex or synthetic rubber and are filled with either hydrogen or helium to help in its flight. The balloon is only about .051 mm thick and will be only .0025 mm thick when it finally bursts. The balloons will start at around 6 ft wide before being released and can expect to up to 20 ft in diameter.
Attached to the balloon is a device called the radiosonde. It measures pressure, temperatures and relative humidity as it moves upward through the atmosphere. The instrument often interacts with temperatures as cold as -195 degrees Fahrenheit, relative humidity between 0% and 100%, air pressures only few thousandths of what is found on the Earth’s surface, ice, rain, thunderstorms and wind speeds of nearly 200 mph.
That National Weather Service receives the data via a transmitter on the radiosonde and sends the data to the ground every one to two seconds. By tracking the radiosonde itself, we can calculate wind speed and direction. All this being powered by one small battery.
A parachute is attached to the end of the balloon, which allowed the radiosonde to fall slowly to the ground at speeds lower than 22 miles per hour, after the balloon bursts. Every radiosonde has a mailing back and instructions on how to return the device. Just about 20% of the 75,000 radiosondes sent up each year are returned, explained the National Weather Service. If returned they can be reused to save money.
Weather balloons are the primary source of data above ground and provide valuable input for computer models, local data for meteorologist to make forecasts and predict storms, along with data for research.