Weather balloons: How do they work and how long do they stay in the air?

DAVENPORT, Iowa (KWQC) - We have been hearing a lot about the suspected Chinese “surveillance balloon” in the headlines lately.

China reportedly claimed it was a type of weather balloon that drifted off course.

Last year, TV6 visited the National Weather Service Quad Cities in Davenport to watch a weather balloon launch.

Every day at around 6 a.m. and 6 p.m., the National Weather Service in the Quad Cities and more than 90 other offices across the United States launch a weather balloon, carrying a small instrument called a radiosonde.

A radiosonde is an instrument that is carried aloft by a balloon to send back information on atmospheric temperature, pressure and humidity by means of a small, expendable radio transmitter.

The radiosonde is attached to a balloon that is filled with hydrogen, and launched near the Davenport Municipal Airport.

It is equipped with GPS tracking to calculate the wind speed and direction, in addition to the other data gathered.

Weather balloons are launched from more than 900 sites across the world, twice per day.

As the weather balloon rises higher into the air, the pressure falls, causing the balloon to expand to nearly 20 feet in diameter.

They typically have a flight that lasts one to two hours until the balloon bursts when it reaches roughly 100 thousand feet.

A small parachute attached to the balloon allows the radiosonde to fall back to earth.

About 20% of radiosondes sent up in the air are found each year and can be reused.

If you find one, there are instructions on how to send it back to the respective national weather service office.

The data gathered from radiosondes across the world are then fed into the weather models that help meteorologists forecast the weather.

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