Breakdown: Why the National Weather Service uses balloons to explore the atmosphere
MEMPHIS, Tenn. (WMC) - Twice a day, every day of the year, weather balloons are released simultaneously from almost 900 locations worldwide! This includes 92 released by the National Weather Service (NWS) in the US and its territories.
The balloon flights last for around 2 hours, can drift as far as 125 miles away, and rise up to over 100,000 ft. (about 20 miles) in the atmosphere!
According to the NWS, weather balloons are made of latex or synthetic rubber (neoprene) and filled with either hydrogen or helium. The balloons start out measuring about 6 ft. wide before release and expand as they rise to about 20 ft. in diameter before they burst.
An instrument called a radiosonde is attached to the balloon to measure pressure, temperature and relative humidity as it ascends up into the atmosphere. These instruments will often endure temperatures as cold as -139°F (-95°C), relative humidities from 0% to 100%, air pressures only a few thousandths of what is found on the Earth’s surface, ice, rain, thunderstorms, and wind speeds of almost 200 mph!
A transmitter on the radiosonde sends the data back to tracking equipment on the ground every one to two seconds. By tracking the position of the radiosonde, we can also calculate wind speed and wind direction. The radiosonde is powered by a small battery.
A parachute, attached to the end of the balloon, allows the radiosonde to fall slowly to the ground at speeds less than 22 mph after the balloon bursts.
Weather balloons are the primary source of data above the ground. They provide valuable input for computer forecast models, local data for meteorologists to make forecasts and predict storms, and data for research.
Computer forecast models which use weather balloon data are used by all forecasters worldwide, from National Weather Service meteorologists to your local TV meteorologists! Without this information, accurate forecasts beyond a few hours would be almost impossible!
The NWS uses multiple platforms to observe the weather: Doppler radar, satellite, aircraft observations, automated surface observation stations, etc. However, the weather balloon remains the best platform for observing temperature, wind, relative humidity, and pressure above the ground.
According to the NWS Office of Public Affairs: “The technology has come a long way in the last 80+ years, and we’ve made significant progress to reduce environmental impacts. We’ve reduced the amount of material used in the balloon construction by about 20 percent in the last 10 years, and radiosondes weigh four ounces or less today, compared to 2 pounds in the 1990s. Today, balloons are made with a natural, biodegradable latex, and the parachute and string are also biodegradable. We encourage people who find the radiosonde equipment to drop it in the mail if possible to do so safely, which allows us to rebuild it and use it again or have it recycled. This saves taxpayer dollars and also is helpful to the environment. We try to make it easy for people to send us the equipment by enclosing an addressed mailbag.”
About 20% of the 75,000 radiosondes sent up each year in the US are found and returned.
The NWS has been flying weather balloons since the 1930s. The data collected by these weather balloon flights are critical for weather model performance and forecast accuracy.
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