It was just another day at sea for Captain Ryan and his trusty mate Chelsea when they were driving students from the reef back to MarineLab. Someone spotted plastic in the water so Cap’n stopped to retrieve it. Turns out the plastic they were picking up was part of a NOAA radiosonde. Once back to the dock, we were all intrigued and immediately got online to figure out what it was that they found.
The radiosonde is a small, expendable instrument package (weighs 100 to 500 grams) that is suspended below a large balloon inflated with hydrogen or helium gas. These “weather balloons” are deployed by NOAA National Weather Service to get data on forecasts, weather and climate change research, input for air pollution models, and ground truthing for satellite data. As the radiosonde rises at about 1,000 feet/minute, sensors on the radiosonde measure profiles of pressure, temperature, and relative humidity. These sensors are linked to a battery powered radio transmitter that sends the sensor measurements to a sensitive ground tracking antenna.
If the radiosonde could talk, oh the places it has been…
- A typical “weather balloon” sounding can last in excess of two hours, and the radiosonde can ascend to over 115,000 feet and drift more than 180 miles from the release point.
- During the flight, the radiosonde is exposed to temperatures as cold as -130oF and an air pressure less than 1 percent of what is found on the Earth’s surface.
- If the radiosonde enters a strong jet stream it can travel at speeds exceeding 250 mph
When released, the balloon is about 1.5 meters (about 5 feet) in diameter and gradually expands as it rises owing to the decrease in air pressure. When the balloon reaches a diameter of 6 to 8 meters (20 to 25 feet) in diameter, it bursts. A small, orange colored parachute slows the descent of the radiosonde, minimizing the danger to lives and property.
Ryan, Chelsea and Southwest Florida Christian students retrieved the waterlogged radiosonde (with it’s balloon and parachute) from the water just after seeing some see turtles mating at the surface. An exciting day and we all get to learn something new. The science never stops at MarineLab!