Once the radiosonde, parachute and balloon are prepared, the wind, temperature and humidity are measured at the nearby surface shelter and the balloon launched. As before, click on an image to see a closup.

As the radiosonde rises, a nearby radar or automatic direction finder locates the transponder in the unit and measures the wind speed and direction.

The radiosonde radios back the measurements of temperature and humidity at pressure levels as the balloon ascends through the atmosphere moving upwards to lower and lower pressure.