A radiosonde is an small, expendable instrument package suspended about 80 feet below a balloon that has been inflated with helium or hydrogen gas. The radiosonde rises around 1,000 feet per minute, and sensors attached to the radiosonde measure relative humidity, temperature and certain types of pressure profiles.Continue Reading
The sensors on the radiosonde are linked up to 300 milliwatt radio transmitter that runs on battery power. This radio transmitter sends sensor measurements to the ground tracking antenna via radio frequencies that range around 403 megahertz. Additionally, direction aloft and wind speed are obtainable when the radiosonde���s position is tracked using GPS in flight. Observations whereby wind aloft are derived from a radiosonde are known as rawinsonde observations.
Radio signals that are obtained by the ground tracking antenna are then converted into meteorological values. These data levels are placed into a code form by computers, which is then transmitted to various data users. The weather experienced on ground level is from various dynamic processes taking place in the atmosphere. Similar to how observations take place for surface weather, it is important to understand the processes taking place in the atmosphere. For more than 60 years, radiosondes have been used by the National Weather Service for air observations.Learn more about Weather Forecasts