A device created by National Center for Atmospheric Research (NCAR) to more accurately track tropical storm conditions. Released by airplane, the canister containing GPS receivers with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data in hurricanes descends by parachute (diagram), transmitting the data it collects via radio frequency (RF) transmitters twice per second. The dropsondes also use GPS positioning to detect horizontal and vertical winds.

References

GPS World

National Weather Service Forecast Office - Melbourne, Florida