Dropsonde

A dropsonde is a weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude to more accurately measure (and therefore track) tropical storm conditions as the device falls to the ground. The dropsonde contains a GPS receiver, along with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data. It typically relays these data to a computer in the aircraft by radio transmission. The device's descent is usually slowed by a parachute, allowing for more readings to be taken before it reaches the water beneath.

Other websites
 Home page of NOAA's Aircraft Operations Center--includes info on dropsondes and the missions where dropsondes are used 
 Site about the development of a dropsonde 
 Company that makes them 

Category:Weather