Dropsonde

Part of speech: noun

Definitions

1. A specialized instrument released from an aircraft to gather atmospheric data as it falls towards the ground
2. A weather data collection device that operates by deploying sensors from an aircraft while it descends
3. A tool released from a plane to measure weather conditions during its descent

Etymology: "Sonde" is a French word for a probe or sounding line, borrowed into English in the early 20th century for instruments that send back measurements from the upper air. The word "sonde" itself traces to the French "sonder," meaning to sound out the depth of water with a weighted line, and it came to describe any device lowered or launched to take readings where people cannot easily go. A dropsonde combines "drop," describing how the instrument falls from an aircraft, with "sonde." As the device parachutes down through the atmosphere, it transmits readings of pressure, temperature, humidity and wind, which lets meteorologists sample conditions that are otherwise hard to observe, such as inside a storm.