What is a SoDAR device and what is it used for?

A Sonic Detection and Ranging (SoDAR) device works by emitting a sound wave and recording the sound that bounces back off surfaces. When wind up to 200m high passes over top of the device, the turbulent air it creates reflects the sound wave back to the device. An analyser within the device interprets the signal to calculate the different wind speeds in the package of air above the SoDAR from 0m all the way up to 200m.