You do realize that Sonar uses sound waves but your picture depicts a weather balloon carrying a Radar reflector.
It may look like a radar reflector, but it is actually a hybrid of both a radar and sonar device. Both methods are used in gathering and creating data.
Given your history of not providing citations and believing that you need only say something to be credible, I hesitate asking, but do: Citations please. How did you determine that it;s a sonar device? What microphone could possibly hear sound reflected off such a device? Where is that diagram you committed to? Can you reproduce such data gathering and creating? Where is your data?