Active sonar is primarily used underwater for various purposes such as navigation, communication, and detecting underwater objects. The sound waves produced by active sonar systems travel through the water, bounce off objects, and return to the sonar receiver, allowing the system to create a detailed image of the underwater environment.
Above the water's surface, the sound produced by active sonar is generally not audible to human ears. This is because the sound waves generated by the sonar system are specifically designed to propagate efficiently through water, which is a denser medium than air. The properties of sound propagation in water, such as its speed and the way it interacts with objects, are different from those in air.
When active sonar waves reach the surface of the water, some of the sound energy may be transmitted into the air, but it quickly dissipates and weakens due to the significant difference in the acoustic properties of air and water. As a result, the sound produced by active sonar above the surface is typically faint and indistinguishable from background noise. It would not be recognizable or identifiable as the distinct "ping" or "pinging" sound commonly associated with active sonar underwater.