This is due to the layer of air next to the ground being stationary. A wind gradient results in sound waves propagating ... Conditions on Sound Propagation," Journal of the Acoustical Society of ...

THE propagation of finite waves in fluids or solids generally presents ... the experimental difficulties are greatly reduced; for example, a finite pulse of unloading may be propagated simply ...

The TRANSMISSION of acoustic energy through a medium via a SOUND WAVE ... features such as ground cover, hills and other obstacles between the source and the receiver. There are several important ...